arch/arm/plat-s3c/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) 2004,2006,2008 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
  39 static u32 crc_size;    /* size needed for the crc block */
  40 static u32 *crcs;       /* allocated over suspend/resume */
  41
  42 typedef 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
  49 static 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                                   (unsigned long)ptr->start,
  59                                   (unsigned long)ptr->end);
  60                         arg = (fn)(ptr, arg);
  61                 }
  62
  63                 ptr = ptr->sibling;
  64         }
  65 }
  66
  67 static void s3c_pm_run_sysram(run_fn_t fn, u32 *arg)
  68 {
  69         s3c_pm_run_res(&iomem_resource, fn, arg);
  70 }
  71
  72 static u32 *s3c_pm_countram(struct resource *res, u32 *val)
  73 {
  74         u32 size = (u32)(res->end - res->start)+1;
  75
  76         size += CHECK_CHUNKSIZE-1;
  77         size /= CHECK_CHUNKSIZE;
  78
  79         S3C_PMDBG("Area %08lx..%08lx, %d blocks\n",
  80                   (unsigned long)res->start, (unsigned long)res->end, size);
  81
  82         *val += size * sizeof(u32);
  83         return val;
  84 }
  85
  86 /* s3c_pm_prepare_check
  87  *
  88  * prepare the necessary information for creating the CRCs. This
  89  * must be done before the final save, as it will require memory
  90  * allocating, and thus touching bits of the kernel we do not
  91  * know about.
  92 */
  93
  94 void s3c_pm_check_prepare(void)
  95 {
  96         crc_size = 0;
  97
  98         s3c_pm_run_sysram(s3c_pm_countram, &crc_size);
  99
 100         S3C_PMDBG("s3c_pm_prepare_check: %u checks needed\n", crc_size);
 101
 102         crcs = kmalloc(crc_size+4, GFP_KERNEL);
 103         if (crcs == NULL)
 104                 printk(KERN_ERR "Cannot allocated CRC save area\n");
 105 }
 106
 107 static u32 *s3c_pm_makecheck(struct resource *res, u32 *val)
 108 {
 109         unsigned long addr, left;
 110
 111         for (addr = res->start; addr < res->end;
 112              addr += CHECK_CHUNKSIZE) {
 113                 left = res->end - addr;
 114
 115                 if (left > CHECK_CHUNKSIZE)
 116                         left = CHECK_CHUNKSIZE;
 117
 118                 *val = crc32_le(~0, phys_to_virt(addr), left);
 119                 val++;
 120         }
 121
 122         return val;
 123 }
 124
 125 /* s3c_pm_check_store
 126  *
 127  * compute the CRC values for the memory blocks before the final
 128  * sleep.
 129 */
 130
 131 void s3c_pm_check_store(void)
 132 {
 133         if (crcs != NULL)
 134                 s3c_pm_run_sysram(s3c_pm_makecheck, crcs);
 135 }
 136
 137 /* in_region
 138  *
 139  * return TRUE if the area defined by ptr..ptr+size contains the
 140  * what..what+whatsz
 141 */
 142
 143 static inline int in_region(void *ptr, int size, void *what, size_t whatsz)
 144 {
 145         if ((what+whatsz) < ptr)
 146                 return 0;
 147
 148         if (what > (ptr+size))
 149                 return 0;
 150
 151         return 1;
 152 }
 153
 154 /**
 155  * s3c_pm_runcheck() - helper to check a resource on restore.
 156  * @res: The resource to check
 157  * @vak: Pointer to list of CRC32 values to check.
 158  *
 159  * Called from the s3c_pm_check_restore() via s3c_pm_run_sysram(), this
 160  * function runs the given memory resource checking it against the stored
 161  * CRC to ensure that memory is restored. The function tries to skip as
 162  * many of the areas used during the suspend process.
 163  */
 164 static u32 *s3c_pm_runcheck(struct resource *res, u32 *val)
 165 {
 166         void *save_at = phys_to_virt(s3c_sleep_save_phys);
 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                 if (in_region(ptr, left, save_at, 32*4 )) {
 195                         S3C_PMDBG("skipping %08lx, has save block in\n", addr);
 196                         goto skip_check;
 197                 }
 198
 199                 /* calculate and check the checksum */
 200
 201                 calc = crc32_le(~0, ptr, left);
 202                 if (calc != *val) {
 203                         printk(KERN_ERR "Restore CRC error at "
 204                                "%08lx (%08x vs %08x)\n", addr, calc, *val);
 205
 206                         S3C_PMDBG("Restore CRC error at %08lx (%08x vs %08x)\n",
 207                             addr, calc, *val);
 208                 }
 209
 210         skip_check:
 211                 val++;
 212         }
 213
 214         return val;
 215 }
 216
 217 /**
 218  * s3c_pm_check_restore() - memory check called on resume
 219  *
 220  * check the CRCs after the restore event and free the memory used
 221  * to hold them
 222 */
 223 void s3c_pm_check_restore(void)
 224 {
 225         if (crcs != NULL)
 226                 s3c_pm_run_sysram(s3c_pm_runcheck, crcs);
 227 }
 228
 229 /**
 230  * s3c_pm_check_cleanup() - free memory resources
 231  *
 232  * Free the resources that where allocated by the suspend
 233  * memory check code. We do this separately from the
 234  * s3c_pm_check_restore() function as we cannot call any
 235  * functions that might sleep during that resume.
 236  */
 237 void s3c_pm_check_cleanup(void)
 238 {
 239         kfree(crcs);
 240         crcs = NULL;
 241 }
 242