w1_ds2433.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *	w1_ds2433.c - w1 family 23 (DS2433) & 43 (DS28EC20) eeprom driver
  4 *
  5 * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
  6 * Copyright (c) 2023 Marc Ferland <marc.ferland@sonatest.com>
  7 */
  8
  9#include <linux/kernel.h>
 10#include <linux/module.h>
 11#include <linux/moduleparam.h>
 12#include <linux/device.h>
 13#include <linux/types.h>
 14#include <linux/delay.h>
 15#include <linux/slab.h>
 16#ifdef CONFIG_W1_SLAVE_DS2433_CRC
 17#include <linux/crc16.h>
 18
 19#define CRC16_INIT		0
 20#define CRC16_VALID		0xb001
 21
 22#endif
 23
 24#include <linux/w1.h>
 25
 26#define W1_EEPROM_DS2433	0x23
 27#define W1_EEPROM_DS28EC20	0x43
 28
 29#define W1_EEPROM_DS2433_SIZE	512
 30#define W1_EEPROM_DS28EC20_SIZE 2560
 31
 32#define W1_PAGE_SIZE		32
 33#define W1_PAGE_BITS		5
 34#define W1_PAGE_MASK		0x1F
 35#define W1_VALIDCRC_MAX		96
 36
 37#define W1_F23_READ_EEPROM	0xF0
 38#define W1_F23_WRITE_SCRATCH	0x0F
 39#define W1_F23_READ_SCRATCH	0xAA
 40#define W1_F23_COPY_SCRATCH	0x55
 41
 42struct ds2433_config {
 43	size_t eeprom_size;		/* eeprom size in bytes */
 44	unsigned int page_count;	/* number of 256 bits pages */
 45	unsigned int tprog;		/* time in ms for page programming */
 46};
 47
 48static const struct ds2433_config config_f23 = {
 49	.eeprom_size = W1_EEPROM_DS2433_SIZE,
 50	.page_count = 16,
 51	.tprog = 5,
 52};
 53
 54static const struct ds2433_config config_f43 = {
 55	.eeprom_size = W1_EEPROM_DS28EC20_SIZE,
 56	.page_count = 80,
 57	.tprog = 10,
 58};
 59
 60struct w1_f23_data {
 61#ifdef CONFIG_W1_SLAVE_DS2433_CRC
 62	u8 *memory;
 63	DECLARE_BITMAP(validcrc, W1_VALIDCRC_MAX);
 64#endif
 65	const struct ds2433_config *cfg;
 66};
 67
 68/*
 69 * Check the file size bounds and adjusts count as needed.
 70 * This would not be needed if the file size didn't reset to 0 after a write.
 71 */
 72static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
 73{
 74	if (off > size)
 75		return 0;
 76
 77	if ((off + count) > size)
 78		return (size - off);
 79
 80	return count;
 81}
 82
 83#ifdef CONFIG_W1_SLAVE_DS2433_CRC
 84static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
 85				int block)
 86{
 87	u8	wrbuf[3];
 88	int	off = block * W1_PAGE_SIZE;
 89
 90	if (test_bit(block, data->validcrc))
 91		return 0;
 92
 93	if (w1_reset_select_slave(sl)) {
 94		bitmap_zero(data->validcrc, data->cfg->page_count);
 95		return -EIO;
 96	}
 97
 98	wrbuf[0] = W1_F23_READ_EEPROM;
 99	wrbuf[1] = off & 0xff;
100	wrbuf[2] = off >> 8;
101	w1_write_block(sl->master, wrbuf, 3);
102	w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
103
104	/* cache the block if the CRC is valid */
105	if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
106		set_bit(block, data->validcrc);
107
108	return 0;
109}
110#endif	/* CONFIG_W1_SLAVE_DS2433_CRC */
111
112static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
113			   const struct bin_attribute *bin_attr, char *buf,
114			   loff_t off, size_t count)
115{
116	struct w1_slave *sl = kobj_to_w1_slave(kobj);
117#ifdef CONFIG_W1_SLAVE_DS2433_CRC
118	struct w1_f23_data *data = sl->family_data;
119	int i, min_page, max_page;
120#else
121	u8 wrbuf[3];
122#endif
123
124	count = w1_f23_fix_count(off, count, bin_attr->size);
125	if (!count)
126		return 0;
127
128	mutex_lock(&sl->master->bus_mutex);
129
130#ifdef CONFIG_W1_SLAVE_DS2433_CRC
131
132	min_page = (off >> W1_PAGE_BITS);
133	max_page = (off + count - 1) >> W1_PAGE_BITS;
134	for (i = min_page; i <= max_page; i++) {
135		if (w1_f23_refresh_block(sl, data, i)) {
136			count = -EIO;
137			goto out_up;
138		}
139	}
140	memcpy(buf, &data->memory[off], count);
141
142#else	/* CONFIG_W1_SLAVE_DS2433_CRC */
143
144	/* read directly from the EEPROM */
145	if (w1_reset_select_slave(sl)) {
146		count = -EIO;
147		goto out_up;
148	}
149
150	wrbuf[0] = W1_F23_READ_EEPROM;
151	wrbuf[1] = off & 0xff;
152	wrbuf[2] = off >> 8;
153	w1_write_block(sl->master, wrbuf, 3);
154	w1_read_block(sl->master, buf, count);
155
156#endif	/* CONFIG_W1_SLAVE_DS2433_CRC */
157
158out_up:
159	mutex_unlock(&sl->master->bus_mutex);
160
161	return count;
162}
163
164/**
165 * w1_f23_write() - Writes to the scratchpad and reads it back for verification.
166 * @sl:		The slave structure
167 * @addr:	Address for the write
168 * @len:	length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
169 * @data:	The data to write
170 *
171 * Then copies the scratchpad to EEPROM.
172 * The data must be on one page.
173 * The master must be locked.
174 *
175 * Return:	0=Success, -1=failure
176 */
177static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
178{
179	struct w1_f23_data *f23 = sl->family_data;
180	u8 wrbuf[4];
181	u8 rdbuf[W1_PAGE_SIZE + 3];
182	u8 es = (addr + len - 1) & 0x1f;
183
184	/* Write the data to the scratchpad */
185	if (w1_reset_select_slave(sl))
186		return -1;
187
188	wrbuf[0] = W1_F23_WRITE_SCRATCH;
189	wrbuf[1] = addr & 0xff;
190	wrbuf[2] = addr >> 8;
191
192	w1_write_block(sl->master, wrbuf, 3);
193	w1_write_block(sl->master, data, len);
194
195	/* Read the scratchpad and verify */
196	if (w1_reset_select_slave(sl))
197		return -1;
198
199	w1_write_8(sl->master, W1_F23_READ_SCRATCH);
200	w1_read_block(sl->master, rdbuf, len + 3);
201
202	/* Compare what was read against the data written */
203	if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
204	    (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
205		return -1;
206
207	/* Copy the scratchpad to EEPROM */
208	if (w1_reset_select_slave(sl))
209		return -1;
210
211	wrbuf[0] = W1_F23_COPY_SCRATCH;
212	wrbuf[3] = es;
213	w1_write_block(sl->master, wrbuf, 4);
214
215	/* Sleep for tprog ms to wait for the write to complete */
216	msleep(f23->cfg->tprog);
217
218	/* Reset the bus to wake up the EEPROM (this may not be needed) */
219	w1_reset_bus(sl->master);
220#ifdef CONFIG_W1_SLAVE_DS2433_CRC
221	clear_bit(addr >> W1_PAGE_BITS, f23->validcrc);
222#endif
223	return 0;
224}
225
226static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
227			    const struct bin_attribute *bin_attr, char *buf,
228			    loff_t off, size_t count)
229{
230	struct w1_slave *sl = kobj_to_w1_slave(kobj);
231	int addr, len, idx;
232
233	count = w1_f23_fix_count(off, count, bin_attr->size);
234	if (!count)
235		return 0;
236
237#ifdef CONFIG_W1_SLAVE_DS2433_CRC
238	/* can only write full blocks in cached mode */
239	if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
240		dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
241			(int)off, count);
242		return -EINVAL;
243	}
244
245	/* make sure the block CRCs are valid */
246	for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
247		if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
248			dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
249			return -EINVAL;
250		}
251	}
252#endif	/* CONFIG_W1_SLAVE_DS2433_CRC */
253
254	mutex_lock(&sl->master->bus_mutex);
255
256	/* Can only write data to one page at a time */
257	idx = 0;
258	while (idx < count) {
259		addr = off + idx;
260		len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
261		if (len > (count - idx))
262			len = count - idx;
263
264		if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
265			count = -EIO;
266			goto out_up;
267		}
268		idx += len;
269	}
270
271out_up:
272	mutex_unlock(&sl->master->bus_mutex);
273
274	return count;
275}
276
277static const struct bin_attribute bin_attr_f23_eeprom = {
278	.attr = { .name = "eeprom", .mode = 0644 },
279	.read = eeprom_read,
280	.write = eeprom_write,
281	.size = W1_EEPROM_DS2433_SIZE,
282};
283
284static const struct bin_attribute bin_attr_f43_eeprom = {
285	.attr = { .name = "eeprom", .mode = 0644 },
286	.read = eeprom_read,
287	.write = eeprom_write,
288	.size = W1_EEPROM_DS28EC20_SIZE,
289};
290
291static const struct bin_attribute *const w1_f23_bin_attributes[] = {
292	&bin_attr_f23_eeprom,
293	NULL,
294};
295
296static const struct attribute_group w1_f23_group = {
297	.bin_attrs = w1_f23_bin_attributes,
298};
299
300static const struct attribute_group *w1_f23_groups[] = {
301	&w1_f23_group,
302	NULL,
303};
304
305static const struct bin_attribute *const w1_f43_bin_attributes[] = {
306	&bin_attr_f43_eeprom,
307	NULL,
308};
309
310static const struct attribute_group w1_f43_group = {
311	.bin_attrs = w1_f43_bin_attributes,
312};
313
314static const struct attribute_group *w1_f43_groups[] = {
315	&w1_f43_group,
316	NULL,
317};
318
319static int w1_f23_add_slave(struct w1_slave *sl)
320{
321	struct w1_f23_data *data;
322
323	data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
324	if (!data)
325		return -ENOMEM;
326
327	switch (sl->family->fid) {
328	case W1_EEPROM_DS2433:
329		data->cfg = &config_f23;
330		break;
331	case W1_EEPROM_DS28EC20:
332		data->cfg = &config_f43;
333		break;
334	}
335
336#ifdef CONFIG_W1_SLAVE_DS2433_CRC
337	if (data->cfg->page_count > W1_VALIDCRC_MAX) {
338		dev_err(&sl->dev, "page count too big for crc bitmap\n");
339		kfree(data);
340		return -EINVAL;
341	}
342	data->memory = kzalloc(data->cfg->eeprom_size, GFP_KERNEL);
343	if (!data->memory) {
344		kfree(data);
345		return -ENOMEM;
346	}
347	bitmap_zero(data->validcrc, data->cfg->page_count);
348#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
349	sl->family_data = data;
350
351	return 0;
352}
353
354static void w1_f23_remove_slave(struct w1_slave *sl)
355{
356	struct w1_f23_data *data = sl->family_data;
357	sl->family_data = NULL;
358#ifdef CONFIG_W1_SLAVE_DS2433_CRC
359	kfree(data->memory);
360#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
361	kfree(data);
362}
363
364static const struct w1_family_ops w1_f23_fops = {
365	.add_slave      = w1_f23_add_slave,
366	.remove_slave   = w1_f23_remove_slave,
367	.groups		= w1_f23_groups,
368};
369
370static const struct w1_family_ops w1_f43_fops = {
371	.add_slave      = w1_f23_add_slave,
372	.remove_slave   = w1_f23_remove_slave,
373	.groups         = w1_f43_groups,
374};
375
376static struct w1_family w1_family_23 = {
377	.fid = W1_EEPROM_DS2433,
378	.fops = &w1_f23_fops,
379};
380
381static struct w1_family w1_family_43 = {
382	.fid = W1_EEPROM_DS28EC20,
383	.fops = &w1_f43_fops,
384};
385
386static int __init w1_ds2433_init(void)
387{
388	int err;
389
390	err = w1_register_family(&w1_family_23);
391	if (err)
392		return err;
393
394	err = w1_register_family(&w1_family_43);
395	if (err)
396		goto err_43;
397
398	return 0;
399
400err_43:
401	w1_unregister_family(&w1_family_23);
402	return err;
403}
404
405static void __exit w1_ds2433_exit(void)
406{
407	w1_unregister_family(&w1_family_23);
408	w1_unregister_family(&w1_family_43);
409}
410
411module_init(w1_ds2433_init);
412module_exit(w1_ds2433_exit);
413
414MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
415MODULE_AUTHOR("Marc Ferland <marc.ferland@sonatest.com>");
416MODULE_DESCRIPTION("w1 family 23/43 driver for DS2433 (4kb) and DS28EC20 (20kb)");
417MODULE_LICENSE("GPL");
418MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2433));
419MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS28EC20));