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, 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
136out2:
137	iounmap(new->mtd.priv);
138out1:
139	kfree(new);
140out0:
141	return ret;
142}
143
144static 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
162static 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
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 = 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
195static 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 */
216static __initdata char phram_paramline[64+12+12];
217
218static 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
267static 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
280module_param_call(phram, phram_param_call, NULL, NULL, 000);
281MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
282
283
284static int __init init_phram(void)
285{
286	if (phram_paramline[0])
287		return phram_setup(phram_paramline);
288
289	return 0;
290}
291
292static void __exit cleanup_phram(void)
293{
294	unregister_devices();
295}
296
297module_init(init_phram);
298module_exit(cleanup_phram);
299
300MODULE_LICENSE("GPL");
301MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
302MODULE_DESCRIPTION("MTD driver for physical RAM");
303