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: 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(ptr: &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(crc: ~0, p: phys_to_virt(addr), len: 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, size: left, what: stkpage, whatsz: 4096)) {
181 S3C_PMDBG("skipping %08lx, has stack in\n", addr);
182 goto skip_check;
183 }
184
185 if (in_region(ptr, size: left, what: crcs, whatsz: 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(crc: ~0, p: ptr, len: 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
234

source code of linux/drivers/soc/samsung/s3c-pm-check.c