2 * Copyright (c) ???? Jochen Schäuble <psionic@psionic.de>
3 * Copyright (c) 2003-2004 Joern Engel <joern@wh.fh-wedel.de>
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
15 * phram=swap,64Mi,128Mi phram=test,900Mi,1Mi
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
29 struct phram_mtd_list {
31 struct list_head list;
34 static LIST_HEAD(phram_list);
36 static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
38 u_char *start = mtd->priv;
40 memset(start + instr->addr, 0xff, instr->len);
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.
47 instr->state = MTD_ERASE_DONE;
48 mtd_erase_callback(instr);
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)
55 *virt = mtd->priv + from;
60 static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
65 static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
66 size_t *retlen, u_char *buf)
68 u_char *start = mtd->priv;
70 memcpy(buf, start + from, len);
75 static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
76 size_t *retlen, const u_char *buf)
78 u_char *start = mtd->priv;
80 memcpy(start + to, buf, len);
85 static void unregister_devices(void)
87 struct phram_mtd_list *this, *safe;
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);
97 static int register_device(char *name, phys_addr_t start, size_t len)
99 struct phram_mtd_list *new;
102 new = kzalloc(sizeof(*new), GFP_KERNEL);
107 new->mtd.priv = ioremap(start, len);
108 if (!new->mtd.priv) {
109 pr_err("ioremap failed\n");
114 new->mtd.name = name;
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;
128 if (mtd_device_register(&new->mtd, NULL, 0)) {
129 pr_err("Failed to register new device\n");
133 list_add_tail(&new->list, &phram_list);
137 iounmap(new->mtd.priv);
144 static int parse_num64(uint64_t *num64, char *token)
151 /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
153 if (token[len - 1] == 'i') {
154 switch (token[len - 2]) {
169 ret = kstrtou64(token, 0, num64);
175 static int parse_name(char **pname, const char *token)
180 len = strlen(token) + 1;
184 name = kstrdup(token, GFP_KERNEL);
193 static inline void kill_final_newline(char *str)
195 char *newline = strrchr(str, '\n');
197 if (newline && !newline[1])
202 #define parse_err(fmt, args...) do { \
203 pr_err(fmt , ## args); \
208 static int phram_init_called;
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
215 * Example: phram.phram=rootfs,0xa0000000,512Mi
217 static char phram_paramline[64 + 20 + 20];
220 static int phram_setup(const char *val)
222 char buf[64 + 20 + 20], *str = buf;
229 if (strnlen(val, sizeof(buf)) >= sizeof(buf))
230 parse_err("parameter too long\n");
233 kill_final_newline(str);
235 for (i = 0; i < 3; i++)
236 token[i] = strsep(&str, ",");
239 parse_err("too many arguments\n");
242 parse_err("not enough arguments\n");
244 ret = parse_name(&name, token[0]);
248 ret = parse_num64(&start, token[1]);
251 parse_err("illegal start address\n");
254 ret = parse_num64(&len, token[2]);
257 parse_err("illegal device length\n");
260 ret = register_device(name, start, len);
262 pr_info("%s device: %#llx at %#llx\n", name, len, start);
269 static int phram_param_call(const char *val, struct kernel_param *kp)
272 return phram_setup(val);
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.
281 if (phram_init_called)
282 return phram_setup(val);
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
293 if (strlen(val) >= sizeof(phram_paramline))
295 strcpy(phram_paramline, val);
301 module_param_call(phram, phram_param_call, NULL, NULL, 000);
302 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
305 static int __init init_phram(void)
310 if (phram_paramline[0])
311 ret = phram_setup(phram_paramline);
312 phram_init_called = 1;
318 static void __exit cleanup_phram(void)
320 unregister_devices();
323 module_init(init_phram);
324 module_exit(cleanup_phram);
326 MODULE_LICENSE("GPL");
327 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
328 MODULE_DESCRIPTION("MTD driver for physical RAM");