s3c-pm-check.c

  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
 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_res
 42 *
 43 * go through the given resource list, and look for system ram
 44*/
 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_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
 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_store
123 *
124 * compute the CRC values for the memory blocks before the final
125 * 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_region
135 *
136 * return TRUE if the area defined by ptr..ptr+size contains the
137 * what..what+whatsz
138*/
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 check
154 * @val: 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 */
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 resume
210 *
211 * check the CRCs after the restore event and free the memory used
212 * to hold them
213*/
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 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 */
228void s3c_pm_check_cleanup(void)
229{
230	kfree(crcs);
231	crcs = NULL;
232}
233