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1// SPDX-License-Identifier: GPL-2.0-only
2/*======================================================================
3
4 This driver provides a method to access memory not used by the kernel
5 itself (i.e. if the kernel commandline mem=xxx is used). To actually
6 use slram at least mtdblock or mtdchar is required (for block or
7 character device access).
8
9 Usage:
10
11 if compiled as loadable module:
12 modprobe slram map=<name>,<start>,<end/offset>
13 if statically linked into the kernel use the following kernel cmd.line
14 slram=<name>,<start>,<end/offset>
15
16 <name>: name of the device that will be listed in /proc/mtd
17 <start>: start of the memory region, decimal or hex (0xabcdef)
18 <end/offset>: end of the memory region. It's possible to use +0x1234
19 to specify the offset instead of the absolute address
20
21 NOTE:
22 With slram it's only possible to map a contiguous memory region. Therefore
23 if there's a device mapped somewhere in the region specified slram will
24 fail to load (see kernel log if modprobe fails).
25
26 -
27
28 Jochen Schaeuble <psionic@psionic.de>
29
30======================================================================*/
31
32
33#include <linux/module.h>
34#include <linux/uaccess.h>
35#include <linux/types.h>
36#include <linux/kernel.h>
37#include <linux/ptrace.h>
38#include <linux/slab.h>
39#include <linux/string.h>
40#include <linux/timer.h>
41#include <linux/major.h>
42#include <linux/fs.h>
43#include <linux/ioctl.h>
44#include <linux/init.h>
45#include <linux/io.h>
46
47#include <linux/mtd/mtd.h>
48
49#define SLRAM_MAX_DEVICES_PARAMS 6 /* 3 parameters / device */
50#define SLRAM_BLK_SZ 0x4000
51
52#define T(fmt, args...) printk(KERN_DEBUG fmt, ## args)
53#define E(fmt, args...) printk(KERN_NOTICE fmt, ## args)
54
55typedef struct slram_priv {
56 u_char *start;
57 u_char *end;
58} slram_priv_t;
59
60typedef struct slram_mtd_list {
61 struct mtd_info *mtdinfo;
62 struct slram_mtd_list *next;
63} slram_mtd_list_t;
64
65#ifdef MODULE
66static char *map[SLRAM_MAX_DEVICES_PARAMS];
67
68module_param_array(map, charp, NULL, 0);
69MODULE_PARM_DESC(map, "List of memory regions to map. \"map=<name>, <start>, <length / end>\"");
70#else
71static char *map;
72#endif
73
74static slram_mtd_list_t *slram_mtdlist = NULL;
75
76static int slram_erase(struct mtd_info *, struct erase_info *);
77static int slram_point(struct mtd_info *, loff_t, size_t, size_t *, void **,
78 resource_size_t *);
79static int slram_unpoint(struct mtd_info *, loff_t, size_t);
80static int slram_read(struct mtd_info *, loff_t, size_t, size_t *, u_char *);
81static int slram_write(struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
82
83static int slram_erase(struct mtd_info *mtd, struct erase_info *instr)
84{
85 slram_priv_t *priv = mtd->priv;
86
87 memset(priv->start + instr->addr, 0xff, instr->len);
88
89 return(0);
90}
91
92static int slram_point(struct mtd_info *mtd, loff_t from, size_t len,
93 size_t *retlen, void **virt, resource_size_t *phys)
94{
95 slram_priv_t *priv = mtd->priv;
96
97 *virt = priv->start + from;
98 *retlen = len;
99 return(0);
100}
101
102static int slram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
103{
104 return 0;
105}
106
107static int slram_read(struct mtd_info *mtd, loff_t from, size_t len,
108 size_t *retlen, u_char *buf)
109{
110 slram_priv_t *priv = mtd->priv;
111
112 memcpy(buf, priv->start + from, len);
113 *retlen = len;
114 return(0);
115}
116
117static int slram_write(struct mtd_info *mtd, loff_t to, size_t len,
118 size_t *retlen, const u_char *buf)
119{
120 slram_priv_t *priv = mtd->priv;
121
122 memcpy(priv->start + to, buf, len);
123 *retlen = len;
124 return(0);
125}
126
127/*====================================================================*/
128
129static int register_device(char *name, unsigned long start, unsigned long length)
130{
131 slram_mtd_list_t **curmtd;
132
133 curmtd = &slram_mtdlist;
134 while (*curmtd) {
135 curmtd = &(*curmtd)->next;
136 }
137
138 *curmtd = kmalloc(sizeof(slram_mtd_list_t), GFP_KERNEL);
139 if (!(*curmtd)) {
140 E("slram: Cannot allocate new MTD device.\n");
141 return(-ENOMEM);
142 }
143 (*curmtd)->mtdinfo = kzalloc(sizeof(struct mtd_info), GFP_KERNEL);
144 (*curmtd)->next = NULL;
145
146 if ((*curmtd)->mtdinfo) {
147 (*curmtd)->mtdinfo->priv =
148 kzalloc(sizeof(slram_priv_t), GFP_KERNEL);
149
150 if (!(*curmtd)->mtdinfo->priv) {
151 kfree((*curmtd)->mtdinfo);
152 (*curmtd)->mtdinfo = NULL;
153 }
154 }
155
156 if (!(*curmtd)->mtdinfo) {
157 E("slram: Cannot allocate new MTD device.\n");
158 return(-ENOMEM);
159 }
160
161 if (!(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start =
162 memremap(start, length,
163 MEMREMAP_WB | MEMREMAP_WT | MEMREMAP_WC))) {
164 E("slram: memremap failed\n");
165 return -EIO;
166 }
167 ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end =
168 ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start + length;
169
170
171 (*curmtd)->mtdinfo->name = name;
172 (*curmtd)->mtdinfo->size = length;
173 (*curmtd)->mtdinfo->flags = MTD_CAP_RAM;
174 (*curmtd)->mtdinfo->_erase = slram_erase;
175 (*curmtd)->mtdinfo->_point = slram_point;
176 (*curmtd)->mtdinfo->_unpoint = slram_unpoint;
177 (*curmtd)->mtdinfo->_read = slram_read;
178 (*curmtd)->mtdinfo->_write = slram_write;
179 (*curmtd)->mtdinfo->owner = THIS_MODULE;
180 (*curmtd)->mtdinfo->type = MTD_RAM;
181 (*curmtd)->mtdinfo->erasesize = SLRAM_BLK_SZ;
182 (*curmtd)->mtdinfo->writesize = 1;
183
184 if (mtd_device_register((*curmtd)->mtdinfo, NULL, 0)) {
185 E("slram: Failed to register new device\n");
186 memunmap(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start);
187 kfree((*curmtd)->mtdinfo->priv);
188 kfree((*curmtd)->mtdinfo);
189 return(-EAGAIN);
190 }
191 T("slram: Registered device %s from %luKiB to %luKiB\n", name,
192 (start / 1024), ((start + length) / 1024));
193 T("slram: Mapped from 0x%p to 0x%p\n",
194 ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start,
195 ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end);
196 return(0);
197}
198
199static void unregister_devices(void)
200{
201 slram_mtd_list_t *nextitem;
202
203 while (slram_mtdlist) {
204 nextitem = slram_mtdlist->next;
205 mtd_device_unregister(slram_mtdlist->mtdinfo);
206 memunmap(((slram_priv_t *)slram_mtdlist->mtdinfo->priv)->start);
207 kfree(slram_mtdlist->mtdinfo->priv);
208 kfree(slram_mtdlist->mtdinfo);
209 kfree(slram_mtdlist);
210 slram_mtdlist = nextitem;
211 }
212}
213
214static unsigned long handle_unit(unsigned long value, char *unit)
215{
216 if ((*unit == 'M') || (*unit == 'm')) {
217 return(value * 1024 * 1024);
218 } else if ((*unit == 'K') || (*unit == 'k')) {
219 return(value * 1024);
220 }
221 return(value);
222}
223
224static int parse_cmdline(char *devname, char *szstart, char *szlength)
225{
226 char *buffer;
227 unsigned long devstart;
228 unsigned long devlength;
229
230 if ((!devname) || (!szstart) || (!szlength)) {
231 unregister_devices();
232 return(-EINVAL);
233 }
234
235 devstart = simple_strtoul(szstart, &buffer, 0);
236 devstart = handle_unit(devstart, buffer);
237
238 if (*(szlength) != '+') {
239 devlength = simple_strtoul(szlength, &buffer, 0);
240 devlength = handle_unit(devlength, buffer);
241 if (devlength < devstart)
242 goto err_out;
243
244 devlength -= devstart;
245 } else {
246 devlength = simple_strtoul(szlength + 1, &buffer, 0);
247 devlength = handle_unit(devlength, buffer);
248 }
249 T("slram: devname=%s, devstart=0x%lx, devlength=0x%lx\n",
250 devname, devstart, devlength);
251 if (devlength % SLRAM_BLK_SZ != 0)
252 goto err_out;
253
254 if ((devstart = register_device(devname, devstart, devlength))){
255 unregister_devices();
256 return((int)devstart);
257 }
258 return(0);
259
260err_out:
261 E("slram: Illegal length parameter.\n");
262 return(-EINVAL);
263}
264
265#ifndef MODULE
266
267static int __init mtd_slram_setup(char *str)
268{
269 map = str;
270 return(1);
271}
272
273__setup("slram=", mtd_slram_setup);
274
275#endif
276
277static int __init init_slram(void)
278{
279 char *devname;
280
281#ifndef MODULE
282 char *devstart;
283 char *devlength;
284
285 if (!map) {
286 E("slram: not enough parameters.\n");
287 return(-EINVAL);
288 }
289 while (map) {
290 devname = devstart = devlength = NULL;
291
292 if (!(devname = strsep(&map, ","))) {
293 E("slram: No devicename specified.\n");
294 break;
295 }
296 T("slram: devname = %s\n", devname);
297 if ((!map) || (!(devstart = strsep(&map, ",")))) {
298 E("slram: No devicestart specified.\n");
299 }
300 T("slram: devstart = %s\n", devstart);
301 if ((!map) || (!(devlength = strsep(&map, ",")))) {
302 E("slram: No devicelength / -end specified.\n");
303 }
304 T("slram: devlength = %s\n", devlength);
305 if (parse_cmdline(devname, devstart, devlength) != 0) {
306 return(-EINVAL);
307 }
308 }
309#else
310 int count;
311 int i;
312
313 for (count = 0; count < SLRAM_MAX_DEVICES_PARAMS && map[count];
314 count++) {
315 }
316
317 if ((count % 3 != 0) || (count == 0)) {
318 E("slram: not enough parameters.\n");
319 return(-EINVAL);
320 }
321 for (i = 0; i < (count / 3); i++) {
322 devname = map[i * 3];
323
324 if (parse_cmdline(devname, map[i * 3 + 1], map[i * 3 + 2])!=0) {
325 return(-EINVAL);
326 }
327
328 }
329#endif /* !MODULE */
330
331 return(0);
332}
333
334static void __exit cleanup_slram(void)
335{
336 unregister_devices();
337}
338
339module_init(init_slram);
340module_exit(cleanup_slram);
341
342MODULE_LICENSE("GPL");
343MODULE_AUTHOR("Jochen Schaeuble <psionic@psionic.de>");
344MODULE_DESCRIPTION("MTD driver for uncached system RAM");
1/*======================================================================
2
3 This driver provides a method to access memory not used by the kernel
4 itself (i.e. if the kernel commandline mem=xxx is used). To actually
5 use slram at least mtdblock or mtdchar is required (for block or
6 character device access).
7
8 Usage:
9
10 if compiled as loadable module:
11 modprobe slram map=<name>,<start>,<end/offset>
12 if statically linked into the kernel use the following kernel cmd.line
13 slram=<name>,<start>,<end/offset>
14
15 <name>: name of the device that will be listed in /proc/mtd
16 <start>: start of the memory region, decimal or hex (0xabcdef)
17 <end/offset>: end of the memory region. It's possible to use +0x1234
18 to specify the offset instead of the absolute address
19
20 NOTE:
21 With slram it's only possible to map a contiguous memory region. Therefore
22 if there's a device mapped somewhere in the region specified slram will
23 fail to load (see kernel log if modprobe fails).
24
25 -
26
27 Jochen Schaeuble <psionic@psionic.de>
28
29======================================================================*/
30
31
32#include <linux/module.h>
33#include <asm/uaccess.h>
34#include <linux/types.h>
35#include <linux/kernel.h>
36#include <linux/ptrace.h>
37#include <linux/slab.h>
38#include <linux/string.h>
39#include <linux/timer.h>
40#include <linux/major.h>
41#include <linux/fs.h>
42#include <linux/ioctl.h>
43#include <linux/init.h>
44#include <asm/io.h>
45
46#include <linux/mtd/mtd.h>
47
48#define SLRAM_MAX_DEVICES_PARAMS 6 /* 3 parameters / device */
49#define SLRAM_BLK_SZ 0x4000
50
51#define T(fmt, args...) printk(KERN_DEBUG fmt, ## args)
52#define E(fmt, args...) printk(KERN_NOTICE fmt, ## args)
53
54typedef struct slram_priv {
55 u_char *start;
56 u_char *end;
57} slram_priv_t;
58
59typedef struct slram_mtd_list {
60 struct mtd_info *mtdinfo;
61 struct slram_mtd_list *next;
62} slram_mtd_list_t;
63
64#ifdef MODULE
65static char *map[SLRAM_MAX_DEVICES_PARAMS];
66
67module_param_array(map, charp, NULL, 0);
68MODULE_PARM_DESC(map, "List of memory regions to map. \"map=<name>, <start>, <length / end>\"");
69#else
70static char *map;
71#endif
72
73static slram_mtd_list_t *slram_mtdlist = NULL;
74
75static int slram_erase(struct mtd_info *, struct erase_info *);
76static int slram_point(struct mtd_info *, loff_t, size_t, size_t *, void **,
77 resource_size_t *);
78static int slram_unpoint(struct mtd_info *, loff_t, size_t);
79static int slram_read(struct mtd_info *, loff_t, size_t, size_t *, u_char *);
80static int slram_write(struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
81
82static int slram_erase(struct mtd_info *mtd, struct erase_info *instr)
83{
84 slram_priv_t *priv = mtd->priv;
85
86 memset(priv->start + instr->addr, 0xff, instr->len);
87 /* This'll catch a few races. Free the thing before returning :)
88 * I don't feel at all ashamed. This kind of thing is possible anyway
89 * with flash, but unlikely.
90 */
91 instr->state = MTD_ERASE_DONE;
92 mtd_erase_callback(instr);
93 return(0);
94}
95
96static int slram_point(struct mtd_info *mtd, loff_t from, size_t len,
97 size_t *retlen, void **virt, resource_size_t *phys)
98{
99 slram_priv_t *priv = mtd->priv;
100
101 *virt = priv->start + from;
102 *retlen = len;
103 return(0);
104}
105
106static int slram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
107{
108 return 0;
109}
110
111static int slram_read(struct mtd_info *mtd, loff_t from, size_t len,
112 size_t *retlen, u_char *buf)
113{
114 slram_priv_t *priv = mtd->priv;
115
116 memcpy(buf, priv->start + from, len);
117 *retlen = len;
118 return(0);
119}
120
121static int slram_write(struct mtd_info *mtd, loff_t to, size_t len,
122 size_t *retlen, const u_char *buf)
123{
124 slram_priv_t *priv = mtd->priv;
125
126 memcpy(priv->start + to, buf, len);
127 *retlen = len;
128 return(0);
129}
130
131/*====================================================================*/
132
133static int register_device(char *name, unsigned long start, unsigned long length)
134{
135 slram_mtd_list_t **curmtd;
136
137 curmtd = &slram_mtdlist;
138 while (*curmtd) {
139 curmtd = &(*curmtd)->next;
140 }
141
142 *curmtd = kmalloc(sizeof(slram_mtd_list_t), GFP_KERNEL);
143 if (!(*curmtd)) {
144 E("slram: Cannot allocate new MTD device.\n");
145 return(-ENOMEM);
146 }
147 (*curmtd)->mtdinfo = kzalloc(sizeof(struct mtd_info), GFP_KERNEL);
148 (*curmtd)->next = NULL;
149
150 if ((*curmtd)->mtdinfo) {
151 (*curmtd)->mtdinfo->priv =
152 kzalloc(sizeof(slram_priv_t), GFP_KERNEL);
153
154 if (!(*curmtd)->mtdinfo->priv) {
155 kfree((*curmtd)->mtdinfo);
156 (*curmtd)->mtdinfo = NULL;
157 }
158 }
159
160 if (!(*curmtd)->mtdinfo) {
161 E("slram: Cannot allocate new MTD device.\n");
162 return(-ENOMEM);
163 }
164
165 if (!(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start =
166 ioremap(start, length))) {
167 E("slram: ioremap failed\n");
168 return -EIO;
169 }
170 ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end =
171 ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start + length;
172
173
174 (*curmtd)->mtdinfo->name = name;
175 (*curmtd)->mtdinfo->size = length;
176 (*curmtd)->mtdinfo->flags = MTD_CAP_RAM;
177 (*curmtd)->mtdinfo->_erase = slram_erase;
178 (*curmtd)->mtdinfo->_point = slram_point;
179 (*curmtd)->mtdinfo->_unpoint = slram_unpoint;
180 (*curmtd)->mtdinfo->_read = slram_read;
181 (*curmtd)->mtdinfo->_write = slram_write;
182 (*curmtd)->mtdinfo->owner = THIS_MODULE;
183 (*curmtd)->mtdinfo->type = MTD_RAM;
184 (*curmtd)->mtdinfo->erasesize = SLRAM_BLK_SZ;
185 (*curmtd)->mtdinfo->writesize = 1;
186
187 if (mtd_device_register((*curmtd)->mtdinfo, NULL, 0)) {
188 E("slram: Failed to register new device\n");
189 iounmap(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start);
190 kfree((*curmtd)->mtdinfo->priv);
191 kfree((*curmtd)->mtdinfo);
192 return(-EAGAIN);
193 }
194 T("slram: Registered device %s from %luKiB to %luKiB\n", name,
195 (start / 1024), ((start + length) / 1024));
196 T("slram: Mapped from 0x%p to 0x%p\n",
197 ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start,
198 ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end);
199 return(0);
200}
201
202static void unregister_devices(void)
203{
204 slram_mtd_list_t *nextitem;
205
206 while (slram_mtdlist) {
207 nextitem = slram_mtdlist->next;
208 mtd_device_unregister(slram_mtdlist->mtdinfo);
209 iounmap(((slram_priv_t *)slram_mtdlist->mtdinfo->priv)->start);
210 kfree(slram_mtdlist->mtdinfo->priv);
211 kfree(slram_mtdlist->mtdinfo);
212 kfree(slram_mtdlist);
213 slram_mtdlist = nextitem;
214 }
215}
216
217static unsigned long handle_unit(unsigned long value, char *unit)
218{
219 if ((*unit == 'M') || (*unit == 'm')) {
220 return(value * 1024 * 1024);
221 } else if ((*unit == 'K') || (*unit == 'k')) {
222 return(value * 1024);
223 }
224 return(value);
225}
226
227static int parse_cmdline(char *devname, char *szstart, char *szlength)
228{
229 char *buffer;
230 unsigned long devstart;
231 unsigned long devlength;
232
233 if ((!devname) || (!szstart) || (!szlength)) {
234 unregister_devices();
235 return(-EINVAL);
236 }
237
238 devstart = simple_strtoul(szstart, &buffer, 0);
239 devstart = handle_unit(devstart, buffer);
240
241 if (*(szlength) != '+') {
242 devlength = simple_strtoul(szlength, &buffer, 0);
243 devlength = handle_unit(devlength, buffer);
244 if (devlength < devstart)
245 goto err_out;
246
247 devlength -= devstart;
248 } else {
249 devlength = simple_strtoul(szlength + 1, &buffer, 0);
250 devlength = handle_unit(devlength, buffer);
251 }
252 T("slram: devname=%s, devstart=0x%lx, devlength=0x%lx\n",
253 devname, devstart, devlength);
254 if (devlength % SLRAM_BLK_SZ != 0)
255 goto err_out;
256
257 if ((devstart = register_device(devname, devstart, devlength))){
258 unregister_devices();
259 return((int)devstart);
260 }
261 return(0);
262
263err_out:
264 E("slram: Illegal length parameter.\n");
265 return(-EINVAL);
266}
267
268#ifndef MODULE
269
270static int __init mtd_slram_setup(char *str)
271{
272 map = str;
273 return(1);
274}
275
276__setup("slram=", mtd_slram_setup);
277
278#endif
279
280static int __init init_slram(void)
281{
282 char *devname;
283 int i;
284
285#ifndef MODULE
286 char *devstart;
287 char *devlength;
288
289 i = 0;
290
291 if (!map) {
292 E("slram: not enough parameters.\n");
293 return(-EINVAL);
294 }
295 while (map) {
296 devname = devstart = devlength = NULL;
297
298 if (!(devname = strsep(&map, ","))) {
299 E("slram: No devicename specified.\n");
300 break;
301 }
302 T("slram: devname = %s\n", devname);
303 if ((!map) || (!(devstart = strsep(&map, ",")))) {
304 E("slram: No devicestart specified.\n");
305 }
306 T("slram: devstart = %s\n", devstart);
307 if ((!map) || (!(devlength = strsep(&map, ",")))) {
308 E("slram: No devicelength / -end specified.\n");
309 }
310 T("slram: devlength = %s\n", devlength);
311 if (parse_cmdline(devname, devstart, devlength) != 0) {
312 return(-EINVAL);
313 }
314 }
315#else
316 int count;
317
318 for (count = 0; count < SLRAM_MAX_DEVICES_PARAMS && map[count];
319 count++) {
320 }
321
322 if ((count % 3 != 0) || (count == 0)) {
323 E("slram: not enough parameters.\n");
324 return(-EINVAL);
325 }
326 for (i = 0; i < (count / 3); i++) {
327 devname = map[i * 3];
328
329 if (parse_cmdline(devname, map[i * 3 + 1], map[i * 3 + 2])!=0) {
330 return(-EINVAL);
331 }
332
333 }
334#endif /* !MODULE */
335
336 return(0);
337}
338
339static void __exit cleanup_slram(void)
340{
341 unregister_devices();
342}
343
344module_init(init_slram);
345module_exit(cleanup_slram);
346
347MODULE_LICENSE("GPL");
348MODULE_AUTHOR("Jochen Schaeuble <psionic@psionic.de>");
349MODULE_DESCRIPTION("MTD driver for uncached system RAM");