1 /* linux/arch/arm/plat-s3c/pm-check.c
2 * originally in linux/arch/arm/plat-s3c24xx/pm.c
4 * Copyright (c) 2004-2008 Simtec Electronics
5 * http://armlinux.simtec.co.uk
6 * Ben Dooks <ben@simtec.co.uk>
8 * S3C Power Mangament - suspend/resume memory corruptiuon check.
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.
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>
24 #if CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE < 1
25 #error CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE must be a positive non-zero value
28 /* suspend checking code...
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.
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
38 #define CHECK_CHUNKSIZE (CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE * 1024)
40 static u32 crc_size; /* size needed for the crc block */
41 static u32 *crcs; /* allocated over suspend/resume */
43 typedef u32 *(run_fn_t)(struct resource *ptr, u32 *arg);
47 * go through the given resource list, and look for system ram
50 static void s3c_pm_run_res(struct resource *ptr, run_fn_t fn, u32 *arg)
53 if (ptr->child != NULL)
54 s3c_pm_run_res(ptr->child, fn, arg);
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);
68 static void s3c_pm_run_sysram(run_fn_t fn, u32 *arg)
70 s3c_pm_run_res(&iomem_resource, fn, arg);
73 static u32 *s3c_pm_countram(struct resource *res, u32 *val)
75 u32 size = (u32)(res->end - res->start)+1;
77 size += CHECK_CHUNKSIZE-1;
78 size /= CHECK_CHUNKSIZE;
80 S3C_PMDBG("Area %08lx..%08lx, %d blocks\n",
81 (unsigned long)res->start, (unsigned long)res->end, size);
83 *val += size * sizeof(u32);
87 /* s3c_pm_prepare_check
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
95 void s3c_pm_check_prepare(void)
99 s3c_pm_run_sysram(s3c_pm_countram, &crc_size);
101 S3C_PMDBG("s3c_pm_prepare_check: %u checks needed\n", crc_size);
103 crcs = kmalloc(crc_size+4, GFP_KERNEL);
105 printk(KERN_ERR "Cannot allocated CRC save area\n");
108 static u32 *s3c_pm_makecheck(struct resource *res, u32 *val)
110 unsigned long addr, left;
112 for (addr = res->start; addr < res->end;
113 addr += CHECK_CHUNKSIZE) {
114 left = res->end - addr;
116 if (left > CHECK_CHUNKSIZE)
117 left = CHECK_CHUNKSIZE;
119 *val = crc32_le(~0, phys_to_virt(addr), left);
126 /* s3c_pm_check_store
128 * compute the CRC values for the memory blocks before the final
132 void s3c_pm_check_store(void)
135 s3c_pm_run_sysram(s3c_pm_makecheck, crcs);
140 * return TRUE if the area defined by ptr..ptr+size contains the
144 static inline int in_region(void *ptr, int size, void *what, size_t whatsz)
146 if ((what+whatsz) < ptr)
149 if (what > (ptr+size))
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.
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.
165 static u32 *s3c_pm_runcheck(struct resource *res, u32 *val)
173 stkpage = (void *)((u32)&calc & ~PAGE_MASK);
175 for (addr = res->start; addr < res->end;
176 addr += CHECK_CHUNKSIZE) {
177 left = res->end - addr;
179 if (left > CHECK_CHUNKSIZE)
180 left = CHECK_CHUNKSIZE;
182 ptr = phys_to_virt(addr);
184 if (in_region(ptr, left, stkpage, 4096)) {
185 S3C_PMDBG("skipping %08lx, has stack in\n", addr);
189 if (in_region(ptr, left, crcs, crc_size)) {
190 S3C_PMDBG("skipping %08lx, has crc block in\n", addr);
194 /* calculate and check the checksum */
196 calc = crc32_le(~0, ptr, left);
198 printk(KERN_ERR "Restore CRC error at "
199 "%08lx (%08x vs %08x)\n", addr, calc, *val);
201 S3C_PMDBG("Restore CRC error at %08lx (%08x vs %08x)\n",
213 * s3c_pm_check_restore() - memory check called on resume
215 * check the CRCs after the restore event and free the memory used
218 void s3c_pm_check_restore(void)
221 s3c_pm_run_sysram(s3c_pm_runcheck, crcs);
225 * s3c_pm_check_cleanup() - free memory resources
227 * Free the resources that where allocated by the suspend
228 * memory check code. We do this separately from the
229 * s3c_pm_check_restore() function as we cannot call any
230 * functions that might sleep during that resume.
232 void s3c_pm_check_cleanup(void)