/* linux/arch/arm/plat-s3c/pm-check.c
* 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 corruptiuon check.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#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 <plat/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_MEM) &&
strcmp(ptr->name, "System RAM") == 0) {
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
* @vak: 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;
}
