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1// SPDX-License-Identifier: GPL-2.02//3// originally in linux/arch/arm/plat-s3c24xx/pm.c4//5// Copyright (c) 2004-2008 Simtec Electronics6// http://armlinux.simtec.co.uk7// 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 < 121#error CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE must be a positive non-zero value22#endif23 24/* suspend checking code...25 *26 * this next area does a set of crc checks over all the installed27 * 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 grow32*/33 34#define CHECK_CHUNKSIZE (CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE * 1024)35 36static u32 crc_size; /* size needed for the crc block */37static u32 *crcs; /* allocated over suspend/resume */38 39typedef u32 *(run_fn_t)(struct resource *ptr, u32 *arg);40 41/* s3c_pm_run_res42 *43 * go through the given resource list, and look for system ram44*/45 46static 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 64static void s3c_pm_run_sysram(run_fn_t fn, u32 *arg)65{66 s3c_pm_run_res(&iomem_resource, fn, arg);67}68 69static 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_check84 *85 * prepare the necessary information for creating the CRCs. This86 * must be done before the final save, as it will require memory87 * allocating, and thus touching bits of the kernel we do not88 * know about.89*/90 91void 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 104static 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_store123 *124 * compute the CRC values for the memory blocks before the final125 * sleep.126*/127 128void s3c_pm_check_store(void)129{130 if (crcs != NULL)131 s3c_pm_run_sysram(s3c_pm_makecheck, crcs);132}133 134/* in_region135 *136 * return TRUE if the area defined by ptr..ptr+size contains the137 * what..what+whatsz138*/139 140static 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 check154 * @val: Pointer to list of CRC32 values to check.155 *156 * Called from the s3c_pm_check_restore() via s3c_pm_run_sysram(), this157 * function runs the given memory resource checking it against the stored158 * CRC to ensure that memory is restored. The function tries to skip as159 * many of the areas used during the suspend process.160 */161static 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 resume210 *211 * check the CRCs after the restore event and free the memory used212 * to hold them213*/214void 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 resources222 *223 * Free the resources that where allocated by the suspend224 * memory check code. We do this separately from the225 * s3c_pm_check_restore() function as we cannot call any226 * functions that might sleep during that resume.227 */228void s3c_pm_check_cleanup(void)229{230 kfree(crcs);231 crcs = NULL;232}233 234