1
2
3
4#include <linux/module.h>
5#include <asm/uaccess.h>
6#include <linux/types.h>
7#include <linux/kernel.h>
8#include <linux/ptrace.h>
9#include <linux/slab.h>
10#include <linux/string.h>
11#include <linux/timer.h>
12#include <linux/major.h>
13#include <linux/fs.h>
14#include <linux/ioctl.h>
15#include <linux/init.h>
16#include <asm/io.h>
17#include <asm/system.h>
18
19#include <linux/mtd/mtd.h>
20
21#define SLRAM_MAX_DEVICES_PARAMS 6		/* 3 parameters / device */
22#define SLRAM_BLK_SZ 0x4000
23
24#define T(fmt, args...) printk(KERN_DEBUG fmt, ## args)
25#define E(fmt, args...) printk(KERN_NOTICE fmt, ## args)
26
27typedef struct slram_priv {
28	u_char *start;
29	u_char *end;
30} slram_priv_t;
31
32typedef struct slram_mtd_list {
33	struct mtd_info *mtdinfo;
34	struct slram_mtd_list *next;
35} slram_mtd_list_t;
36
37#ifdef MODULE
38static char *map[SLRAM_MAX_DEVICES_PARAMS];
39
40module_param_array(map, charp, NULL, 0);
41MODULE_PARM_DESC(map, "List of memory regions to map. \"map=<name>, <start>, <length / end>\"");
42#else
43static char *map;
44#endif
45
46static slram_mtd_list_t *slram_mtdlist = NULL;
47
48static int slram_erase(struct mtd_info *, struct erase_info *);
49static int slram_point(struct mtd_info *, loff_t, size_t, size_t *, u_char **);
50static void slram_unpoint(struct mtd_info *, u_char *, loff_t,	size_t);
51static int slram_read(struct mtd_info *, loff_t, size_t, size_t *, u_char *);
52static int slram_write(struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
53
54static int slram_erase(struct mtd_info *mtd, struct erase_info *instr)
55{
56	slram_priv_t *priv = mtd->priv;
57
58	if (instr->addr + instr->len > mtd->size) {
59		return(-EINVAL);
60	}
61
62	memset(priv->start + instr->addr, 0xff, instr->len);
63
64	/* This'll catch a few races. Free the thing before returning :)
65	 * I don't feel at all ashamed. This kind of thing is possible anyway
66	 * with flash, but unlikely.
67	 */
68
69	instr->state = MTD_ERASE_DONE;
70
71	mtd_erase_callback(instr);
72
73	return(0);
74}
75
76static int slram_point(struct mtd_info *mtd, loff_t from, size_t len,
77		size_t *retlen, u_char **mtdbuf)
78{
79	slram_priv_t *priv = mtd->priv;
80
81	if (from + len > mtd->size)
82		return -EINVAL;
83
84	*mtdbuf = priv->start + from;
85	*retlen = len;
86	return(0);
87}
88
89static void slram_unpoint(struct mtd_info *mtd, u_char *addr, loff_t from, size_t len)
90{
91}
92
93static int slram_read(struct mtd_info *mtd, loff_t from, size_t len,
94		size_t *retlen, u_char *buf)
95{
96	slram_priv_t *priv = mtd->priv;
97
98	if (from > mtd->size)
99		return -EINVAL;
100
101	if (from + len > mtd->size)
102		len = mtd->size - from;
103
104	memcpy(buf, priv->start + from, len);
105
106	*retlen = len;
107	return(0);
108}
109
110static int slram_write(struct mtd_info *mtd, loff_t to, size_t len,
111		size_t *retlen, const u_char *buf)
112{
113	slram_priv_t *priv = mtd->priv;
114
115	if (to + len > mtd->size)
116		return -EINVAL;
117
118	memcpy(priv->start + to, buf, len);
119
120	*retlen = len;
121	return(0);
122}
123
124/*====================================================================*/
125
126static int register_device(char *name, unsigned long start, unsigned long length)
127{
128	slram_mtd_list_t **curmtd;
129
130	curmtd = &slram_mtdlist;
131	while (*curmtd) {
132		curmtd = &(*curmtd)->next;
133	}
134
135	*curmtd = kmalloc(sizeof(slram_mtd_list_t), GFP_KERNEL);
136	if (!(*curmtd)) {
137		E("slram: Cannot allocate new MTD device.\n");
138		return(-ENOMEM);
139	}
140	(*curmtd)->mtdinfo = kzalloc(sizeof(struct mtd_info), GFP_KERNEL);
141	(*curmtd)->next = NULL;
142
143	if ((*curmtd)->mtdinfo)	{
144		(*curmtd)->mtdinfo->priv =
145			kzalloc(sizeof(slram_priv_t), GFP_KERNEL);
146
147		if (!(*curmtd)->mtdinfo->priv) {
148			kfree((*curmtd)->mtdinfo);
149			(*curmtd)->mtdinfo = NULL;
150		}
151	}
152
153	if (!(*curmtd)->mtdinfo) {
154		E("slram: Cannot allocate new MTD device.\n");
155		return(-ENOMEM);
156	}
157
158	if (!(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start =
159				ioremap(start, length))) {
160		E("slram: ioremap failed\n");
161		return -EIO;
162	}
163	((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end =
164		((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start + length;
165
166
167	(*curmtd)->mtdinfo->name = name;
168	(*curmtd)->mtdinfo->size = length;
169	(*curmtd)->mtdinfo->flags = MTD_CAP_RAM;
170        (*curmtd)->mtdinfo->erase = slram_erase;
171	(*curmtd)->mtdinfo->point = slram_point;
172	(*curmtd)->mtdinfo->unpoint = slram_unpoint;
173	(*curmtd)->mtdinfo->read = slram_read;
174	(*curmtd)->mtdinfo->write = slram_write;
175	(*curmtd)->mtdinfo->owner = THIS_MODULE;
176	(*curmtd)->mtdinfo->type = MTD_RAM;
177	(*curmtd)->mtdinfo->erasesize = SLRAM_BLK_SZ;
178	(*curmtd)->mtdinfo->writesize = 1;
179
180	if (add_mtd_device((*curmtd)->mtdinfo))	{
181		E("slram: Failed to register new device\n");
182		iounmap(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start);
183		kfree((*curmtd)->mtdinfo->priv);
184		kfree((*curmtd)->mtdinfo);
185		return(-EAGAIN);
186	}
187	T("slram: Registered device %s from %luKiB to %luKiB\n", name,
188			(start / 1024), ((start + length) / 1024));
189	T("slram: Mapped from 0x%p to 0x%p\n",
190			((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start,
191			((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end);
192	return(0);
193}
194
195static void unregister_devices(void)
196{
197	slram_mtd_list_t *nextitem;
198
199	while (slram_mtdlist) {
200		nextitem = slram_mtdlist->next;
201		del_mtd_device(slram_mtdlist->mtdinfo);
202		iounmap(((slram_priv_t *)slram_mtdlist->mtdinfo->priv)->start);
203		kfree(slram_mtdlist->mtdinfo->priv);
204		kfree(slram_mtdlist->mtdinfo);
205		kfree(slram_mtdlist);
206		slram_mtdlist = nextitem;
207	}
208}
209
210static unsigned long handle_unit(unsigned long value, char *unit)
211{
212	if ((*unit == 'M') || (*unit == 'm')) {
213		return(value * 1024 * 1024);
214	} else if ((*unit == 'K') || (*unit == 'k')) {
215		return(value * 1024);
216	}
217	return(value);
218}
219
220static int parse_cmdline(char *devname, char *szstart, char *szlength)
221{
222	char *buffer;
223	unsigned long devstart;
224	unsigned long devlength;
225
226	if ((!devname) || (!szstart) || (!szlength)) {
227		unregister_devices();
228		return(-EINVAL);
229	}
230
231	devstart = simple_strtoul(szstart, &buffer, 0);
232	devstart = handle_unit(devstart, buffer);
233
234	if (*(szlength) != '+') {
235		devlength = simple_strtoul(szlength, &buffer, 0);
236		devlength = handle_unit(devlength, buffer) - devstart;
237	} else {
238		devlength = simple_strtoul(szlength + 1, &buffer, 0);
239		devlength = handle_unit(devlength, buffer);
240	}
241	T("slram: devname=%s, devstart=0x%lx, devlength=0x%lx\n",
242			devname, devstart, devlength);
243	if ((devstart < 0) || (devlength < 0) || (devlength % SLRAM_BLK_SZ != 0)) {
244		E("slram: Illegal start / length parameter.\n");
245		return(-EINVAL);
246	}
247
248	if ((devstart = register_device(devname, devstart, devlength))){
249		unregister_devices();
250		return((int)devstart);
251	}
252	return(0);
253}
254
255#ifndef MODULE
256
257static int __init mtd_slram_setup(char *str)
258{
259	map = str;
260	return(1);
261}
262
263__setup("slram=", mtd_slram_setup);
264
265#endif
266
267static int init_slram(void)
268{
269	char *devname;
270	int i;
271
272#ifndef MODULE
273	char *devstart;
274	char *devlength;
275
276	i = 0;
277
278	if (!map) {
279		E("slram: not enough parameters.\n");
280		return(-EINVAL);
281	}
282	while (map) {
283		devname = devstart = devlength = NULL;
284
285		if (!(devname = strsep(&map, ","))) {
286			E("slram: No devicename specified.\n");
287			break;
288		}
289		T("slram: devname = %s\n", devname);
290		if ((!map) || (!(devstart = strsep(&map, ",")))) {
291			E("slram: No devicestart specified.\n");
292		}
293		T("slram: devstart = %s\n", devstart);
294		if ((!map) || (!(devlength = strsep(&map, ",")))) {
295			E("slram: No devicelength / -end specified.\n");
296		}
297		T("slram: devlength = %s\n", devlength);
298		if (parse_cmdline(devname, devstart, devlength) != 0) {
299			return(-EINVAL);
300		}
301	}
302#else
303	int count;
304
305	for (count = 0; (map[count]) && (count < SLRAM_MAX_DEVICES_PARAMS);
306			count++) {
307	}
308
309	if ((count % 3 != 0) || (count == 0)) {
310		E("slram: not enough parameters.\n");
311		return(-EINVAL);
312	}
313	for (i = 0; i < (count / 3); i++) {
314		devname = map[i * 3];
315
316		if (parse_cmdline(devname, map[i * 3 + 1], map[i * 3 + 2])!=0) {
317			return(-EINVAL);
318		}
319
320	}
321#endif /* !MODULE */
322
323	return(0);
324}
325
326static void __exit cleanup_slram(void)
327{
328	unregister_devices();
329}
330
331module_init(init_slram);
332module_exit(cleanup_slram);
333
334MODULE_LICENSE("GPL");
335MODULE_AUTHOR("Jochen Schaeuble <psionic@psionic.de>");
336MODULE_DESCRIPTION("MTD driver for uncached system RAM");
337