diff options
Diffstat (limited to 'drivers/soc/samsung/s3c-pm-check.c')
| -rw-r--r-- | drivers/soc/samsung/s3c-pm-check.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/drivers/soc/samsung/s3c-pm-check.c b/drivers/soc/samsung/s3c-pm-check.c new file mode 100644 index 000000000..439d5c372 --- /dev/null +++ b/drivers/soc/samsung/s3c-pm-check.c @@ -0,0 +1,233 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// originally in linux/arch/arm/plat-s3c24xx/pm.c +// +// Copyright (c) 2004-2008 Simtec Electronics +// http://armlinux.simtec.co.uk +// Ben Dooks <ben@simtec.co.uk> +// +// S3C Power Mangament - suspend/resume memory corruption check. + +#include <linux/kernel.h> +#include <linux/suspend.h> +#include <linux/init.h> +#include <linux/crc32.h> +#include <linux/ioport.h> +#include <linux/slab.h> + +#include <linux/soc/samsung/s3c-pm.h> + +#if CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE < 1 +#error CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE must be a positive non-zero value +#endif + +/* suspend checking code... + * + * this next area does a set of crc checks over all the installed + * memory, so the system can verify if the resume was ok. + * + * CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE defines the block-size for the CRC, + * increasing it will mean that the area corrupted will be less easy to spot, + * and reducing the size will cause the CRC save area to grow +*/ + +#define CHECK_CHUNKSIZE (CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE * 1024) + +static u32 crc_size; /* size needed for the crc block */ +static u32 *crcs; /* allocated over suspend/resume */ + +typedef u32 *(run_fn_t)(struct resource *ptr, u32 *arg); + +/* s3c_pm_run_res + * + * go through the given resource list, and look for system ram +*/ + +static void s3c_pm_run_res(struct resource *ptr, run_fn_t fn, u32 *arg) +{ + while (ptr != NULL) { + if (ptr->child != NULL) + s3c_pm_run_res(ptr->child, fn, arg); + + if ((ptr->flags & IORESOURCE_SYSTEM_RAM) + == IORESOURCE_SYSTEM_RAM) { + S3C_PMDBG("Found system RAM at %08lx..%08lx\n", + (unsigned long)ptr->start, + (unsigned long)ptr->end); + arg = (fn)(ptr, arg); + } + + ptr = ptr->sibling; + } +} + +static void s3c_pm_run_sysram(run_fn_t fn, u32 *arg) +{ + s3c_pm_run_res(&iomem_resource, fn, arg); +} + +static u32 *s3c_pm_countram(struct resource *res, u32 *val) +{ + u32 size = (u32)resource_size(res); + + size += CHECK_CHUNKSIZE-1; + size /= CHECK_CHUNKSIZE; + + S3C_PMDBG("Area %08lx..%08lx, %d blocks\n", + (unsigned long)res->start, (unsigned long)res->end, size); + + *val += size * sizeof(u32); + return val; +} + +/* s3c_pm_prepare_check + * + * prepare the necessary information for creating the CRCs. This + * must be done before the final save, as it will require memory + * allocating, and thus touching bits of the kernel we do not + * know about. +*/ + +void s3c_pm_check_prepare(void) +{ + crc_size = 0; + + s3c_pm_run_sysram(s3c_pm_countram, &crc_size); + + S3C_PMDBG("s3c_pm_prepare_check: %u checks needed\n", crc_size); + + crcs = kmalloc(crc_size+4, GFP_KERNEL); + if (crcs == NULL) + printk(KERN_ERR "Cannot allocated CRC save area\n"); +} + +static u32 *s3c_pm_makecheck(struct resource *res, u32 *val) +{ + unsigned long addr, left; + + for (addr = res->start; addr < res->end; + addr += CHECK_CHUNKSIZE) { + left = res->end - addr; + + if (left > CHECK_CHUNKSIZE) + left = CHECK_CHUNKSIZE; + + *val = crc32_le(~0, phys_to_virt(addr), left); + val++; + } + + return val; +} + +/* s3c_pm_check_store + * + * compute the CRC values for the memory blocks before the final + * sleep. +*/ + +void s3c_pm_check_store(void) +{ + if (crcs != NULL) + s3c_pm_run_sysram(s3c_pm_makecheck, crcs); +} + +/* in_region + * + * return TRUE if the area defined by ptr..ptr+size contains the + * what..what+whatsz +*/ + +static inline int in_region(void *ptr, int size, void *what, size_t whatsz) +{ + if ((what+whatsz) < ptr) + return 0; + + if (what > (ptr+size)) + return 0; + + return 1; +} + +/** + * s3c_pm_runcheck() - helper to check a resource on restore. + * @res: The resource to check + * @val: Pointer to list of CRC32 values to check. + * + * Called from the s3c_pm_check_restore() via s3c_pm_run_sysram(), this + * function runs the given memory resource checking it against the stored + * CRC to ensure that memory is restored. The function tries to skip as + * many of the areas used during the suspend process. + */ +static u32 *s3c_pm_runcheck(struct resource *res, u32 *val) +{ + unsigned long addr; + unsigned long left; + void *stkpage; + void *ptr; + u32 calc; + + stkpage = (void *)((u32)&calc & ~PAGE_MASK); + + for (addr = res->start; addr < res->end; + addr += CHECK_CHUNKSIZE) { + left = res->end - addr; + + if (left > CHECK_CHUNKSIZE) + left = CHECK_CHUNKSIZE; + + ptr = phys_to_virt(addr); + + if (in_region(ptr, left, stkpage, 4096)) { + S3C_PMDBG("skipping %08lx, has stack in\n", addr); + goto skip_check; + } + + if (in_region(ptr, left, crcs, crc_size)) { + S3C_PMDBG("skipping %08lx, has crc block in\n", addr); + goto skip_check; + } + + /* calculate and check the checksum */ + + calc = crc32_le(~0, ptr, left); + if (calc != *val) { + printk(KERN_ERR "Restore CRC error at " + "%08lx (%08x vs %08x)\n", addr, calc, *val); + + S3C_PMDBG("Restore CRC error at %08lx (%08x vs %08x)\n", + addr, calc, *val); + } + + skip_check: + val++; + } + + return val; +} + +/** + * s3c_pm_check_restore() - memory check called on resume + * + * check the CRCs after the restore event and free the memory used + * to hold them +*/ +void s3c_pm_check_restore(void) +{ + if (crcs != NULL) + s3c_pm_run_sysram(s3c_pm_runcheck, crcs); +} + +/** + * s3c_pm_check_cleanup() - free memory resources + * + * Free the resources that where allocated by the suspend + * memory check code. We do this separately from the + * s3c_pm_check_restore() function as we cannot call any + * functions that might sleep during that resume. + */ +void s3c_pm_check_cleanup(void) +{ + kfree(crcs); + crcs = NULL; +} + |