mtip32xx: updates based on feedback

[~shefty/rdma-dev.git] / drivers / block / mtip32xx / mtip32xx.c

/*
 * Driver for the Micron P320 SSD
 *   Copyright (C) 2011 Micron Technology, Inc.
 *
 * Portions of this code were derived from works subjected to the
 * following copyright:
 *    Copyright (C) 2009 Integrated Device Technology, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/ata.h>
#include <linux/delay.h>
#include <linux/hdreg.h>
#include <linux/uaccess.h>
#include <linux/random.h>
#include <linux/smp.h>
#include <linux/compat.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/genhd.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/dma-mapping.h>
#include <linux/idr.h>
#include <linux/kthread.h>
#include <../drivers/ata/ahci.h>
#include "mtip32xx.h"

#define HW_CMD_SLOT_SZ          (MTIP_MAX_COMMAND_SLOTS * 32)
#define HW_CMD_TBL_SZ           (AHCI_CMD_TBL_HDR_SZ + (MTIP_MAX_SG * 16))
#define HW_CMD_TBL_AR_SZ        (HW_CMD_TBL_SZ * MTIP_MAX_COMMAND_SLOTS)
#define HW_PORT_PRIV_DMA_SZ \
                (HW_CMD_SLOT_SZ + HW_CMD_TBL_AR_SZ + AHCI_RX_FIS_SZ)

#define HOST_HSORG              0xFC
#define HSORG_DISABLE_SLOTGRP_INTR (1<<24)
#define HSORG_DISABLE_SLOTGRP_PXIS (1<<16)
#define HSORG_HWREV             0xFF00
#define HSORG_STYLE             0x8
#define HSORG_SLOTGROUPS        0x7

#define PORT_COMMAND_ISSUE      0x38
#define PORT_SDBV               0x7C

#define PORT_OFFSET             0x100
#define PORT_MEM_SIZE           0x80

#define PORT_IRQ_ERR \
        (PORT_IRQ_HBUS_ERR | PORT_IRQ_IF_ERR | PORT_IRQ_CONNECT | \
         PORT_IRQ_PHYRDY | PORT_IRQ_UNK_FIS | PORT_IRQ_BAD_PMP | \
         PORT_IRQ_TF_ERR | PORT_IRQ_HBUS_DATA_ERR | PORT_IRQ_IF_NONFATAL | \
         PORT_IRQ_OVERFLOW)
#define PORT_IRQ_LEGACY \
        (PORT_IRQ_PIOS_FIS | PORT_IRQ_D2H_REG_FIS)
#define PORT_IRQ_HANDLED \
        (PORT_IRQ_SDB_FIS | PORT_IRQ_LEGACY | \
         PORT_IRQ_TF_ERR | PORT_IRQ_IF_ERR | \
         PORT_IRQ_CONNECT | PORT_IRQ_PHYRDY)
#define DEF_PORT_IRQ \
        (PORT_IRQ_ERR | PORT_IRQ_LEGACY | PORT_IRQ_SDB_FIS)

/* product numbers */
#define MTIP_PRODUCT_UNKNOWN    0x00
#define MTIP_PRODUCT_ASICFPGA   0x11

/* Device instance number, incremented each time a device is probed. */
static int instance;

/*
 * Global variable used to hold the major block device number
 * allocated in mtip_init().
 */
static int mtip_major;

static DEFINE_SPINLOCK(rssd_index_lock);
static DEFINE_IDA(rssd_index_ida);

#ifdef CONFIG_COMPAT
struct mtip_compat_ide_task_request_s {
        __u8            io_ports[8];
        __u8            hob_ports[8];
        ide_reg_valid_t out_flags;
        ide_reg_valid_t in_flags;
        int             data_phase;
        int             req_cmd;
        compat_ulong_t  out_size;
        compat_ulong_t  in_size;
};
#endif

/*
 * This function check_for_surprise_removal is called
 * while card is removed from the system and it will
 * read the vendor id from the configration space
 *
 * @pdev Pointer to the pci_dev structure.
 *
 * return value
 *       true if device removed, else false
 */
static bool mtip_check_surprise_removal(struct pci_dev *pdev)
{
        u16 vendor_id = 0;

       /* Read the vendorID from the configuration space */
        pci_read_config_word(pdev, 0x00, &vendor_id);
        if (vendor_id == 0xFFFF)
                return true; /* device removed */

        return false; /* device present */
}

/*
 * This function is called for clean the pending command in the
 * command slot during the surprise removal of device and return
 * error to the upper layer.
 *
 * @dd Pointer to the DRIVER_DATA structure.
 *
 * return value
 *      None
 */
static void mtip_command_cleanup(struct driver_data *dd)
{
        int group = 0, commandslot = 0, commandindex = 0;
        struct mtip_cmd *command;
        struct mtip_port *port = dd->port;

        for (group = 0; group < 4; group++) {
                for (commandslot = 0; commandslot < 32; commandslot++) {
                        if (!(port->allocated[group] & (1 << commandslot)))
                                continue;

                        commandindex = group << 5 | commandslot;
                        command = &port->commands[commandindex];

                        if (atomic_read(&command->active)
                            && (command->async_callback)) {
                                command->async_callback(command->async_data,
                                        -ENODEV);
                                command->async_callback = NULL;
                                command->async_data = NULL;
                        }

                        dma_unmap_sg(&port->dd->pdev->dev,
                                command->sg,
                                command->scatter_ents,
                                command->direction);
                }
        }

        up(&port->cmd_slot);

        atomic_set(&dd->drv_cleanup_done, true);
}

/*
 * Obtain an empty command slot.
 *
 * This function needs to be reentrant since it could be called
 * at the same time on multiple CPUs. The allocation of the
 * command slot must be atomic.
 *
 * @port Pointer to the port data structure.
 *
 * return value
 *      >= 0    Index of command slot obtained.
 *      -1      No command slots available.
 */
static int get_slot(struct mtip_port *port)
{
        int slot, i;
        unsigned int num_command_slots = port->dd->slot_groups * 32;

        /*
         * Try 10 times, because there is a small race here.
         *  that's ok, because it's still cheaper than a lock.
         *
         * Race: Since this section is not protected by lock, same bit
         * could be chosen by different process contexts running in
         * different processor. So instead of costly lock, we are going
         * with loop.
         */
        for (i = 0; i < 10; i++) {
                slot = find_next_zero_bit(port->allocated,
                                         num_command_slots, 1);
                if ((slot < num_command_slots) &&
                    (!test_and_set_bit(slot, port->allocated)))
                        return slot;
        }
        dev_warn(&port->dd->pdev->dev, "Failed to get a tag.\n");

        if (mtip_check_surprise_removal(port->dd->pdev)) {
                /* Device not present, clean outstanding commands */
                mtip_command_cleanup(port->dd);
        }
        return -1;
}

/*
 * Release a command slot.
 *
 * @port Pointer to the port data structure.
 * @tag  Tag of command to release
 *
 * return value
 *      None
 */
static inline void release_slot(struct mtip_port *port, int tag)
{
        smp_mb__before_clear_bit();
        clear_bit(tag, port->allocated);
        smp_mb__after_clear_bit();
}

/*
 * Reset the HBA (without sleeping)
 *
 * Just like hba_reset, except does not call sleep, so can be
 * run from interrupt/tasklet context.
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      0       The reset was successful.
 *      -1      The HBA Reset bit did not clear.
 */
static int hba_reset_nosleep(struct driver_data *dd)
{
        unsigned long timeout;

        /* Chip quirk: quiesce any chip function */
        mdelay(10);

        /* Set the reset bit */
        writel(HOST_RESET, dd->mmio + HOST_CTL);

        /* Flush */
        readl(dd->mmio + HOST_CTL);

        /*
         * Wait 10ms then spin for up to 1 second
         * waiting for reset acknowledgement
         */
        timeout = jiffies + msecs_to_jiffies(1000);
        mdelay(10);
        while ((readl(dd->mmio + HOST_CTL) & HOST_RESET)
                 && time_before(jiffies, timeout))
                mdelay(1);

        if (readl(dd->mmio + HOST_CTL) & HOST_RESET)
                return -1;

        return 0;
}

/*
 * Issue a command to the hardware.
 *
 * Set the appropriate bit in the s_active and Command Issue hardware
 * registers, causing hardware command processing to begin.
 *
 * @port Pointer to the port structure.
 * @tag  The tag of the command to be issued.
 *
 * return value
 *      None
 */
static inline void mtip_issue_ncq_command(struct mtip_port *port, int tag)
{
        unsigned long flags = 0;

        atomic_set(&port->commands[tag].active, 1);

        spin_lock_irqsave(&port->cmd_issue_lock, flags);

        writel((1 << MTIP_TAG_BIT(tag)),
                        port->s_active[MTIP_TAG_INDEX(tag)]);
        writel((1 << MTIP_TAG_BIT(tag)),
                        port->cmd_issue[MTIP_TAG_INDEX(tag)]);

        spin_unlock_irqrestore(&port->cmd_issue_lock, flags);
}

/*
 * Enable/disable the reception of FIS
 *
 * @port   Pointer to the port data structure
 * @enable 1 to enable, 0 to disable
 *
 * return value
 *      Previous state: 1 enabled, 0 disabled
 */
static int mtip_enable_fis(struct mtip_port *port, int enable)
{
        u32 tmp;

        /* enable FIS reception */
        tmp = readl(port->mmio + PORT_CMD);
        if (enable)
                writel(tmp | PORT_CMD_FIS_RX, port->mmio + PORT_CMD);
        else
                writel(tmp & ~PORT_CMD_FIS_RX, port->mmio + PORT_CMD);

        /* Flush */
        readl(port->mmio + PORT_CMD);

        return (((tmp & PORT_CMD_FIS_RX) == PORT_CMD_FIS_RX));
}

/*
 * Enable/disable the DMA engine
 *
 * @port   Pointer to the port data structure
 * @enable 1 to enable, 0 to disable
 *
 * return value
 *      Previous state: 1 enabled, 0 disabled.
 */
static int mtip_enable_engine(struct mtip_port *port, int enable)
{
        u32 tmp;

        /* enable FIS reception */
        tmp = readl(port->mmio + PORT_CMD);
        if (enable)
                writel(tmp | PORT_CMD_START, port->mmio + PORT_CMD);
        else
                writel(tmp & ~PORT_CMD_START, port->mmio + PORT_CMD);

        readl(port->mmio + PORT_CMD);
        return (((tmp & PORT_CMD_START) == PORT_CMD_START));
}

/*
 * Enables the port DMA engine and FIS reception.
 *
 * return value
 *      None
 */
static inline void mtip_start_port(struct mtip_port *port)
{
        /* Enable FIS reception */
        mtip_enable_fis(port, 1);

        /* Enable the DMA engine */
        mtip_enable_engine(port, 1);
}

/*
 * Deinitialize a port by disabling port interrupts, the DMA engine,
 * and FIS reception.
 *
 * @port Pointer to the port structure
 *
 * return value
 *      None
 */
static inline void mtip_deinit_port(struct mtip_port *port)
{
        /* Disable interrupts on this port */
        writel(0, port->mmio + PORT_IRQ_MASK);

        /* Disable the DMA engine */
        mtip_enable_engine(port, 0);

        /* Disable FIS reception */
        mtip_enable_fis(port, 0);
}

/*
 * Initialize a port.
 *
 * This function deinitializes the port by calling mtip_deinit_port() and
 * then initializes it by setting the command header and RX FIS addresses,
 * clearing the SError register and any pending port interrupts before
 * re-enabling the default set of port interrupts.
 *
 * @port Pointer to the port structure.
 *
 * return value
 *      None
 */
static void mtip_init_port(struct mtip_port *port)
{
        int i;
        mtip_deinit_port(port);

        /* Program the command list base and FIS base addresses */
        if (readl(port->dd->mmio + HOST_CAP) & HOST_CAP_64) {
                writel((port->command_list_dma >> 16) >> 16,
                         port->mmio + PORT_LST_ADDR_HI);
                writel((port->rxfis_dma >> 16) >> 16,
                         port->mmio + PORT_FIS_ADDR_HI);
        }

        writel(port->command_list_dma & 0xFFFFFFFF,
                        port->mmio + PORT_LST_ADDR);
        writel(port->rxfis_dma & 0xFFFFFFFF, port->mmio + PORT_FIS_ADDR);

        /* Clear SError */
        writel(readl(port->mmio + PORT_SCR_ERR), port->mmio + PORT_SCR_ERR);

        /* reset the completed registers.*/
        for (i = 0; i < port->dd->slot_groups; i++)
                writel(0xFFFFFFFF, port->completed[i]);

        /* Clear any pending interrupts for this port */
        writel(readl(port->mmio + PORT_IRQ_STAT), port->mmio + PORT_IRQ_STAT);

        /* Enable port interrupts */
        writel(DEF_PORT_IRQ, port->mmio + PORT_IRQ_MASK);
}

/*
 * Restart a port
 *
 * @port Pointer to the port data structure.
 *
 * return value
 *      None
 */
static void mtip_restart_port(struct mtip_port *port)
{
        unsigned long timeout;

        /* Disable the DMA engine */
        mtip_enable_engine(port, 0);

        /* Chip quirk: wait up to 500ms for PxCMD.CR == 0 */
        timeout = jiffies + msecs_to_jiffies(500);
        while ((readl(port->mmio + PORT_CMD) & PORT_CMD_LIST_ON)
                 && time_before(jiffies, timeout))
                ;

        /*
         * Chip quirk: escalate to hba reset if
         * PxCMD.CR not clear after 500 ms
         */
        if (readl(port->mmio + PORT_CMD) & PORT_CMD_LIST_ON) {
                dev_warn(&port->dd->pdev->dev,
                        "PxCMD.CR not clear, escalating reset\n");

                if (hba_reset_nosleep(port->dd))
                        dev_err(&port->dd->pdev->dev,
                                "HBA reset escalation failed.\n");

                /* 30 ms delay before com reset to quiesce chip */
                mdelay(30);
        }

        dev_warn(&port->dd->pdev->dev, "Issuing COM reset\n");

        /* Set PxSCTL.DET */
        writel(readl(port->mmio + PORT_SCR_CTL) |
                         1, port->mmio + PORT_SCR_CTL);
        readl(port->mmio + PORT_SCR_CTL);

        /* Wait 1 ms to quiesce chip function */
        timeout = jiffies + msecs_to_jiffies(1);
        while (time_before(jiffies, timeout))
                ;

        /* Clear PxSCTL.DET */
        writel(readl(port->mmio + PORT_SCR_CTL) & ~1,
                         port->mmio + PORT_SCR_CTL);
        readl(port->mmio + PORT_SCR_CTL);

        /* Wait 500 ms for bit 0 of PORT_SCR_STS to be set */
        timeout = jiffies + msecs_to_jiffies(500);
        while (((readl(port->mmio + PORT_SCR_STAT) & 0x01) == 0)
                         && time_before(jiffies, timeout))
                ;

        if ((readl(port->mmio + PORT_SCR_STAT) & 0x01) == 0)
                dev_warn(&port->dd->pdev->dev,
                        "COM reset failed\n");

        /* Clear SError, the PxSERR.DIAG.x should be set so clear it */
        writel(readl(port->mmio + PORT_SCR_ERR), port->mmio + PORT_SCR_ERR);

        /* Enable the DMA engine */
        mtip_enable_engine(port, 1);
}

/*
 * Called periodically to see if any read/write commands are
 * taking too long to complete.
 *
 * @data Pointer to the PORT data structure.
 *
 * return value
 *      None
 */
static void mtip_timeout_function(unsigned long int data)
{
        struct mtip_port *port = (struct mtip_port *) data;
        struct host_to_dev_fis *fis;
        struct mtip_cmd *command;
        int tag, cmdto_cnt = 0;
        unsigned int bit, group;
        unsigned int num_command_slots = port->dd->slot_groups * 32;

        if (unlikely(!port))
                return;

        if (atomic_read(&port->dd->resumeflag) == true) {
                mod_timer(&port->cmd_timer,
                        jiffies + msecs_to_jiffies(30000));
                return;
        }

        for (tag = 0; tag < num_command_slots; tag++) {
                /*
                 * Skip internal command slot as it has
                 * its own timeout mechanism
                 */
                if (tag == MTIP_TAG_INTERNAL)
                        continue;

                if (atomic_read(&port->commands[tag].active) &&
                   (time_after(jiffies, port->commands[tag].comp_time))) {
                        group = tag >> 5;
                        bit = tag & 0x1F;

                        command = &port->commands[tag];
                        fis = (struct host_to_dev_fis *) command->command;

                        dev_warn(&port->dd->pdev->dev,
                                "Timeout for command tag %d\n", tag);

                        cmdto_cnt++;
                        if (cmdto_cnt == 1)
                                set_bit(MTIP_FLAG_EH_ACTIVE_BIT, &port->flags);

                        /*
                         * Clear the completed bit. This should prevent
                         *  any interrupt handlers from trying to retire
                         *  the command.
                         */
                        writel(1 << bit, port->completed[group]);

                        /* Call the async completion callback. */
                        if (likely(command->async_callback))
                                command->async_callback(command->async_data,
                                                         -EIO);
                        command->async_callback = NULL;
                        command->comp_func = NULL;

                        /* Unmap the DMA scatter list entries */
                        dma_unmap_sg(&port->dd->pdev->dev,
                                        command->sg,
                                        command->scatter_ents,
                                        command->direction);

                        /*
                         * Clear the allocated bit and active tag for the
                         * command.
                         */
                        atomic_set(&port->commands[tag].active, 0);
                        release_slot(port, tag);

                        up(&port->cmd_slot);
                }
        }

        if (cmdto_cnt) {
                dev_warn(&port->dd->pdev->dev,
                        "%d commands timed out: restarting port",
                        cmdto_cnt);
                mtip_restart_port(port);
                clear_bit(MTIP_FLAG_EH_ACTIVE_BIT, &port->flags);
                wake_up_interruptible(&port->svc_wait);
        }

        /* Restart the timer */
        mod_timer(&port->cmd_timer,
                jiffies + msecs_to_jiffies(MTIP_TIMEOUT_CHECK_PERIOD));
}

/*
 * IO completion function.
 *
 * This completion function is called by the driver ISR when a
 * command that was issued by the kernel completes. It first calls the
 * asynchronous completion function which normally calls back into the block
 * layer passing the asynchronous callback data, then unmaps the
 * scatter list associated with the completed command, and finally
 * clears the allocated bit associated with the completed command.
 *
 * @port   Pointer to the port data structure.
 * @tag    Tag of the command.
 * @data   Pointer to driver_data.
 * @status Completion status.
 *
 * return value
 *      None
 */
static void mtip_async_complete(struct mtip_port *port,
                                int tag,
                                void *data,
                                int status)
{
        struct mtip_cmd *command;
        struct driver_data *dd = data;
        int cb_status = status ? -EIO : 0;

        if (unlikely(!dd) || unlikely(!port))
                return;

        command = &port->commands[tag];

        if (unlikely(status == PORT_IRQ_TF_ERR)) {
                dev_warn(&port->dd->pdev->dev,
                        "Command tag %d failed due to TFE\n", tag);
        }

        /* Upper layer callback */
        if (likely(command->async_callback))
                command->async_callback(command->async_data, cb_status);

        command->async_callback = NULL;
        command->comp_func = NULL;

        /* Unmap the DMA scatter list entries */
        dma_unmap_sg(&dd->pdev->dev,
                command->sg,
                command->scatter_ents,
                command->direction);

        /* Clear the allocated and active bits for the command */
        atomic_set(&port->commands[tag].active, 0);
        release_slot(port, tag);

        up(&port->cmd_slot);
}

/*
 * Internal command completion callback function.
 *
 * This function is normally called by the driver ISR when an internal
 * command completed. This function signals the command completion by
 * calling complete().
 *
 * @port   Pointer to the port data structure.
 * @tag    Tag of the command that has completed.
 * @data   Pointer to a completion structure.
 * @status Completion status.
 *
 * return value
 *      None
 */
static void mtip_completion(struct mtip_port *port,
                            int tag,
                            void *data,
                            int status)
{
        struct mtip_cmd *command = &port->commands[tag];
        struct completion *waiting = data;
        if (unlikely(status == PORT_IRQ_TF_ERR))
                dev_warn(&port->dd->pdev->dev,
                        "Internal command %d completed with TFE\n", tag);

        command->async_callback = NULL;
        command->comp_func = NULL;

        complete(waiting);
}

/*
 * Helper function for tag logging
 */
static void print_tags(struct driver_data *dd,
                        char *msg,
                        unsigned long *tagbits)
{
        unsigned int tag, count = 0;

        for (tag = 0; tag < (dd->slot_groups) * 32; tag++) {
                if (test_bit(tag, tagbits))
                        count++;
        }
        if (count)
                dev_info(&dd->pdev->dev, "%s [%i tags]\n", msg, count);
}

/*
 * Handle an error.
 *
 * @dd Pointer to the DRIVER_DATA structure.
 *
 * return value
 *      None
 */
static void mtip_handle_tfe(struct driver_data *dd)
{
        int group, tag, bit, reissue;
        struct mtip_port *port;
        struct mtip_cmd  *command;
        u32 completed;
        struct host_to_dev_fis *fis;
        unsigned long tagaccum[SLOTBITS_IN_LONGS];

        dev_warn(&dd->pdev->dev, "Taskfile error\n");

        port = dd->port;

        /* Stop the timer to prevent command timeouts. */
        del_timer(&port->cmd_timer);

        /* Set eh_active */
        set_bit(MTIP_FLAG_EH_ACTIVE_BIT, &port->flags);

        /* Loop through all the groups */
        for (group = 0; group < dd->slot_groups; group++) {
                completed = readl(port->completed[group]);

                /* clear completed status register in the hardware.*/
                writel(completed, port->completed[group]);

                /* clear the tag accumulator */
                memset(tagaccum, 0, SLOTBITS_IN_LONGS * sizeof(long));

                /* Process successfully completed commands */
                for (bit = 0; bit < 32 && completed; bit++) {
                        if (!(completed & (1<<bit)))
                                continue;
                        tag = (group << 5) + bit;

                        /* Skip the internal command slot */
                        if (tag == MTIP_TAG_INTERNAL)
                                continue;

                        command = &port->commands[tag];
                        if (likely(command->comp_func)) {
                                set_bit(tag, tagaccum);
                                atomic_set(&port->commands[tag].active, 0);
                                command->comp_func(port,
                                         tag,
                                         command->comp_data,
                                         0);
                        } else {
                                dev_err(&port->dd->pdev->dev,
                                        "Missing completion func for tag %d",
                                        tag);
                                if (mtip_check_surprise_removal(dd->pdev)) {
                                        mtip_command_cleanup(dd);
                                        /* don't proceed further */
                                        return;
                                }
                        }
                }
        }
        print_tags(dd, "TFE tags completed:", tagaccum);

        /* Restart the port */
        mdelay(20);
        mtip_restart_port(port);

        /* clear the tag accumulator */
        memset(tagaccum, 0, SLOTBITS_IN_LONGS * sizeof(long));

        /* Loop through all the groups */
        for (group = 0; group < dd->slot_groups; group++) {
                for (bit = 0; bit < 32; bit++) {
                        reissue = 1;
                        tag = (group << 5) + bit;

                        /* If the active bit is set re-issue the command */
                        if (atomic_read(&port->commands[tag].active) == 0)
                                continue;

                        fis = (struct host_to_dev_fis *)
                                port->commands[tag].command;

                        /* Should re-issue? */
                        if (tag == MTIP_TAG_INTERNAL ||
                            fis->command == ATA_CMD_SET_FEATURES)
                                reissue = 0;

                        /*
                         * First check if this command has
                         *  exceeded its retries.
                         */
                        if (reissue &&
                            (port->commands[tag].retries-- > 0)) {

                                set_bit(tag, tagaccum);

                                /* Update the timeout value. */
                                port->commands[tag].comp_time =
                                        jiffies + msecs_to_jiffies(
                                        MTIP_NCQ_COMMAND_TIMEOUT_MS);
                                /* Re-issue the command. */
                                mtip_issue_ncq_command(port, tag);

                                continue;
                        }

                        /* Retire a command that will not be reissued */
                        dev_warn(&port->dd->pdev->dev,
                                "retiring tag %d\n", tag);
                        atomic_set(&port->commands[tag].active, 0);

                        if (port->commands[tag].comp_func)
                                port->commands[tag].comp_func(
                                        port,
                                        tag,
                                        port->commands[tag].comp_data,
                                        PORT_IRQ_TF_ERR);
                        else
                                dev_warn(&port->dd->pdev->dev,
                                        "Bad completion for tag %d\n",
                                        tag);
                }
        }
        print_tags(dd, "TFE tags reissued:", tagaccum);

        /* clear eh_active */
        clear_bit(MTIP_FLAG_EH_ACTIVE_BIT, &port->flags);
        wake_up_interruptible(&port->svc_wait);

        mod_timer(&port->cmd_timer,
                 jiffies + msecs_to_jiffies(MTIP_TIMEOUT_CHECK_PERIOD));
}

/*
 * Handle a set device bits interrupt
 */
static inline void mtip_process_sdbf(struct driver_data *dd)
{
        struct mtip_port  *port = dd->port;
        int group, tag, bit;
        u32 completed;
        struct mtip_cmd *command;

        /* walk all bits in all slot groups */
        for (group = 0; group < dd->slot_groups; group++) {
                completed = readl(port->completed[group]);

                /* clear completed status register in the hardware.*/
                writel(completed, port->completed[group]);

                /* Process completed commands. */
                for (bit = 0;
                     (bit < 32) && completed;
                     bit++, completed >>= 1) {
                        if (completed & 0x01) {
                                tag = (group << 5) | bit;

                                /* skip internal command slot. */
                                if (unlikely(tag == MTIP_TAG_INTERNAL))
                                        continue;

                                command = &port->commands[tag];
                                /* make internal callback */
                                if (likely(command->comp_func)) {
                                        command->comp_func(
                                                port,
                                                tag,
                                                command->comp_data,
                                                0);
                                } else {
                                        dev_warn(&dd->pdev->dev,
                                                "Null completion "
                                                "for tag %d",
                                                tag);

                                        if (mtip_check_surprise_removal(
                                                dd->pdev)) {
                                                mtip_command_cleanup(dd);
                                                return;
                                        }
                                }
                        }
                }
        }
}

/*
 * Process legacy pio and d2h interrupts
 */
static inline void mtip_process_legacy(struct driver_data *dd, u32 port_stat)
{
        struct mtip_port *port = dd->port;
        struct mtip_cmd *cmd = &port->commands[MTIP_TAG_INTERNAL];

        if (test_bit(MTIP_FLAG_IC_ACTIVE_BIT, &port->flags) &&
            (cmd != NULL) && !(readl(port->cmd_issue[MTIP_TAG_INTERNAL])
                & (1 << MTIP_TAG_INTERNAL))) {
                if (cmd->comp_func) {
                        cmd->comp_func(port,
                                MTIP_TAG_INTERNAL,
                                cmd->comp_data,
                                0);
                        return;
                }
        }

        dev_warn(&dd->pdev->dev, "IRQ status 0x%x ignored.\n", port_stat);

        return;
}

/*
 * Demux and handle errors
 */
static inline void mtip_process_errors(struct driver_data *dd, u32 port_stat)
{
        if (likely(port_stat & (PORT_IRQ_TF_ERR | PORT_IRQ_IF_ERR)))
                mtip_handle_tfe(dd);

        if (unlikely(port_stat & PORT_IRQ_CONNECT)) {
                dev_warn(&dd->pdev->dev,
                        "Clearing PxSERR.DIAG.x\n");
                writel((1 << 26), dd->port->mmio + PORT_SCR_ERR);
        }

        if (unlikely(port_stat & PORT_IRQ_PHYRDY)) {
                dev_warn(&dd->pdev->dev,
                        "Clearing PxSERR.DIAG.n\n");
                writel((1 << 16), dd->port->mmio + PORT_SCR_ERR);
        }

        if (unlikely(port_stat & ~PORT_IRQ_HANDLED)) {
                dev_warn(&dd->pdev->dev,
                        "Port stat errors %x unhandled\n",
                        (port_stat & ~PORT_IRQ_HANDLED));
        }
}

static inline irqreturn_t mtip_handle_irq(struct driver_data *data)
{
        struct driver_data *dd = (struct driver_data *) data;
        struct mtip_port *port = dd->port;
        u32 hba_stat, port_stat;
        int rv = IRQ_NONE;

        hba_stat = readl(dd->mmio + HOST_IRQ_STAT);
        if (hba_stat) {
                rv = IRQ_HANDLED;

                /* Acknowledge the interrupt status on the port.*/
                port_stat = readl(port->mmio + PORT_IRQ_STAT);
                writel(port_stat, port->mmio + PORT_IRQ_STAT);

                /* Demux port status */
                if (likely(port_stat & PORT_IRQ_SDB_FIS))
                        mtip_process_sdbf(dd);

                if (unlikely(port_stat & PORT_IRQ_ERR)) {
                        if (unlikely(mtip_check_surprise_removal(dd->pdev))) {
                                mtip_command_cleanup(dd);
                                /* don't proceed further */
                                return IRQ_HANDLED;
                        }

                        mtip_process_errors(dd, port_stat & PORT_IRQ_ERR);
                }

                if (unlikely(port_stat & PORT_IRQ_LEGACY))
                        mtip_process_legacy(dd, port_stat & PORT_IRQ_LEGACY);
        }

        /* acknowledge interrupt */
        writel(hba_stat, dd->mmio + HOST_IRQ_STAT);

        return rv;
}

/*
 * Wrapper for mtip_handle_irq
 * (ignores return code)
 */
static void mtip_tasklet(unsigned long data)
{
        mtip_handle_irq((struct driver_data *) data);
}

/*
 * HBA interrupt subroutine.
 *
 * @irq         IRQ number.
 * @instance    Pointer to the driver data structure.
 *
 * return value
 *      IRQ_HANDLED     A HBA interrupt was pending and handled.
 *      IRQ_NONE        This interrupt was not for the HBA.
 */
static irqreturn_t mtip_irq_handler(int irq, void *instance)
{
        struct driver_data *dd = instance;
        tasklet_schedule(&dd->tasklet);
        return IRQ_HANDLED;
}

static void mtip_issue_non_ncq_command(struct mtip_port *port, int tag)
{
        atomic_set(&port->commands[tag].active, 1);
        writel(1 << MTIP_TAG_BIT(tag),
                port->cmd_issue[MTIP_TAG_INDEX(tag)]);
}

/*
 * Wait for port to quiesce
 *
 * @port    Pointer to port data structure
 * @timeout Max duration to wait (ms)
 *
 * return value
 *      0       Success
 *      -EBUSY  Commands still active
 */
static int mtip_quiesce_io(struct mtip_port *port, unsigned long timeout)
{
        unsigned long to;
        unsigned int n, active;

        to = jiffies + msecs_to_jiffies(timeout);
        do {
                if (test_bit(MTIP_FLAG_SVC_THD_ACTIVE_BIT, &port->flags)) {
                        msleep(20);
                        continue; /* svc thd is actively issuing commands */
                }
                /*
                 * Ignore s_active bit 0 of array element 0.
                 * This bit will always be set
                 */
                active = readl(port->s_active[0]) & 0xFFFFFFFE;
                for (n = 1; n < port->dd->slot_groups; n++)
                        active |= readl(port->s_active[n]);

                if (!active)
                        break;

                msleep(20);
        } while (time_before(jiffies, to));

        return active ? -EBUSY : 0;
}

/*
 * Execute an internal command and wait for the completion.
 *
 * @port    Pointer to the port data structure.
 * @fis     Pointer to the FIS that describes the command.
 * @fis_len  Length in WORDS of the FIS.
 * @buffer  DMA accessible for command data.
 * @buf_len  Length, in bytes, of the data buffer.
 * @opts    Command header options, excluding the FIS length
 *             and the number of PRD entries.
 * @timeout Time in ms to wait for the command to complete.
 *
 * return value
 *      0        Command completed successfully.
 *      -EFAULT  The buffer address is not correctly aligned.
 *      -EBUSY   Internal command or other IO in progress.
 *      -EAGAIN  Time out waiting for command to complete.
 */
static int mtip_exec_internal_command(struct mtip_port *port,
                                        void *fis,
                                        int fis_len,
                                        dma_addr_t buffer,
                                        int buf_len,
                                        u32 opts,
                                        gfp_t atomic,
                                        unsigned long timeout)
{
        struct mtip_cmd_sg *command_sg;
        DECLARE_COMPLETION_ONSTACK(wait);
        int rv = 0;
        struct mtip_cmd *int_cmd = &port->commands[MTIP_TAG_INTERNAL];

        /* Make sure the buffer is 8 byte aligned. This is asic specific. */
        if (buffer & 0x00000007) {
                dev_err(&port->dd->pdev->dev,
                        "SG buffer is not 8 byte aligned\n");
                return -EFAULT;
        }

        /* Only one internal command should be running at a time */
        if (test_and_set_bit(MTIP_TAG_INTERNAL, port->allocated)) {
                dev_warn(&port->dd->pdev->dev,
                        "Internal command already active\n");
                return -EBUSY;
        }
        set_bit(MTIP_FLAG_IC_ACTIVE_BIT, &port->flags);

        if (atomic == GFP_KERNEL) {
                /* wait for io to complete if non atomic */
                if (mtip_quiesce_io(port, 5000) < 0) {
                        dev_warn(&port->dd->pdev->dev,
                                "Failed to quiesce IO\n");
                        release_slot(port, MTIP_TAG_INTERNAL);
                        clear_bit(MTIP_FLAG_IC_ACTIVE_BIT, &port->flags);
                        wake_up_interruptible(&port->svc_wait);
                        return -EBUSY;
                }

                /* Set the completion function and data for the command. */
                int_cmd->comp_data = &wait;
                int_cmd->comp_func = mtip_completion;

        } else {
                /* Clear completion - we're going to poll */
                int_cmd->comp_data = NULL;
                int_cmd->comp_func = NULL;
        }

        /* Copy the command to the command table */
        memcpy(int_cmd->command, fis, fis_len*4);

        /* Populate the SG list */
        int_cmd->command_header->opts =
                 __force_bit2int cpu_to_le32(opts | fis_len);
        if (buf_len) {
                command_sg = int_cmd->command + AHCI_CMD_TBL_HDR_SZ;

                command_sg->info =
                        __force_bit2int cpu_to_le32((buf_len-1) & 0x3FFFFF);
                command_sg->dba =
                        __force_bit2int cpu_to_le32(buffer & 0xFFFFFFFF);
                command_sg->dba_upper =
                        __force_bit2int cpu_to_le32((buffer >> 16) >> 16);

                int_cmd->command_header->opts |=
                        __force_bit2int cpu_to_le32((1 << 16));
        }

        /* Populate the command header */
        int_cmd->command_header->byte_count = 0;

        /* Issue the command to the hardware */
        mtip_issue_non_ncq_command(port, MTIP_TAG_INTERNAL);

        /* Poll if atomic, wait_for_completion otherwise */
        if (atomic == GFP_KERNEL) {
                /* Wait for the command to complete or timeout. */
                if (wait_for_completion_timeout(
                                &wait,
                                msecs_to_jiffies(timeout)) == 0) {
                        dev_err(&port->dd->pdev->dev,
                                "Internal command did not complete [%d] "
                                "within timeout of  %lu ms\n",
                                atomic, timeout);
                        rv = -EAGAIN;
                }

                if (readl(port->cmd_issue[MTIP_TAG_INTERNAL])
                        & (1 << MTIP_TAG_INTERNAL)) {
                        dev_warn(&port->dd->pdev->dev,
                                "Retiring internal command but CI is 1.\n");
                }

        } else {
                /* Spin for <timeout> checking if command still outstanding */
                timeout = jiffies + msecs_to_jiffies(timeout);

                while ((readl(
                        port->cmd_issue[MTIP_TAG_INTERNAL])
                        & (1 << MTIP_TAG_INTERNAL))
                        && time_before(jiffies, timeout))
                        ;

                if (readl(port->cmd_issue[MTIP_TAG_INTERNAL])
                        & (1 << MTIP_TAG_INTERNAL)) {
                        dev_err(&port->dd->pdev->dev,
                                "Internal command did not complete [%d]\n",
                                atomic);
                        rv = -EAGAIN;
                }
        }

        /* Clear the allocated and active bits for the internal command. */
        atomic_set(&int_cmd->active, 0);
        release_slot(port, MTIP_TAG_INTERNAL);
        clear_bit(MTIP_FLAG_IC_ACTIVE_BIT, &port->flags);
        wake_up_interruptible(&port->svc_wait);

        return rv;
}

/*
 * Byte-swap ATA ID strings.
 *
 * ATA identify data contains strings in byte-swapped 16-bit words.
 * They must be swapped (on all architectures) to be usable as C strings.
 * This function swaps bytes in-place.
 *
 * @buf The buffer location of the string
 * @len The number of bytes to swap
 *
 * return value
 *      None
 */
static inline void ata_swap_string(u16 *buf, unsigned int len)
{
        int i;
        for (i = 0; i < (len/2); i++)
                be16_to_cpus(&buf[i]);
}

/*
 * Request the device identity information.
 *
 * If a user space buffer is not specified, i.e. is NULL, the
 * identify information is still read from the drive and placed
 * into the identify data buffer (@e port->identify) in the
 * port data structure.
 * When the identify buffer contains valid identify information @e
 * port->identify_valid is non-zero.
 *
 * @port         Pointer to the port structure.
 * @user_buffer  A user space buffer where the identify data should be
 *                    copied.
 *
 * return value
 *      0       Command completed successfully.
 *      -EFAULT An error occurred while coping data to the user buffer.
 *      -1      Command failed.
 */
static int mtip_get_identify(struct mtip_port *port, void __user *user_buffer)
{
        int rv = 0;
        struct host_to_dev_fis fis;

        /* Build the FIS. */
        memset(&fis, 0, sizeof(struct host_to_dev_fis));
        fis.type        = 0x27;
        fis.opts        = 1 << 7;
        fis.command     = ATA_CMD_ID_ATA;

        /* Set the identify information as invalid. */
        port->identify_valid = 0;

        /* Clear the identify information. */
        memset(port->identify, 0, sizeof(u16) * ATA_ID_WORDS);

        /* Execute the command. */
        if (mtip_exec_internal_command(port,
                                &fis,
                                5,
                                port->identify_dma,
                                sizeof(u16) * ATA_ID_WORDS,
                                0,
                                GFP_KERNEL,
                                MTIP_INTERNAL_COMMAND_TIMEOUT_MS)
                                < 0) {
                rv = -1;
                goto out;
        }

        /*
         * Perform any necessary byte-swapping.  Yes, the kernel does in fact
         * perform field-sensitive swapping on the string fields.
         * See the kernel use of ata_id_string() for proof of this.
         */
#ifdef __LITTLE_ENDIAN
        ata_swap_string(port->identify + 27, 40);  /* model string*/
        ata_swap_string(port->identify + 23, 8);   /* firmware string*/
        ata_swap_string(port->identify + 10, 20);  /* serial# string*/
#else
        {
                int i;
                for (i = 0; i < ATA_ID_WORDS; i++)
                        port->identify[i] = le16_to_cpu(port->identify[i]);
        }
#endif

        /* Set the identify buffer as valid. */
        port->identify_valid = 1;

        if (user_buffer) {
                if (copy_to_user(
                        user_buffer,
                        port->identify,
                        ATA_ID_WORDS * sizeof(u16))) {
                        rv = -EFAULT;
                        goto out;
                }
        }

out:
        return rv;
}

/*
 * Issue a standby immediate command to the device.
 *
 * @port Pointer to the port structure.
 *
 * return value
 *      0       Command was executed successfully.
 *      -1      An error occurred while executing the command.
 */
static int mtip_standby_immediate(struct mtip_port *port)
{
        int rv;
        struct host_to_dev_fis  fis;

        /* Build the FIS. */
        memset(&fis, 0, sizeof(struct host_to_dev_fis));
        fis.type        = 0x27;
        fis.opts        = 1 << 7;
        fis.command     = ATA_CMD_STANDBYNOW1;

        /* Execute the command.  Use a 15-second timeout for large drives. */
        rv = mtip_exec_internal_command(port,
                                        &fis,
                                        5,
                                        0,
                                        0,
                                        0,
                                        GFP_KERNEL,
                                        15000);

        return rv;
}

/*
 * Get the drive capacity.
 *
 * @dd      Pointer to the device data structure.
 * @sectors Pointer to the variable that will receive the sector count.
 *
 * return value
 *      1 Capacity was returned successfully.
 *      0 The identify information is invalid.
 */
static bool mtip_hw_get_capacity(struct driver_data *dd, sector_t *sectors)
{
        struct mtip_port *port = dd->port;
        u64 total, raw0, raw1, raw2, raw3;
        raw0 = port->identify[100];
        raw1 = port->identify[101];
        raw2 = port->identify[102];
        raw3 = port->identify[103];
        total = raw0 | raw1<<16 | raw2<<32 | raw3<<48;
        *sectors = total;
        return (bool) !!port->identify_valid;
}

/*
 * Reset the HBA.
 *
 * Resets the HBA by setting the HBA Reset bit in the Global
 * HBA Control register. After setting the HBA Reset bit the
 * function waits for 1 second before reading the HBA Reset
 * bit to make sure it has cleared. If HBA Reset is not clear
 * an error is returned. Cannot be used in non-blockable
 * context.
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      0  The reset was successful.
 *      -1 The HBA Reset bit did not clear.
 */
static int mtip_hba_reset(struct driver_data *dd)
{
        mtip_deinit_port(dd->port);

        /* Set the reset bit */
        writel(HOST_RESET, dd->mmio + HOST_CTL);

        /* Flush */
        readl(dd->mmio + HOST_CTL);

        /* Wait for reset to clear */
        ssleep(1);

        /* Check the bit has cleared */
        if (readl(dd->mmio + HOST_CTL) & HOST_RESET) {
                dev_err(&dd->pdev->dev,
                        "Reset bit did not clear.\n");
                return -1;
        }

        return 0;
}

/*
 * Display the identify command data.
 *
 * @port Pointer to the port data structure.
 *
 * return value
 *      None
 */
static void mtip_dump_identify(struct mtip_port *port)
{
        sector_t sectors;
        unsigned short revid;
        char cbuf[42];

        if (!port->identify_valid)
                return;

        strlcpy(cbuf, (char *)(port->identify+10), 21);
        dev_info(&port->dd->pdev->dev,
                "Serial No.: %s\n", cbuf);

        strlcpy(cbuf, (char *)(port->identify+23), 9);
        dev_info(&port->dd->pdev->dev,
                "Firmware Ver.: %s\n", cbuf);

        strlcpy(cbuf, (char *)(port->identify+27), 41);
        dev_info(&port->dd->pdev->dev, "Model: %s\n", cbuf);

        if (mtip_hw_get_capacity(port->dd, &sectors))
                dev_info(&port->dd->pdev->dev,
                        "Capacity: %llu sectors (%llu MB)\n",
                         (u64)sectors,
                         ((u64)sectors) * ATA_SECT_SIZE >> 20);

        pci_read_config_word(port->dd->pdev, PCI_REVISION_ID, &revid);
        switch (revid & 0xFF) {
        case 0x1:
                strlcpy(cbuf, "A0", 3);
                break;
        case 0x3:
                strlcpy(cbuf, "A2", 3);
                break;
        default:
                strlcpy(cbuf, "?", 2);
                break;
        }
        dev_info(&port->dd->pdev->dev,
                "Card Type: %s\n", cbuf);
}

/*
 * Map the commands scatter list into the command table.
 *
 * @command Pointer to the command.
 * @nents Number of scatter list entries.
 *
 * return value
 *      None
 */
static inline void fill_command_sg(struct driver_data *dd,
                                struct mtip_cmd *command,
                                int nents)
{
        int n;
        unsigned int dma_len;
        struct mtip_cmd_sg *command_sg;
        struct scatterlist *sg = command->sg;

        command_sg = command->command + AHCI_CMD_TBL_HDR_SZ;

        for (n = 0; n < nents; n++) {
                dma_len = sg_dma_len(sg);
                if (dma_len > 0x400000)
                        dev_err(&dd->pdev->dev,
                                "DMA segment length truncated\n");
                command_sg->info = __force_bit2int
                        cpu_to_le32((dma_len-1) & 0x3FFFFF);
                command_sg->dba = __force_bit2int
                        cpu_to_le32(sg_dma_address(sg));
                command_sg->dba_upper = __force_bit2int
                        cpu_to_le32((sg_dma_address(sg) >> 16) >> 16);
                command_sg++;
                sg++;
        }
}

/*
 * @brief Execute a drive command.
 *
 * return value 0 The command completed successfully.
 * return value -1 An error occurred while executing the command.
 */
static int exec_drive_task(struct mtip_port *port, u8 *command)
{
        struct host_to_dev_fis  fis;
        struct host_to_dev_fis *reply = (port->rxfis + RX_FIS_D2H_REG);

        /* Build the FIS. */
        memset(&fis, 0, sizeof(struct host_to_dev_fis));
        fis.type        = 0x27;
        fis.opts        = 1 << 7;
        fis.command     = command[0];
        fis.features    = command[1];
        fis.sect_count  = command[2];
        fis.sector      = command[3];
        fis.cyl_low     = command[4];
        fis.cyl_hi      = command[5];
        fis.device      = command[6] & ~0x10; /* Clear the dev bit*/


        dbg_printk(MTIP_DRV_NAME "%s: User Command: cmd %x, feat %x, "
                "nsect %x, sect %x, lcyl %x, "
                "hcyl %x, sel %x\n",
                __func__,
                command[0],
                command[1],
                command[2],
                command[3],
                command[4],
                command[5],
                command[6]);

        /* Execute the command. */
        if (mtip_exec_internal_command(port,
                                 &fis,
                                 5,
                                 0,
                                 0,
                                 0,
                                 GFP_KERNEL,
                                 MTIP_IOCTL_COMMAND_TIMEOUT_MS) < 0) {
                return -1;
        }

        command[0] = reply->command; /* Status*/
        command[1] = reply->features; /* Error*/
        command[4] = reply->cyl_low;
        command[5] = reply->cyl_hi;

        dbg_printk(MTIP_DRV_NAME "%s: Completion Status: stat %x, "
                "err %x , cyl_lo %x cyl_hi %x\n",
                __func__,
                command[0],
                command[1],
                command[4],
                command[5]);

        return 0;
}

/*
 * @brief Execute a drive command.
 *
 * @param port Pointer to the port data structure.
 * @param command Pointer to the user specified command parameters.
 * @param user_buffer Pointer to the user space buffer where read sector
 *                   data should be copied.
 *
 * return value 0 The command completed successfully.
 * return value -EFAULT An error occurred while copying the completion
 *                 data to the user space buffer.
 * return value -1 An error occurred while executing the command.
 */
static int exec_drive_command(struct mtip_port *port, u8 *command,
                                void __user *user_buffer)
{
        struct host_to_dev_fis  fis;
        struct host_to_dev_fis *reply = (port->rxfis + RX_FIS_D2H_REG);

        /* Build the FIS. */
        memset(&fis, 0, sizeof(struct host_to_dev_fis));
        fis.type                = 0x27;
        fis.opts                = 1 << 7;
        fis.command             = command[0];
        fis.features    = command[2];
        fis.sect_count  = command[3];
        if (fis.command == ATA_CMD_SMART) {
                fis.sector      = command[1];
                fis.cyl_low     = 0x4F;
                fis.cyl_hi      = 0xC2;
        }

        dbg_printk(MTIP_DRV_NAME
                "%s: User Command: cmd %x, sect %x, "
                "feat %x, sectcnt %x\n",
                __func__,
                command[0],
                command[1],
                command[2],
                command[3]);

        memset(port->sector_buffer, 0x00, ATA_SECT_SIZE);

        /* Execute the command. */
        if (mtip_exec_internal_command(port,
                                &fis,
                                 5,
                                 port->sector_buffer_dma,
                                 (command[3] != 0) ? ATA_SECT_SIZE : 0,
                                 0,
                                 GFP_KERNEL,
                                 MTIP_IOCTL_COMMAND_TIMEOUT_MS)
                                 < 0) {
                return -1;
        }

        /* Collect the completion status. */
        command[0] = reply->command; /* Status*/
        command[1] = reply->features; /* Error*/
        command[2] = command[3];

        dbg_printk(MTIP_DRV_NAME
                "%s: Completion Status: stat %x, "
                "err %x, cmd %x\n",
                __func__,
                command[0],
                command[1],
                command[2]);

        if (user_buffer && command[3]) {
                if (copy_to_user(user_buffer,
                                 port->sector_buffer,
                                 ATA_SECT_SIZE * command[3])) {
                        return -EFAULT;
                }
        }

        return 0;
}

/*
 *  Indicates whether a command has a single sector payload.
 *
 *  @command passed to the device to perform the certain event.
 *  @features passed to the device to perform the certain event.
 *
 *  return value
 *      1       command is one that always has a single sector payload,
 *              regardless of the value in the Sector Count field.
 *      0       otherwise
 *
 */
static unsigned int implicit_sector(unsigned char command,
                                    unsigned char features)
{
        unsigned int rv = 0;

        /* list of commands that have an implicit sector count of 1 */
        switch (command) {
        case ATA_CMD_SEC_SET_PASS:
        case ATA_CMD_SEC_UNLOCK:
        case ATA_CMD_SEC_ERASE_PREP:
        case ATA_CMD_SEC_ERASE_UNIT:
        case ATA_CMD_SEC_FREEZE_LOCK:
        case ATA_CMD_SEC_DISABLE_PASS:
        case ATA_CMD_PMP_READ:
        case ATA_CMD_PMP_WRITE:
                rv = 1;
                break;
        case ATA_CMD_SET_MAX:
                if (features == ATA_SET_MAX_UNLOCK)
                        rv = 1;
                break;
        case ATA_CMD_SMART:
                if ((features == ATA_SMART_READ_VALUES) ||
                                (features == ATA_SMART_READ_THRESHOLDS))
                        rv = 1;
                break;
        case ATA_CMD_CONF_OVERLAY:
                if ((features == ATA_DCO_IDENTIFY) ||
                                (features == ATA_DCO_SET))
                        rv = 1;
                break;
        }
        return rv;
}

/*
 * Executes a taskfile
 * See ide_taskfile_ioctl() for derivation
 */
static int exec_drive_taskfile(struct driver_data *dd,
                               void __user *buf,
                               ide_task_request_t *req_task,
                               int outtotal)
{
        struct host_to_dev_fis  fis;
        struct host_to_dev_fis *reply;
        u8 *outbuf = NULL;
        u8 *inbuf = NULL;
        dma_addr_t outbuf_dma = 0;
        dma_addr_t inbuf_dma = 0;
        dma_addr_t dma_buffer = 0;
        int err = 0;
        unsigned int taskin = 0;
        unsigned int taskout = 0;
        u8 nsect = 0;
        unsigned int timeout = MTIP_IOCTL_COMMAND_TIMEOUT_MS;
        unsigned int force_single_sector;
        unsigned int transfer_size;
        unsigned long task_file_data;
        int intotal = outtotal + req_task->out_size;

        taskout = req_task->out_size;
        taskin = req_task->in_size;
        /* 130560 = 512 * 0xFF*/
        if (taskin > 130560 || taskout > 130560) {
                err = -EINVAL;
                goto abort;
        }

        if (taskout) {
                outbuf = kzalloc(taskout, GFP_KERNEL);
                if (outbuf == NULL) {
                        err = -ENOMEM;
                        goto abort;
                }
                if (copy_from_user(outbuf, buf + outtotal, taskout)) {
                        err = -EFAULT;
                        goto abort;
                }
                outbuf_dma = pci_map_single(dd->pdev,
                                         outbuf,
                                         taskout,
                                         DMA_TO_DEVICE);
                if (outbuf_dma == 0) {
                        err = -ENOMEM;
                        goto abort;
                }
                dma_buffer = outbuf_dma;
        }

        if (taskin) {
                inbuf = kzalloc(taskin, GFP_KERNEL);
                if (inbuf == NULL) {
                        err = -ENOMEM;
                        goto abort;
                }

                if (copy_from_user(inbuf, buf + intotal, taskin)) {
                        err = -EFAULT;
                        goto abort;
                }
                inbuf_dma = pci_map_single(dd->pdev,
                                         inbuf,
                                         taskin, DMA_FROM_DEVICE);
                if (inbuf_dma == 0) {
                        err = -ENOMEM;
                        goto abort;
                }
                dma_buffer = inbuf_dma;
        }

        /* only supports PIO and non-data commands from this ioctl. */
        switch (req_task->data_phase) {
        case TASKFILE_OUT:
                nsect = taskout / ATA_SECT_SIZE;
                reply = (dd->port->rxfis + RX_FIS_PIO_SETUP);
                break;
        case TASKFILE_IN:
                reply = (dd->port->rxfis + RX_FIS_PIO_SETUP);
                break;
        case TASKFILE_NO_DATA:
                reply = (dd->port->rxfis + RX_FIS_D2H_REG);
                break;
        default:
                err = -EINVAL;
                goto abort;
        }

        /* Build the FIS. */
        memset(&fis, 0, sizeof(struct host_to_dev_fis));

        fis.type        = 0x27;
        fis.opts        = 1 << 7;
        fis.command     = req_task->io_ports[7];
        fis.features    = req_task->io_ports[1];
        fis.sect_count  = req_task->io_ports[2];
        fis.lba_low     = req_task->io_ports[3];
        fis.lba_mid     = req_task->io_ports[4];
        fis.lba_hi      = req_task->io_ports[5];
         /* Clear the dev bit*/
        fis.device      = req_task->io_ports[6] & ~0x10;

        if ((req_task->in_flags.all == 0) && (req_task->out_flags.all & 1)) {
                req_task->in_flags.all  =
                        IDE_TASKFILE_STD_IN_FLAGS |
                        (IDE_HOB_STD_IN_FLAGS << 8);
                fis.lba_low_ex          = req_task->hob_ports[3];
                fis.lba_mid_ex          = req_task->hob_ports[4];
                fis.lba_hi_ex           = req_task->hob_ports[5];
                fis.features_ex         = req_task->hob_ports[1];
                fis.sect_cnt_ex         = req_task->hob_ports[2];

        } else {
                req_task->in_flags.all = IDE_TASKFILE_STD_IN_FLAGS;
        }

        force_single_sector = implicit_sector(fis.command, fis.features);

        if ((taskin || taskout) && (!fis.sect_count)) {
                if (nsect)
                        fis.sect_count = nsect;
                else {
                        if (!force_single_sector) {
                                dev_warn(&dd->pdev->dev,
                                        "data movement but "
                                        "sect_count is 0\n");
                                        err = -EINVAL;
                                        goto abort;
                        }
                }
        }

        dbg_printk(MTIP_DRV_NAME
                "taskfile: cmd %x, feat %x, nsect %x,"
                " sect/lbal %x, lcyl/lbam %x, hcyl/lbah %x,"
                " head/dev %x\n",
                fis.command,
                fis.features,
                fis.sect_count,
                fis.lba_low,
                fis.lba_mid,
                fis.lba_hi,
                fis.device);

        switch (fis.command) {
        case ATA_CMD_DOWNLOAD_MICRO:
                /* Change timeout for Download Microcode to 60 seconds.*/
                timeout = 60000;
                break;
        case ATA_CMD_SEC_ERASE_UNIT:
                /* Change timeout for Security Erase Unit to 4 minutes.*/
                timeout = 240000;
                break;
        case ATA_CMD_STANDBYNOW1:
                /* Change timeout for standby immediate to 10 seconds.*/
                timeout = 10000;
                break;
        case 0xF7:
        case 0xFA:
                /* Change timeout for vendor unique command to 10 secs */
                timeout = 10000;
                break;
        case ATA_CMD_SMART:
                /* Change timeout for vendor unique command to 10 secs */
                timeout = 10000;
                break;
        default:
                timeout = MTIP_IOCTL_COMMAND_TIMEOUT_MS;
                break;
        }

        /* Determine the correct transfer size.*/
        if (force_single_sector)
                transfer_size = ATA_SECT_SIZE;
        else
                transfer_size = ATA_SECT_SIZE * fis.sect_count;

        /* Execute the command.*/
        if (mtip_exec_internal_command(dd->port,
                                 &fis,
                                 5,
                                 dma_buffer,
                                 transfer_size,
                                 0,
                                 GFP_KERNEL,
                                 timeout) < 0) {
                err = -EIO;
                goto abort;
        }

        task_file_data = readl(dd->port->mmio+PORT_TFDATA);

        if ((req_task->data_phase == TASKFILE_IN) && !(task_file_data & 1)) {
                reply = dd->port->rxfis + RX_FIS_PIO_SETUP;
                req_task->io_ports[7] = reply->control;
        } else {
                reply = dd->port->rxfis + RX_FIS_D2H_REG;
                req_task->io_ports[7] = reply->command;
        }

        /* reclaim the DMA buffers.*/
        if (inbuf_dma)
                pci_unmap_single(dd->pdev, inbuf_dma,
                        taskin, DMA_FROM_DEVICE);
        if (outbuf_dma)
                pci_unmap_single(dd->pdev, outbuf_dma,
                        taskout, DMA_TO_DEVICE);
        inbuf_dma  = 0;
        outbuf_dma = 0;

        /* return the ATA registers to the caller.*/
        req_task->io_ports[1] = reply->features;
        req_task->io_ports[2] = reply->sect_count;
        req_task->io_ports[3] = reply->lba_low;
        req_task->io_ports[4] = reply->lba_mid;
        req_task->io_ports[5] = reply->lba_hi;
        req_task->io_ports[6] = reply->device;

        if (req_task->out_flags.all & 1)  {

                req_task->hob_ports[3] = reply->lba_low_ex;
                req_task->hob_ports[4] = reply->lba_mid_ex;
                req_task->hob_ports[5] = reply->lba_hi_ex;
                req_task->hob_ports[1] = reply->features_ex;
                req_task->hob_ports[2] = reply->sect_cnt_ex;
        }

        /* Com rest after secure erase or lowlevel format */
        if (((fis.command == ATA_CMD_SEC_ERASE_UNIT) ||
                ((fis.command == 0xFC) &&
                        (fis.features == 0x27 || fis.features == 0x72 ||
                         fis.features == 0x62 || fis.features == 0x26))) &&
                         !(reply->command & 1)) {
                mtip_restart_port(dd->port);
        }

        dbg_printk(MTIP_DRV_NAME
                "%s: Completion: stat %x,"
                "err %x, sect_cnt %x, lbalo %x,"
                "lbamid %x, lbahi %x, dev %x\n",
                __func__,
                req_task->io_ports[7],
                req_task->io_ports[1],
                req_task->io_ports[2],
                req_task->io_ports[3],
                req_task->io_ports[4],
                req_task->io_ports[5],
                req_task->io_ports[6]);

        if (taskout) {
                if (copy_to_user(buf + outtotal, outbuf, taskout)) {
                        err = -EFAULT;
                        goto abort;
                }
        }
        if (taskin) {
                if (copy_to_user(buf + intotal, inbuf, taskin)) {
                        err = -EFAULT;
                        goto abort;
                }
        }
abort:
        if (inbuf_dma)
                pci_unmap_single(dd->pdev, inbuf_dma,
                                        taskin, DMA_FROM_DEVICE);
        if (outbuf_dma)
                pci_unmap_single(dd->pdev, outbuf_dma,
                                        taskout, DMA_TO_DEVICE);
        kfree(outbuf);
        kfree(inbuf);

        return err;
}

/*
 * Handle IOCTL calls from the Block Layer.
 *
 * This function is called by the Block Layer when it receives an IOCTL
 * command that it does not understand. If the IOCTL command is not supported
 * this function returns -ENOTTY.
 *
 * @dd  Pointer to the driver data structure.
 * @cmd IOCTL command passed from the Block Layer.
 * @arg IOCTL argument passed from the Block Layer.
 *
 * return value
 *      0       The IOCTL completed successfully.
 *      -ENOTTY The specified command is not supported.
 *      -EFAULT An error occurred copying data to a user space buffer.
 *      -EIO    An error occurred while executing the command.
 */
static int mtip_hw_ioctl(struct driver_data *dd, unsigned int cmd,
                         unsigned long arg)
{
        switch (cmd) {
        case HDIO_GET_IDENTITY:
                if (mtip_get_identify(dd->port, (void __user *) arg) < 0) {
                        dev_warn(&dd->pdev->dev,
                                "Unable to read identity\n");
                        return -EIO;
                }

                break;
        case HDIO_DRIVE_CMD:
        {
                u8 drive_command[4];

                /* Copy the user command info to our buffer. */
                if (copy_from_user(drive_command,
                                         (void __user *) arg,
                                         sizeof(drive_command)))
                        return -EFAULT;

                /* Execute the drive command. */
                if (exec_drive_command(dd->port,
                                         drive_command,
                                         (void __user *) (arg+4)))
                        return -EIO;

                /* Copy the status back to the users buffer. */
                if (copy_to_user((void __user *) arg,
                                         drive_command,
                                         sizeof(drive_command)))
                        return -EFAULT;

                break;
        }
        case HDIO_DRIVE_TASK:
        {
                u8 drive_command[7];

                /* Copy the user command info to our buffer. */
                if (copy_from_user(drive_command,
                                         (void __user *) arg,
                                         sizeof(drive_command)))
                        return -EFAULT;

                /* Execute the drive command. */
                if (exec_drive_task(dd->port, drive_command))
                        return -EIO;

                /* Copy the status back to the users buffer. */
                if (copy_to_user((void __user *) arg,
                                         drive_command,
                                         sizeof(drive_command)))
                        return -EFAULT;

                break;
        }
        case HDIO_DRIVE_TASKFILE: {
                ide_task_request_t req_task;
                int ret, outtotal;

                if (copy_from_user(&req_task, (void __user *) arg,
                                        sizeof(req_task)))
                        return -EFAULT;

                outtotal = sizeof(req_task);

                ret = exec_drive_taskfile(dd, (void __user *) arg,
                                                &req_task, outtotal);

                if (copy_to_user((void __user *) arg, &req_task,
                                                        sizeof(req_task)))
                        return -EFAULT;

                return ret;
        }

        default:
                return -EINVAL;
        }
        return 0;
}

/*
 * Submit an IO to the hw
 *
 * This function is called by the block layer to issue an io
 * to the device. Upon completion, the callback function will
 * be called with the data parameter passed as the callback data.
 *
 * @dd       Pointer to the driver data structure.
 * @start    First sector to read.
 * @nsect    Number of sectors to read.
 * @nents    Number of entries in scatter list for the read command.
 * @tag      The tag of this read command.
 * @callback Pointer to the function that should be called
 *           when the read completes.
 * @data     Callback data passed to the callback function
 *           when the read completes.
 * @barrier  If non-zero, this command must be completed before
 *           issuing any other commands.
 * @dir      Direction (read or write)
 *
 * return value
 *      None
 */
static void mtip_hw_submit_io(struct driver_data *dd, sector_t start,
                              int nsect, int nents, int tag, void *callback,
                              void *data, int barrier, int dir)
{
        struct host_to_dev_fis  *fis;
        struct mtip_port *port = dd->port;
        struct mtip_cmd *command = &port->commands[tag];

        /* Map the scatter list for DMA access */
        if (dir == READ)
                nents = dma_map_sg(&dd->pdev->dev, command->sg,
                                        nents, DMA_FROM_DEVICE);
        else
                nents = dma_map_sg(&dd->pdev->dev, command->sg,
                                        nents, DMA_TO_DEVICE);

        command->scatter_ents = nents;

        /*
         * The number of retries for this command before it is
         * reported as a failure to the upper layers.
         */
        command->retries = MTIP_MAX_RETRIES;

        /* Fill out fis */
        fis = command->command;
        fis->type        = 0x27;
        fis->opts        = 1 << 7;
        fis->command     =
                (dir == READ ? ATA_CMD_FPDMA_READ : ATA_CMD_FPDMA_WRITE);
        *((unsigned int *) &fis->lba_low) = (start & 0xFFFFFF);
        *((unsigned int *) &fis->lba_low_ex) = ((start >> 24) & 0xFFFFFF);
        fis->device      = 1 << 6;
        if (barrier)
                fis->device |= FUA_BIT;
        fis->features    = nsect & 0xFF;
        fis->features_ex = (nsect >> 8) & 0xFF;
        fis->sect_count  = ((tag << 3) | (tag >> 5));
        fis->sect_cnt_ex = 0;
        fis->control     = 0;
        fis->res2        = 0;
        fis->res3        = 0;
        fill_command_sg(dd, command, nents);

        /* Populate the command header */
        command->command_header->opts =
                        __force_bit2int cpu_to_le32(
                                (nents << 16) | 5 | AHCI_CMD_PREFETCH);
        command->command_header->byte_count = 0;

        /*
         * Set the completion function and data for the command
         * within this layer.
         */
        command->comp_data = dd;
        command->comp_func = mtip_async_complete;
        command->direction = (dir == READ ? DMA_FROM_DEVICE : DMA_TO_DEVICE);

        /*
         * Set the completion function and data for the command passed
         * from the upper layer.
         */
        command->async_data = data;
        command->async_callback = callback;

        /*
         * To prevent this command from being issued
         * if an internal command is in progress or error handling is active.
         */
        if (unlikely(test_bit(MTIP_FLAG_IC_ACTIVE_BIT, &port->flags) ||
                        test_bit(MTIP_FLAG_EH_ACTIVE_BIT, &port->flags))) {
                set_bit(tag, port->cmds_to_issue);
                set_bit(MTIP_FLAG_ISSUE_CMDS_BIT, &port->flags);
                return;
        }

        /* Issue the command to the hardware */
        mtip_issue_ncq_command(port, tag);

        /* Set the command's timeout value.*/
        port->commands[tag].comp_time = jiffies + msecs_to_jiffies(
                                        MTIP_NCQ_COMMAND_TIMEOUT_MS);
}

/*
 * Release a command slot.
 *
 * @dd  Pointer to the driver data structure.
 * @tag Slot tag
 *
 * return value
 *      None
 */
static void mtip_hw_release_scatterlist(struct driver_data *dd, int tag)
{
        release_slot(dd->port, tag);
}

/*
 * Obtain a command slot and return its associated scatter list.
 *
 * @dd  Pointer to the driver data structure.
 * @tag Pointer to an int that will receive the allocated command
 *            slot tag.
 *
 * return value
 *      Pointer to the scatter list for the allocated command slot
 *      or NULL if no command slots are available.
 */
static struct scatterlist *mtip_hw_get_scatterlist(struct driver_data *dd,
                                                   int *tag)
{
        /*
         * It is possible that, even with this semaphore, a thread
         * may think that no command slots are available. Therefore, we
         * need to make an attempt to get_slot().
         */
        down(&dd->port->cmd_slot);
        *tag = get_slot(dd->port);

        if (unlikely(*tag < 0))
                return NULL;

        return dd->port->commands[*tag].sg;
}

/*
 * Sysfs register/status dump.
 *
 * @dev  Pointer to the device structure, passed by the kernrel.
 * @attr Pointer to the device_attribute structure passed by the kernel.
 * @buf  Pointer to the char buffer that will receive the stats info.
 *
 * return value
 *      The size, in bytes, of the data copied into buf.
 */
static ssize_t hw_show_registers(struct device *dev,
                                struct device_attribute *attr,
                                char *buf)
{
        u32 group_allocated;
        struct driver_data *dd = dev_to_disk(dev)->private_data;
        int size = 0;
        int n;

        size += sprintf(&buf[size], "%s:\ns_active:\n", __func__);

        for (n = 0; n < dd->slot_groups; n++)
                size += sprintf(&buf[size], "0x%08x\n",
                                         readl(dd->port->s_active[n]));

        size += sprintf(&buf[size], "Command Issue:\n");

        for (n = 0; n < dd->slot_groups; n++)
                size += sprintf(&buf[size], "0x%08x\n",
                                        readl(dd->port->cmd_issue[n]));

        size += sprintf(&buf[size], "Allocated:\n");

        for (n = 0; n < dd->slot_groups; n++) {
                if (sizeof(long) > sizeof(u32))
                        group_allocated =
                                dd->port->allocated[n/2] >> (32*(n&1));
                else
                        group_allocated = dd->port->allocated[n];
                size += sprintf(&buf[size], "0x%08x\n",
                                 group_allocated);
        }

        size += sprintf(&buf[size], "completed:\n");

        for (n = 0; n < dd->slot_groups; n++)
                size += sprintf(&buf[size], "0x%08x\n",
                                readl(dd->port->completed[n]));

        size += sprintf(&buf[size], "PORT_IRQ_STAT 0x%08x\n",
                                readl(dd->port->mmio + PORT_IRQ_STAT));
        size += sprintf(&buf[size], "HOST_IRQ_STAT 0x%08x\n",
                                readl(dd->mmio + HOST_IRQ_STAT));

        return size;
}
static DEVICE_ATTR(registers, S_IRUGO, hw_show_registers, NULL);

/*
 * Create the sysfs related attributes.
 *
 * @dd   Pointer to the driver data structure.
 * @kobj Pointer to the kobj for the block device.
 *
 * return value
 *      0       Operation completed successfully.
 *      -EINVAL Invalid parameter.
 */
static int mtip_hw_sysfs_init(struct driver_data *dd, struct kobject *kobj)
{
        if (!kobj || !dd)
                return -EINVAL;

        if (sysfs_create_file(kobj, &dev_attr_registers.attr))
                dev_warn(&dd->pdev->dev,
                        "Error creating registers sysfs entry\n");
        return 0;
}

/*
 * Remove the sysfs related attributes.
 *
 * @dd   Pointer to the driver data structure.
 * @kobj Pointer to the kobj for the block device.
 *
 * return value
 *      0       Operation completed successfully.
 *      -EINVAL Invalid parameter.
 */
static int mtip_hw_sysfs_exit(struct driver_data *dd, struct kobject *kobj)
{
        if (!kobj || !dd)
                return -EINVAL;

        sysfs_remove_file(kobj, &dev_attr_registers.attr);

        return 0;
}

/*
 * Perform any init/resume time hardware setup
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      None
 */
static inline void hba_setup(struct driver_data *dd)
{
        u32 hwdata;
        hwdata = readl(dd->mmio + HOST_HSORG);

        /* interrupt bug workaround: use only 1 IS bit.*/
        writel(hwdata |
                HSORG_DISABLE_SLOTGRP_INTR |
                HSORG_DISABLE_SLOTGRP_PXIS,
                dd->mmio + HOST_HSORG);
}

/*
 * Detect the details of the product, and store anything needed
 * into the driver data structure.  This includes product type and
 * version and number of slot groups.
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      None
 */
static void mtip_detect_product(struct driver_data *dd)
{
        u32 hwdata;
        unsigned int rev, slotgroups;

        /*
         * HBA base + 0xFC [15:0] - vendor-specific hardware interface
         * info register:
         * [15:8] hardware/software interface rev#
         * [   3] asic-style interface
         * [ 2:0] number of slot groups, minus 1 (only valid for asic-style).
         */
        hwdata = readl(dd->mmio + HOST_HSORG);

        dd->product_type = MTIP_PRODUCT_UNKNOWN;
        dd->slot_groups = 1;

        if (hwdata & 0x8) {
                dd->product_type = MTIP_PRODUCT_ASICFPGA;
                rev = (hwdata & HSORG_HWREV) >> 8;
                slotgroups = (hwdata & HSORG_SLOTGROUPS) + 1;
                dev_info(&dd->pdev->dev,
                        "ASIC-FPGA design, HS rev 0x%x, "
                        "%i slot groups [%i slots]\n",
                         rev,
                         slotgroups,
                         slotgroups * 32);

                if (slotgroups > MTIP_MAX_SLOT_GROUPS) {
                        dev_warn(&dd->pdev->dev,
                                "Warning: driver only supports "
                                "%i slot groups.\n", MTIP_MAX_SLOT_GROUPS);
                        slotgroups = MTIP_MAX_SLOT_GROUPS;
                }
                dd->slot_groups = slotgroups;
                return;
        }

        dev_warn(&dd->pdev->dev, "Unrecognized product id\n");
}

/*
 * Blocking wait for FTL rebuild to complete
 *
 * @dd Pointer to the DRIVER_DATA structure.
 *
 * return value
 *      0       FTL rebuild completed successfully
 *      -EFAULT FTL rebuild error/timeout/interruption
 */
static int mtip_ftl_rebuild_poll(struct driver_data *dd)
{
        unsigned long timeout, cnt = 0, start;

        dev_warn(&dd->pdev->dev,
                "FTL rebuild in progress. Polling for completion.\n");

        start = jiffies;
        dd->ftlrebuildflag = 1;
        timeout = jiffies + msecs_to_jiffies(MTIP_FTL_REBUILD_TIMEOUT_MS);

        do {
                if (mtip_check_surprise_removal(dd->pdev))
                        return -EFAULT;

                if (mtip_get_identify(dd->port, NULL) < 0)
                        return -EFAULT;

                if (*(dd->port->identify + MTIP_FTL_REBUILD_OFFSET) ==
                        MTIP_FTL_REBUILD_MAGIC) {
                        ssleep(1);
                        /* Print message every 3 minutes */
                        if (cnt++ >= 180) {
                                dev_warn(&dd->pdev->dev,
                                "FTL rebuild in progress (%d secs).\n",
                                jiffies_to_msecs(jiffies - start) / 1000);
                                cnt = 0;
                        }
                } else {
                        dev_warn(&dd->pdev->dev,
                                "FTL rebuild complete (%d secs).\n",
                        jiffies_to_msecs(jiffies - start) / 1000);
                        dd->ftlrebuildflag = 0;
                        break;
                }
                ssleep(10);
        } while (time_before(jiffies, timeout));

        /* Check for timeout */
        if (dd->ftlrebuildflag) {
                dev_err(&dd->pdev->dev,
                "Timed out waiting for FTL rebuild to complete (%d secs).\n",
                jiffies_to_msecs(jiffies - start) / 1000);
                return -EFAULT;
        }

        return 0;
}

/*
 * service thread to issue queued commands
 *
 * @data Pointer to the driver data structure.
 *
 * return value
 *      0
 */

static int mtip_service_thread(void *data)
{
        struct driver_data *dd = (struct driver_data *)data;
        unsigned long slot, slot_start, slot_wrap;
        unsigned int num_cmd_slots = dd->slot_groups * 32;
        struct mtip_port *port = dd->port;

        while (1) {
                /*
                 * the condition is to check neither an internal command is
                 * is in progress nor error handling is active
                 */
                wait_event_interruptible(port->svc_wait, (port->flags) &&
                        !test_bit(MTIP_FLAG_IC_ACTIVE_BIT, &port->flags) &&
                        !test_bit(MTIP_FLAG_EH_ACTIVE_BIT, &port->flags));

                if (kthread_should_stop())
                        break;

                if (test_bit(MTIP_FLAG_ISSUE_CMDS_BIT, &port->flags)) {
                        set_bit(MTIP_FLAG_SVC_THD_ACTIVE_BIT, &port->flags);
                        slot = 1;
                        /* used to restrict the loop to one iteration */
                        slot_start = num_cmd_slots;
                        slot_wrap = 0;
                        while (1) {
                                slot = find_next_bit(port->cmds_to_issue,
                                                num_cmd_slots, slot);
                                if (slot_wrap == 1) {
                                        if ((slot_start >= slot) ||
                                                (slot >= num_cmd_slots))
                                                break;
                                }
                                if (unlikely(slot_start == num_cmd_slots))
                                        slot_start = slot;

                                if (unlikely(slot == num_cmd_slots)) {
                                        slot = 1;
                                        slot_wrap = 1;
                                        continue;
                                }

                                /* Issue the command to the hardware */
                                mtip_issue_ncq_command(port, slot);

                                /* Set the command's timeout value.*/
                                port->commands[slot].comp_time = jiffies +
                                msecs_to_jiffies(MTIP_NCQ_COMMAND_TIMEOUT_MS);

                                clear_bit(slot, port->cmds_to_issue);
                        }

                        clear_bit(MTIP_FLAG_ISSUE_CMDS_BIT, &port->flags);
                        clear_bit(MTIP_FLAG_SVC_THD_ACTIVE_BIT, &port->flags);
                }
        }
        return 0;
}

/*
 * Called once for each card.
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      0 on success, else an error code.
 */
static int mtip_hw_init(struct driver_data *dd)
{
        int i;
        int rv;
        unsigned int num_command_slots;

        dd->mmio = pcim_iomap_table(dd->pdev)[MTIP_ABAR];

        mtip_detect_product(dd);
        if (dd->product_type == MTIP_PRODUCT_UNKNOWN) {
                rv = -EIO;
                goto out1;
        }
        num_command_slots = dd->slot_groups * 32;

        hba_setup(dd);

        tasklet_init(&dd->tasklet, mtip_tasklet, (unsigned long)dd);

        dd->port = kzalloc(sizeof(struct mtip_port), GFP_KERNEL);
        if (!dd->port) {
                dev_err(&dd->pdev->dev,
                        "Memory allocation: port structure\n");
                return -ENOMEM;
        }

        /* Counting semaphore to track command slot usage */
        sema_init(&dd->port->cmd_slot, num_command_slots - 1);

        /* Spinlock to prevent concurrent issue */
        spin_lock_init(&dd->port->cmd_issue_lock);

        /* Set the port mmio base address. */
        dd->port->mmio  = dd->mmio + PORT_OFFSET;
        dd->port->dd    = dd;

        /* Allocate memory for the command list. */
        dd->port->command_list =
                dmam_alloc_coherent(&dd->pdev->dev,
                        HW_PORT_PRIV_DMA_SZ + (ATA_SECT_SIZE * 2),
                        &dd->port->command_list_dma,
                        GFP_KERNEL);
        if (!dd->port->command_list) {
                dev_err(&dd->pdev->dev,
                        "Memory allocation: command list\n");
                rv = -ENOMEM;
                goto out1;
        }

        /* Clear the memory we have allocated. */
        memset(dd->port->command_list,
                0,
                HW_PORT_PRIV_DMA_SZ + (ATA_SECT_SIZE * 2));

        /* Setup the addresse of the RX FIS. */
        dd->port->rxfis     = dd->port->command_list + HW_CMD_SLOT_SZ;
        dd->port->rxfis_dma = dd->port->command_list_dma + HW_CMD_SLOT_SZ;

        /* Setup the address of the command tables. */
        dd->port->command_table   = dd->port->rxfis + AHCI_RX_FIS_SZ;
        dd->port->command_tbl_dma = dd->port->rxfis_dma + AHCI_RX_FIS_SZ;

        /* Setup the address of the identify data. */
        dd->port->identify     = dd->port->command_table +
                                        HW_CMD_TBL_AR_SZ;
        dd->port->identify_dma = dd->port->command_tbl_dma +
                                        HW_CMD_TBL_AR_SZ;

        /* Setup the address of the sector buffer. */
        dd->port->sector_buffer = (void *) dd->port->identify + ATA_SECT_SIZE;
        dd->port->sector_buffer_dma = dd->port->identify_dma + ATA_SECT_SIZE;

        /* Point the command headers at the command tables. */
        for (i = 0; i < num_command_slots; i++) {
                dd->port->commands[i].command_header =
                                        dd->port->command_list +
                                        (sizeof(struct mtip_cmd_hdr) * i);
                dd->port->commands[i].command_header_dma =
                                        dd->port->command_list_dma +
                                        (sizeof(struct mtip_cmd_hdr) * i);

                dd->port->commands[i].command =
                        dd->port->command_table + (HW_CMD_TBL_SZ * i);
                dd->port->commands[i].command_dma =
                        dd->port->command_tbl_dma + (HW_CMD_TBL_SZ * i);

                if (readl(dd->mmio + HOST_CAP) & HOST_CAP_64)
                        dd->port->commands[i].command_header->ctbau =
                        __force_bit2int cpu_to_le32(
                        (dd->port->commands[i].command_dma >> 16) >> 16);
                dd->port->commands[i].command_header->ctba =
                        __force_bit2int cpu_to_le32(
                        dd->port->commands[i].command_dma & 0xFFFFFFFF);

                /*
                 * If this is not done, a bug is reported by the stock
                 * FC11 i386. Due to the fact that it has lots of kernel
                 * debugging enabled.
                 */
                sg_init_table(dd->port->commands[i].sg, MTIP_MAX_SG);

                /* Mark all commands as currently inactive.*/
                atomic_set(&dd->port->commands[i].active, 0);
        }

        /* Setup the pointers to the extended s_active and CI registers. */
        for (i = 0; i < dd->slot_groups; i++) {
                dd->port->s_active[i] =
                        dd->port->mmio + i*0x80 + PORT_SCR_ACT;
                dd->port->cmd_issue[i] =
                        dd->port->mmio + i*0x80 + PORT_COMMAND_ISSUE;
                dd->port->completed[i] =
                        dd->port->mmio + i*0x80 + PORT_SDBV;
        }

        /* Reset the HBA. */
        if (mtip_hba_reset(dd) < 0) {
                dev_err(&dd->pdev->dev,
                        "Card did not reset within timeout\n");
                rv = -EIO;
                goto out2;
        }

        mtip_init_port(dd->port);
        mtip_start_port(dd->port);

        /* Setup the ISR and enable interrupts. */
        rv = devm_request_irq(&dd->pdev->dev,
                                dd->pdev->irq,
                                mtip_irq_handler,
                                IRQF_SHARED,
                                dev_driver_string(&dd->pdev->dev),
                                dd);

        if (rv) {
                dev_err(&dd->pdev->dev,
                        "Unable to allocate IRQ %d\n", dd->pdev->irq);
                goto out2;
        }

        /* Enable interrupts on the HBA. */
        writel(readl(dd->mmio + HOST_CTL) | HOST_IRQ_EN,
                                        dd->mmio + HOST_CTL);

        init_timer(&dd->port->cmd_timer);
        init_waitqueue_head(&dd->port->svc_wait);

        dd->port->cmd_timer.data = (unsigned long int) dd->port;
        dd->port->cmd_timer.function = mtip_timeout_function;
        mod_timer(&dd->port->cmd_timer,
                jiffies + msecs_to_jiffies(MTIP_TIMEOUT_CHECK_PERIOD));

        if (mtip_get_identify(dd->port, NULL) < 0) {
                rv = -EFAULT;
                goto out3;
        }
        mtip_dump_identify(dd->port);

        if (*(dd->port->identify + MTIP_FTL_REBUILD_OFFSET) ==
                MTIP_FTL_REBUILD_MAGIC) {
                return mtip_ftl_rebuild_poll(dd);
        }
        return rv;

out3:
        del_timer_sync(&dd->port->cmd_timer);

        /* Disable interrupts on the HBA. */
        writel(readl(dd->mmio + HOST_CTL) & ~HOST_IRQ_EN,
                        dd->mmio + HOST_CTL);

        /*Release the IRQ. */
        devm_free_irq(&dd->pdev->dev, dd->pdev->irq, dd);

out2:
        mtip_deinit_port(dd->port);

        /* Free the command/command header memory. */
        dmam_free_coherent(&dd->pdev->dev,
                                HW_PORT_PRIV_DMA_SZ + (ATA_SECT_SIZE * 2),
                                dd->port->command_list,
                                dd->port->command_list_dma);
out1:
        /* Free the memory allocated for the for structure. */
        kfree(dd->port);

        return rv;
}

/*
 * Called to deinitialize an interface.
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      0
 */
static int mtip_hw_exit(struct driver_data *dd)
{
        /*
         * Send standby immediate (E0h) to the drive so that it
         * saves its state.
         */
        if (atomic_read(&dd->drv_cleanup_done) != true) {

                mtip_standby_immediate(dd->port);

                /* de-initialize the port. */
                mtip_deinit_port(dd->port);

                /* Disable interrupts on the HBA. */
                writel(readl(dd->mmio + HOST_CTL) & ~HOST_IRQ_EN,
                                dd->mmio + HOST_CTL);
        }

        del_timer_sync(&dd->port->cmd_timer);

        /* Release the IRQ. */
        devm_free_irq(&dd->pdev->dev, dd->pdev->irq, dd);

        /* Stop the bottom half tasklet. */
        tasklet_kill(&dd->tasklet);

        /* Free the command/command header memory. */
        dmam_free_coherent(&dd->pdev->dev,
                        HW_PORT_PRIV_DMA_SZ + (ATA_SECT_SIZE * 2),
                        dd->port->command_list,
                        dd->port->command_list_dma);
        /* Free the memory allocated for the for structure. */
        kfree(dd->port);

        return 0;
}

/*
 * Issue a Standby Immediate command to the device.
 *
 * This function is called by the Block Layer just before the
 * system powers off during a shutdown.
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      0
 */
static int mtip_hw_shutdown(struct driver_data *dd)
{
        /*
         * Send standby immediate (E0h) to the drive so that it
         * saves its state.
         */
        mtip_standby_immediate(dd->port);

        return 0;
}

/*
 * Suspend function
 *
 * This function is called by the Block Layer just before the
 * system hibernates.
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      0       Suspend was successful
 *      -EFAULT Suspend was not successful
 */
static int mtip_hw_suspend(struct driver_data *dd)
{
        /*
         * Send standby immediate (E0h) to the drive
         * so that it saves its state.
         */
        if (mtip_standby_immediate(dd->port) != 0) {
                dev_err(&dd->pdev->dev,
                        "Failed standby-immediate command\n");
                return -EFAULT;
        }

        /* Disable interrupts on the HBA.*/
        writel(readl(dd->mmio + HOST_CTL) & ~HOST_IRQ_EN,
                        dd->mmio + HOST_CTL);
        mtip_deinit_port(dd->port);

        return 0;
}

/*
 * Resume function
 *
 * This function is called by the Block Layer as the
 * system resumes.
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      0       Resume was successful
 *      -EFAULT Resume was not successful
 */
static int mtip_hw_resume(struct driver_data *dd)
{
        /* Perform any needed hardware setup steps */
        hba_setup(dd);

        /* Reset the HBA */
        if (mtip_hba_reset(dd) != 0) {
                dev_err(&dd->pdev->dev,
                        "Unable to reset the HBA\n");
                return -EFAULT;
        }

        /*
         * Enable the port, DMA engine, and FIS reception specific
         * h/w in controller.
         */
        mtip_init_port(dd->port);
        mtip_start_port(dd->port);

        /* Enable interrupts on the HBA.*/
        writel(readl(dd->mmio + HOST_CTL) | HOST_IRQ_EN,
                        dd->mmio + HOST_CTL);

        return 0;
}

/*
 * Helper function for reusing disk name
 * upon hot insertion.
 */
static int rssd_disk_name_format(char *prefix,
                                 int index,
                                 char *buf,
                                 int buflen)
{
        const int base = 'z' - 'a' + 1;
        char *begin = buf + strlen(prefix);
        char *end = buf + buflen;
        char *p;
        int unit;

        p = end - 1;
        *p = '\0';
        unit = base;
        do {
                if (p == begin)
                        return -EINVAL;
                *--p = 'a' + (index % unit);
                index = (index / unit) - 1;
        } while (index >= 0);

        memmove(begin, p, end - p);
        memcpy(buf, prefix, strlen(prefix));

        return 0;
}

/*
 * Block layer IOCTL handler.
 *
 * @dev Pointer to the block_device structure.
 * @mode ignored
 * @cmd IOCTL command passed from the user application.
 * @arg Argument passed from the user application.
 *
 * return value
 *      0        IOCTL completed successfully.
 *      -ENOTTY  IOCTL not supported or invalid driver data
 *                 structure pointer.
 */
static int mtip_block_ioctl(struct block_device *dev,
                            fmode_t mode,
                            unsigned cmd,
                            unsigned long arg)
{
        struct driver_data *dd = dev->bd_disk->private_data;

        if (!capable(CAP_SYS_ADMIN))
                return -EACCES;

        if (!dd)
                return -ENOTTY;

        switch (cmd) {
        case BLKFLSBUF:
                return -ENOTTY;
        default:
                return mtip_hw_ioctl(dd, cmd, arg);
        }
}

#ifdef CONFIG_COMPAT
/*
 * Block layer compat IOCTL handler.
 *
 * @dev Pointer to the block_device structure.
 * @mode ignored
 * @cmd IOCTL command passed from the user application.
 * @arg Argument passed from the user application.
 *
 * return value
 *      0        IOCTL completed successfully.
 *      -ENOTTY  IOCTL not supported or invalid driver data
 *                 structure pointer.
 */
static int mtip_block_compat_ioctl(struct block_device *dev,
                            fmode_t mode,
                            unsigned cmd,
                            unsigned long arg)
{
        struct driver_data *dd = dev->bd_disk->private_data;

        if (!capable(CAP_SYS_ADMIN))
                return -EACCES;

        if (!dd)
                return -ENOTTY;

        switch (cmd) {
        case BLKFLSBUF:
                return -ENOTTY;
        case HDIO_DRIVE_TASKFILE: {
                struct mtip_compat_ide_task_request_s __user *compat_req_task;
                ide_task_request_t req_task;
                int compat_tasksize, outtotal, ret;

                compat_tasksize =
                        sizeof(struct mtip_compat_ide_task_request_s);

                compat_req_task =
                        (struct mtip_compat_ide_task_request_s __user *) arg;

                if (copy_from_user(&req_task, (void __user *) arg,
                        compat_tasksize - (2 * sizeof(compat_long_t))))
                        return -EFAULT;

                if (get_user(req_task.out_size, &compat_req_task->out_size))
                        return -EFAULT;

                if (get_user(req_task.in_size, &compat_req_task->in_size))
                        return -EFAULT;

                outtotal = sizeof(struct mtip_compat_ide_task_request_s);

                ret = exec_drive_taskfile(dd, (void __user *) arg,
                                                &req_task, outtotal);

                if (copy_to_user((void __user *) arg, &req_task,
                                compat_tasksize -
                                (2 * sizeof(compat_long_t))))
                        return -EFAULT;

                if (put_user(req_task.out_size, &compat_req_task->out_size))
                        return -EFAULT;

                if (put_user(req_task.in_size, &compat_req_task->in_size))
                        return -EFAULT;

                return ret;
        }
        default:
                return mtip_hw_ioctl(dd, cmd, arg);
        }
}
#endif

/*
 * Obtain the geometry of the device.
 *
 * You may think that this function is obsolete, but some applications,
 * fdisk for example still used CHS values. This function describes the
 * device as having 224 heads and 56 sectors per cylinder. These values are
 * chosen so that each cylinder is aligned on a 4KB boundary. Since a
 * partition is described in terms of a start and end cylinder this means
 * that each partition is also 4KB aligned. Non-aligned partitions adversely
 * affects performance.
 *
 * @dev Pointer to the block_device strucutre.
 * @geo Pointer to a hd_geometry structure.
 *
 * return value
 *      0       Operation completed successfully.
 *      -ENOTTY An error occurred while reading the drive capacity.
 */
static int mtip_block_getgeo(struct block_device *dev,
                                struct hd_geometry *geo)
{
        struct driver_data *dd = dev->bd_disk->private_data;
        sector_t capacity;

        if (!dd)
                return -ENOTTY;

        if (!(mtip_hw_get_capacity(dd, &capacity))) {
                dev_warn(&dd->pdev->dev,
                        "Could not get drive capacity.\n");
                return -ENOTTY;
        }

        geo->heads = 224;
        geo->sectors = 56;
        sector_div(capacity, (geo->heads * geo->sectors));
        geo->cylinders = capacity;
        return 0;
}

/*
 * Block device operation function.
 *
 * This structure contains pointers to the functions required by the block
 * layer.
 */
static const struct block_device_operations mtip_block_ops = {
        .ioctl          = mtip_block_ioctl,
#ifdef CONFIG_COMPAT
        .compat_ioctl   = mtip_block_compat_ioctl,
#endif
        .getgeo         = mtip_block_getgeo,
        .owner          = THIS_MODULE
};

/*
 * Block layer make request function.
 *
 * This function is called by the kernel to process a BIO for
 * the P320 device.
 *
 * @queue Pointer to the request queue. Unused other than to obtain
 *              the driver data structure.
 * @bio   Pointer to the BIO.
 *
 */
static void mtip_make_request(struct request_queue *queue, struct bio *bio)
{
        struct driver_data *dd = queue->queuedata;
        struct scatterlist *sg;
        struct bio_vec *bvec;
        int nents = 0;
        int tag = 0;

        if (unlikely(!bio_has_data(bio))) {
                blk_queue_flush(queue, 0);
                bio_endio(bio, 0);
                return;
        }

        sg = mtip_hw_get_scatterlist(dd, &tag);
        if (likely(sg != NULL)) {
                blk_queue_bounce(queue, &bio);

                if (unlikely((bio)->bi_vcnt > MTIP_MAX_SG)) {
                        dev_warn(&dd->pdev->dev,
                                "Maximum number of SGL entries exceeded");
                        bio_io_error(bio);
                        mtip_hw_release_scatterlist(dd, tag);
                        return;
                }

                /* Create the scatter list for this bio. */
                bio_for_each_segment(bvec, bio, nents) {
                        sg_set_page(&sg[nents],
                                        bvec->bv_page,
                                        bvec->bv_len,
                                        bvec->bv_offset);
                }

                /* Issue the read/write. */
                mtip_hw_submit_io(dd,
                                bio->bi_sector,
                                bio_sectors(bio),
                                nents,
                                tag,
                                bio_endio,
                                bio,
                                bio->bi_rw & REQ_FUA,
                                bio_data_dir(bio));
        } else
                bio_io_error(bio);
}

/*
 * Block layer initialization function.
 *
 * This function is called once by the PCI layer for each P320
 * device that is connected to the system.
 *
 * @dd Pointer to the driver data structure.
 *
 * return value
 *      0 on success else an error code.
 */
static int mtip_block_initialize(struct driver_data *dd)
{
        int rv = 0;
        sector_t capacity;
        unsigned int index = 0;
        struct kobject *kobj;
        unsigned char thd_name[16];

        /* Initialize the protocol layer. */
        rv = mtip_hw_init(dd);
        if (rv < 0) {
                dev_err(&dd->pdev->dev,
                        "Protocol layer initialization failed\n");
                rv = -EINVAL;
                goto protocol_init_error;
        }

        /* Allocate the request queue. */
        dd->queue = blk_alloc_queue(GFP_KERNEL);
        if (dd->queue == NULL) {
                dev_err(&dd->pdev->dev,
                        "Unable to allocate request queue\n");
                rv = -ENOMEM;
                goto block_queue_alloc_init_error;
        }

        /* Attach our request function to the request queue. */
        blk_queue_make_request(dd->queue, mtip_make_request);

        /* Set device limits. */
        set_bit(QUEUE_FLAG_NONROT, &dd->queue->queue_flags);
        blk_queue_max_segments(dd->queue, MTIP_MAX_SG);
        blk_queue_physical_block_size(dd->queue, 4096);
        blk_queue_io_min(dd->queue, 4096);
        blk_queue_flush(dd->queue, 0);

        dd->disk = alloc_disk(MTIP_MAX_MINORS);
        if (dd->disk  == NULL) {
                dev_err(&dd->pdev->dev,
                        "Unable to allocate gendisk structure\n");
                rv = -EINVAL;
                goto alloc_disk_error;
        }

        /* Generate the disk name, implemented same as in sd.c */
        do {
                if (!ida_pre_get(&rssd_index_ida, GFP_KERNEL))
                        goto ida_get_error;

                spin_lock(&rssd_index_lock);
                rv = ida_get_new(&rssd_index_ida, &index);
                spin_unlock(&rssd_index_lock);
        } while (rv == -EAGAIN);

        if (rv)
                goto ida_get_error;

        rv = rssd_disk_name_format("rssd",
                                index,
                                dd->disk->disk_name,
                                DISK_NAME_LEN);
        if (rv)
                goto disk_index_error;

        dd->disk->driverfs_dev  = &dd->pdev->dev;
        dd->disk->major         = dd->major;
        dd->disk->first_minor   = dd->instance * MTIP_MAX_MINORS;
        dd->disk->fops          = &mtip_block_ops;
        dd->disk->queue         = dd->queue;
        dd->disk->private_data  = dd;
        dd->queue->queuedata    = dd;
        dd->index               = index;

        /* Set the capacity of the device in 512 byte sectors. */
        if (!(mtip_hw_get_capacity(dd, &capacity))) {
                dev_warn(&dd->pdev->dev,
                        "Could not read drive capacity\n");
                rv = -EIO;
                goto read_capacity_error;
        }
        set_capacity(dd->disk, capacity);

        /* Enable the block device and add it to /dev */
        add_disk(dd->disk);

        /*
         * Now that the disk is active, initialize any sysfs attributes
         * managed by the protocol layer.
         */
        kobj = kobject_get(&disk_to_dev(dd->disk)->kobj);
        if (kobj) {
                mtip_hw_sysfs_init(dd, kobj);
                kobject_put(kobj);
        }

        sprintf(thd_name, "mtip_svc_thd_%02d", index);

        dd->mtip_svc_handler = kthread_run(mtip_service_thread,
                                                dd, thd_name);

        if (IS_ERR(dd->mtip_svc_handler)) {
                printk(KERN_ERR "mtip32xx: service thread failed to start\n");
                dd->mtip_svc_handler = NULL;
                rv = -EFAULT;
                goto read_capacity_error;
        }

        return rv;

read_capacity_error:
        /*
         * Delete our gendisk structure. This also removes the device
         * from /dev
         */