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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 <linux/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 <linux/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
88 return(0);
89}
90
91static int slram_point(struct mtd_info *mtd, loff_t from, size_t len,
92 size_t *retlen, void **virt, resource_size_t *phys)
93{
94 slram_priv_t *priv = mtd->priv;
95
96 *virt = priv->start + from;
97 *retlen = len;
98 return(0);
99}
100
101static int slram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
102{
103 return 0;
104}
105
106static int slram_read(struct mtd_info *mtd, loff_t from, size_t len,
107 size_t *retlen, u_char *buf)
108{
109 slram_priv_t *priv = mtd->priv;
110
111 memcpy(buf, priv->start + from, len);
112 *retlen = len;
113 return(0);
114}
115
116static int slram_write(struct mtd_info *mtd, loff_t to, size_t len,
117 size_t *retlen, const u_char *buf)
118{
119 slram_priv_t *priv = mtd->priv;
120
121 memcpy(priv->start + to, buf, len);
122 *retlen = len;
123 return(0);
124}
125
126/*====================================================================*/
127
128static int register_device(char *name, unsigned long start, unsigned long length)
129{
130 slram_mtd_list_t **curmtd;
131
132 curmtd = &slram_mtdlist;
133 while (*curmtd) {
134 curmtd = &(*curmtd)->next;
135 }
136
137 *curmtd = kmalloc(sizeof(slram_mtd_list_t), GFP_KERNEL);
138 if (!(*curmtd)) {
139 E("slram: Cannot allocate new MTD device.\n");
140 return(-ENOMEM);
141 }
142 (*curmtd)->mtdinfo = kzalloc(sizeof(struct mtd_info), GFP_KERNEL);
143 (*curmtd)->next = NULL;
144
145 if ((*curmtd)->mtdinfo) {
146 (*curmtd)->mtdinfo->priv =
147 kzalloc(sizeof(slram_priv_t), GFP_KERNEL);
148
149 if (!(*curmtd)->mtdinfo->priv) {
150 kfree((*curmtd)->mtdinfo);
151 (*curmtd)->mtdinfo = NULL;
152 }
153 }
154
155 if (!(*curmtd)->mtdinfo) {
156 E("slram: Cannot allocate new MTD device.\n");
157 return(-ENOMEM);
158 }
159
160 if (!(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start =
161 memremap(start, length,
162 MEMREMAP_WB | MEMREMAP_WT | MEMREMAP_WC))) {
163 E("slram: memremap failed\n");
164 return -EIO;
165 }
166 ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end =
167 ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start + length;
168
169
170 (*curmtd)->mtdinfo->name = name;
171 (*curmtd)->mtdinfo->size = length;
172 (*curmtd)->mtdinfo->flags = MTD_CAP_RAM;
173 (*curmtd)->mtdinfo->_erase = slram_erase;
174 (*curmtd)->mtdinfo->_point = slram_point;
175 (*curmtd)->mtdinfo->_unpoint = slram_unpoint;
176 (*curmtd)->mtdinfo->_read = slram_read;
177 (*curmtd)->mtdinfo->_write = slram_write;
178 (*curmtd)->mtdinfo->owner = THIS_MODULE;
179 (*curmtd)->mtdinfo->type = MTD_RAM;
180 (*curmtd)->mtdinfo->erasesize = SLRAM_BLK_SZ;
181 (*curmtd)->mtdinfo->writesize = 1;
182
183 if (mtd_device_register((*curmtd)->mtdinfo, NULL, 0)) {
184 E("slram: Failed to register new device\n");
185 memunmap(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start);
186 kfree((*curmtd)->mtdinfo->priv);
187 kfree((*curmtd)->mtdinfo);
188 return(-EAGAIN);
189 }
190 T("slram: Registered device %s from %luKiB to %luKiB\n", name,
191 (start / 1024), ((start + length) / 1024));
192 T("slram: Mapped from 0x%p to 0x%p\n",
193 ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start,
194 ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end);
195 return(0);
196}
197
198static void unregister_devices(void)
199{
200 slram_mtd_list_t *nextitem;
201
202 while (slram_mtdlist) {
203 nextitem = slram_mtdlist->next;
204 mtd_device_unregister(slram_mtdlist->mtdinfo);
205 memunmap(((slram_priv_t *)slram_mtdlist->mtdinfo->priv)->start);
206 kfree(slram_mtdlist->mtdinfo->priv);
207 kfree(slram_mtdlist->mtdinfo);
208 kfree(slram_mtdlist);
209 slram_mtdlist = nextitem;
210 }
211}
212
213static unsigned long handle_unit(unsigned long value, char *unit)
214{
215 if ((*unit == 'M') || (*unit == 'm')) {
216 return(value * 1024 * 1024);
217 } else if ((*unit == 'K') || (*unit == 'k')) {
218 return(value * 1024);
219 }
220 return(value);
221}
222
223static int parse_cmdline(char *devname, char *szstart, char *szlength)
224{
225 char *buffer;
226 unsigned long devstart;
227 unsigned long devlength;
228
229 if ((!devname) || (!szstart) || (!szlength)) {
230 unregister_devices();
231 return(-EINVAL);
232 }
233
234 devstart = simple_strtoul(szstart, &buffer, 0);
235 devstart = handle_unit(devstart, buffer);
236
237 if (*(szlength) != '+') {
238 devlength = simple_strtoul(szlength, &buffer, 0);
239 devlength = handle_unit(devlength, buffer);
240 if (devlength < devstart)
241 goto err_out;
242
243 devlength -= devstart;
244 } else {
245 devlength = simple_strtoul(szlength + 1, &buffer, 0);
246 devlength = handle_unit(devlength, buffer);
247 }
248 T("slram: devname=%s, devstart=0x%lx, devlength=0x%lx\n",
249 devname, devstart, devlength);
250 if (devlength % SLRAM_BLK_SZ != 0)
251 goto err_out;
252
253 if ((devstart = register_device(devname, devstart, devlength))){
254 unregister_devices();
255 return((int)devstart);
256 }
257 return(0);
258
259err_out:
260 E("slram: Illegal length parameter.\n");
261 return(-EINVAL);
262}
263
264#ifndef MODULE
265
266static int __init mtd_slram_setup(char *str)
267{
268 map = str;
269 return(1);
270}
271
272__setup("slram=", mtd_slram_setup);
273
274#endif
275
276static int __init init_slram(void)
277{
278 char *devname;
279
280#ifndef MODULE
281 char *devstart;
282 char *devlength;
283
284 if (!map) {
285 E("slram: not enough parameters.\n");
286 return(-EINVAL);
287 }
288 while (map) {
289 devname = devstart = devlength = NULL;
290
291 if (!(devname = strsep(&map, ","))) {
292 E("slram: No devicename specified.\n");
293 break;
294 }
295 T("slram: devname = %s\n", devname);
296 if ((!map) || (!(devstart = strsep(&map, ",")))) {
297 E("slram: No devicestart specified.\n");
298 }
299 T("slram: devstart = %s\n", devstart);
300 if ((!map) || (!(devlength = strsep(&map, ",")))) {
301 E("slram: No devicelength / -end specified.\n");
302 }
303 T("slram: devlength = %s\n", devlength);
304 if (parse_cmdline(devname, devstart, devlength) != 0) {
305 return(-EINVAL);
306 }
307 }
308#else
309 int count;
310 int i;
311
312 for (count = 0; count < SLRAM_MAX_DEVICES_PARAMS && map[count];
313 count++) {
314 }
315
316 if ((count % 3 != 0) || (count == 0)) {
317 E("slram: not enough parameters.\n");
318 return(-EINVAL);
319 }
320 for (i = 0; i < (count / 3); i++) {
321 devname = map[i * 3];
322
323 if (parse_cmdline(devname, map[i * 3 + 1], map[i * 3 + 2])!=0) {
324 return(-EINVAL);
325 }
326
327 }
328#endif /* !MODULE */
329
330 return(0);
331}
332
333static void __exit cleanup_slram(void)
334{
335 unregister_devices();
336}
337
338module_init(init_slram);
339module_exit(cleanup_slram);
340
341MODULE_LICENSE("GPL");
342MODULE_AUTHOR("Jochen Schaeuble <psionic@psionic.de>");
343MODULE_DESCRIPTION("MTD driver for uncached system RAM");