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                             ptr->start, ptr->end);
  59                         arg = (fn)(ptr, arg);
  60                 }
  61
  62                 ptr = ptr->sibling;
  63         }
  64 }
  65
  66 static void s3c_pm_run_sysram(run_fn_t fn, u32 *arg)
  67 {
  68         s3c_pm_run_res(&iomem_resource, fn, arg);
  69 }
  70
  71 static 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
  92 void 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
 105 static 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
 129 void 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
 141 static 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  */
 162 static 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 */
 213 void 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 }