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[~shefty/rdma-dev.git] / drivers / char / ramoops.c
1 /*
2  * RAM Oops/Panic logger
3  *
4  * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * version 2 as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
18  * 02110-1301 USA
19  *
20  */
21
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23
24 #include <linux/kernel.h>
25 #include <linux/err.h>
26 #include <linux/module.h>
27 #include <linux/kmsg_dump.h>
28 #include <linux/time.h>
29 #include <linux/io.h>
30 #include <linux/ioport.h>
31 #include <linux/platform_device.h>
32 #include <linux/slab.h>
33 #include <linux/ramoops.h>
34
35 #define RAMOOPS_KERNMSG_HDR "===="
36 #define MIN_MEM_SIZE 4096UL
37
38 static ulong record_size = MIN_MEM_SIZE;
39 module_param(record_size, ulong, 0400);
40 MODULE_PARM_DESC(record_size,
41                 "size of each dump done on oops/panic");
42
43 static ulong mem_address;
44 module_param(mem_address, ulong, 0400);
45 MODULE_PARM_DESC(mem_address,
46                 "start of reserved RAM used to store oops/panic logs");
47
48 static ulong mem_size;
49 module_param(mem_size, ulong, 0400);
50 MODULE_PARM_DESC(mem_size,
51                 "size of reserved RAM used to store oops/panic logs");
52
53 static int dump_oops = 1;
54 module_param(dump_oops, int, 0600);
55 MODULE_PARM_DESC(dump_oops,
56                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
57
58 static struct ramoops_context {
59         struct kmsg_dumper dump;
60         void *virt_addr;
61         phys_addr_t phys_addr;
62         unsigned long size;
63         unsigned long record_size;
64         int dump_oops;
65         int count;
66         int max_count;
67 } oops_cxt;
68
69 static struct platform_device *dummy;
70 static struct ramoops_platform_data *dummy_data;
71
72 static void ramoops_do_dump(struct kmsg_dumper *dumper,
73                 enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
74                 const char *s2, unsigned long l2)
75 {
76         struct ramoops_context *cxt = container_of(dumper,
77                         struct ramoops_context, dump);
78         unsigned long s1_start, s2_start;
79         unsigned long l1_cpy, l2_cpy;
80         int res, hdr_size;
81         char *buf, *buf_orig;
82         struct timeval timestamp;
83
84         if (reason != KMSG_DUMP_OOPS &&
85             reason != KMSG_DUMP_PANIC &&
86             reason != KMSG_DUMP_KEXEC)
87                 return;
88
89         /* Only dump oopses if dump_oops is set */
90         if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
91                 return;
92
93         buf = cxt->virt_addr + (cxt->count * cxt->record_size);
94         buf_orig = buf;
95
96         memset(buf, '\0', cxt->record_size);
97         res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
98         buf += res;
99         do_gettimeofday(&timestamp);
100         res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
101         buf += res;
102
103         hdr_size = buf - buf_orig;
104         l2_cpy = min(l2, cxt->record_size - hdr_size);
105         l1_cpy = min(l1, cxt->record_size - hdr_size - l2_cpy);
106
107         s2_start = l2 - l2_cpy;
108         s1_start = l1 - l1_cpy;
109
110         memcpy(buf, s1 + s1_start, l1_cpy);
111         memcpy(buf + l1_cpy, s2 + s2_start, l2_cpy);
112
113         cxt->count = (cxt->count + 1) % cxt->max_count;
114 }
115
116 static int __init ramoops_probe(struct platform_device *pdev)
117 {
118         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
119         struct ramoops_context *cxt = &oops_cxt;
120         int err = -EINVAL;
121
122         if (!pdata->mem_size || !pdata->record_size) {
123                 pr_err("The memory size and the record size must be "
124                         "non-zero\n");
125                 goto fail3;
126         }
127
128         rounddown_pow_of_two(pdata->mem_size);
129         rounddown_pow_of_two(pdata->record_size);
130
131         /* Check for the minimum memory size */
132         if (pdata->mem_size < MIN_MEM_SIZE &&
133                         pdata->record_size < MIN_MEM_SIZE) {
134                 pr_err("memory size too small, minium is %lu\n", MIN_MEM_SIZE);
135                 goto fail3;
136         }
137
138         if (pdata->mem_size < pdata->record_size) {
139                 pr_err("The memory size must be larger than the "
140                         "records size\n");
141                 goto fail3;
142         }
143
144         cxt->max_count = pdata->mem_size / pdata->record_size;
145         cxt->count = 0;
146         cxt->size = pdata->mem_size;
147         cxt->phys_addr = pdata->mem_address;
148         cxt->record_size = pdata->record_size;
149         cxt->dump_oops = pdata->dump_oops;
150
151         if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
152                 pr_err("request mem region failed\n");
153                 err = -EINVAL;
154                 goto fail3;
155         }
156
157         cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
158         if (!cxt->virt_addr) {
159                 pr_err("ioremap failed\n");
160                 goto fail2;
161         }
162
163         cxt->dump.dump = ramoops_do_dump;
164         err = kmsg_dump_register(&cxt->dump);
165         if (err) {
166                 pr_err("registering kmsg dumper failed\n");
167                 goto fail1;
168         }
169
170         return 0;
171
172 fail1:
173         iounmap(cxt->virt_addr);
174 fail2:
175         release_mem_region(cxt->phys_addr, cxt->size);
176 fail3:
177         return err;
178 }
179
180 static int __exit ramoops_remove(struct platform_device *pdev)
181 {
182         struct ramoops_context *cxt = &oops_cxt;
183
184         if (kmsg_dump_unregister(&cxt->dump) < 0)
185                 pr_warn("could not unregister kmsg_dumper\n");
186
187         iounmap(cxt->virt_addr);
188         release_mem_region(cxt->phys_addr, cxt->size);
189         return 0;
190 }
191
192 static struct platform_driver ramoops_driver = {
193         .remove         = __exit_p(ramoops_remove),
194         .driver         = {
195                 .name   = "ramoops",
196                 .owner  = THIS_MODULE,
197         },
198 };
199
200 static int __init ramoops_init(void)
201 {
202         int ret;
203         ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
204         if (ret == -ENODEV) {
205                 /*
206                  * If we didn't find a platform device, we use module parameters
207                  * building platform data on the fly.
208                  */
209                 pr_info("platform device not found, using module parameters\n");
210                 dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
211                                      GFP_KERNEL);
212                 if (!dummy_data)
213                         return -ENOMEM;
214                 dummy_data->mem_size = mem_size;
215                 dummy_data->mem_address = mem_address;
216                 dummy_data->record_size = record_size;
217                 dummy_data->dump_oops = dump_oops;
218                 dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
219                         NULL, 0, dummy_data,
220                         sizeof(struct ramoops_platform_data));
221
222                 if (IS_ERR(dummy))
223                         ret = PTR_ERR(dummy);
224                 else
225                         ret = 0;
226         }
227
228         return ret;
229 }
230
231 static void __exit ramoops_exit(void)
232 {
233         platform_driver_unregister(&ramoops_driver);
234         kfree(dummy_data);
235 }
236
237 module_init(ramoops_init);
238 module_exit(ramoops_exit);
239
240 MODULE_LICENSE("GPL");
241 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
242 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");