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/err.h>
30#include <linux/io.h>
31#include <linux/ioport.h>
32#include <linux/platform_device.h>
33#include <linux/slab.h>
34#include <linux/ramoops.h>
35
36#define RAMOOPS_KERNMSG_HDR "===="
37#define MIN_MEM_SIZE 4096UL
38
39static ulong record_size = MIN_MEM_SIZE;
40module_param(record_size, ulong, 0400);
41MODULE_PARM_DESC(record_size,
42		"size of each dump done on oops/panic");
43
44static ulong mem_address;
45module_param(mem_address, ulong, 0400);
46MODULE_PARM_DESC(mem_address,
47		"start of reserved RAM used to store oops/panic logs");
48
49static ulong mem_size;
50module_param(mem_size, ulong, 0400);
51MODULE_PARM_DESC(mem_size,
52		"size of reserved RAM used to store oops/panic logs");
53
54static int dump_oops = 1;
55module_param(dump_oops, int, 0600);
56MODULE_PARM_DESC(dump_oops,
57		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
58
59static struct ramoops_context {
60	struct kmsg_dumper dump;
61	void *virt_addr;
62	phys_addr_t phys_addr;
63	unsigned long size;
64	unsigned long record_size;
65	int dump_oops;
66	int count;
67	int max_count;
68} oops_cxt;
69
70static struct platform_device *dummy;
71static struct ramoops_platform_data *dummy_data;
72
73static void ramoops_do_dump(struct kmsg_dumper *dumper,
74		enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
75		const char *s2, unsigned long l2)
76{
77	struct ramoops_context *cxt = container_of(dumper,
78			struct ramoops_context, dump);
79	unsigned long s1_start, s2_start;
80	unsigned long l1_cpy, l2_cpy;
81	int res, hdr_size;
82	char *buf, *buf_orig;
83	struct timeval timestamp;
84
85	if (reason != KMSG_DUMP_OOPS &&
86	    reason != KMSG_DUMP_PANIC)
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
116static 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	pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
129	pdata->record_size = 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	/*
171	 * Update the module parameter variables as well so they are visible
172	 * through /sys/module/ramoops/parameters/
173	 */
174	mem_size = pdata->mem_size;
175	mem_address = pdata->mem_address;
176	record_size = pdata->record_size;
177	dump_oops = pdata->dump_oops;
178
179	return 0;
180
181fail1:
182	iounmap(cxt->virt_addr);
183fail2:
184	release_mem_region(cxt->phys_addr, cxt->size);
185fail3:
186	return err;
187}
188
189static int __exit ramoops_remove(struct platform_device *pdev)
190{
191	struct ramoops_context *cxt = &oops_cxt;
192
193	if (kmsg_dump_unregister(&cxt->dump) < 0)
194		pr_warn("could not unregister kmsg_dumper\n");
195
196	iounmap(cxt->virt_addr);
197	release_mem_region(cxt->phys_addr, cxt->size);
198	return 0;
199}
200
201static struct platform_driver ramoops_driver = {
202	.remove		= __exit_p(ramoops_remove),
203	.driver		= {
204		.name	= "ramoops",
205		.owner	= THIS_MODULE,
206	},
207};
208
209static int __init ramoops_init(void)
210{
211	int ret;
212	ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
213	if (ret == -ENODEV) {
214		/*
215		 * If we didn't find a platform device, we use module parameters
216		 * building platform data on the fly.
217		 */
218		pr_info("platform device not found, using module parameters\n");
219		dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
220				     GFP_KERNEL);
221		if (!dummy_data)
222			return -ENOMEM;
223		dummy_data->mem_size = mem_size;
224		dummy_data->mem_address = mem_address;
225		dummy_data->record_size = record_size;
226		dummy_data->dump_oops = dump_oops;
227		dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
228			NULL, 0, dummy_data,
229			sizeof(struct ramoops_platform_data));
230
231		if (IS_ERR(dummy))
232			ret = PTR_ERR(dummy);
233		else
234			ret = 0;
235	}
236
237	return ret;
238}
239
240static void __exit ramoops_exit(void)
241{
242	platform_driver_unregister(&ramoops_driver);
243	kfree(dummy_data);
244}
245
246module_init(ramoops_init);
247module_exit(ramoops_exit);
248
249MODULE_LICENSE("GPL");
250MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
251MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
252