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

// SPDX-License-Identifier: GPL-2.0-only
/**
 * 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);

	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;
				/* fall through */
			case 'M':
				shift += 10;
				/* fall through */
			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, const 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
09c434b8	1	// SPDX-License-Identifier: GPL-2.0-only
1da177e4	2	/**
151e7659	3	* Copyright (c) ???? Jochen Schäuble <psionic@psionic.de>
2b54aaef	4	* Copyright (c) 2003-2004 Joern Engel <joern@wh.fh-wedel.de>
1da177e4 LT	5	*
	6	* Usage:
	7	*
	8	* one commend line parameter per device, each in the form:
	9	* phram=<name>,<start>,<len>
	10	* <name> may be up to 63 characters.
	11	* <start> and <len> can be octal, decimal or hexadecimal. If followed
	12	* by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
	13	* gigabytes.
	14	*
	15	* Example:
	16	* phram=swap,64Mi,128Mi phram=test,900Mi,1Mi
1da177e4	17	*/
64da392a	18
1cd844fe	19	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
64da392a	20
b85b8d92	21	#include <linux/io.h>
1da177e4 LT	22	#include <linux/init.h>
	23	#include <linux/kernel.h>
	24	#include <linux/list.h>
	25	#include <linux/module.h>
	26	#include <linux/moduleparam.h>
4e57b681	27	#include <linux/slab.h>
1da177e4 LT	28	#include <linux/mtd/mtd.h>
1da177e4 LT	29
1da177e4 LT	30	struct phram_mtd_list {
	31	struct mtd_info mtd;
	32	struct list_head list;
	33	};
	34
	35	static LIST_HEAD(phram_list);
	36
1da177e4 LT	37	static int phram_erase(struct mtd_info mtd, struct erase_info instr)
	38	{
	39	u_char *start = mtd->priv;
	40
1da177e4 LT	41	memset(start + instr->addr, 0xff, instr->len);
1da177e4 LT	42
1da177e4 LT	43	return 0;
	44	}
	45
	46	static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
a98889f3	47	size_t retlen, void virt, resource_size_t phys)
1da177e4	48	{
a98889f3	49	*virt = mtd->priv + from;
1da177e4 LT	50	*retlen = len;
	51	return 0;
	52	}
	53
5e4e6e3f	54	static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
1da177e4	55	{
5e4e6e3f	56	return 0;
1da177e4 LT	57	}
	58
	59	static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
	60	size_t retlen, u_char buf)
	61	{
	62	u_char *start = mtd->priv;
	63
1da177e4	64	memcpy(buf, start + from, len);
1da177e4 LT	65	*retlen = len;
	66	return 0;
	67	}
	68
	69	static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
	70	size_t retlen, const u_char buf)
	71	{
	72	u_char *start = mtd->priv;
	73
1da177e4	74	memcpy(start + to, buf, len);
1da177e4 LT	75	*retlen = len;
	76	return 0;
	77	}
	78
1da177e4 LT	79	static void unregister_devices(void)
1da177e4 LT	80	{
d30f11d2	81	struct phram_mtd_list this, safe;
1da177e4	82
d30f11d2	83	list_for_each_entry_safe(this, safe, &phram_list, list) {
ee0e87b1	84	mtd_device_unregister(&this->mtd);
1da177e4	85	iounmap(this->mtd.priv);
f17f12ce	86	kfree(this->mtd.name);
1da177e4 LT	87	kfree(this);
	88	}
	89	}
	90
2a46f835	91	static int register_device(char *name, phys_addr_t start, size_t len)
1da177e4 LT	92	{
	93	struct phram_mtd_list *new;
	94	int ret = -ENOMEM;
	95
95b93a0c	96	new = kzalloc(sizeof(*new), GFP_KERNEL);
1da177e4 LT	97	if (!new)
	98	goto out0;
	99
1da177e4 LT	100	ret = -EIO;
	101	new->mtd.priv = ioremap(start, len);
	102	if (!new->mtd.priv) {
64da392a	103	pr_err("ioremap failed\n");
1da177e4 LT	104	goto out1;
	105	}
	106
	107
	108	new->mtd.name = name;
	109	new->mtd.size = len;
a6c591ed	110	new->mtd.flags = MTD_CAP_RAM;
3c3c10bb AB	111	new->mtd._erase = phram_erase;
	112	new->mtd._point = phram_point;
	113	new->mtd._unpoint = phram_unpoint;
	114	new->mtd._read = phram_read;
	115	new->mtd._write = phram_write;
1da177e4	116	new->mtd.owner = THIS_MODULE;
21c8db9e	117	new->mtd.type = MTD_RAM;
663259a4	118	new->mtd.erasesize = PAGE_SIZE;
17ffc7ba	119	new->mtd.writesize = 1;
1da177e4 LT	120
1da177e4 LT	121	ret = -EAGAIN;
ee0e87b1	122	if (mtd_device_register(&new->mtd, NULL, 0)) {
64da392a	123	pr_err("Failed to register new device\n");
1da177e4 LT	124	goto out2;
	125	}
	126
	127	list_add_tail(&new->list, &phram_list);
e5580fbe	128	return 0;
1da177e4 LT	129
	130	out2:
	131	iounmap(new->mtd.priv);
	132	out1:
	133	kfree(new);
	134	out0:
	135	return ret;
	136	}
	137
2a46f835	138	static int parse_num64(uint64_t num64, char token)
1da177e4	139	{
2a46f835 AS	140	size_t len;
	141	int shift = 0;
	142	int ret;
	143
	144	len = strlen(token);
1da177e4	145	/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
2a46f835 AS	146	if (len > 2) {
	147	if (token[len - 1] == 'i') {
	148	switch (token[len - 2]) {
	149	case 'G':
	150	shift += 10;
098d74b4	151	/* fall through */
2a46f835 AS	152	case 'M':
2a46f835 AS	153	shift += 10;
098d74b4	154	/* fall through */
2a46f835 AS	155	case 'k':
	156	shift += 10;
	157	token[len - 2] = 0;
	158	break;
	159	default:
	160	return -EINVAL;
	161	}
	162	}
1da177e4	163	}
1da177e4	164
2a46f835 AS	165	ret = kstrtou64(token, 0, num64);
2a46f835 AS	166	*num64 <<= shift;
1da177e4	167
2a46f835	168	return ret;
1da177e4 LT	169	}
	170
	171	static int parse_name(char *pname, const char token)
	172	{
	173	size_t len;
	174	char *name;
	175
	176	len = strlen(token) + 1;
	177	if (len > 64)
	178	return -ENOSPC;
	179
89384f64	180	name = kstrdup(token, GFP_KERNEL);
1da177e4 LT	181	if (!name)
	182	return -ENOMEM;
	183
1da177e4 LT	184	*pname = name;
	185	return 0;
	186	}
	187
663259a4 JE	188
	189	static inline void kill_final_newline(char *str)
	190	{
	191	char *newline = strrchr(str, '\n');
c95777a4	192
663259a4 JE	193	if (newline && !newline[1])
	194	*newline = 0;
	195	}
	196
	197
1da177e4	198	#define parse_err(fmt, args...) do { \
64da392a MF	199	pr_err(fmt , ## args); \
64da392a MF	200	return 1; \
1da177e4 LT	201	} while (0)
1da177e4 LT	202
6f6b9fee AS	203	#ifndef MODULE
6f6b9fee AS	204	static int phram_init_called;
b2a2a84d HF	205	/*
	206	* This shall contain the module parameter if any. It is of the form:
	207	* - phram=<device>,<address>,<size> for module case
	208	* - phram.phram=<device>,<address>,<size> for built-in case
2a46f835	209	* We leave 64 bytes for the device name, 20 for the address and 20 for the
b2a2a84d HF	210	* size.
	211	* Example: phram.phram=rootfs,0xa0000000,512Mi
	212	*/
6f6b9fee AS	213	static char phram_paramline[64 + 20 + 20];
6f6b9fee AS	214	#endif
b2a2a84d	215
6f6b9fee	216	static int phram_setup(const char *val)
1da177e4	217	{
2a46f835	218	char buf[64 + 20 + 20], *str = buf;
1da177e4 LT	219	char *token[3];
1da177e4 LT	220	char *name;
2a46f835 AS	221	uint64_t start;
2a46f835 AS	222	uint64_t len;
1da177e4 LT	223	int i, ret;
	224
	225	if (strnlen(val, sizeof(buf)) >= sizeof(buf))
	226	parse_err("parameter too long\n");
	227
	228	strcpy(str, val);
663259a4	229	kill_final_newline(str);
1da177e4	230
c95777a4	231	for (i = 0; i < 3; i++)
1da177e4 LT	232	token[i] = strsep(&str, ",");
	233
	234	if (str)
	235	parse_err("too many arguments\n");
	236
	237	if (!token[2])
	238	parse_err("not enough arguments\n");
	239
	240	ret = parse_name(&name, token[0]);
1da177e4	241	if (ret)
64da392a	242	return ret;
1da177e4	243
2a46f835	244	ret = parse_num64(&start, token[1]);
4f678a58 JJ	245	if (ret) {
4f678a58 JJ	246	kfree(name);
1da177e4	247	parse_err("illegal start address\n");
4f678a58	248	}
1da177e4	249
2a46f835	250	ret = parse_num64(&len, token[2]);
4f678a58 JJ	251	if (ret) {
4f678a58 JJ	252	kfree(name);
1da177e4	253	parse_err("illegal device length\n");
4f678a58	254	}
1da177e4	255
64da392a MF	256	ret = register_device(name, start, len);
64da392a MF	257	if (!ret)
2a46f835	258	pr_info("%s device: %#llx at %#llx\n", name, len, start);
f17f12ce MK	259	else
f17f12ce MK	260	kfree(name);
1da177e4	261
64da392a	262	return ret;
1da177e4 LT	263	}
1da177e4 LT	264
e4dca7b7	265	static int phram_param_call(const char val, const struct kernel_param kp)
b2a2a84d	266	{
6f6b9fee AS	267	#ifdef MODULE
	268	return phram_setup(val);
	269	#else
b2a2a84d	270	/*
6f6b9fee AS	271	* If more parameters are later passed in via
	272	* /sys/module/phram/parameters/phram
	273	* and init_phram() has already been called,
	274	* we can parse the argument now.
b2a2a84d	275	*/
6f6b9fee AS	276
	277	if (phram_init_called)
	278	return phram_setup(val);
	279
	280	/*
	281	* During early boot stage, we only save the parameters
	282	* here. We must parse them later: if the param passed
	283	* from kernel boot command line, phram_param_call() is
	284	* called so early that it is not possible to resolve
	285	* the device (even kmalloc() fails). Defer that work to
	286	* phram_setup().
	287	*/
	288
b2a2a84d HF	289	if (strlen(val) >= sizeof(phram_paramline))
	290	return -ENOSPC;
	291	strcpy(phram_paramline, val);
	292
	293	return 0;
6f6b9fee	294	#endif
b2a2a84d HF	295	}
	296
	297	module_param_call(phram, phram_param_call, NULL, NULL, 000);
f72561cf	298	MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
1da177e4 LT	299
	300
	301	static int __init init_phram(void)
	302	{
6f6b9fee AS	303	int ret = 0;
	304
	305	#ifndef MODULE
b2a2a84d	306	if (phram_paramline[0])
6f6b9fee AS	307	ret = phram_setup(phram_paramline);
	308	phram_init_called = 1;
	309	#endif
b2a2a84d	310
6f6b9fee	311	return ret;
1da177e4 LT	312	}
	313
	314	static void __exit cleanup_phram(void)
	315	{
	316	unregister_devices();
	317	}
	318
	319	module_init(init_phram);
	320	module_exit(cleanup_phram);
	321
	322	MODULE_LICENSE("GPL");
2b54aaef	323	MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
1da177e4	324	MODULE_DESCRIPTION("MTD driver for physical RAM");