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 
36 static u32 crc_size;	/* size needed for the crc block */
37 static u32 *crcs;	/* allocated over suspend/resume */
38 
39 typedef 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 
s3c_pm_run_res(struct resource * ptr,run_fn_t fn,u32 * arg)46 static 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 
s3c_pm_run_sysram(run_fn_t fn,u32 * arg)64 static void s3c_pm_run_sysram(run_fn_t fn, u32 *arg)
65 {
66 	s3c_pm_run_res(&iomem_resource, fn, arg);
67 }
68 
s3c_pm_countram(struct resource * res,u32 * val)69 static 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 
s3c_pm_check_prepare(void)91 void 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 
s3c_pm_makecheck(struct resource * res,u32 * val)104 static 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 
s3c_pm_check_store(void)128 void 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 
in_region(void * ptr,int size,void * what,size_t whatsz)140 static 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  */
s3c_pm_runcheck(struct resource * res,u32 * val)161 static 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 */
s3c_pm_check_restore(void)214 void 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  */
s3c_pm_check_cleanup(void)228 void s3c_pm_check_cleanup(void)
229 {
230 	kfree(crcs);
231 	crcs = NULL;
232 }
233 
234