arch/arm/plat-samsung/pm-check.c

   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
  40 static u32 crc_size;    /* size needed for the crc block */
  41 static u32 *crcs;       /* allocated over suspend/resume */
  42
  43 typedef 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
  50 static 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
  68 static void s3c_pm_run_sysram(run_fn_t fn, u32 *arg)
  69 {
  70         s3c_pm_run_res(&iomem_resource, fn, arg);
  71 }
  72
  73 static 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
  95 void 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
 108 static 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
 132 void 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
 144 static 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  */
 165 static 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 */
 218 void 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  */
 232 void s3c_pm_check_cleanup(void)
 233 {
 234         kfree(crcs);
 235         crcs = NULL;
 236 }
 237