Commit | Line | Data |
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1da177e4 LT |
1 | /*====================================================================== |
2 | ||
1da177e4 LT |
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 | |
e5580fbe | 19 | |
1da177e4 | 20 | NOTE: |
af901ca1 | 21 | With slram it's only possible to map a contiguous memory region. Therefore |
1da177e4 LT |
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 | - | |
e5580fbe | 26 | |
1da177e4 LT |
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> | |
1da177e4 LT |
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 | #include <asm/system.h> | |
46 | ||
47 | #include <linux/mtd/mtd.h> | |
48 | ||
49 | #define SLRAM_MAX_DEVICES_PARAMS 6 /* 3 parameters / device */ | |
14f8351a | 50 | #define SLRAM_BLK_SZ 0x4000 |
1da177e4 LT |
51 | |
52 | #define T(fmt, args...) printk(KERN_DEBUG fmt, ## args) | |
53 | #define E(fmt, args...) printk(KERN_NOTICE fmt, ## args) | |
54 | ||
55 | typedef struct slram_priv { | |
56 | u_char *start; | |
57 | u_char *end; | |
58 | } slram_priv_t; | |
59 | ||
60 | typedef struct slram_mtd_list { | |
61 | struct mtd_info *mtdinfo; | |
62 | struct slram_mtd_list *next; | |
63 | } slram_mtd_list_t; | |
64 | ||
65 | #ifdef MODULE | |
66 | static char *map[SLRAM_MAX_DEVICES_PARAMS]; | |
67 | ||
68 | module_param_array(map, charp, NULL, 0); | |
69 | MODULE_PARM_DESC(map, "List of memory regions to map. \"map=<name>, <start>, <length / end>\""); | |
70 | #else | |
71 | static char *map; | |
72 | #endif | |
73 | ||
74 | static slram_mtd_list_t *slram_mtdlist = NULL; | |
75 | ||
76 | static int slram_erase(struct mtd_info *, struct erase_info *); | |
a98889f3 JH |
77 | static int slram_point(struct mtd_info *, loff_t, size_t, size_t *, void **, |
78 | resource_size_t *); | |
79 | static void slram_unpoint(struct mtd_info *, loff_t, size_t); | |
1da177e4 LT |
80 | static int slram_read(struct mtd_info *, loff_t, size_t, size_t *, u_char *); |
81 | static int slram_write(struct mtd_info *, loff_t, size_t, size_t *, const u_char *); | |
82 | ||
83 | static int slram_erase(struct mtd_info *mtd, struct erase_info *instr) | |
84 | { | |
85 | slram_priv_t *priv = mtd->priv; | |
86 | ||
87 | if (instr->addr + instr->len > mtd->size) { | |
88 | return(-EINVAL); | |
89 | } | |
e5580fbe | 90 | |
1da177e4 LT |
91 | memset(priv->start + instr->addr, 0xff, instr->len); |
92 | ||
e5580fbe | 93 | /* This'll catch a few races. Free the thing before returning :) |
1da177e4 LT |
94 | * I don't feel at all ashamed. This kind of thing is possible anyway |
95 | * with flash, but unlikely. | |
96 | */ | |
97 | ||
98 | instr->state = MTD_ERASE_DONE; | |
99 | ||
100 | mtd_erase_callback(instr); | |
101 | ||
102 | return(0); | |
103 | } | |
104 | ||
105 | static int slram_point(struct mtd_info *mtd, loff_t from, size_t len, | |
a98889f3 | 106 | size_t *retlen, void **virt, resource_size_t *phys) |
1da177e4 LT |
107 | { |
108 | slram_priv_t *priv = mtd->priv; | |
109 | ||
a98889f3 JH |
110 | /* can we return a physical address with this driver? */ |
111 | if (phys) | |
112 | return -EINVAL; | |
113 | ||
14f8351a JB |
114 | if (from + len > mtd->size) |
115 | return -EINVAL; | |
116 | ||
a98889f3 | 117 | *virt = priv->start + from; |
1da177e4 LT |
118 | *retlen = len; |
119 | return(0); | |
120 | } | |
121 | ||
a98889f3 | 122 | static void slram_unpoint(struct mtd_info *mtd, loff_t from, size_t len) |
1da177e4 LT |
123 | { |
124 | } | |
125 | ||
126 | static int slram_read(struct mtd_info *mtd, loff_t from, size_t len, | |
127 | size_t *retlen, u_char *buf) | |
128 | { | |
129 | slram_priv_t *priv = mtd->priv; | |
14f8351a JB |
130 | |
131 | if (from > mtd->size) | |
132 | return -EINVAL; | |
133 | ||
134 | if (from + len > mtd->size) | |
135 | len = mtd->size - from; | |
136 | ||
1da177e4 LT |
137 | memcpy(buf, priv->start + from, len); |
138 | ||
139 | *retlen = len; | |
140 | return(0); | |
141 | } | |
142 | ||
143 | static int slram_write(struct mtd_info *mtd, loff_t to, size_t len, | |
144 | size_t *retlen, const u_char *buf) | |
145 | { | |
146 | slram_priv_t *priv = mtd->priv; | |
147 | ||
14f8351a JB |
148 | if (to + len > mtd->size) |
149 | return -EINVAL; | |
150 | ||
1da177e4 LT |
151 | memcpy(priv->start + to, buf, len); |
152 | ||
153 | *retlen = len; | |
154 | return(0); | |
155 | } | |
156 | ||
157 | /*====================================================================*/ | |
158 | ||
159 | static int register_device(char *name, unsigned long start, unsigned long length) | |
160 | { | |
161 | slram_mtd_list_t **curmtd; | |
162 | ||
163 | curmtd = &slram_mtdlist; | |
164 | while (*curmtd) { | |
165 | curmtd = &(*curmtd)->next; | |
166 | } | |
167 | ||
168 | *curmtd = kmalloc(sizeof(slram_mtd_list_t), GFP_KERNEL); | |
169 | if (!(*curmtd)) { | |
170 | E("slram: Cannot allocate new MTD device.\n"); | |
171 | return(-ENOMEM); | |
172 | } | |
95b93a0c | 173 | (*curmtd)->mtdinfo = kzalloc(sizeof(struct mtd_info), GFP_KERNEL); |
1da177e4 | 174 | (*curmtd)->next = NULL; |
e5580fbe | 175 | |
1da177e4 | 176 | if ((*curmtd)->mtdinfo) { |
1da177e4 | 177 | (*curmtd)->mtdinfo->priv = |
95b93a0c | 178 | kzalloc(sizeof(slram_priv_t), GFP_KERNEL); |
e5580fbe | 179 | |
1da177e4 LT |
180 | if (!(*curmtd)->mtdinfo->priv) { |
181 | kfree((*curmtd)->mtdinfo); | |
182 | (*curmtd)->mtdinfo = NULL; | |
1da177e4 LT |
183 | } |
184 | } | |
185 | ||
186 | if (!(*curmtd)->mtdinfo) { | |
187 | E("slram: Cannot allocate new MTD device.\n"); | |
188 | return(-ENOMEM); | |
189 | } | |
e5580fbe | 190 | |
1da177e4 LT |
191 | if (!(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start = |
192 | ioremap(start, length))) { | |
193 | E("slram: ioremap failed\n"); | |
194 | return -EIO; | |
195 | } | |
196 | ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end = | |
197 | ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start + length; | |
198 | ||
199 | ||
200 | (*curmtd)->mtdinfo->name = name; | |
201 | (*curmtd)->mtdinfo->size = length; | |
a6c591ed | 202 | (*curmtd)->mtdinfo->flags = MTD_CAP_RAM; |
1da177e4 LT |
203 | (*curmtd)->mtdinfo->erase = slram_erase; |
204 | (*curmtd)->mtdinfo->point = slram_point; | |
205 | (*curmtd)->mtdinfo->unpoint = slram_unpoint; | |
206 | (*curmtd)->mtdinfo->read = slram_read; | |
207 | (*curmtd)->mtdinfo->write = slram_write; | |
208 | (*curmtd)->mtdinfo->owner = THIS_MODULE; | |
21c8db9e | 209 | (*curmtd)->mtdinfo->type = MTD_RAM; |
14f8351a | 210 | (*curmtd)->mtdinfo->erasesize = SLRAM_BLK_SZ; |
17ffc7ba | 211 | (*curmtd)->mtdinfo->writesize = 1; |
1da177e4 LT |
212 | |
213 | if (add_mtd_device((*curmtd)->mtdinfo)) { | |
214 | E("slram: Failed to register new device\n"); | |
215 | iounmap(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start); | |
216 | kfree((*curmtd)->mtdinfo->priv); | |
217 | kfree((*curmtd)->mtdinfo); | |
218 | return(-EAGAIN); | |
219 | } | |
220 | T("slram: Registered device %s from %luKiB to %luKiB\n", name, | |
221 | (start / 1024), ((start + length) / 1024)); | |
222 | T("slram: Mapped from 0x%p to 0x%p\n", | |
223 | ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start, | |
224 | ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end); | |
e5580fbe | 225 | return(0); |
1da177e4 LT |
226 | } |
227 | ||
228 | static void unregister_devices(void) | |
229 | { | |
230 | slram_mtd_list_t *nextitem; | |
231 | ||
232 | while (slram_mtdlist) { | |
233 | nextitem = slram_mtdlist->next; | |
234 | del_mtd_device(slram_mtdlist->mtdinfo); | |
235 | iounmap(((slram_priv_t *)slram_mtdlist->mtdinfo->priv)->start); | |
236 | kfree(slram_mtdlist->mtdinfo->priv); | |
237 | kfree(slram_mtdlist->mtdinfo); | |
238 | kfree(slram_mtdlist); | |
239 | slram_mtdlist = nextitem; | |
240 | } | |
241 | } | |
242 | ||
243 | static unsigned long handle_unit(unsigned long value, char *unit) | |
244 | { | |
245 | if ((*unit == 'M') || (*unit == 'm')) { | |
246 | return(value * 1024 * 1024); | |
247 | } else if ((*unit == 'K') || (*unit == 'k')) { | |
248 | return(value * 1024); | |
249 | } | |
250 | return(value); | |
251 | } | |
252 | ||
253 | static int parse_cmdline(char *devname, char *szstart, char *szlength) | |
254 | { | |
255 | char *buffer; | |
256 | unsigned long devstart; | |
257 | unsigned long devlength; | |
e5580fbe | 258 | |
1da177e4 LT |
259 | if ((!devname) || (!szstart) || (!szlength)) { |
260 | unregister_devices(); | |
261 | return(-EINVAL); | |
262 | } | |
263 | ||
264 | devstart = simple_strtoul(szstart, &buffer, 0); | |
265 | devstart = handle_unit(devstart, buffer); | |
e5580fbe | 266 | |
1da177e4 LT |
267 | if (*(szlength) != '+') { |
268 | devlength = simple_strtoul(szlength, &buffer, 0); | |
269 | devlength = handle_unit(devlength, buffer) - devstart; | |
3afd522d RK |
270 | if (devlength < devstart) |
271 | goto err_out; | |
272 | ||
273 | devlength -= devstart; | |
1da177e4 LT |
274 | } else { |
275 | devlength = simple_strtoul(szlength + 1, &buffer, 0); | |
276 | devlength = handle_unit(devlength, buffer); | |
277 | } | |
278 | T("slram: devname=%s, devstart=0x%lx, devlength=0x%lx\n", | |
279 | devname, devstart, devlength); | |
3afd522d RK |
280 | if (devlength % SLRAM_BLK_SZ != 0) |
281 | goto err_out; | |
e5580fbe | 282 | |
1da177e4 LT |
283 | if ((devstart = register_device(devname, devstart, devlength))){ |
284 | unregister_devices(); | |
285 | return((int)devstart); | |
286 | } | |
287 | return(0); | |
3afd522d RK |
288 | |
289 | err_out: | |
290 | E("slram: Illegal length parameter.\n"); | |
291 | return(-EINVAL); | |
1da177e4 LT |
292 | } |
293 | ||
294 | #ifndef MODULE | |
295 | ||
296 | static int __init mtd_slram_setup(char *str) | |
297 | { | |
298 | map = str; | |
299 | return(1); | |
300 | } | |
301 | ||
302 | __setup("slram=", mtd_slram_setup); | |
303 | ||
304 | #endif | |
305 | ||
627df23c | 306 | static int __init init_slram(void) |
1da177e4 LT |
307 | { |
308 | char *devname; | |
309 | int i; | |
310 | ||
311 | #ifndef MODULE | |
312 | char *devstart; | |
313 | char *devlength; | |
314 | ||
315 | i = 0; | |
316 | ||
317 | if (!map) { | |
318 | E("slram: not enough parameters.\n"); | |
319 | return(-EINVAL); | |
320 | } | |
321 | while (map) { | |
322 | devname = devstart = devlength = NULL; | |
323 | ||
324 | if (!(devname = strsep(&map, ","))) { | |
325 | E("slram: No devicename specified.\n"); | |
326 | break; | |
327 | } | |
328 | T("slram: devname = %s\n", devname); | |
329 | if ((!map) || (!(devstart = strsep(&map, ",")))) { | |
330 | E("slram: No devicestart specified.\n"); | |
331 | } | |
332 | T("slram: devstart = %s\n", devstart); | |
333 | if ((!map) || (!(devlength = strsep(&map, ",")))) { | |
334 | E("slram: No devicelength / -end specified.\n"); | |
335 | } | |
336 | T("slram: devlength = %s\n", devlength); | |
337 | if (parse_cmdline(devname, devstart, devlength) != 0) { | |
338 | return(-EINVAL); | |
339 | } | |
340 | } | |
341 | #else | |
342 | int count; | |
e5580fbe | 343 | |
269c0ee6 | 344 | for (count = 0; count < SLRAM_MAX_DEVICES_PARAMS && map[count]; |
1da177e4 LT |
345 | count++) { |
346 | } | |
347 | ||
348 | if ((count % 3 != 0) || (count == 0)) { | |
349 | E("slram: not enough parameters.\n"); | |
350 | return(-EINVAL); | |
351 | } | |
352 | for (i = 0; i < (count / 3); i++) { | |
353 | devname = map[i * 3]; | |
354 | ||
355 | if (parse_cmdline(devname, map[i * 3 + 1], map[i * 3 + 2])!=0) { | |
356 | return(-EINVAL); | |
357 | } | |
e5580fbe | 358 | |
1da177e4 LT |
359 | } |
360 | #endif /* !MODULE */ | |
e5580fbe | 361 | |
1da177e4 LT |
362 | return(0); |
363 | } | |
364 | ||
365 | static void __exit cleanup_slram(void) | |
366 | { | |
367 | unregister_devices(); | |
368 | } | |
369 | ||
370 | module_init(init_slram); | |
371 | module_exit(cleanup_slram); | |
372 | ||
373 | MODULE_LICENSE("GPL"); | |
374 | MODULE_AUTHOR("Jochen Schaeuble <psionic@psionic.de>"); | |
375 | MODULE_DESCRIPTION("MTD driver for uncached system RAM"); |