1 // SPDX-License-Identifier: GPL-2.0 2 // 3 // originally in linux/arch/arm/plat-s3c24xx/pm.c 4 // 5 // Copyright (c) 2004-2008 Simtec Electronics 6 // http://armlinux.simtec.co.uk 7 // Ben Dooks <ben@simtec.co.uk> 8 // 9 // S3C Power Mangament - suspend/resume memory corruption check. 10 11 #include <linux/kernel.h> 12 #include <linux/suspend.h> 13 #include <linux/init.h> 14 #include <linux/crc32.h> 15 #include <linux/ioport.h> 16 #include <linux/slab.h> 17 18 #include <linux/soc/samsung/s3c-pm.h> 19 20 #if CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE < 1 21 #error CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE must be a positive non-zero value 22 #endif 23 24 /* suspend checking code... 25 * 26 * this next area does a set of crc checks over all the installed 27 * memory, so the system can verify if the resume was ok. 28 * 29 * CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE defines the block-size for the CRC, 30 * increasing it will mean that the area corrupted will be less easy to spot, 31 * and reducing the size will cause the CRC save area to grow 32 */ 33 34 #define CHECK_CHUNKSIZE (CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE * 1024) 35 36 static u32 crc_size; /* size needed for the crc block */ 37 static u32 *crcs; /* allocated over suspend/resume */ 38 39 typedef u32 *(run_fn_t)(struct resource *ptr, u32 *arg); 40 41 /* s3c_pm_run_res 42 * 43 * go through the given resource list, and look for system ram 44 */ 45 46 static void s3c_pm_run_res(struct resource *ptr, run_fn_t fn, u32 *arg) 47 { 48 while (ptr != NULL) { 49 if (ptr->child != NULL) 50 s3c_pm_run_res(ptr->child, fn, arg); 51 52 if ((ptr->flags & IORESOURCE_SYSTEM_RAM) 53 == IORESOURCE_SYSTEM_RAM) { 54 S3C_PMDBG("Found system RAM at %08lx..%08lx\n", 55 (unsigned long)ptr->start, 56 (unsigned long)ptr->end); 57 arg = (fn)(ptr, arg); 58 } 59 60 ptr = ptr->sibling; 61 } 62 } 63 64 static void s3c_pm_run_sysram(run_fn_t fn, u32 *arg) 65 { 66 s3c_pm_run_res(&iomem_resource, fn, arg); 67 } 68 69 static u32 *s3c_pm_countram(struct resource *res, u32 *val) 70 { 71 u32 size = (u32)resource_size(res); 72 73 size += CHECK_CHUNKSIZE-1; 74 size /= CHECK_CHUNKSIZE; 75 76 S3C_PMDBG("Area %08lx..%08lx, %d blocks\n", 77 (unsigned long)res->start, (unsigned long)res->end, size); 78 79 *val += size * sizeof(u32); 80 return val; 81 } 82 83 /* s3c_pm_prepare_check 84 * 85 * prepare the necessary information for creating the CRCs. This 86 * must be done before the final save, as it will require memory 87 * allocating, and thus touching bits of the kernel we do not 88 * know about. 89 */ 90 91 void s3c_pm_check_prepare(void) 92 { 93 crc_size = 0; 94 95 s3c_pm_run_sysram(s3c_pm_countram, &crc_size); 96 97 S3C_PMDBG("s3c_pm_prepare_check: %u checks needed\n", crc_size); 98 99 crcs = kmalloc(crc_size+4, GFP_KERNEL); 100 if (crcs == NULL) 101 printk(KERN_ERR "Cannot allocated CRC save area\n"); 102 } 103 104 static u32 *s3c_pm_makecheck(struct resource *res, u32 *val) 105 { 106 unsigned long addr, left; 107 108 for (addr = res->start; addr < res->end; 109 addr += CHECK_CHUNKSIZE) { 110 left = res->end - addr; 111 112 if (left > CHECK_CHUNKSIZE) 113 left = CHECK_CHUNKSIZE; 114 115 *val = crc32_le(~0, phys_to_virt(addr), left); 116 val++; 117 } 118 119 return val; 120 } 121 122 /* s3c_pm_check_store 123 * 124 * compute the CRC values for the memory blocks before the final 125 * sleep. 126 */ 127 128 void s3c_pm_check_store(void) 129 { 130 if (crcs != NULL) 131 s3c_pm_run_sysram(s3c_pm_makecheck, crcs); 132 } 133 134 /* in_region 135 * 136 * return TRUE if the area defined by ptr..ptr+size contains the 137 * what..what+whatsz 138 */ 139 140 static inline int in_region(void *ptr, int size, void *what, size_t whatsz) 141 { 142 if ((what+whatsz) < ptr) 143 return 0; 144 145 if (what > (ptr+size)) 146 return 0; 147 148 return 1; 149 } 150 151 /** 152 * s3c_pm_runcheck() - helper to check a resource on restore. 153 * @res: The resource to check 154 * @vak: Pointer to list of CRC32 values to check. 155 * 156 * Called from the s3c_pm_check_restore() via s3c_pm_run_sysram(), this 157 * function runs the given memory resource checking it against the stored 158 * CRC to ensure that memory is restored. The function tries to skip as 159 * many of the areas used during the suspend process. 160 */ 161 static u32 *s3c_pm_runcheck(struct resource *res, u32 *val) 162 { 163 unsigned long addr; 164 unsigned long left; 165 void *stkpage; 166 void *ptr; 167 u32 calc; 168 169 stkpage = (void *)((u32)&calc & ~PAGE_MASK); 170 171 for (addr = res->start; addr < res->end; 172 addr += CHECK_CHUNKSIZE) { 173 left = res->end - addr; 174 175 if (left > CHECK_CHUNKSIZE) 176 left = CHECK_CHUNKSIZE; 177 178 ptr = phys_to_virt(addr); 179 180 if (in_region(ptr, left, stkpage, 4096)) { 181 S3C_PMDBG("skipping %08lx, has stack in\n", addr); 182 goto skip_check; 183 } 184 185 if (in_region(ptr, left, crcs, crc_size)) { 186 S3C_PMDBG("skipping %08lx, has crc block in\n", addr); 187 goto skip_check; 188 } 189 190 /* calculate and check the checksum */ 191 192 calc = crc32_le(~0, ptr, left); 193 if (calc != *val) { 194 printk(KERN_ERR "Restore CRC error at " 195 "%08lx (%08x vs %08x)\n", addr, calc, *val); 196 197 S3C_PMDBG("Restore CRC error at %08lx (%08x vs %08x)\n", 198 addr, calc, *val); 199 } 200 201 skip_check: 202 val++; 203 } 204 205 return val; 206 } 207 208 /** 209 * s3c_pm_check_restore() - memory check called on resume 210 * 211 * check the CRCs after the restore event and free the memory used 212 * to hold them 213 */ 214 void s3c_pm_check_restore(void) 215 { 216 if (crcs != NULL) 217 s3c_pm_run_sysram(s3c_pm_runcheck, crcs); 218 } 219 220 /** 221 * s3c_pm_check_cleanup() - free memory resources 222 * 223 * Free the resources that where allocated by the suspend 224 * memory check code. We do this separately from the 225 * s3c_pm_check_restore() function as we cannot call any 226 * functions that might sleep during that resume. 227 */ 228 void s3c_pm_check_cleanup(void) 229 { 230 kfree(crcs); 231 crcs = NULL; 232 } 233 234