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 <asm/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 /*
43 * This'll catch a few races. Free the thing before returning :)
44 * I don't feel at all ashamed. This kind of thing is possible anyway
45 * with flash, but unlikely.
46 */
47 instr->state = MTD_ERASE_DONE;
48 mtd_erase_callback(instr);
49 return 0;
50 }
51
phram_point(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,void ** virt,resource_size_t * phys)52 static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
53 size_t *retlen, void **virt, resource_size_t *phys)
54 {
55 *virt = mtd->priv + from;
56 *retlen = len;
57 return 0;
58 }
59
phram_unpoint(struct mtd_info * mtd,loff_t from,size_t len)60 static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
61 {
62 return 0;
63 }
64
phram_read(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,u_char * buf)65 static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
66 size_t *retlen, u_char *buf)
67 {
68 u_char *start = mtd->priv;
69
70 memcpy(buf, start + from, len);
71 *retlen = len;
72 return 0;
73 }
74
phram_write(struct mtd_info * mtd,loff_t to,size_t len,size_t * retlen,const u_char * buf)75 static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
76 size_t *retlen, const u_char *buf)
77 {
78 u_char *start = mtd->priv;
79
80 memcpy(start + to, buf, len);
81 *retlen = len;
82 return 0;
83 }
84
unregister_devices(void)85 static void unregister_devices(void)
86 {
87 struct phram_mtd_list *this, *safe;
88
89 list_for_each_entry_safe(this, safe, &phram_list, list) {
90 mtd_device_unregister(&this->mtd);
91 iounmap(this->mtd.priv);
92 kfree(this->mtd.name);
93 kfree(this);
94 }
95 }
96
register_device(char * name,phys_addr_t start,size_t len)97 static int register_device(char *name, phys_addr_t start, size_t len)
98 {
99 struct phram_mtd_list *new;
100 int ret = -ENOMEM;
101
102 new = kzalloc(sizeof(*new), GFP_KERNEL);
103 if (!new)
104 goto out0;
105
106 ret = -EIO;
107 new->mtd.priv = ioremap(start, len);
108 if (!new->mtd.priv) {
109 pr_err("ioremap failed\n");
110 goto out1;
111 }
112
113
114 new->mtd.name = name;
115 new->mtd.size = len;
116 new->mtd.flags = MTD_CAP_RAM;
117 new->mtd._erase = phram_erase;
118 new->mtd._point = phram_point;
119 new->mtd._unpoint = phram_unpoint;
120 new->mtd._read = phram_read;
121 new->mtd._write = phram_write;
122 new->mtd.owner = THIS_MODULE;
123 new->mtd.type = MTD_RAM;
124 new->mtd.erasesize = PAGE_SIZE;
125 new->mtd.writesize = 1;
126
127 ret = -EAGAIN;
128 if (mtd_device_register(&new->mtd, NULL, 0)) {
129 pr_err("Failed to register new device\n");
130 goto out2;
131 }
132
133 list_add_tail(&new->list, &phram_list);
134 return 0;
135
136 out2:
137 iounmap(new->mtd.priv);
138 out1:
139 kfree(new);
140 out0:
141 return ret;
142 }
143
parse_num64(uint64_t * num64,char * token)144 static int parse_num64(uint64_t *num64, char *token)
145 {
146 size_t len;
147 int shift = 0;
148 int ret;
149
150 len = strlen(token);
151 /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
152 if (len > 2) {
153 if (token[len - 1] == 'i') {
154 switch (token[len - 2]) {
155 case 'G':
156 shift += 10;
157 case 'M':
158 shift += 10;
159 case 'k':
160 shift += 10;
161 token[len - 2] = 0;
162 break;
163 default:
164 return -EINVAL;
165 }
166 }
167 }
168
169 ret = kstrtou64(token, 0, num64);
170 *num64 <<= shift;
171
172 return ret;
173 }
174
parse_name(char ** pname,const char * token)175 static int parse_name(char **pname, const char *token)
176 {
177 size_t len;
178 char *name;
179
180 len = strlen(token) + 1;
181 if (len > 64)
182 return -ENOSPC;
183
184 name = kstrdup(token, GFP_KERNEL);
185 if (!name)
186 return -ENOMEM;
187
188 *pname = name;
189 return 0;
190 }
191
192
kill_final_newline(char * str)193 static inline void kill_final_newline(char *str)
194 {
195 char *newline = strrchr(str, '\n');
196
197 if (newline && !newline[1])
198 *newline = 0;
199 }
200
201
202 #define parse_err(fmt, args...) do { \
203 pr_err(fmt , ## args); \
204 return 1; \
205 } while (0)
206
207 #ifndef MODULE
208 static int phram_init_called;
209 /*
210 * This shall contain the module parameter if any. It is of the form:
211 * - phram=<device>,<address>,<size> for module case
212 * - phram.phram=<device>,<address>,<size> for built-in case
213 * We leave 64 bytes for the device name, 20 for the address and 20 for the
214 * size.
215 * Example: phram.phram=rootfs,0xa0000000,512Mi
216 */
217 static char phram_paramline[64 + 20 + 20];
218 #endif
219
phram_setup(const char * val)220 static int phram_setup(const char *val)
221 {
222 char buf[64 + 20 + 20], *str = buf;
223 char *token[3];
224 char *name;
225 uint64_t start;
226 uint64_t len;
227 int i, ret;
228
229 if (strnlen(val, sizeof(buf)) >= sizeof(buf))
230 parse_err("parameter too long\n");
231
232 strcpy(str, val);
233 kill_final_newline(str);
234
235 for (i = 0; i < 3; i++)
236 token[i] = strsep(&str, ",");
237
238 if (str)
239 parse_err("too many arguments\n");
240
241 if (!token[2])
242 parse_err("not enough arguments\n");
243
244 ret = parse_name(&name, token[0]);
245 if (ret)
246 return ret;
247
248 ret = parse_num64(&start, token[1]);
249 if (ret) {
250 kfree(name);
251 parse_err("illegal start address\n");
252 }
253
254 ret = parse_num64(&len, token[2]);
255 if (ret) {
256 kfree(name);
257 parse_err("illegal device length\n");
258 }
259
260 ret = register_device(name, start, len);
261 if (!ret)
262 pr_info("%s device: %#llx at %#llx\n", name, len, start);
263 else
264 kfree(name);
265
266 return ret;
267 }
268
phram_param_call(const char * val,struct kernel_param * kp)269 static int phram_param_call(const char *val, struct kernel_param *kp)
270 {
271 #ifdef MODULE
272 return phram_setup(val);
273 #else
274 /*
275 * If more parameters are later passed in via
276 * /sys/module/phram/parameters/phram
277 * and init_phram() has already been called,
278 * we can parse the argument now.
279 */
280
281 if (phram_init_called)
282 return phram_setup(val);
283
284 /*
285 * During early boot stage, we only save the parameters
286 * here. We must parse them later: if the param passed
287 * from kernel boot command line, phram_param_call() is
288 * called so early that it is not possible to resolve
289 * the device (even kmalloc() fails). Defer that work to
290 * phram_setup().
291 */
292
293 if (strlen(val) >= sizeof(phram_paramline))
294 return -ENOSPC;
295 strcpy(phram_paramline, val);
296
297 return 0;
298 #endif
299 }
300
301 module_param_call(phram, phram_param_call, NULL, NULL, 000);
302 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
303
304
init_phram(void)305 static int __init init_phram(void)
306 {
307 int ret = 0;
308
309 #ifndef MODULE
310 if (phram_paramline[0])
311 ret = phram_setup(phram_paramline);
312 phram_init_called = 1;
313 #endif
314
315 return ret;
316 }
317
cleanup_phram(void)318 static void __exit cleanup_phram(void)
319 {
320 unregister_devices();
321 }
322
323 module_init(init_phram);
324 module_exit(cleanup_phram);
325
326 MODULE_LICENSE("GPL");
327 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
328 MODULE_DESCRIPTION("MTD driver for physical RAM");
329