1 /**
2 * Copyright (c) ???? Jochen Schäuble <psionic@psionic.de>
3 * Copyright (c) 2003-2004 Joern Engel <joern@wh.fh-wedel.de>
4 *
5 * Usage:
6 *
7 * one commend line parameter per device, each in the form:
8 * phram=<name>,<start>,<len>
9 * <name> may be up to 63 characters.
10 * <start> and <len> can be octal, decimal or hexadecimal. If followed
11 * by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
12 * gigabytes.
13 *
14 * Example:
15 * phram=swap,64Mi,128Mi phram=test,900Mi,1Mi
16 */
17
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
20 #include <linux/io.h>
21 #include <linux/init.h>
22 #include <linux/kernel.h>
23 #include <linux/list.h>
24 #include <linux/module.h>
25 #include <linux/moduleparam.h>
26 #include <linux/slab.h>
27 #include <linux/mtd/mtd.h>
28
29 struct phram_mtd_list {
30 struct mtd_info mtd;
31 struct list_head list;
32 };
33
34 static LIST_HEAD(phram_list);
35
phram_erase(struct mtd_info * mtd,struct erase_info * instr)36 static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
37 {
38 u_char *start = mtd->priv;
39
40 memset(start + instr->addr, 0xff, instr->len);
41
42 return 0;
43 }
44
phram_point(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,void ** virt,resource_size_t * phys)45 static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
46 size_t *retlen, void **virt, resource_size_t *phys)
47 {
48 *virt = mtd->priv + from;
49 *retlen = len;
50 return 0;
51 }
52
phram_unpoint(struct mtd_info * mtd,loff_t from,size_t len)53 static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
54 {
55 return 0;
56 }
57
phram_read(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,u_char * buf)58 static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
59 size_t *retlen, u_char *buf)
60 {
61 u_char *start = mtd->priv;
62
63 memcpy(buf, start + from, len);
64 *retlen = len;
65 return 0;
66 }
67
phram_write(struct mtd_info * mtd,loff_t to,size_t len,size_t * retlen,const u_char * buf)68 static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
69 size_t *retlen, const u_char *buf)
70 {
71 u_char *start = mtd->priv;
72
73 memcpy(start + to, buf, len);
74 *retlen = len;
75 return 0;
76 }
77
unregister_devices(void)78 static void unregister_devices(void)
79 {
80 struct phram_mtd_list *this, *safe;
81
82 list_for_each_entry_safe(this, safe, &phram_list, list) {
83 mtd_device_unregister(&this->mtd);
84 iounmap(this->mtd.priv);
85 kfree(this->mtd.name);
86 kfree(this);
87 }
88 }
89
register_device(char * name,phys_addr_t start,size_t len)90 static int register_device(char *name, phys_addr_t start, size_t len)
91 {
92 struct phram_mtd_list *new;
93 int ret = -ENOMEM;
94
95 new = kzalloc(sizeof(*new), GFP_KERNEL);
96 if (!new)
97 goto out0;
98
99 ret = -EIO;
100 new->mtd.priv = ioremap(start, len);
101 if (!new->mtd.priv) {
102 pr_err("ioremap failed\n");
103 goto out1;
104 }
105
106
107 new->mtd.name = name;
108 new->mtd.size = len;
109 new->mtd.flags = MTD_CAP_RAM;
110 new->mtd._erase = phram_erase;
111 new->mtd._point = phram_point;
112 new->mtd._unpoint = phram_unpoint;
113 new->mtd._read = phram_read;
114 new->mtd._write = phram_write;
115 new->mtd.owner = THIS_MODULE;
116 new->mtd.type = MTD_RAM;
117 new->mtd.erasesize = PAGE_SIZE;
118 new->mtd.writesize = 1;
119
120 ret = -EAGAIN;
121 if (mtd_device_register(&new->mtd, NULL, 0)) {
122 pr_err("Failed to register new device\n");
123 goto out2;
124 }
125
126 list_add_tail(&new->list, &phram_list);
127 return 0;
128
129 out2:
130 iounmap(new->mtd.priv);
131 out1:
132 kfree(new);
133 out0:
134 return ret;
135 }
136
parse_num64(uint64_t * num64,char * token)137 static int parse_num64(uint64_t *num64, char *token)
138 {
139 size_t len;
140 int shift = 0;
141 int ret;
142
143 len = strlen(token);
144 /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
145 if (len > 2) {
146 if (token[len - 1] == 'i') {
147 switch (token[len - 2]) {
148 case 'G':
149 shift += 10;
150 case 'M':
151 shift += 10;
152 case 'k':
153 shift += 10;
154 token[len - 2] = 0;
155 break;
156 default:
157 return -EINVAL;
158 }
159 }
160 }
161
162 ret = kstrtou64(token, 0, num64);
163 *num64 <<= shift;
164
165 return ret;
166 }
167
parse_name(char ** pname,const char * token)168 static int parse_name(char **pname, const char *token)
169 {
170 size_t len;
171 char *name;
172
173 len = strlen(token) + 1;
174 if (len > 64)
175 return -ENOSPC;
176
177 name = kstrdup(token, GFP_KERNEL);
178 if (!name)
179 return -ENOMEM;
180
181 *pname = name;
182 return 0;
183 }
184
185
kill_final_newline(char * str)186 static inline void kill_final_newline(char *str)
187 {
188 char *newline = strrchr(str, '\n');
189
190 if (newline && !newline[1])
191 *newline = 0;
192 }
193
194
195 #define parse_err(fmt, args...) do { \
196 pr_err(fmt , ## args); \
197 return 1; \
198 } while (0)
199
200 #ifndef MODULE
201 static int phram_init_called;
202 /*
203 * This shall contain the module parameter if any. It is of the form:
204 * - phram=<device>,<address>,<size> for module case
205 * - phram.phram=<device>,<address>,<size> for built-in case
206 * We leave 64 bytes for the device name, 20 for the address and 20 for the
207 * size.
208 * Example: phram.phram=rootfs,0xa0000000,512Mi
209 */
210 static char phram_paramline[64 + 20 + 20];
211 #endif
212
phram_setup(const char * val)213 static int phram_setup(const char *val)
214 {
215 char buf[64 + 20 + 20], *str = buf;
216 char *token[3];
217 char *name;
218 uint64_t start;
219 uint64_t len;
220 int i, ret;
221
222 if (strnlen(val, sizeof(buf)) >= sizeof(buf))
223 parse_err("parameter too long\n");
224
225 strcpy(str, val);
226 kill_final_newline(str);
227
228 for (i = 0; i < 3; i++)
229 token[i] = strsep(&str, ",");
230
231 if (str)
232 parse_err("too many arguments\n");
233
234 if (!token[2])
235 parse_err("not enough arguments\n");
236
237 ret = parse_name(&name, token[0]);
238 if (ret)
239 return ret;
240
241 ret = parse_num64(&start, token[1]);
242 if (ret) {
243 kfree(name);
244 parse_err("illegal start address\n");
245 }
246
247 ret = parse_num64(&len, token[2]);
248 if (ret) {
249 kfree(name);
250 parse_err("illegal device length\n");
251 }
252
253 ret = register_device(name, start, len);
254 if (!ret)
255 pr_info("%s device: %#llx at %#llx\n", name, len, start);
256 else
257 kfree(name);
258
259 return ret;
260 }
261
phram_param_call(const char * val,const struct kernel_param * kp)262 static int phram_param_call(const char *val, const struct kernel_param *kp)
263 {
264 #ifdef MODULE
265 return phram_setup(val);
266 #else
267 /*
268 * If more parameters are later passed in via
269 * /sys/module/phram/parameters/phram
270 * and init_phram() has already been called,
271 * we can parse the argument now.
272 */
273
274 if (phram_init_called)
275 return phram_setup(val);
276
277 /*
278 * During early boot stage, we only save the parameters
279 * here. We must parse them later: if the param passed
280 * from kernel boot command line, phram_param_call() is
281 * called so early that it is not possible to resolve
282 * the device (even kmalloc() fails). Defer that work to
283 * phram_setup().
284 */
285
286 if (strlen(val) >= sizeof(phram_paramline))
287 return -ENOSPC;
288 strcpy(phram_paramline, val);
289
290 return 0;
291 #endif
292 }
293
294 module_param_call(phram, phram_param_call, NULL, NULL, 000);
295 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
296
297
init_phram(void)298 static int __init init_phram(void)
299 {
300 int ret = 0;
301
302 #ifndef MODULE
303 if (phram_paramline[0])
304 ret = phram_setup(phram_paramline);
305 phram_init_called = 1;
306 #endif
307
308 return ret;
309 }
310
cleanup_phram(void)311 static void __exit cleanup_phram(void)
312 {
313 unregister_devices();
314 }
315
316 module_init(init_phram);
317 module_exit(cleanup_phram);
318
319 MODULE_LICENSE("GPL");
320 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
321 MODULE_DESCRIPTION("MTD driver for physical RAM");
322
