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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 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/kmsg_dump.h>
25 #include <linux/time.h>
26 #include <linux/io.h>
27 #include <linux/ioport.h>
28 #include <linux/platform_device.h>
29 #include <linux/ramoops.h>
30
31 #define RAMOOPS_KERNMSG_HDR "===="
32 #define RAMOOPS_HEADER_SIZE   (5 + sizeof(struct timeval))
33
34 #define RECORD_SIZE 4096
35
36 static ulong mem_address;
37 module_param(mem_address, ulong, 0400);
38 MODULE_PARM_DESC(mem_address,
39                 "start of reserved RAM used to store oops/panic logs");
40
41 static ulong mem_size;
42 module_param(mem_size, ulong, 0400);
43 MODULE_PARM_DESC(mem_size,
44                 "size of reserved RAM used to store oops/panic logs");
45
46 static int dump_oops = 1;
47 module_param(dump_oops, int, 0600);
48 MODULE_PARM_DESC(dump_oops,
49                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
50
51 static struct ramoops_context {
52         struct kmsg_dumper dump;
53         void *virt_addr;
54         phys_addr_t phys_addr;
55         unsigned long size;
56         int count;
57         int max_count;
58 } oops_cxt;
59
60 static void ramoops_do_dump(struct kmsg_dumper *dumper,
61                 enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
62                 const char *s2, unsigned long l2)
63 {
64         struct ramoops_context *cxt = container_of(dumper,
65                         struct ramoops_context, dump);
66         unsigned long s1_start, s2_start;
67         unsigned long l1_cpy, l2_cpy;
68         int res;
69         char *buf;
70         struct timeval timestamp;
71
72         /* Only dump oopses if dump_oops is set */
73         if (reason == KMSG_DUMP_OOPS && !dump_oops)
74                 return;
75
76         buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE));
77         memset(buf, '\0', RECORD_SIZE);
78         res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
79         buf += res;
80         do_gettimeofday(&timestamp);
81         res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
82         buf += res;
83
84         l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE));
85         l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE) - l2_cpy);
86
87         s2_start = l2 - l2_cpy;
88         s1_start = l1 - l1_cpy;
89
90         memcpy(buf, s1 + s1_start, l1_cpy);
91         memcpy(buf + l1_cpy, s2 + s2_start, l2_cpy);
92
93         cxt->count = (cxt->count + 1) % cxt->max_count;
94 }
95
96 static int __init ramoops_probe(struct platform_device *pdev)
97 {
98         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
99         struct ramoops_context *cxt = &oops_cxt;
100         int err = -EINVAL;
101
102         if (pdata) {
103                 mem_size = pdata->mem_size;
104                 mem_address = pdata->mem_address;
105         }
106
107         if (!mem_size) {
108                 printk(KERN_ERR "ramoops: invalid size specification");
109                 goto fail3;
110         }
111
112         rounddown_pow_of_two(mem_size);
113
114         if (mem_size < RECORD_SIZE) {
115                 printk(KERN_ERR "ramoops: size too small");
116                 goto fail3;
117         }
118
119         cxt->max_count = mem_size / RECORD_SIZE;
120         cxt->count = 0;
121         cxt->size = mem_size;
122         cxt->phys_addr = mem_address;
123
124         if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
125                 printk(KERN_ERR "ramoops: request mem region failed");
126                 err = -EINVAL;
127                 goto fail3;
128         }
129
130         cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
131         if (!cxt->virt_addr) {
132                 printk(KERN_ERR "ramoops: ioremap failed");
133                 goto fail2;
134         }
135
136         cxt->dump.dump = ramoops_do_dump;
137         err = kmsg_dump_register(&cxt->dump);
138         if (err) {
139                 printk(KERN_ERR "ramoops: registering kmsg dumper failed");
140                 goto fail1;
141         }
142
143         return 0;
144
145 fail1:
146         iounmap(cxt->virt_addr);
147 fail2:
148         release_mem_region(cxt->phys_addr, cxt->size);
149 fail3:
150         return err;
151 }
152
153 static int __exit ramoops_remove(struct platform_device *pdev)
154 {
155         struct ramoops_context *cxt = &oops_cxt;
156
157         if (kmsg_dump_unregister(&cxt->dump) < 0)
158                 printk(KERN_WARNING "ramoops: could not unregister kmsg_dumper");
159
160         iounmap(cxt->virt_addr);
161         release_mem_region(cxt->phys_addr, cxt->size);
162         return 0;
163 }
164
165 static struct platform_driver ramoops_driver = {
166         .remove         = __exit_p(ramoops_remove),
167         .driver         = {
168                 .name   = "ramoops",
169                 .owner  = THIS_MODULE,
170         },
171 };
172
173 static int __init ramoops_init(void)
174 {
175         return platform_driver_probe(&ramoops_driver, ramoops_probe);
176 }
177
178 static void __exit ramoops_exit(void)
179 {
180         platform_driver_unregister(&ramoops_driver);
181 }
182
183 module_init(ramoops_init);
184 module_exit(ramoops_exit);
185
186 MODULE_LICENSE("GPL");
187 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
188 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");