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,unsigned long start,unsigned long len)97 static int register_device(char *name, unsigned long start, unsigned long 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
ustrtoul(const char * cp,char ** endp,unsigned int base)144 static int ustrtoul(const char *cp, char **endp, unsigned int base)
145 {
146 unsigned long result = simple_strtoul(cp, endp, base);
147
148 switch (**endp) {
149 case 'G':
150 result *= 1024;
151 case 'M':
152 result *= 1024;
153 case 'k':
154 result *= 1024;
155 /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
156 if ((*endp)[1] == 'i')
157 (*endp) += 2;
158 }
159 return result;
160 }
161
parse_num32(uint32_t * num32,const char * token)162 static int parse_num32(uint32_t *num32, const char *token)
163 {
164 char *endp;
165 unsigned long n;
166
167 n = ustrtoul(token, &endp, 0);
168 if (*endp)
169 return -EINVAL;
170
171 *num32 = n;
172 return 0;
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 = kmalloc(len, GFP_KERNEL);
185 if (!name)
186 return -ENOMEM;
187
188 strcpy(name, token);
189
190 *pname = name;
191 return 0;
192 }
193
194
kill_final_newline(char * str)195 static inline void kill_final_newline(char *str)
196 {
197 char *newline = strrchr(str, '\n');
198 if (newline && !newline[1])
199 *newline = 0;
200 }
201
202
203 #define parse_err(fmt, args...) do { \
204 pr_err(fmt , ## args); \
205 return 1; \
206 } while (0)
207
208 /*
209 * This shall contain the module parameter if any. It is of the form:
210 * - phram=<device>,<address>,<size> for module case
211 * - phram.phram=<device>,<address>,<size> for built-in case
212 * We leave 64 bytes for the device name, 12 for the address and 12 for the
213 * size.
214 * Example: phram.phram=rootfs,0xa0000000,512Mi
215 */
216 static __initdata char phram_paramline[64+12+12];
217
phram_setup(const char * val)218 static int __init phram_setup(const char *val)
219 {
220 char buf[64+12+12], *str = buf;
221 char *token[3];
222 char *name;
223 uint32_t start;
224 uint32_t len;
225 int i, ret;
226
227 if (strnlen(val, sizeof(buf)) >= sizeof(buf))
228 parse_err("parameter too long\n");
229
230 strcpy(str, val);
231 kill_final_newline(str);
232
233 for (i=0; i<3; i++)
234 token[i] = strsep(&str, ",");
235
236 if (str)
237 parse_err("too many arguments\n");
238
239 if (!token[2])
240 parse_err("not enough arguments\n");
241
242 ret = parse_name(&name, token[0]);
243 if (ret)
244 return ret;
245
246 ret = parse_num32(&start, token[1]);
247 if (ret) {
248 kfree(name);
249 parse_err("illegal start address\n");
250 }
251
252 ret = parse_num32(&len, token[2]);
253 if (ret) {
254 kfree(name);
255 parse_err("illegal device length\n");
256 }
257
258 ret = register_device(name, start, len);
259 if (!ret)
260 pr_info("%s device: %#x at %#x\n", name, len, start);
261 else
262 kfree(name);
263
264 return ret;
265 }
266
phram_param_call(const char * val,struct kernel_param * kp)267 static int __init phram_param_call(const char *val, struct kernel_param *kp)
268 {
269 /*
270 * This function is always called before 'init_phram()', whether
271 * built-in or module.
272 */
273 if (strlen(val) >= sizeof(phram_paramline))
274 return -ENOSPC;
275 strcpy(phram_paramline, val);
276
277 return 0;
278 }
279
280 module_param_call(phram, phram_param_call, NULL, NULL, 000);
281 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
282
283
init_phram(void)284 static int __init init_phram(void)
285 {
286 if (phram_paramline[0])
287 return phram_setup(phram_paramline);
288
289 return 0;
290 }
291
cleanup_phram(void)292 static void __exit cleanup_phram(void)
293 {
294 unregister_devices();
295 }
296
297 module_init(init_phram);
298 module_exit(cleanup_phram);
299
300 MODULE_LICENSE("GPL");
301 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
302 MODULE_DESCRIPTION("MTD driver for physical RAM");
303