1 /**
2 * $Id: phram.c,v 1.11 2005/01/05 18:05:13 dwmw2 Exp $
3 *
4 * Copyright (c) ???? Jochen Schäuble <psionic@psionic.de>
5 * Copyright (c) 2003-2004 Jörn Engel <joern@wh.fh-wedel.de>
6 *
7 * Usage:
8 *
9 * one commend line parameter per device, each in the form:
10 * phram=<name>,<start>,<len>
11 * <name> may be up to 63 characters.
12 * <start> and <len> can be octal, decimal or hexadecimal. If followed
13 * by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
14 * gigabytes.
15 *
16 * Example:
17 * phram=swap,64Mi,128Mi phram=test,900Mi,1Mi
18 *
19 */
20
21 #include <asm/io.h>
22 #include <linux/init.h>
23 #include <linux/kernel.h>
24 #include <linux/list.h>
25 #include <linux/module.h>
26 #include <linux/moduleparam.h>
27 #include <linux/mtd/mtd.h>
28
29 #define ERROR(fmt, args...) printk(KERN_ERR "phram: " fmt , ## args)
30
31 struct phram_mtd_list {
32 struct mtd_info mtd;
33 struct list_head list;
34 };
35
36 static LIST_HEAD(phram_list);
37
38
39
40 static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
41 {
42 u_char *start = mtd->priv;
43
44 if (instr->addr + instr->len > mtd->size)
45 return -EINVAL;
46
47 memset(start + instr->addr, 0xff, instr->len);
48
49 /* This'll catch a few races. Free the thing before returning :)
50 * I don't feel at all ashamed. This kind of thing is possible anyway
51 * with flash, but unlikely.
52 */
53
54 instr->state = MTD_ERASE_DONE;
55
56 mtd_erase_callback(instr);
57
58 return 0;
59 }
60
61 static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
62 size_t *retlen, u_char **mtdbuf)
63 {
64 u_char *start = mtd->priv;
65
66 if (from + len > mtd->size)
67 return -EINVAL;
68
69 *mtdbuf = start + from;
70 *retlen = len;
71 return 0;
72 }
73
74 static void phram_unpoint(struct mtd_info *mtd, u_char *addr, loff_t from, size_t len)
75 {
76 }
77
78 static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
79 size_t *retlen, u_char *buf)
80 {
81 u_char *start = mtd->priv;
82
83 if (from + len > mtd->size)
84 return -EINVAL;
85
86 memcpy(buf, start + from, len);
87
88 *retlen = len;
89 return 0;
90 }
91
92 static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
93 size_t *retlen, const u_char *buf)
94 {
95 u_char *start = mtd->priv;
96
97 if (to + len > mtd->size)
98 return -EINVAL;
99
100 memcpy(start + to, buf, len);
101
102 *retlen = len;
103 return 0;
104 }
105
106
107
108 static void unregister_devices(void)
109 {
110 struct phram_mtd_list *this;
111
112 list_for_each_entry(this, &phram_list, list) {
113 del_mtd_device(&this->mtd);
114 iounmap(this->mtd.priv);
115 kfree(this);
116 }
117 }
118
119 static int register_device(char *name, unsigned long start, unsigned long len)
120 {
121 struct phram_mtd_list *new;
122 int ret = -ENOMEM;
123
124 new = kmalloc(sizeof(*new), GFP_KERNEL);
125 if (!new)
126 goto out0;
127
128 memset(new, 0, sizeof(*new));
129
130 ret = -EIO;
131 new->mtd.priv = ioremap(start, len);
132 if (!new->mtd.priv) {
133 ERROR("ioremap failed\n");
134 goto out1;
135 }
136
137
138 new->mtd.name = name;
139 new->mtd.size = len;
140 new->mtd.flags = MTD_CAP_RAM | MTD_ERASEABLE | MTD_VOLATILE;
141 new->mtd.erase = phram_erase;
142 new->mtd.point = phram_point;
143 new->mtd.unpoint = phram_unpoint;
144 new->mtd.read = phram_read;
145 new->mtd.write = phram_write;
146 new->mtd.owner = THIS_MODULE;
147 new->mtd.type = MTD_RAM;
148 new->mtd.erasesize = 0;
149
150 ret = -EAGAIN;
151 if (add_mtd_device(&new->mtd)) {
152 ERROR("Failed to register new device\n");
153 goto out2;
154 }
155
156 list_add_tail(&new->list, &phram_list);
157 return 0;
158
159 out2:
160 iounmap(new->mtd.priv);
161 out1:
162 kfree(new);
163 out0:
164 return ret;
165 }
166
167 static int ustrtoul(const char *cp, char **endp, unsigned int base)
168 {
169 unsigned long result = simple_strtoul(cp, endp, base);
170
171 switch (**endp) {
172 case 'G':
173 result *= 1024;
174 case 'M':
175 result *= 1024;
176 case 'k':
177 result *= 1024;
178 /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
179 if ((*endp)[1] == 'i')
180 (*endp) += 2;
181 }
182 return result;
183 }
184
185 static int parse_num32(uint32_t *num32, const char *token)
186 {
187 char *endp;
188 unsigned long n;
189
190 n = ustrtoul(token, &endp, 0);
191 if (*endp)
192 return -EINVAL;
193
194 *num32 = n;
195 return 0;
196 }
197
198 static int parse_name(char **pname, const char *token)
199 {
200 size_t len;
201 char *name;
202
203 len = strlen(token) + 1;
204 if (len > 64)
205 return -ENOSPC;
206
207 name = kmalloc(len, GFP_KERNEL);
208 if (!name)
209 return -ENOMEM;
210
211 strcpy(name, token);
212
213 *pname = name;
214 return 0;
215 }
216
217 #define parse_err(fmt, args...) do { \
218 ERROR(fmt , ## args); \
219 return 0; \
220 } while (0)
221
222 static int phram_setup(const char *val, struct kernel_param *kp)
223 {
224 char buf[64+12+12], *str = buf;
225 char *token[3];
226 char *name;
227 uint32_t start;
228 uint32_t len;
229 int i, ret;
230
231 if (strnlen(val, sizeof(buf)) >= sizeof(buf))
232 parse_err("parameter too long\n");
233
234 strcpy(str, val);
235
236 for (i=0; i<3; i++)
237 token[i] = strsep(&str, ",");
238
239 if (str)
240 parse_err("too many arguments\n");
241
242 if (!token[2])
243 parse_err("not enough arguments\n");
244
245 ret = parse_name(&name, token[0]);
246 if (ret == -ENOMEM)
247 parse_err("out of memory\n");
248 if (ret == -ENOSPC)
249 parse_err("name too long\n");
250 if (ret)
251 return 0;
252
253 ret = parse_num32(&start, token[1]);
254 if (ret)
255 parse_err("illegal start address\n");
256
257 ret = parse_num32(&len, token[2]);
258 if (ret)
259 parse_err("illegal device length\n");
260
261 register_device(name, start, len);
262
263 return 0;
264 }
265
266 module_param_call(phram, phram_setup, NULL, NULL, 000);
267 MODULE_PARM_DESC(phram,"Memory region to map. \"map=<name>,<start>,<length>\"");
268
269
270 static int __init init_phram(void)
271 {
272 return 0;
273 }
274
275 static void __exit cleanup_phram(void)
276 {
277 unregister_devices();
278 }
279
280 module_init(init_phram);
281 module_exit(cleanup_phram);
282
283 MODULE_LICENSE("GPL");
284 MODULE_AUTHOR("Jörn Engel <joern@wh.fh-wedel.de>");
285 MODULE_DESCRIPTION("MTD driver for physical RAM");
286
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