[net-next-2.6.git] / drivers / w1 / w1_ds2433.c

/*
 *	w1_ds2433.c - w1 family 23 (DS2433) driver
 *
 * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2. See the file COPYING for more details.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/delay.h>
#ifdef CONFIG_W1_F23_CRC
#include <linux/crc16.h>

#define CRC16_INIT		0
#define CRC16_VALID		0xb001

#endif

#include "w1.h"
#include "w1_io.h"
#include "w1_int.h"
#include "w1_family.h"

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");

#define W1_EEPROM_SIZE		512
#define W1_PAGE_COUNT		16
#define W1_PAGE_SIZE		32
#define W1_PAGE_BITS		5
#define W1_PAGE_MASK		0x1F

#define W1_F23_TIME		300

#define W1_F23_READ_EEPROM	0xF0
#define W1_F23_WRITE_SCRATCH	0x0F
#define W1_F23_READ_SCRATCH	0xAA
#define W1_F23_COPY_SCRATCH	0x55

struct w1_f23_data {
	u8	memory[W1_EEPROM_SIZE];
	u32	validcrc;
};

/**
 * Check the file size bounds and adjusts count as needed.
 * This would not be needed if the file size didn't reset to 0 after a write.
 */
static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
{
	if (off > size)
		return 0;

	if ((off + count) > size)
		return (size - off);

	return count;
}

#ifdef CONFIG_W1_F23_CRC
static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
				int block)
{
	u8	wrbuf[3];
	int	off = block * W1_PAGE_SIZE;

	if (data->validcrc & (1 << block))
		return 0;

	if (w1_reset_select_slave(sl)) {
		data->validcrc = 0;
		return -EIO;
	}

	wrbuf[0] = W1_F23_READ_EEPROM;
	wrbuf[1] = off & 0xff;
	wrbuf[2] = off >> 8;
	w1_write_block(sl->master, wrbuf, 3);
	w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);

	/* cache the block if the CRC is valid */
	if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
		data->validcrc |= (1 << block);

	return 0;
}
#endif	/* CONFIG_W1_F23_CRC */

static ssize_t w1_f23_read_bin(struct kobject *kobj, char *buf, loff_t off,
			       size_t count)
{
	struct w1_slave *sl = kobj_to_w1_slave(kobj);
#ifdef CONFIG_W1_F23_CRC
	struct w1_f23_data *data = sl->family_data;
	int i, min_page, max_page;
#else
	u8 wrbuf[3];
#endif

	if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
		return 0;

	atomic_inc(&sl->refcnt);
	if (down_interruptible(&sl->master->mutex)) {
		count = 0;
		goto out_dec;
	}

#ifdef CONFIG_W1_F23_CRC

	min_page = (off >> W1_PAGE_BITS);
	max_page = (off + count - 1) >> W1_PAGE_BITS;
	for (i = min_page; i <= max_page; i++) {
		if (w1_f23_refresh_block(sl, data, i)) {
			count = -EIO;
			goto out_up;
		}
	}
	memcpy(buf, &data->memory[off], count);

#else 	/* CONFIG_W1_F23_CRC */

	/* read directly from the EEPROM */
	if (w1_reset_select_slave(sl)) {
		count = -EIO;
		goto out_up;
	}

	wrbuf[0] = W1_F23_READ_EEPROM;
	wrbuf[1] = off & 0xff;
	wrbuf[2] = off >> 8;
	w1_write_block(sl->master, wrbuf, 3);
	w1_read_block(sl->master, buf, count);

#endif	/* CONFIG_W1_F23_CRC */

out_up:
	up(&sl->master->mutex);
out_dec:
	atomic_dec(&sl->refcnt);

	return count;
}

/**
 * Writes to the scratchpad and reads it back for verification.
 * Then copies the scratchpad to EEPROM.
 * The data must be on one page.
 * The master must be locked.
 *
 * @param sl	The slave structure
 * @param addr	Address for the write
 * @param len   length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
 * @param data	The data to write
 * @return	0=Success -1=failure
 */
static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
{
	u8 wrbuf[4];
	u8 rdbuf[W1_PAGE_SIZE + 3];
	u8 es = (addr + len - 1) & 0x1f;

	/* Write the data to the scratchpad */
	if (w1_reset_select_slave(sl))
		return -1;

	wrbuf[0] = W1_F23_WRITE_SCRATCH;
	wrbuf[1] = addr & 0xff;
	wrbuf[2] = addr >> 8;

	w1_write_block(sl->master, wrbuf, 3);
	w1_write_block(sl->master, data, len);

	/* Read the scratchpad and verify */
	if (w1_reset_select_slave(sl))
		return -1;

	w1_write_8(sl->master, W1_F23_READ_SCRATCH);
	w1_read_block(sl->master, rdbuf, len + 3);

	/* Compare what was read against the data written */
	if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
	    (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
		return -1;

	/* Copy the scratchpad to EEPROM */
	if (w1_reset_select_slave(sl))
		return -1;

	wrbuf[0] = W1_F23_COPY_SCRATCH;
	wrbuf[3] = es;
	w1_write_block(sl->master, wrbuf, 4);

	/* Sleep for 5 ms to wait for the write to complete */
	msleep(5);

	/* Reset the bus to wake up the EEPROM (this may not be needed) */
	w1_reset_bus(sl->master);

	return 0;
}

static ssize_t w1_f23_write_bin(struct kobject *kobj, char *buf, loff_t off,
				size_t count)
{
	struct w1_slave *sl = kobj_to_w1_slave(kobj);
	int addr, len, idx;

	if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
		return 0;

#ifdef CONFIG_W1_F23_CRC
	/* can only write full blocks in cached mode */
	if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
		dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
			(int)off, count);
		return -EINVAL;
	}

	/* make sure the block CRCs are valid */
	for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
		if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
			dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
			return -EINVAL;
		}
	}
#endif	/* CONFIG_W1_F23_CRC */

	atomic_inc(&sl->refcnt);
	if (down_interruptible(&sl->master->mutex)) {
		count = 0;
		goto out_dec;
	}

	/* Can only write data to one page at a time */
	idx = 0;
	while (idx < count) {
		addr = off + idx;
		len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
		if (len > (count - idx))
			len = count - idx;

		if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
			count = -EIO;
			goto out_up;
		}
		idx += len;
	}

out_up:
	up(&sl->master->mutex);
out_dec:
	atomic_dec(&sl->refcnt);

	return count;
}

static struct bin_attribute w1_f23_bin_attr = {
	.attr = {
		.name = "eeprom",
		.mode = S_IRUGO | S_IWUSR,
		.owner = THIS_MODULE,
	},
	.size = W1_EEPROM_SIZE,
	.read = w1_f23_read_bin,
	.write = w1_f23_write_bin,
};

static int w1_f23_add_slave(struct w1_slave *sl)
{
	int err;
#ifdef CONFIG_W1_F23_CRC
	struct w1_f23_data *data;

	data = kmalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;
	memset(data, 0, sizeof(struct w1_f23_data));
	sl->family_data = data;

#endif	/* CONFIG_W1_F23_CRC */

	err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);

#ifdef CONFIG_W1_F23_CRC
	if (err)
		kfree(data);
#endif	/* CONFIG_W1_F23_CRC */

	return err;
}

static void w1_f23_remove_slave(struct w1_slave *sl)
{
#ifdef CONFIG_W1_F23_CRC
	if (sl->family_data) {
		kfree(sl->family_data);
		sl->family_data = NULL;
	}
#endif	/* CONFIG_W1_F23_CRC */
	sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
}

static struct w1_family_ops w1_f23_fops = {
	.add_slave      = w1_f23_add_slave,
	.remove_slave   = w1_f23_remove_slave,
};

static struct w1_family w1_family_23 = {
	.fid = W1_EEPROM_DS2433,
	.fops = &w1_f23_fops,
};

static int __init w1_f23_init(void)
{
	return w1_register_family(&w1_family_23);
}

static void __exit w1_f23_fini(void)
{
	w1_unregister_family(&w1_family_23);
}

module_init(w1_f23_init);
module_exit(w1_f23_fini);
Commit	Line	Data
80895392 EP	1	/*
	2	* w1_ds2433.c - w1 family 23 (DS2433) driver
	3	*
	4	* Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
	5	*
0a25e4d5 EP	6	* This source code is licensed under the GNU General Public License,
0a25e4d5 EP	7	* Version 2. See the file COPYING for more details.
80895392 EP	8	*/
	9
	10	#include <linux/kernel.h>
	11	#include <linux/module.h>
	12	#include <linux/moduleparam.h>
	13	#include <linux/device.h>
	14	#include <linux/types.h>
	15	#include <linux/delay.h>
0a25e4d5 EP	16	#ifdef CONFIG_W1_F23_CRC
0a25e4d5 EP	17	#include <linux/crc16.h>
f24ec7f6 EP	18
	19	#define CRC16_INIT 0
	20	#define CRC16_VALID 0xb001
	21
0a25e4d5	22	#endif
80895392 EP	23
	24	#include "w1.h"
	25	#include "w1_io.h"
	26	#include "w1_int.h"
	27	#include "w1_family.h"
	28
	29	MODULE_LICENSE("GPL");
	30	MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
	31	MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
	32
	33	#define W1_EEPROM_SIZE 512
0a25e4d5	34	#define W1_PAGE_COUNT 16
80895392 EP	35	#define W1_PAGE_SIZE 32
	36	#define W1_PAGE_BITS 5
	37	#define W1_PAGE_MASK 0x1F
	38
0a25e4d5 EP	39	#define W1_F23_TIME 300
0a25e4d5 EP	40
80895392 EP	41	#define W1_F23_READ_EEPROM 0xF0
	42	#define W1_F23_WRITE_SCRATCH 0x0F
	43	#define W1_F23_READ_SCRATCH 0xAA
	44	#define W1_F23_COPY_SCRATCH 0x55
	45
0a25e4d5 EP	46	struct w1_f23_data {
	47	u8 memory[W1_EEPROM_SIZE];
	48	u32 validcrc;
	49	};
	50
80895392 EP	51	/**
80895392 EP	52	* Check the file size bounds and adjusts count as needed.
0a25e4d5	53	* This would not be needed if the file size didn't reset to 0 after a write.
80895392 EP	54	*/
	55	static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
	56	{
	57	if (off > size)
	58	return 0;
	59
	60	if ((off + count) > size)
	61	return (size - off);
	62
	63	return count;
	64	}
	65
0a25e4d5 EP	66	#ifdef CONFIG_W1_F23_CRC
	67	static int w1_f23_refresh_block(struct w1_slave sl, struct w1_f23_data data,
	68	int block)
	69	{
	70	u8 wrbuf[3];
	71	int off = block * W1_PAGE_SIZE;
	72
	73	if (data->validcrc & (1 << block))
	74	return 0;
	75
	76	if (w1_reset_select_slave(sl)) {
	77	data->validcrc = 0;
	78	return -EIO;
	79	}
	80
	81	wrbuf[0] = W1_F23_READ_EEPROM;
	82	wrbuf[1] = off & 0xff;
	83	wrbuf[2] = off >> 8;
	84	w1_write_block(sl->master, wrbuf, 3);
	85	w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
	86
	87	/* cache the block if the CRC is valid */
	88	if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
	89	data->validcrc \|= (1 << block);
	90
	91	return 0;
	92	}
	93	#endif /* CONFIG_W1_F23_CRC */
	94
	95	static ssize_t w1_f23_read_bin(struct kobject kobj, char buf, loff_t off,
	96	size_t count)
80895392 EP	97	{
80895392 EP	98	struct w1_slave *sl = kobj_to_w1_slave(kobj);
0a25e4d5 EP	99	#ifdef CONFIG_W1_F23_CRC
	100	struct w1_f23_data *data = sl->family_data;
	101	int i, min_page, max_page;
	102	#else
80895392	103	u8 wrbuf[3];
0a25e4d5	104	#endif
80895392 EP	105
	106	if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
	107	return 0;
	108
	109	atomic_inc(&sl->refcnt);
	110	if (down_interruptible(&sl->master->mutex)) {
	111	count = 0;
	112	goto out_dec;
	113	}
	114
0a25e4d5 EP	115	#ifdef CONFIG_W1_F23_CRC
	116
	117	min_page = (off >> W1_PAGE_BITS);
	118	max_page = (off + count - 1) >> W1_PAGE_BITS;
	119	for (i = min_page; i <= max_page; i++) {
	120	if (w1_f23_refresh_block(sl, data, i)) {
	121	count = -EIO;
	122	goto out_up;
	123	}
	124	}
	125	memcpy(buf, &data->memory[off], count);
	126
	127	#else /* CONFIG_W1_F23_CRC */
	128
80895392 EP	129	/* read directly from the EEPROM */
	130	if (w1_reset_select_slave(sl)) {
	131	count = -EIO;
	132	goto out_up;
	133	}
	134
	135	wrbuf[0] = W1_F23_READ_EEPROM;
	136	wrbuf[1] = off & 0xff;
	137	wrbuf[2] = off >> 8;
	138	w1_write_block(sl->master, wrbuf, 3);
	139	w1_read_block(sl->master, buf, count);
	140
0a25e4d5 EP	141	#endif /* CONFIG_W1_F23_CRC */
0a25e4d5 EP	142
80895392 EP	143	out_up:
	144	up(&sl->master->mutex);
	145	out_dec:
	146	atomic_dec(&sl->refcnt);
	147
	148	return count;
	149	}
	150
	151	/**
	152	* Writes to the scratchpad and reads it back for verification.
0a25e4d5 EP	153	* Then copies the scratchpad to EEPROM.
0a25e4d5 EP	154	* The data must be on one page.
80895392 EP	155	* The master must be locked.
	156	*
	157	* @param sl The slave structure
	158	* @param addr Address for the write
	159	* @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
	160	* @param data The data to write
	161	* @return 0=Success -1=failure
	162	*/
	163	static int w1_f23_write(struct w1_slave sl, int addr, int len, const u8 data)
	164	{
	165	u8 wrbuf[4];
	166	u8 rdbuf[W1_PAGE_SIZE + 3];
	167	u8 es = (addr + len - 1) & 0x1f;
	168
	169	/* Write the data to the scratchpad */
	170	if (w1_reset_select_slave(sl))
	171	return -1;
	172
	173	wrbuf[0] = W1_F23_WRITE_SCRATCH;
	174	wrbuf[1] = addr & 0xff;
	175	wrbuf[2] = addr >> 8;
	176
	177	w1_write_block(sl->master, wrbuf, 3);
	178	w1_write_block(sl->master, data, len);
	179
	180	/* Read the scratchpad and verify */
	181	if (w1_reset_select_slave(sl))
	182	return -1;
	183
	184	w1_write_8(sl->master, W1_F23_READ_SCRATCH);
	185	w1_read_block(sl->master, rdbuf, len + 3);
	186
	187	/* Compare what was read against the data written */
	188	if ((rdbuf[0] != wrbuf[1]) \|\| (rdbuf[1] != wrbuf[2]) \|\|
	189	(rdbuf[2] != es) \|\| (memcmp(data, &rdbuf[3], len) != 0))
	190	return -1;
	191
	192	/* Copy the scratchpad to EEPROM */
	193	if (w1_reset_select_slave(sl))
	194	return -1;
	195
	196	wrbuf[0] = W1_F23_COPY_SCRATCH;
	197	wrbuf[3] = es;
	198	w1_write_block(sl->master, wrbuf, 4);
	199
	200	/* Sleep for 5 ms to wait for the write to complete */
	201	msleep(5);
	202
	203	/* Reset the bus to wake up the EEPROM (this may not be needed) */
	204	w1_reset_bus(sl->master);
	205
	206	return 0;
	207	}
	208
	209	static ssize_t w1_f23_write_bin(struct kobject kobj, char buf, loff_t off,
	210	size_t count)
	211	{
	212	struct w1_slave *sl = kobj_to_w1_slave(kobj);
	213	int addr, len, idx;
	214
	215	if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
	216	return 0;
	217
0a25e4d5 EP	218	#ifdef CONFIG_W1_F23_CRC
	219	/* can only write full blocks in cached mode */
	220	if ((off & W1_PAGE_MASK) \|\| (count & W1_PAGE_MASK)) {
f24ec7f6	221	dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
0a25e4d5 EP	222	(int)off, count);
	223	return -EINVAL;
	224	}
	225
	226	/* make sure the block CRCs are valid */
	227	for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
	228	if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
	229	dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
	230	return -EINVAL;
	231	}
	232	}
	233	#endif /* CONFIG_W1_F23_CRC */
	234
80895392 EP	235	atomic_inc(&sl->refcnt);
	236	if (down_interruptible(&sl->master->mutex)) {
	237	count = 0;
	238	goto out_dec;
	239	}
	240
	241	/* Can only write data to one page at a time */
	242	idx = 0;
	243	while (idx < count) {
	244	addr = off + idx;
	245	len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
	246	if (len > (count - idx))
	247	len = count - idx;
	248
	249	if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
	250	count = -EIO;
	251	goto out_up;
	252	}
	253	idx += len;
	254	}
	255
	256	out_up:
	257	up(&sl->master->mutex);
	258	out_dec:
	259	atomic_dec(&sl->refcnt);
	260
	261	return count;
	262	}
	263
	264	static struct bin_attribute w1_f23_bin_attr = {
	265	.attr = {
	266	.name = "eeprom",
	267	.mode = S_IRUGO \| S_IWUSR,
	268	.owner = THIS_MODULE,
	269	},
	270	.size = W1_EEPROM_SIZE,
	271	.read = w1_f23_read_bin,
	272	.write = w1_f23_write_bin,
	273	};
	274
	275	static int w1_f23_add_slave(struct w1_slave *sl)
	276	{
0a25e4d5 EP	277	int err;
	278	#ifdef CONFIG_W1_F23_CRC
	279	struct w1_f23_data *data;
	280
	281	data = kmalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
	282	if (!data)
	283	return -ENOMEM;
	284	memset(data, 0, sizeof(struct w1_f23_data));
	285	sl->family_data = data;
	286
	287	#endif /* CONFIG_W1_F23_CRC */
	288
	289	err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
	290
	291	#ifdef CONFIG_W1_F23_CRC
	292	if (err)
	293	kfree(data);
	294	#endif /* CONFIG_W1_F23_CRC */
	295
	296	return err;
80895392 EP	297	}
	298
	299	static void w1_f23_remove_slave(struct w1_slave *sl)
	300	{
0a25e4d5 EP	301	#ifdef CONFIG_W1_F23_CRC
	302	if (sl->family_data) {
	303	kfree(sl->family_data);
	304	sl->family_data = NULL;
	305	}
	306	#endif /* CONFIG_W1_F23_CRC */
80895392 EP	307	sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
	308	}
	309
	310	static struct w1_family_ops w1_f23_fops = {
	311	.add_slave = w1_f23_add_slave,
	312	.remove_slave = w1_f23_remove_slave,
	313	};
	314
	315	static struct w1_family w1_family_23 = {
	316	.fid = W1_EEPROM_DS2433,
	317	.fops = &w1_f23_fops,
	318	};
	319
	320	static int __init w1_f23_init(void)
	321	{
	322	return w1_register_family(&w1_family_23);
	323	}
	324
	325	static void __exit w1_f23_fini(void)
	326	{
	327	w1_unregister_family(&w1_family_23);
	328	}
	329
	330	module_init(w1_f23_init);
	331	module_exit(w1_f23_fini);