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)(res->end - res->start)+1; 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 void *save_at = phys_to_virt(s3c_sleep_save_phys); 168 unsigned long addr; 169 unsigned long left; 170 void *stkpage; 171 void *ptr; 172 u32 calc; 173 174 stkpage = (void *)((u32)&calc & ~PAGE_MASK); 175 176 for (addr = res->start; addr < res->end; 177 addr += CHECK_CHUNKSIZE) { 178 left = res->end - addr; 179 180 if (left > CHECK_CHUNKSIZE) 181 left = CHECK_CHUNKSIZE; 182 183 ptr = phys_to_virt(addr); 184 185 if (in_region(ptr, left, stkpage, 4096)) { 186 S3C_PMDBG("skipping %08lx, has stack in\n", addr); 187 goto skip_check; 188 } 189 190 if (in_region(ptr, left, crcs, crc_size)) { 191 S3C_PMDBG("skipping %08lx, has crc block in\n", addr); 192 goto skip_check; 193 } 194 195 if (in_region(ptr, left, save_at, 32*4 )) { 196 S3C_PMDBG("skipping %08lx, has save block in\n", addr); 197 goto skip_check; 198 } 199 200 /* calculate and check the checksum */ 201 202 calc = crc32_le(~0, ptr, left); 203 if (calc != *val) { 204 printk(KERN_ERR "Restore CRC error at " 205 "%08lx (%08x vs %08x)\n", addr, calc, *val); 206 207 S3C_PMDBG("Restore CRC error at %08lx (%08x vs %08x)\n", 208 addr, calc, *val); 209 } 210 211 skip_check: 212 val++; 213 } 214 215 return val; 216} 217 218/** 219 * s3c_pm_check_restore() - memory check called on resume 220 * 221 * check the CRCs after the restore event and free the memory used 222 * to hold them 223*/ 224void s3c_pm_check_restore(void) 225{ 226 if (crcs != NULL) 227 s3c_pm_run_sysram(s3c_pm_runcheck, crcs); 228} 229 230/** 231 * s3c_pm_check_cleanup() - free memory resources 232 * 233 * Free the resources that where allocated by the suspend 234 * memory check code. We do this separately from the 235 * s3c_pm_check_restore() function as we cannot call any 236 * functions that might sleep during that resume. 237 */ 238void s3c_pm_check_cleanup(void) 239{ 240 kfree(crcs); 241 crcs = NULL; 242} 243