[go: nahoru, domu]
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
29struct phram_mtd_list {
30	struct mtd_info mtd;
31	struct list_head list;
32};
33
34static LIST_HEAD(phram_list);
35
36static 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
52static 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
60static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
61{
62	return 0;
63}
64
65static 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
75static 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
85static 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
97static 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
136out2:
137	iounmap(new->mtd.priv);
138out1:
139	kfree(new);
140out0:
141	return ret;
142}
143
144static 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
175static 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
193static 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
208static 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 */
217static char phram_paramline[64 + 20 + 20];
218#endif
219
220static 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
269static 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
301module_param_call(phram, phram_param_call, NULL, NULL, 000);
302MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
303
304
305static 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
318static void __exit cleanup_phram(void)
319{
320	unregister_devices();
321}
322
323module_init(init_phram);
324module_exit(cleanup_phram);
325
326MODULE_LICENSE("GPL");
327MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
328MODULE_DESCRIPTION("MTD driver for physical RAM");
329