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Ben Dooks549c7e32008-12-12 00:24:07 +00001/* linux/arch/arm/plat-s3c/pm-check.c
2 * originally in linux/arch/arm/plat-s3c24xx/pm.c
3 *
4 * Copyright (c) 2004,2006,2008 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
21#include <plat/pm.h>
22
23#if CONFIG_S3C2410_PM_CHECK_CHUNKSIZE < 1
24#error CONFIG_S3C2410_PM_CHECK_CHUNKSIZE must be a positive non-zero value
25#endif
26
27/* suspend checking code...
28 *
29 * this next area does a set of crc checks over all the installed
30 * memory, so the system can verify if the resume was ok.
31 *
32 * CONFIG_S3C2410_PM_CHECK_CHUNKSIZE defines the block-size for the CRC,
33 * increasing it will mean that the area corrupted will be less easy to spot,
34 * and reducing the size will cause the CRC save area to grow
35*/
36
37#define CHECK_CHUNKSIZE (CONFIG_S3C2410_PM_CHECK_CHUNKSIZE * 1024)
38
39static u32 crc_size; /* size needed for the crc block */
40static u32 *crcs; /* allocated over suspend/resume */
41
42typedef u32 *(run_fn_t)(struct resource *ptr, u32 *arg);
43
44/* s3c_pm_run_res
45 *
46 * go through the given resource list, and look for system ram
47*/
48
49static void s3c_pm_run_res(struct resource *ptr, run_fn_t fn, u32 *arg)
50{
51 while (ptr != NULL) {
52 if (ptr->child != NULL)
53 s3c_pm_run_res(ptr->child, fn, arg);
54
55 if ((ptr->flags & IORESOURCE_MEM) &&
56 strcmp(ptr->name, "System RAM") == 0) {
57 S3C_PMDBG("Found system RAM at %08lx..%08lx\n",
58 ptr->start, ptr->end);
59 arg = (fn)(ptr, arg);
60 }
61
62 ptr = ptr->sibling;
63 }
64}
65
66static void s3c_pm_run_sysram(run_fn_t fn, u32 *arg)
67{
68 s3c_pm_run_res(&iomem_resource, fn, arg);
69}
70
71static u32 *s3c_pm_countram(struct resource *res, u32 *val)
72{
73 u32 size = (u32)(res->end - res->start)+1;
74
75 size += CHECK_CHUNKSIZE-1;
76 size /= CHECK_CHUNKSIZE;
77
78 S3C_PMDBG("Area %08lx..%08lx, %d blocks\n", res->start, res->end, size);
79
80 *val += size * sizeof(u32);
81 return val;
82}
83
84/* s3c_pm_prepare_check
85 *
86 * prepare the necessary information for creating the CRCs. This
87 * must be done before the final save, as it will require memory
88 * allocating, and thus touching bits of the kernel we do not
89 * know about.
90*/
91
92void s3c_pm_check_prepare(void)
93{
94 crc_size = 0;
95
96 s3c_pm_run_sysram(s3c_pm_countram, &crc_size);
97
98 S3C_PMDBG("s3c_pm_prepare_check: %u checks needed\n", crc_size);
99
100 crcs = kmalloc(crc_size+4, GFP_KERNEL);
101 if (crcs == NULL)
102 printk(KERN_ERR "Cannot allocated CRC save area\n");
103}
104
105static u32 *s3c_pm_makecheck(struct resource *res, u32 *val)
106{
107 unsigned long addr, left;
108
109 for (addr = res->start; addr < res->end;
110 addr += CHECK_CHUNKSIZE) {
111 left = res->end - addr;
112
113 if (left > CHECK_CHUNKSIZE)
114 left = CHECK_CHUNKSIZE;
115
116 *val = crc32_le(~0, phys_to_virt(addr), left);
117 val++;
118 }
119
120 return val;
121}
122
123/* s3c_pm_check_store
124 *
125 * compute the CRC values for the memory blocks before the final
126 * sleep.
127*/
128
129void s3c_pm_check_store(void)
130{
131 if (crcs != NULL)
132 s3c_pm_run_sysram(s3c_pm_makecheck, crcs);
133}
134
135/* in_region
136 *
137 * return TRUE if the area defined by ptr..ptr+size contains the
138 * what..what+whatsz
139*/
140
141static inline int in_region(void *ptr, int size, void *what, size_t whatsz)
142{
143 if ((what+whatsz) < ptr)
144 return 0;
145
146 if (what > (ptr+size))
147 return 0;
148
149 return 1;
150}
151
152/**
153 * s3c_pm_runcheck*() - helper to check a resource on restore.
154 * @res: The resource to check
155 * @vak: Pointer to list of CRC32 values to check.
156 *
157 * Called from the s3c_pm_check_restore() via s3c_pm_run_sysram(), this
158 * function runs the given memory resource checking it against the stored
159 * CRC to ensure that memory is restored. The function tries to skip as
160 * many of the areas used during the suspend process.
161 */
162static u32 *s3c_pm_runcheck(struct resource *res, u32 *val)
163{
164 void *save_at = phys_to_virt(s3c_sleep_save_phys);
165 unsigned long addr;
166 unsigned long left;
167 void *ptr;
168 u32 calc;
169
170 for (addr = res->start; addr < res->end;
171 addr += CHECK_CHUNKSIZE) {
172 left = res->end - addr;
173
174 if (left > CHECK_CHUNKSIZE)
175 left = CHECK_CHUNKSIZE;
176
177 ptr = phys_to_virt(addr);
178
179 if (in_region(ptr, left, crcs, crc_size)) {
180 S3C_PMDBG("skipping %08lx, has crc block in\n", addr);
181 goto skip_check;
182 }
183
184 if (in_region(ptr, left, save_at, 32*4 )) {
185 S3C_PMDBG("skipping %08lx, has save block in\n", addr);
186 goto skip_check;
187 }
188
189 /* calculate and check the checksum */
190
191 calc = crc32_le(~0, ptr, left);
192 if (calc != *val) {
193 printk(KERN_ERR "Restore CRC error at "
194 "%08lx (%08x vs %08x)\n", addr, calc, *val);
195
196 S3C_PMDBG("Restore CRC error at %08lx (%08x vs %08x)\n",
197 addr, calc, *val);
198 }
199
200 skip_check:
201 val++;
202 }
203
204 return val;
205}
206
207/**
208 * s3c_pm_check_restore() - memory check called on resume
209 *
210 * check the CRCs after the restore event and free the memory used
211 * to hold them
212*/
213void s3c_pm_check_restore(void)
214{
215 if (crcs != NULL) {
216 s3c_pm_run_sysram(s3c_pm_runcheck, crcs);
217 kfree(crcs);
218 crcs = NULL;
219 }
220}