[linux-2.6-block.git] / drivers / mtd / devices / phram.c

/**
 * Copyright (c) ????		Jochen Schäuble <psionic@psionic.de>
 * Copyright (c) 2003-2004	Joern Engel <joern@wh.fh-wedel.de>
 *
 * Usage:
 *
 * one commend line parameter per device, each in the form:
 *   phram=<name>,<start>,<len>
 * <name> may be up to 63 characters.
 * <start> and <len> can be octal, decimal or hexadecimal.  If followed
 * by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
 * gigabytes.
 *
 * Example:
 *	phram=swap,64Mi,128Mi phram=test,900Mi,1Mi
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/io.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>

struct phram_mtd_list {
	struct mtd_info mtd;
	struct list_head list;
};

static LIST_HEAD(phram_list);

static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
{
	u_char *start = mtd->priv;

	memset(start + instr->addr, 0xff, instr->len);

	/*
	 * This'll catch a few races. Free the thing before returning :)
	 * I don't feel at all ashamed. This kind of thing is possible anyway
	 * with flash, but unlikely.
	 */
	instr->state = MTD_ERASE_DONE;
	mtd_erase_callback(instr);
	return 0;
}

static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
		size_t *retlen, void **virt, resource_size_t *phys)
{
	*virt = mtd->priv + from;
	*retlen = len;
	return 0;
}

static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
{
	return 0;
}

static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
		size_t *retlen, u_char *buf)
{
	u_char *start = mtd->priv;

	memcpy(buf, start + from, len);
	*retlen = len;
	return 0;
}

static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
		size_t *retlen, const u_char *buf)
{
	u_char *start = mtd->priv;

	memcpy(start + to, buf, len);
	*retlen = len;
	return 0;
}

static void unregister_devices(void)
{
	struct phram_mtd_list *this, *safe;

	list_for_each_entry_safe(this, safe, &phram_list, list) {
		mtd_device_unregister(&this->mtd);
		iounmap(this->mtd.priv);
		kfree(this->mtd.name);
		kfree(this);
	}
}

static int register_device(char *name, phys_addr_t start, size_t len)
{
	struct phram_mtd_list *new;
	int ret = -ENOMEM;

	new = kzalloc(sizeof(*new), GFP_KERNEL);
	if (!new)
		goto out0;

	ret = -EIO;
	new->mtd.priv = ioremap(start, len);
	if (!new->mtd.priv) {
		pr_err("ioremap failed\n");
		goto out1;
	}


	new->mtd.name = name;
	new->mtd.size = len;
	new->mtd.flags = MTD_CAP_RAM;
	new->mtd._erase = phram_erase;
	new->mtd._point = phram_point;
	new->mtd._unpoint = phram_unpoint;
	new->mtd._read = phram_read;
	new->mtd._write = phram_write;
	new->mtd.owner = THIS_MODULE;
	new->mtd.type = MTD_RAM;
	new->mtd.erasesize = PAGE_SIZE;
	new->mtd.writesize = 1;

	ret = -EAGAIN;
	if (mtd_device_register(&new->mtd, NULL, 0)) {
		pr_err("Failed to register new device\n");
		goto out2;
	}

	list_add_tail(&new->list, &phram_list);
	return 0;

out2:
	iounmap(new->mtd.priv);
out1:
	kfree(new);
out0:
	return ret;
}

static int parse_num64(uint64_t *num64, char *token)
{
	size_t len;
	int shift = 0;
	int ret;

	len = strlen(token);
	/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
	if (len > 2) {
		if (token[len - 1] == 'i') {
			switch (token[len - 2]) {
			case 'G':
				shift += 10;
			case 'M':
				shift += 10;
			case 'k':
				shift += 10;
				token[len - 2] = 0;
				break;
			default:
				return -EINVAL;
			}
		}
	}

	ret = kstrtou64(token, 0, num64);
	*num64 <<= shift;

	return ret;
}

static int parse_name(char **pname, const char *token)
{
	size_t len;
	char *name;

	len = strlen(token) + 1;
	if (len > 64)
		return -ENOSPC;

	name = kstrdup(token, GFP_KERNEL);
	if (!name)
		return -ENOMEM;

	*pname = name;
	return 0;
}


static inline void kill_final_newline(char *str)
{
	char *newline = strrchr(str, '\n');

	if (newline && !newline[1])
		*newline = 0;
}


#define parse_err(fmt, args...) do {	\
	pr_err(fmt , ## args);	\
	return 1;		\
} while (0)

#ifndef MODULE
static int phram_init_called;
/*
 * This shall contain the module parameter if any. It is of the form:
 * - phram=<device>,<address>,<size> for module case
 * - phram.phram=<device>,<address>,<size> for built-in case
 * We leave 64 bytes for the device name, 20 for the address and 20 for the
 * size.
 * Example: phram.phram=rootfs,0xa0000000,512Mi
 */
static char phram_paramline[64 + 20 + 20];
#endif

static int phram_setup(const char *val)
{
	char buf[64 + 20 + 20], *str = buf;
	char *token[3];
	char *name;
	uint64_t start;
	uint64_t len;
	int i, ret;

	if (strnlen(val, sizeof(buf)) >= sizeof(buf))
		parse_err("parameter too long\n");

	strcpy(str, val);
	kill_final_newline(str);

	for (i = 0; i < 3; i++)
		token[i] = strsep(&str, ",");

	if (str)
		parse_err("too many arguments\n");

	if (!token[2])
		parse_err("not enough arguments\n");

	ret = parse_name(&name, token[0]);
	if (ret)
		return ret;

	ret = parse_num64(&start, token[1]);
	if (ret) {
		kfree(name);
		parse_err("illegal start address\n");
	}

	ret = parse_num64(&len, token[2]);
	if (ret) {
		kfree(name);
		parse_err("illegal device length\n");
	}

	ret = register_device(name, start, len);
	if (!ret)
		pr_info("%s device: %#llx at %#llx\n", name, len, start);
	else
		kfree(name);

	return ret;
}

static int phram_param_call(const char *val, struct kernel_param *kp)
{
#ifdef MODULE
	return phram_setup(val);
#else
	/*
	 * If more parameters are later passed in via
	 * /sys/module/phram/parameters/phram
	 * and init_phram() has already been called,
	 * we can parse the argument now.
	 */

	if (phram_init_called)
		return phram_setup(val);

	/*
	 * During early boot stage, we only save the parameters
	 * here. We must parse them later: if the param passed
	 * from kernel boot command line, phram_param_call() is
	 * called so early that it is not possible to resolve
	 * the device (even kmalloc() fails). Defer that work to
	 * phram_setup().
	 */

	if (strlen(val) >= sizeof(phram_paramline))
		return -ENOSPC;
	strcpy(phram_paramline, val);

	return 0;
#endif
}

module_param_call(phram, phram_param_call, NULL, NULL, 000);
MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");


static int __init init_phram(void)
{
	int ret = 0;

#ifndef MODULE
	if (phram_paramline[0])
		ret = phram_setup(phram_paramline);
	phram_init_called = 1;
#endif

	return ret;
}

static void __exit cleanup_phram(void)
{
	unregister_devices();
}

module_init(init_phram);
module_exit(cleanup_phram);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
MODULE_DESCRIPTION("MTD driver for physical RAM");
Commit	Line	Data
1da177e4	1	/**
151e7659	2	* Copyright (c) ???? Jochen Schäuble <psionic@psionic.de>
2b54aaef	3	* Copyright (c) 2003-2004 Joern Engel <joern@wh.fh-wedel.de>
1da177e4 LT	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
1da177e4	16	*/
64da392a	17
1cd844fe	18	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
64da392a	19
b85b8d92	20	#include <linux/io.h>
1da177e4 LT	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>
4e57b681	26	#include <linux/slab.h>
1da177e4 LT	27	#include <linux/mtd/mtd.h>
1da177e4 LT	28
1da177e4 LT	29	struct phram_mtd_list {
	30	struct mtd_info mtd;
	31	struct list_head list;
	32	};
	33
	34	static LIST_HEAD(phram_list);
	35
1da177e4 LT	36	static int phram_erase(struct mtd_info mtd, struct erase_info instr)
	37	{
	38	u_char *start = mtd->priv;
	39
1da177e4 LT	40	memset(start + instr->addr, 0xff, instr->len);
1da177e4 LT	41
b2a2a84d HF	42	/*
b2a2a84d HF	43	* This'll catch a few races. Free the thing before returning :)
1da177e4 LT	44	* I don't feel at all ashamed. This kind of thing is possible anyway
	45	* with flash, but unlikely.
	46	*/
1da177e4	47	instr->state = MTD_ERASE_DONE;
1da177e4	48	mtd_erase_callback(instr);
1da177e4 LT	49	return 0;
	50	}
	51
	52	static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
a98889f3	53	size_t retlen, void virt, resource_size_t phys)
1da177e4	54	{
a98889f3	55	*virt = mtd->priv + from;
1da177e4 LT	56	*retlen = len;
	57	return 0;
	58	}
	59
5e4e6e3f	60	static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
1da177e4	61	{
5e4e6e3f	62	return 0;
1da177e4 LT	63	}
	64
	65	static 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
1da177e4	70	memcpy(buf, start + from, len);
1da177e4 LT	71	*retlen = len;
	72	return 0;
	73	}
	74
	75	static 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
1da177e4	80	memcpy(start + to, buf, len);
1da177e4 LT	81	*retlen = len;
	82	return 0;
	83	}
	84
1da177e4 LT	85	static void unregister_devices(void)
1da177e4 LT	86	{
d30f11d2	87	struct phram_mtd_list this, safe;
1da177e4	88
d30f11d2	89	list_for_each_entry_safe(this, safe, &phram_list, list) {
ee0e87b1	90	mtd_device_unregister(&this->mtd);
1da177e4	91	iounmap(this->mtd.priv);
f17f12ce	92	kfree(this->mtd.name);
1da177e4 LT	93	kfree(this);
	94	}
	95	}
	96
2a46f835	97	static int register_device(char *name, phys_addr_t start, size_t len)
1da177e4 LT	98	{
	99	struct phram_mtd_list *new;
	100	int ret = -ENOMEM;
	101
95b93a0c	102	new = kzalloc(sizeof(*new), GFP_KERNEL);
1da177e4 LT	103	if (!new)
	104	goto out0;
	105
1da177e4 LT	106	ret = -EIO;
	107	new->mtd.priv = ioremap(start, len);
	108	if (!new->mtd.priv) {
64da392a	109	pr_err("ioremap failed\n");
1da177e4 LT	110	goto out1;
	111	}
	112
	113
	114	new->mtd.name = name;
	115	new->mtd.size = len;
a6c591ed	116	new->mtd.flags = MTD_CAP_RAM;
3c3c10bb AB	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;
1da177e4	122	new->mtd.owner = THIS_MODULE;
21c8db9e	123	new->mtd.type = MTD_RAM;
663259a4	124	new->mtd.erasesize = PAGE_SIZE;
17ffc7ba	125	new->mtd.writesize = 1;
1da177e4 LT	126
1da177e4 LT	127	ret = -EAGAIN;
ee0e87b1	128	if (mtd_device_register(&new->mtd, NULL, 0)) {
64da392a	129	pr_err("Failed to register new device\n");
1da177e4 LT	130	goto out2;
	131	}
	132
	133	list_add_tail(&new->list, &phram_list);
e5580fbe	134	return 0;
1da177e4 LT	135
	136	out2:
	137	iounmap(new->mtd.priv);
	138	out1:
	139	kfree(new);
	140	out0:
	141	return ret;
	142	}
	143
2a46f835	144	static int parse_num64(uint64_t num64, char token)
1da177e4	145	{
2a46f835 AS	146	size_t len;
	147	int shift = 0;
	148	int ret;
	149
	150	len = strlen(token);
1da177e4	151	/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
2a46f835 AS	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	}
1da177e4	167	}
1da177e4	168
2a46f835 AS	169	ret = kstrtou64(token, 0, num64);
2a46f835 AS	170	*num64 <<= shift;
1da177e4	171
2a46f835	172	return ret;
1da177e4 LT	173	}
	174
	175	static 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
89384f64	184	name = kstrdup(token, GFP_KERNEL);
1da177e4 LT	185	if (!name)
	186	return -ENOMEM;
	187
1da177e4 LT	188	*pname = name;
	189	return 0;
	190	}
	191
663259a4 JE	192
	193	static inline void kill_final_newline(char *str)
	194	{
	195	char *newline = strrchr(str, '\n');
c95777a4	196
663259a4 JE	197	if (newline && !newline[1])
	198	*newline = 0;
	199	}
	200
	201
1da177e4	202	#define parse_err(fmt, args...) do { \
64da392a MF	203	pr_err(fmt , ## args); \
64da392a MF	204	return 1; \
1da177e4 LT	205	} while (0)
1da177e4 LT	206
6f6b9fee AS	207	#ifndef MODULE
6f6b9fee AS	208	static int phram_init_called;
b2a2a84d HF	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
2a46f835	213	* We leave 64 bytes for the device name, 20 for the address and 20 for the
b2a2a84d HF	214	* size.
	215	* Example: phram.phram=rootfs,0xa0000000,512Mi
	216	*/
6f6b9fee AS	217	static char phram_paramline[64 + 20 + 20];
6f6b9fee AS	218	#endif
b2a2a84d	219
6f6b9fee	220	static int phram_setup(const char *val)
1da177e4	221	{
2a46f835	222	char buf[64 + 20 + 20], *str = buf;
1da177e4 LT	223	char *token[3];
1da177e4 LT	224	char *name;
2a46f835 AS	225	uint64_t start;
2a46f835 AS	226	uint64_t len;
1da177e4 LT	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);
663259a4	233	kill_final_newline(str);
1da177e4	234
c95777a4	235	for (i = 0; i < 3; i++)
1da177e4 LT	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]);
1da177e4	245	if (ret)
64da392a	246	return ret;
1da177e4	247
2a46f835	248	ret = parse_num64(&start, token[1]);
4f678a58 JJ	249	if (ret) {
4f678a58 JJ	250	kfree(name);
1da177e4	251	parse_err("illegal start address\n");
4f678a58	252	}
1da177e4	253
2a46f835	254	ret = parse_num64(&len, token[2]);
4f678a58 JJ	255	if (ret) {
4f678a58 JJ	256	kfree(name);
1da177e4	257	parse_err("illegal device length\n");
4f678a58	258	}
1da177e4	259
64da392a MF	260	ret = register_device(name, start, len);
64da392a MF	261	if (!ret)
2a46f835	262	pr_info("%s device: %#llx at %#llx\n", name, len, start);
f17f12ce MK	263	else
f17f12ce MK	264	kfree(name);
1da177e4	265
64da392a	266	return ret;
1da177e4 LT	267	}
1da177e4 LT	268
6f6b9fee	269	static int phram_param_call(const char val, struct kernel_param kp)
b2a2a84d	270	{
6f6b9fee AS	271	#ifdef MODULE
	272	return phram_setup(val);
	273	#else
b2a2a84d	274	/*
6f6b9fee AS	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.
b2a2a84d	279	*/
6f6b9fee AS	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
b2a2a84d HF	293	if (strlen(val) >= sizeof(phram_paramline))
	294	return -ENOSPC;
	295	strcpy(phram_paramline, val);
	296
	297	return 0;
6f6b9fee	298	#endif
b2a2a84d HF	299	}
	300
	301	module_param_call(phram, phram_param_call, NULL, NULL, 000);
f72561cf	302	MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
1da177e4 LT	303
	304
	305	static int __init init_phram(void)
	306	{
6f6b9fee AS	307	int ret = 0;
	308
	309	#ifndef MODULE
b2a2a84d	310	if (phram_paramline[0])
6f6b9fee AS	311	ret = phram_setup(phram_paramline);
	312	phram_init_called = 1;
	313	#endif
b2a2a84d	314
6f6b9fee	315	return ret;
1da177e4 LT	316	}
	317
	318	static void __exit cleanup_phram(void)
	319	{
	320	unregister_devices();
	321	}
	322
	323	module_init(init_phram);
	324	module_exit(cleanup_phram);
	325
	326	MODULE_LICENSE("GPL");
2b54aaef	327	MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
1da177e4	328	MODULE_DESCRIPTION("MTD driver for physical RAM");