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1/* linux/arch/arm/plat-s3c/pm-check.c
2 * originally in linux/arch/arm/plat-s3c24xx/pm.c
3 *
4 * Copyright (c) 2004-2008 Simtec Electronics
5 * http://armlinux.simtec.co.uk
6 * Ben Dooks <ben@simtec.co.uk>
7 *
8 * S3C Power Mangament - suspend/resume memory corruptiuon check.
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13*/
14
15#include <linux/kernel.h>
16#include <linux/suspend.h>
17#include <linux/init.h>
18#include <linux/crc32.h>
19#include <linux/ioport.h>
20#include <linux/slab.h>
21
22#include <plat/pm.h>
23
24#if CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE < 1
25#error CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE must be a positive non-zero value
26#endif
27
28/* suspend checking code...
29 *
30 * this next area does a set of crc checks over all the installed
31 * memory, so the system can verify if the resume was ok.
32 *
33 * CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE defines the block-size for the CRC,
34 * increasing it will mean that the area corrupted will be less easy to spot,
35 * and reducing the size will cause the CRC save area to grow
36*/
37
38#define CHECK_CHUNKSIZE (CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE * 1024)
39
40static u32 crc_size; /* size needed for the crc block */
41static u32 *crcs; /* allocated over suspend/resume */
42
43typedef u32 *(run_fn_t)(struct resource *ptr, u32 *arg);
44
45/* s3c_pm_run_res
46 *
47 * go through the given resource list, and look for system ram
48*/
49
50static void s3c_pm_run_res(struct resource *ptr, run_fn_t fn, u32 *arg)
51{
52 while (ptr != NULL) {
53 if (ptr->child != NULL)
54 s3c_pm_run_res(ptr->child, fn, arg);
55
56 if ((ptr->flags & IORESOURCE_MEM) &&
57 strcmp(ptr->name, "System RAM") == 0) {
58 S3C_PMDBG("Found system RAM at %08lx..%08lx\n",
59 (unsigned long)ptr->start,
60 (unsigned long)ptr->end);
61 arg = (fn)(ptr, arg);
62 }
63
64 ptr = ptr->sibling;
65 }
66}
67
68static void s3c_pm_run_sysram(run_fn_t fn, u32 *arg)
69{
70 s3c_pm_run_res(&iomem_resource, fn, arg);
71}
72
73static u32 *s3c_pm_countram(struct resource *res, u32 *val)
74{
75 u32 size = (u32)resource_size(res);
76
77 size += CHECK_CHUNKSIZE-1;
78 size /= CHECK_CHUNKSIZE;
79
80 S3C_PMDBG("Area %08lx..%08lx, %d blocks\n",
81 (unsigned long)res->start, (unsigned long)res->end, size);
82
83 *val += size * sizeof(u32);
84 return val;
85}
86
87/* s3c_pm_prepare_check
88 *
89 * prepare the necessary information for creating the CRCs. This
90 * must be done before the final save, as it will require memory
91 * allocating, and thus touching bits of the kernel we do not
92 * know about.
93*/
94
95void s3c_pm_check_prepare(void)
96{
97 crc_size = 0;
98
99 s3c_pm_run_sysram(s3c_pm_countram, &crc_size);
100
101 S3C_PMDBG("s3c_pm_prepare_check: %u checks needed\n", crc_size);
102
103 crcs = kmalloc(crc_size+4, GFP_KERNEL);
104 if (crcs == NULL)
105 printk(KERN_ERR "Cannot allocated CRC save area\n");
106}
107
108static u32 *s3c_pm_makecheck(struct resource *res, u32 *val)
109{
110 unsigned long addr, left;
111
112 for (addr = res->start; addr < res->end;
113 addr += CHECK_CHUNKSIZE) {
114 left = res->end - addr;
115
116 if (left > CHECK_CHUNKSIZE)
117 left = CHECK_CHUNKSIZE;
118
119 *val = crc32_le(~0, phys_to_virt(addr), left);
120 val++;
121 }
122
123 return val;
124}
125
126/* s3c_pm_check_store
127 *
128 * compute the CRC values for the memory blocks before the final
129 * sleep.
130*/
131
132void s3c_pm_check_store(void)
133{
134 if (crcs != NULL)
135 s3c_pm_run_sysram(s3c_pm_makecheck, crcs);
136}
137
138/* in_region
139 *
140 * return TRUE if the area defined by ptr..ptr+size contains the
141 * what..what+whatsz
142*/
143
144static inline int in_region(void *ptr, int size, void *what, size_t whatsz)
145{
146 if ((what+whatsz) < ptr)
147 return 0;
148
149 if (what > (ptr+size))
150 return 0;
151
152 return 1;
153}
154
155/**
156 * s3c_pm_runcheck() - helper to check a resource on restore.
157 * @res: The resource to check
158 * @vak: Pointer to list of CRC32 values to check.
159 *
160 * Called from the s3c_pm_check_restore() via s3c_pm_run_sysram(), this
161 * function runs the given memory resource checking it against the stored
162 * CRC to ensure that memory is restored. The function tries to skip as
163 * many of the areas used during the suspend process.
164 */
165static u32 *s3c_pm_runcheck(struct resource *res, u32 *val)
166{
167 unsigned long addr;
168 unsigned long left;
169 void *stkpage;
170 void *ptr;
171 u32 calc;
172
173 stkpage = (void *)((u32)&calc & ~PAGE_MASK);
174
175 for (addr = res->start; addr < res->end;
176 addr += CHECK_CHUNKSIZE) {
177 left = res->end - addr;
178
179 if (left > CHECK_CHUNKSIZE)
180 left = CHECK_CHUNKSIZE;
181
182 ptr = phys_to_virt(addr);
183
184 if (in_region(ptr, left, stkpage, 4096)) {
185 S3C_PMDBG("skipping %08lx, has stack in\n", addr);
186 goto skip_check;
187 }
188
189 if (in_region(ptr, left, crcs, crc_size)) {
190 S3C_PMDBG("skipping %08lx, has crc block in\n", addr);
191 goto skip_check;
192 }
193
194 /* calculate and check the checksum */
195
196 calc = crc32_le(~0, ptr, left);
197 if (calc != *val) {
198 printk(KERN_ERR "Restore CRC error at "
199 "%08lx (%08x vs %08x)\n", addr, calc, *val);
200
201 S3C_PMDBG("Restore CRC error at %08lx (%08x vs %08x)\n",
202 addr, calc, *val);
203 }
204
205 skip_check:
206 val++;
207 }
208
209 return val;
210}
211
212/**
213 * s3c_pm_check_restore() - memory check called on resume
214 *
215 * check the CRCs after the restore event and free the memory used
216 * to hold them
217*/
218void s3c_pm_check_restore(void)
219{
220 if (crcs != NULL)
221 s3c_pm_run_sysram(s3c_pm_runcheck, crcs);
222}
223
224/**
225 * s3c_pm_check_cleanup() - free memory resources
226 *
227 * Free the resources that where allocated by the suspend
228 * memory check code. We do this separately from the
229 * s3c_pm_check_restore() function as we cannot call any
230 * functions that might sleep during that resume.
231 */
232void s3c_pm_check_cleanup(void)
233{
234 kfree(crcs);
235 crcs = NULL;
236}
237