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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
29struct phram_mtd_list {
30 struct mtd_info mtd;
31 struct list_head list;
32};
33
34static LIST_HEAD(phram_list);
35
36
37static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
38{
39 u_char *start = mtd->priv;
40
41 if (instr->addr + instr->len > mtd->size)
42 return -EINVAL;
43
44 memset(start + instr->addr, 0xff, instr->len);
45
46
47
48
49
50
51 instr->state = MTD_ERASE_DONE;
52
53 mtd_erase_callback(instr);
54
55 return 0;
56}
57
58static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
59 size_t *retlen, void **virt, resource_size_t *phys)
60{
61 if (from + len > mtd->size)
62 return -EINVAL;
63
64
65 if (phys)
66 return -EINVAL;
67
68 *virt = mtd->priv + from;
69 *retlen = len;
70 return 0;
71}
72
73static void phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
74{
75}
76
77static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
78 size_t *retlen, u_char *buf)
79{
80 u_char *start = mtd->priv;
81
82 if (from >= mtd->size)
83 return -EINVAL;
84
85 if (len > mtd->size - from)
86 len = mtd->size - from;
87
88 memcpy(buf, start + from, len);
89
90 *retlen = len;
91 return 0;
92}
93
94static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
95 size_t *retlen, const u_char *buf)
96{
97 u_char *start = mtd->priv;
98
99 if (to >= mtd->size)
100 return -EINVAL;
101
102 if (len > mtd->size - to)
103 len = mtd->size - to;
104
105 memcpy(start + to, buf, len);
106
107 *retlen = len;
108 return 0;
109}
110
111
112
113static void unregister_devices(void)
114{
115 struct phram_mtd_list *this, *safe;
116
117 list_for_each_entry_safe(this, safe, &phram_list, list) {
118 mtd_device_unregister(&this->mtd);
119 iounmap(this->mtd.priv);
120 kfree(this->mtd.name);
121 kfree(this);
122 }
123}
124
125static int register_device(char *name, unsigned long start, unsigned long len)
126{
127 struct phram_mtd_list *new;
128 int ret = -ENOMEM;
129
130 new = kzalloc(sizeof(*new), GFP_KERNEL);
131 if (!new)
132 goto out0;
133
134 ret = -EIO;
135 new->mtd.priv = ioremap(start, len);
136 if (!new->mtd.priv) {
137 pr_err("ioremap failed\n");
138 goto out1;
139 }
140
141
142 new->mtd.name = name;
143 new->mtd.size = len;
144 new->mtd.flags = MTD_CAP_RAM;
145 new->mtd.erase = phram_erase;
146 new->mtd.point = phram_point;
147 new->mtd.unpoint = phram_unpoint;
148 new->mtd.read = phram_read;
149 new->mtd.write = phram_write;
150 new->mtd.owner = THIS_MODULE;
151 new->mtd.type = MTD_RAM;
152 new->mtd.erasesize = PAGE_SIZE;
153 new->mtd.writesize = 1;
154
155 ret = -EAGAIN;
156 if (mtd_device_register(&new->mtd, NULL, 0)) {
157 pr_err("Failed to register new device\n");
158 goto out2;
159 }
160
161 list_add_tail(&new->list, &phram_list);
162 return 0;
163
164out2:
165 iounmap(new->mtd.priv);
166out1:
167 kfree(new);
168out0:
169 return ret;
170}
171
172static int ustrtoul(const char *cp, char **endp, unsigned int base)
173{
174 unsigned long result = simple_strtoul(cp, endp, base);
175
176 switch (**endp) {
177 case 'G':
178 result *= 1024;
179 case 'M':
180 result *= 1024;
181 case 'k':
182 result *= 1024;
183
184 if ((*endp)[1] == 'i')
185 (*endp) += 2;
186 }
187 return result;
188}
189
190static int parse_num32(uint32_t *num32, const char *token)
191{
192 char *endp;
193 unsigned long n;
194
195 n = ustrtoul(token, &endp, 0);
196 if (*endp)
197 return -EINVAL;
198
199 *num32 = n;
200 return 0;
201}
202
203static int parse_name(char **pname, const char *token)
204{
205 size_t len;
206 char *name;
207
208 len = strlen(token) + 1;
209 if (len > 64)
210 return -ENOSPC;
211
212 name = kmalloc(len, GFP_KERNEL);
213 if (!name)
214 return -ENOMEM;
215
216 strcpy(name, token);
217
218 *pname = name;
219 return 0;
220}
221
222
223static inline void kill_final_newline(char *str)
224{
225 char *newline = strrchr(str, '\n');
226 if (newline && !newline[1])
227 *newline = 0;
228}
229
230
231#define parse_err(fmt, args...) do { \
232 pr_err(fmt , ## args); \
233 return 1; \
234} while (0)
235
236static int phram_setup(const char *val, struct kernel_param *kp)
237{
238 char buf[64+12+12], *str = buf;
239 char *token[3];
240 char *name;
241 uint32_t start;
242 uint32_t len;
243 int i, ret;
244
245 if (strnlen(val, sizeof(buf)) >= sizeof(buf))
246 parse_err("parameter too long\n");
247
248 strcpy(str, val);
249 kill_final_newline(str);
250
251 for (i=0; i<3; i++)
252 token[i] = strsep(&str, ",");
253
254 if (str)
255 parse_err("too many arguments\n");
256
257 if (!token[2])
258 parse_err("not enough arguments\n");
259
260 ret = parse_name(&name, token[0]);
261 if (ret)
262 return ret;
263
264 ret = parse_num32(&start, token[1]);
265 if (ret) {
266 kfree(name);
267 parse_err("illegal start address\n");
268 }
269
270 ret = parse_num32(&len, token[2]);
271 if (ret) {
272 kfree(name);
273 parse_err("illegal device length\n");
274 }
275
276 ret = register_device(name, start, len);
277 if (!ret)
278 pr_info("%s device: %#x at %#x\n", name, len, start);
279 else
280 kfree(name);
281
282 return ret;
283}
284
285module_param_call(phram, phram_setup, NULL, NULL, 000);
286MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
287
288
289static int __init init_phram(void)
290{
291 return 0;
292}
293
294static void __exit cleanup_phram(void)
295{
296 unregister_devices();
297}
298
299module_init(init_phram);
300module_exit(cleanup_phram);
301
302MODULE_LICENSE("GPL");
303MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
304MODULE_DESCRIPTION("MTD driver for physical RAM");
305
