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> | |
1da177e4 LT |
45 | |
46 | #include <linux/mtd/mtd.h> | |
47 | ||
48 | #define SLRAM_MAX_DEVICES_PARAMS 6 /* 3 parameters / device */ | |
14f8351a | 49 | #define SLRAM_BLK_SZ 0x4000 |
1da177e4 LT |
50 | |
51 | #define T(fmt, args...) printk(KERN_DEBUG fmt, ## args) | |
52 | #define E(fmt, args...) printk(KERN_NOTICE fmt, ## args) | |
53 | ||
54 | typedef struct slram_priv { | |
55 | u_char *start; | |
56 | u_char *end; | |
57 | } slram_priv_t; | |
58 | ||
59 | typedef struct slram_mtd_list { | |
60 | struct mtd_info *mtdinfo; | |
61 | struct slram_mtd_list *next; | |
62 | } slram_mtd_list_t; | |
63 | ||
64 | #ifdef MODULE | |
65 | static char *map[SLRAM_MAX_DEVICES_PARAMS]; | |
66 | ||
67 | module_param_array(map, charp, NULL, 0); | |
68 | MODULE_PARM_DESC(map, "List of memory regions to map. \"map=<name>, <start>, <length / end>\""); | |
69 | #else | |
70 | static char *map; | |
71 | #endif | |
72 | ||
73 | static slram_mtd_list_t *slram_mtdlist = NULL; | |
74 | ||
75 | static int slram_erase(struct mtd_info *, struct erase_info *); | |
a98889f3 JH |
76 | static int slram_point(struct mtd_info *, loff_t, size_t, size_t *, void **, |
77 | resource_size_t *); | |
5e4e6e3f | 78 | static int slram_unpoint(struct mtd_info *, loff_t, size_t); |
1da177e4 LT |
79 | static int slram_read(struct mtd_info *, loff_t, size_t, size_t *, u_char *); |
80 | static int slram_write(struct mtd_info *, loff_t, size_t, size_t *, const u_char *); | |
81 | ||
82 | static int slram_erase(struct mtd_info *mtd, struct erase_info *instr) | |
83 | { | |
84 | slram_priv_t *priv = mtd->priv; | |
85 | ||
1da177e4 | 86 | memset(priv->start + instr->addr, 0xff, instr->len); |
e5580fbe | 87 | /* This'll catch a few races. Free the thing before returning :) |
1da177e4 LT |
88 | * I don't feel at all ashamed. This kind of thing is possible anyway |
89 | * with flash, but unlikely. | |
90 | */ | |
1da177e4 | 91 | instr->state = MTD_ERASE_DONE; |
1da177e4 | 92 | mtd_erase_callback(instr); |
1da177e4 LT |
93 | return(0); |
94 | } | |
95 | ||
96 | static int slram_point(struct mtd_info *mtd, loff_t from, size_t len, | |
a98889f3 | 97 | size_t *retlen, void **virt, resource_size_t *phys) |
1da177e4 LT |
98 | { |
99 | slram_priv_t *priv = mtd->priv; | |
100 | ||
a98889f3 | 101 | *virt = priv->start + from; |
1da177e4 LT |
102 | *retlen = len; |
103 | return(0); | |
104 | } | |
105 | ||
5e4e6e3f | 106 | static int slram_unpoint(struct mtd_info *mtd, loff_t from, size_t len) |
1da177e4 | 107 | { |
5e4e6e3f | 108 | return 0; |
1da177e4 LT |
109 | } |
110 | ||
111 | static 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; | |
14f8351a | 115 | |
1da177e4 | 116 | memcpy(buf, priv->start + from, len); |
1da177e4 LT |
117 | *retlen = len; |
118 | return(0); | |
119 | } | |
120 | ||
121 | static 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); | |
1da177e4 LT |
127 | *retlen = len; |
128 | return(0); | |
129 | } | |
130 | ||
131 | /*====================================================================*/ | |
132 | ||
133 | static 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 | } | |
95b93a0c | 147 | (*curmtd)->mtdinfo = kzalloc(sizeof(struct mtd_info), GFP_KERNEL); |
1da177e4 | 148 | (*curmtd)->next = NULL; |
e5580fbe | 149 | |
1da177e4 | 150 | if ((*curmtd)->mtdinfo) { |
1da177e4 | 151 | (*curmtd)->mtdinfo->priv = |
95b93a0c | 152 | kzalloc(sizeof(slram_priv_t), GFP_KERNEL); |
e5580fbe | 153 | |
1da177e4 LT |
154 | if (!(*curmtd)->mtdinfo->priv) { |
155 | kfree((*curmtd)->mtdinfo); | |
156 | (*curmtd)->mtdinfo = NULL; | |
1da177e4 LT |
157 | } |
158 | } | |
159 | ||
160 | if (!(*curmtd)->mtdinfo) { | |
161 | E("slram: Cannot allocate new MTD device.\n"); | |
162 | return(-ENOMEM); | |
163 | } | |
e5580fbe | 164 | |
1da177e4 LT |
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; | |
a6c591ed | 176 | (*curmtd)->mtdinfo->flags = MTD_CAP_RAM; |
3c3c10bb AB |
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; | |
1da177e4 | 182 | (*curmtd)->mtdinfo->owner = THIS_MODULE; |
21c8db9e | 183 | (*curmtd)->mtdinfo->type = MTD_RAM; |
14f8351a | 184 | (*curmtd)->mtdinfo->erasesize = SLRAM_BLK_SZ; |
17ffc7ba | 185 | (*curmtd)->mtdinfo->writesize = 1; |
1da177e4 | 186 | |
ee0e87b1 | 187 | if (mtd_device_register((*curmtd)->mtdinfo, NULL, 0)) { |
1da177e4 LT |
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); | |
e5580fbe | 199 | return(0); |
1da177e4 LT |
200 | } |
201 | ||
202 | static void unregister_devices(void) | |
203 | { | |
204 | slram_mtd_list_t *nextitem; | |
205 | ||
206 | while (slram_mtdlist) { | |
207 | nextitem = slram_mtdlist->next; | |
ee0e87b1 | 208 | mtd_device_unregister(slram_mtdlist->mtdinfo); |
1da177e4 LT |
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 | ||
217 | static 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 | ||
227 | static int parse_cmdline(char *devname, char *szstart, char *szlength) | |
228 | { | |
229 | char *buffer; | |
230 | unsigned long devstart; | |
231 | unsigned long devlength; | |
e5580fbe | 232 | |
1da177e4 LT |
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); | |
e5580fbe | 240 | |
1da177e4 LT |
241 | if (*(szlength) != '+') { |
242 | devlength = simple_strtoul(szlength, &buffer, 0); | |
c36a7ff4 | 243 | devlength = handle_unit(devlength, buffer); |
3afd522d RK |
244 | if (devlength < devstart) |
245 | goto err_out; | |
246 | ||
247 | devlength -= devstart; | |
1da177e4 LT |
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); | |
3afd522d RK |
254 | if (devlength % SLRAM_BLK_SZ != 0) |
255 | goto err_out; | |
e5580fbe | 256 | |
1da177e4 LT |
257 | if ((devstart = register_device(devname, devstart, devlength))){ |
258 | unregister_devices(); | |
259 | return((int)devstart); | |
260 | } | |
261 | return(0); | |
3afd522d RK |
262 | |
263 | err_out: | |
264 | E("slram: Illegal length parameter.\n"); | |
265 | return(-EINVAL); | |
1da177e4 LT |
266 | } |
267 | ||
268 | #ifndef MODULE | |
269 | ||
270 | static 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 | ||
627df23c | 280 | static int __init init_slram(void) |
1da177e4 LT |
281 | { |
282 | char *devname; | |
1da177e4 LT |
283 | |
284 | #ifndef MODULE | |
285 | char *devstart; | |
286 | char *devlength; | |
287 | ||
1da177e4 LT |
288 | if (!map) { |
289 | E("slram: not enough parameters.\n"); | |
290 | return(-EINVAL); | |
291 | } | |
292 | while (map) { | |
293 | devname = devstart = devlength = NULL; | |
294 | ||
295 | if (!(devname = strsep(&map, ","))) { | |
296 | E("slram: No devicename specified.\n"); | |
297 | break; | |
298 | } | |
299 | T("slram: devname = %s\n", devname); | |
300 | if ((!map) || (!(devstart = strsep(&map, ",")))) { | |
301 | E("slram: No devicestart specified.\n"); | |
302 | } | |
303 | T("slram: devstart = %s\n", devstart); | |
304 | if ((!map) || (!(devlength = strsep(&map, ",")))) { | |
305 | E("slram: No devicelength / -end specified.\n"); | |
306 | } | |
307 | T("slram: devlength = %s\n", devlength); | |
308 | if (parse_cmdline(devname, devstart, devlength) != 0) { | |
309 | return(-EINVAL); | |
310 | } | |
311 | } | |
312 | #else | |
313 | int count; | |
ed491d20 | 314 | int i; |
e5580fbe | 315 | |
269c0ee6 | 316 | for (count = 0; count < SLRAM_MAX_DEVICES_PARAMS && map[count]; |
1da177e4 LT |
317 | count++) { |
318 | } | |
319 | ||
320 | if ((count % 3 != 0) || (count == 0)) { | |
321 | E("slram: not enough parameters.\n"); | |
322 | return(-EINVAL); | |
323 | } | |
324 | for (i = 0; i < (count / 3); i++) { | |
325 | devname = map[i * 3]; | |
326 | ||
327 | if (parse_cmdline(devname, map[i * 3 + 1], map[i * 3 + 2])!=0) { | |
328 | return(-EINVAL); | |
329 | } | |
e5580fbe | 330 | |
1da177e4 LT |
331 | } |
332 | #endif /* !MODULE */ | |
e5580fbe | 333 | |
1da177e4 LT |
334 | return(0); |
335 | } | |
336 | ||
337 | static void __exit cleanup_slram(void) | |
338 | { | |
339 | unregister_devices(); | |
340 | } | |
341 | ||
342 | module_init(init_slram); | |
343 | module_exit(cleanup_slram); | |
344 | ||
345 | MODULE_LICENSE("GPL"); | |
346 | MODULE_AUTHOR("Jochen Schaeuble <psionic@psionic.de>"); | |
347 | MODULE_DESCRIPTION("MTD driver for uncached system RAM"); |