xref: /openbmc/linux/drivers/misc/c2port/core.c (revision d0e22329)
1 /*
2  *  Silicon Labs C2 port core Linux support
3  *
4  *  Copyright (c) 2007 Rodolfo Giometti <giometti@linux.it>
5  *  Copyright (c) 2007 Eurotech S.p.A. <info@eurotech.it>
6  *
7  * This program is free software; you can redistribute it and/or modify it
8  * under the terms of the GNU General Public License version 2 as published by
9  * the Free Software Foundation
10  */
11 
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/device.h>
15 #include <linux/errno.h>
16 #include <linux/err.h>
17 #include <linux/kernel.h>
18 #include <linux/ctype.h>
19 #include <linux/delay.h>
20 #include <linux/idr.h>
21 #include <linux/sched.h>
22 #include <linux/slab.h>
23 
24 #include <linux/c2port.h>
25 
26 #define DRIVER_NAME             "c2port"
27 #define DRIVER_VERSION          "0.51.0"
28 
29 static DEFINE_SPINLOCK(c2port_idr_lock);
30 static DEFINE_IDR(c2port_idr);
31 
32 /*
33  * Local variables
34  */
35 
36 static struct class *c2port_class;
37 
38 /*
39  * C2 registers & commands defines
40  */
41 
42 /* C2 registers */
43 #define C2PORT_DEVICEID		0x00
44 #define C2PORT_REVID		0x01
45 #define C2PORT_FPCTL		0x02
46 #define C2PORT_FPDAT		0xB4
47 
48 /* C2 interface commands */
49 #define C2PORT_GET_VERSION	0x01
50 #define C2PORT_DEVICE_ERASE	0x03
51 #define C2PORT_BLOCK_READ	0x06
52 #define C2PORT_BLOCK_WRITE	0x07
53 #define C2PORT_PAGE_ERASE	0x08
54 
55 /* C2 status return codes */
56 #define C2PORT_INVALID_COMMAND	0x00
57 #define C2PORT_COMMAND_FAILED	0x02
58 #define C2PORT_COMMAND_OK	0x0d
59 
60 /*
61  * C2 port low level signal managements
62  */
63 
64 static void c2port_reset(struct c2port_device *dev)
65 {
66 	struct c2port_ops *ops = dev->ops;
67 
68 	/* To reset the device we have to keep clock line low for at least
69 	 * 20us.
70 	 */
71 	local_irq_disable();
72 	ops->c2ck_set(dev, 0);
73 	udelay(25);
74 	ops->c2ck_set(dev, 1);
75 	local_irq_enable();
76 
77 	udelay(1);
78 }
79 
80 static void c2port_strobe_ck(struct c2port_device *dev)
81 {
82 	struct c2port_ops *ops = dev->ops;
83 
84 	/* During hi-low-hi transition we disable local IRQs to avoid
85 	 * interructions since C2 port specification says that it must be
86 	 * shorter than 5us, otherwise the microcontroller may consider
87 	 * it as a reset signal!
88 	 */
89 	local_irq_disable();
90 	ops->c2ck_set(dev, 0);
91 	udelay(1);
92 	ops->c2ck_set(dev, 1);
93 	local_irq_enable();
94 
95 	udelay(1);
96 }
97 
98 /*
99  * C2 port basic functions
100  */
101 
102 static void c2port_write_ar(struct c2port_device *dev, u8 addr)
103 {
104 	struct c2port_ops *ops = dev->ops;
105 	int i;
106 
107 	/* START field */
108 	c2port_strobe_ck(dev);
109 
110 	/* INS field (11b, LSB first) */
111 	ops->c2d_dir(dev, 0);
112 	ops->c2d_set(dev, 1);
113 	c2port_strobe_ck(dev);
114 	ops->c2d_set(dev, 1);
115 	c2port_strobe_ck(dev);
116 
117 	/* ADDRESS field */
118 	for (i = 0; i < 8; i++) {
119 		ops->c2d_set(dev, addr & 0x01);
120 		c2port_strobe_ck(dev);
121 
122 		addr >>= 1;
123 	}
124 
125 	/* STOP field */
126 	ops->c2d_dir(dev, 1);
127 	c2port_strobe_ck(dev);
128 }
129 
130 static int c2port_read_ar(struct c2port_device *dev, u8 *addr)
131 {
132 	struct c2port_ops *ops = dev->ops;
133 	int i;
134 
135 	/* START field */
136 	c2port_strobe_ck(dev);
137 
138 	/* INS field (10b, LSB first) */
139 	ops->c2d_dir(dev, 0);
140 	ops->c2d_set(dev, 0);
141 	c2port_strobe_ck(dev);
142 	ops->c2d_set(dev, 1);
143 	c2port_strobe_ck(dev);
144 
145 	/* ADDRESS field */
146 	ops->c2d_dir(dev, 1);
147 	*addr = 0;
148 	for (i = 0; i < 8; i++) {
149 		*addr >>= 1;	/* shift in 8-bit ADDRESS field LSB first */
150 
151 		c2port_strobe_ck(dev);
152 		if (ops->c2d_get(dev))
153 			*addr |= 0x80;
154 	}
155 
156 	/* STOP field */
157 	c2port_strobe_ck(dev);
158 
159 	return 0;
160 }
161 
162 static int c2port_write_dr(struct c2port_device *dev, u8 data)
163 {
164 	struct c2port_ops *ops = dev->ops;
165 	int timeout, i;
166 
167 	/* START field */
168 	c2port_strobe_ck(dev);
169 
170 	/* INS field (01b, LSB first) */
171 	ops->c2d_dir(dev, 0);
172 	ops->c2d_set(dev, 1);
173 	c2port_strobe_ck(dev);
174 	ops->c2d_set(dev, 0);
175 	c2port_strobe_ck(dev);
176 
177 	/* LENGTH field (00b, LSB first -> 1 byte) */
178 	ops->c2d_set(dev, 0);
179 	c2port_strobe_ck(dev);
180 	ops->c2d_set(dev, 0);
181 	c2port_strobe_ck(dev);
182 
183 	/* DATA field */
184 	for (i = 0; i < 8; i++) {
185 		ops->c2d_set(dev, data & 0x01);
186 		c2port_strobe_ck(dev);
187 
188 		data >>= 1;
189 	}
190 
191 	/* WAIT field */
192 	ops->c2d_dir(dev, 1);
193 	timeout = 20;
194 	do {
195 		c2port_strobe_ck(dev);
196 		if (ops->c2d_get(dev))
197 			break;
198 
199 		udelay(1);
200 	} while (--timeout > 0);
201 	if (timeout == 0)
202 		return -EIO;
203 
204 	/* STOP field */
205 	c2port_strobe_ck(dev);
206 
207 	return 0;
208 }
209 
210 static int c2port_read_dr(struct c2port_device *dev, u8 *data)
211 {
212 	struct c2port_ops *ops = dev->ops;
213 	int timeout, i;
214 
215 	/* START field */
216 	c2port_strobe_ck(dev);
217 
218 	/* INS field (00b, LSB first) */
219 	ops->c2d_dir(dev, 0);
220 	ops->c2d_set(dev, 0);
221 	c2port_strobe_ck(dev);
222 	ops->c2d_set(dev, 0);
223 	c2port_strobe_ck(dev);
224 
225 	/* LENGTH field (00b, LSB first -> 1 byte) */
226 	ops->c2d_set(dev, 0);
227 	c2port_strobe_ck(dev);
228 	ops->c2d_set(dev, 0);
229 	c2port_strobe_ck(dev);
230 
231 	/* WAIT field */
232 	ops->c2d_dir(dev, 1);
233 	timeout = 20;
234 	do {
235 		c2port_strobe_ck(dev);
236 		if (ops->c2d_get(dev))
237 			break;
238 
239 		udelay(1);
240 	} while (--timeout > 0);
241 	if (timeout == 0)
242 		return -EIO;
243 
244 	/* DATA field */
245 	*data = 0;
246 	for (i = 0; i < 8; i++) {
247 		*data >>= 1;	/* shift in 8-bit DATA field LSB first */
248 
249 		c2port_strobe_ck(dev);
250 		if (ops->c2d_get(dev))
251 			*data |= 0x80;
252 	}
253 
254 	/* STOP field */
255 	c2port_strobe_ck(dev);
256 
257 	return 0;
258 }
259 
260 static int c2port_poll_in_busy(struct c2port_device *dev)
261 {
262 	u8 addr;
263 	int ret, timeout = 20;
264 
265 	do {
266 		ret = (c2port_read_ar(dev, &addr));
267 		if (ret < 0)
268 			return -EIO;
269 
270 		if (!(addr & 0x02))
271 			break;
272 
273 		udelay(1);
274 	} while (--timeout > 0);
275 	if (timeout == 0)
276 		return -EIO;
277 
278 	return 0;
279 }
280 
281 static int c2port_poll_out_ready(struct c2port_device *dev)
282 {
283 	u8 addr;
284 	int ret, timeout = 10000; /* erase flash needs long time... */
285 
286 	do {
287 		ret = (c2port_read_ar(dev, &addr));
288 		if (ret < 0)
289 			return -EIO;
290 
291 		if (addr & 0x01)
292 			break;
293 
294 		udelay(1);
295 	} while (--timeout > 0);
296 	if (timeout == 0)
297 		return -EIO;
298 
299 	return 0;
300 }
301 
302 /*
303  * sysfs methods
304  */
305 
306 static ssize_t c2port_show_name(struct device *dev,
307 				struct device_attribute *attr, char *buf)
308 {
309 	struct c2port_device *c2dev = dev_get_drvdata(dev);
310 
311 	return sprintf(buf, "%s\n", c2dev->name);
312 }
313 static DEVICE_ATTR(name, 0444, c2port_show_name, NULL);
314 
315 static ssize_t c2port_show_flash_blocks_num(struct device *dev,
316 				struct device_attribute *attr, char *buf)
317 {
318 	struct c2port_device *c2dev = dev_get_drvdata(dev);
319 	struct c2port_ops *ops = c2dev->ops;
320 
321 	return sprintf(buf, "%d\n", ops->blocks_num);
322 }
323 static DEVICE_ATTR(flash_blocks_num, 0444, c2port_show_flash_blocks_num, NULL);
324 
325 static ssize_t c2port_show_flash_block_size(struct device *dev,
326 				struct device_attribute *attr, char *buf)
327 {
328 	struct c2port_device *c2dev = dev_get_drvdata(dev);
329 	struct c2port_ops *ops = c2dev->ops;
330 
331 	return sprintf(buf, "%d\n", ops->block_size);
332 }
333 static DEVICE_ATTR(flash_block_size, 0444, c2port_show_flash_block_size, NULL);
334 
335 static ssize_t c2port_show_flash_size(struct device *dev,
336 				struct device_attribute *attr, char *buf)
337 {
338 	struct c2port_device *c2dev = dev_get_drvdata(dev);
339 	struct c2port_ops *ops = c2dev->ops;
340 
341 	return sprintf(buf, "%d\n", ops->blocks_num * ops->block_size);
342 }
343 static DEVICE_ATTR(flash_size, 0444, c2port_show_flash_size, NULL);
344 
345 static ssize_t access_show(struct device *dev, struct device_attribute *attr,
346 			   char *buf)
347 {
348 	struct c2port_device *c2dev = dev_get_drvdata(dev);
349 
350 	return sprintf(buf, "%d\n", c2dev->access);
351 }
352 
353 static ssize_t access_store(struct device *dev, struct device_attribute *attr,
354 			    const char *buf, size_t count)
355 {
356 	struct c2port_device *c2dev = dev_get_drvdata(dev);
357 	struct c2port_ops *ops = c2dev->ops;
358 	int status, ret;
359 
360 	ret = sscanf(buf, "%d", &status);
361 	if (ret != 1)
362 		return -EINVAL;
363 
364 	mutex_lock(&c2dev->mutex);
365 
366 	c2dev->access = !!status;
367 
368 	/* If access is "on" clock should be HIGH _before_ setting the line
369 	 * as output and data line should be set as INPUT anyway */
370 	if (c2dev->access)
371 		ops->c2ck_set(c2dev, 1);
372 	ops->access(c2dev, c2dev->access);
373 	if (c2dev->access)
374 		ops->c2d_dir(c2dev, 1);
375 
376 	mutex_unlock(&c2dev->mutex);
377 
378 	return count;
379 }
380 static DEVICE_ATTR_RW(access);
381 
382 static ssize_t c2port_store_reset(struct device *dev,
383 				struct device_attribute *attr,
384 				const char *buf, size_t count)
385 {
386 	struct c2port_device *c2dev = dev_get_drvdata(dev);
387 
388 	/* Check the device access status */
389 	if (!c2dev->access)
390 		return -EBUSY;
391 
392 	mutex_lock(&c2dev->mutex);
393 
394 	c2port_reset(c2dev);
395 	c2dev->flash_access = 0;
396 
397 	mutex_unlock(&c2dev->mutex);
398 
399 	return count;
400 }
401 static DEVICE_ATTR(reset, 0200, NULL, c2port_store_reset);
402 
403 static ssize_t __c2port_show_dev_id(struct c2port_device *dev, char *buf)
404 {
405 	u8 data;
406 	int ret;
407 
408 	/* Select DEVICEID register for C2 data register accesses */
409 	c2port_write_ar(dev, C2PORT_DEVICEID);
410 
411 	/* Read and return the device ID register */
412 	ret = c2port_read_dr(dev, &data);
413 	if (ret < 0)
414 		return ret;
415 
416 	return sprintf(buf, "%d\n", data);
417 }
418 
419 static ssize_t c2port_show_dev_id(struct device *dev,
420 				struct device_attribute *attr, char *buf)
421 {
422 	struct c2port_device *c2dev = dev_get_drvdata(dev);
423 	ssize_t ret;
424 
425 	/* Check the device access status */
426 	if (!c2dev->access)
427 		return -EBUSY;
428 
429 	mutex_lock(&c2dev->mutex);
430 	ret = __c2port_show_dev_id(c2dev, buf);
431 	mutex_unlock(&c2dev->mutex);
432 
433 	if (ret < 0)
434 		dev_err(dev, "cannot read from %s\n", c2dev->name);
435 
436 	return ret;
437 }
438 static DEVICE_ATTR(dev_id, 0444, c2port_show_dev_id, NULL);
439 
440 static ssize_t __c2port_show_rev_id(struct c2port_device *dev, char *buf)
441 {
442 	u8 data;
443 	int ret;
444 
445 	/* Select REVID register for C2 data register accesses */
446 	c2port_write_ar(dev, C2PORT_REVID);
447 
448 	/* Read and return the revision ID register */
449 	ret = c2port_read_dr(dev, &data);
450 	if (ret < 0)
451 		return ret;
452 
453 	return sprintf(buf, "%d\n", data);
454 }
455 
456 static ssize_t c2port_show_rev_id(struct device *dev,
457 				struct device_attribute *attr, char *buf)
458 {
459 	struct c2port_device *c2dev = dev_get_drvdata(dev);
460 	ssize_t ret;
461 
462 	/* Check the device access status */
463 	if (!c2dev->access)
464 		return -EBUSY;
465 
466 	mutex_lock(&c2dev->mutex);
467 	ret = __c2port_show_rev_id(c2dev, buf);
468 	mutex_unlock(&c2dev->mutex);
469 
470 	if (ret < 0)
471 		dev_err(c2dev->dev, "cannot read from %s\n", c2dev->name);
472 
473 	return ret;
474 }
475 static DEVICE_ATTR(rev_id, 0444, c2port_show_rev_id, NULL);
476 
477 static ssize_t c2port_show_flash_access(struct device *dev,
478 				struct device_attribute *attr, char *buf)
479 {
480 	struct c2port_device *c2dev = dev_get_drvdata(dev);
481 
482 	return sprintf(buf, "%d\n", c2dev->flash_access);
483 }
484 
485 static ssize_t __c2port_store_flash_access(struct c2port_device *dev,
486 						int status)
487 {
488 	int ret;
489 
490 	/* Check the device access status */
491 	if (!dev->access)
492 		return -EBUSY;
493 
494 	dev->flash_access = !!status;
495 
496 	/* If flash_access is off we have nothing to do... */
497 	if (dev->flash_access == 0)
498 		return 0;
499 
500 	/* Target the C2 flash programming control register for C2 data
501 	 * register access */
502 	c2port_write_ar(dev, C2PORT_FPCTL);
503 
504 	/* Write the first keycode to enable C2 Flash programming */
505 	ret = c2port_write_dr(dev, 0x02);
506 	if (ret < 0)
507 		return ret;
508 
509 	/* Write the second keycode to enable C2 Flash programming */
510 	ret = c2port_write_dr(dev, 0x01);
511 	if (ret < 0)
512 		return ret;
513 
514 	/* Delay for at least 20ms to ensure the target is ready for
515 	 * C2 flash programming */
516 	mdelay(25);
517 
518 	return 0;
519 }
520 
521 static ssize_t c2port_store_flash_access(struct device *dev,
522 				struct device_attribute *attr,
523 				const char *buf, size_t count)
524 {
525 	struct c2port_device *c2dev = dev_get_drvdata(dev);
526 	int status;
527 	ssize_t ret;
528 
529 	ret = sscanf(buf, "%d", &status);
530 	if (ret != 1)
531 		return -EINVAL;
532 
533 	mutex_lock(&c2dev->mutex);
534 	ret = __c2port_store_flash_access(c2dev, status);
535 	mutex_unlock(&c2dev->mutex);
536 
537 	if (ret < 0) {
538 		dev_err(c2dev->dev, "cannot enable %s flash programming\n",
539 			c2dev->name);
540 		return ret;
541 	}
542 
543 	return count;
544 }
545 static DEVICE_ATTR(flash_access, 0644, c2port_show_flash_access,
546 		   c2port_store_flash_access);
547 
548 static ssize_t __c2port_write_flash_erase(struct c2port_device *dev)
549 {
550 	u8 status;
551 	int ret;
552 
553 	/* Target the C2 flash programming data register for C2 data register
554 	 * access.
555 	 */
556 	c2port_write_ar(dev, C2PORT_FPDAT);
557 
558 	/* Send device erase command */
559 	c2port_write_dr(dev, C2PORT_DEVICE_ERASE);
560 
561 	/* Wait for input acknowledge */
562 	ret = c2port_poll_in_busy(dev);
563 	if (ret < 0)
564 		return ret;
565 
566 	/* Should check status before starting FLASH access sequence */
567 
568 	/* Wait for status information */
569 	ret = c2port_poll_out_ready(dev);
570 	if (ret < 0)
571 		return ret;
572 
573 	/* Read flash programming interface status */
574 	ret = c2port_read_dr(dev, &status);
575 	if (ret < 0)
576 		return ret;
577 	if (status != C2PORT_COMMAND_OK)
578 		return -EBUSY;
579 
580 	/* Send a three-byte arming sequence to enable the device erase.
581 	 * If the sequence is not received correctly, the command will be
582 	 * ignored.
583 	 * Sequence is: 0xde, 0xad, 0xa5.
584 	 */
585 	c2port_write_dr(dev, 0xde);
586 	ret = c2port_poll_in_busy(dev);
587 	if (ret < 0)
588 		return ret;
589 	c2port_write_dr(dev, 0xad);
590 	ret = c2port_poll_in_busy(dev);
591 	if (ret < 0)
592 		return ret;
593 	c2port_write_dr(dev, 0xa5);
594 	ret = c2port_poll_in_busy(dev);
595 	if (ret < 0)
596 		return ret;
597 
598 	ret = c2port_poll_out_ready(dev);
599 	if (ret < 0)
600 		return ret;
601 
602 	return 0;
603 }
604 
605 static ssize_t c2port_store_flash_erase(struct device *dev,
606 				struct device_attribute *attr,
607 				const char *buf, size_t count)
608 {
609 	struct c2port_device *c2dev = dev_get_drvdata(dev);
610 	int ret;
611 
612 	/* Check the device and flash access status */
613 	if (!c2dev->access || !c2dev->flash_access)
614 		return -EBUSY;
615 
616 	mutex_lock(&c2dev->mutex);
617 	ret = __c2port_write_flash_erase(c2dev);
618 	mutex_unlock(&c2dev->mutex);
619 
620 	if (ret < 0) {
621 		dev_err(c2dev->dev, "cannot erase %s flash\n", c2dev->name);
622 		return ret;
623 	}
624 
625 	return count;
626 }
627 static DEVICE_ATTR(flash_erase, 0200, NULL, c2port_store_flash_erase);
628 
629 static ssize_t __c2port_read_flash_data(struct c2port_device *dev,
630 				char *buffer, loff_t offset, size_t count)
631 {
632 	struct c2port_ops *ops = dev->ops;
633 	u8 status, nread = 128;
634 	int i, ret;
635 
636 	/* Check for flash end */
637 	if (offset >= ops->block_size * ops->blocks_num)
638 		return 0;
639 
640 	if (ops->block_size * ops->blocks_num - offset < nread)
641 		nread = ops->block_size * ops->blocks_num - offset;
642 	if (count < nread)
643 		nread = count;
644 	if (nread == 0)
645 		return nread;
646 
647 	/* Target the C2 flash programming data register for C2 data register
648 	 * access */
649 	c2port_write_ar(dev, C2PORT_FPDAT);
650 
651 	/* Send flash block read command */
652 	c2port_write_dr(dev, C2PORT_BLOCK_READ);
653 
654 	/* Wait for input acknowledge */
655 	ret = c2port_poll_in_busy(dev);
656 	if (ret < 0)
657 		return ret;
658 
659 	/* Should check status before starting FLASH access sequence */
660 
661 	/* Wait for status information */
662 	ret = c2port_poll_out_ready(dev);
663 	if (ret < 0)
664 		return ret;
665 
666 	/* Read flash programming interface status */
667 	ret = c2port_read_dr(dev, &status);
668 	if (ret < 0)
669 		return ret;
670 	if (status != C2PORT_COMMAND_OK)
671 		return -EBUSY;
672 
673 	/* Send address high byte */
674 	c2port_write_dr(dev, offset >> 8);
675 	ret = c2port_poll_in_busy(dev);
676 	if (ret < 0)
677 		return ret;
678 
679 	/* Send address low byte */
680 	c2port_write_dr(dev, offset & 0x00ff);
681 	ret = c2port_poll_in_busy(dev);
682 	if (ret < 0)
683 		return ret;
684 
685 	/* Send address block size */
686 	c2port_write_dr(dev, nread);
687 	ret = c2port_poll_in_busy(dev);
688 	if (ret < 0)
689 		return ret;
690 
691 	/* Should check status before reading FLASH block */
692 
693 	/* Wait for status information */
694 	ret = c2port_poll_out_ready(dev);
695 	if (ret < 0)
696 		return ret;
697 
698 	/* Read flash programming interface status */
699 	ret = c2port_read_dr(dev, &status);
700 	if (ret < 0)
701 		return ret;
702 	if (status != C2PORT_COMMAND_OK)
703 		return -EBUSY;
704 
705 	/* Read flash block */
706 	for (i = 0; i < nread; i++) {
707 		ret = c2port_poll_out_ready(dev);
708 		if (ret < 0)
709 			return ret;
710 
711 		ret = c2port_read_dr(dev, buffer+i);
712 		if (ret < 0)
713 			return ret;
714 	}
715 
716 	return nread;
717 }
718 
719 static ssize_t c2port_read_flash_data(struct file *filp, struct kobject *kobj,
720 				struct bin_attribute *attr,
721 				char *buffer, loff_t offset, size_t count)
722 {
723 	struct c2port_device *c2dev = dev_get_drvdata(kobj_to_dev(kobj));
724 	ssize_t ret;
725 
726 	/* Check the device and flash access status */
727 	if (!c2dev->access || !c2dev->flash_access)
728 		return -EBUSY;
729 
730 	mutex_lock(&c2dev->mutex);
731 	ret = __c2port_read_flash_data(c2dev, buffer, offset, count);
732 	mutex_unlock(&c2dev->mutex);
733 
734 	if (ret < 0)
735 		dev_err(c2dev->dev, "cannot read %s flash\n", c2dev->name);
736 
737 	return ret;
738 }
739 
740 static ssize_t __c2port_write_flash_data(struct c2port_device *dev,
741 				char *buffer, loff_t offset, size_t count)
742 {
743 	struct c2port_ops *ops = dev->ops;
744 	u8 status, nwrite = 128;
745 	int i, ret;
746 
747 	if (nwrite > count)
748 		nwrite = count;
749 	if (ops->block_size * ops->blocks_num - offset < nwrite)
750 		nwrite = ops->block_size * ops->blocks_num - offset;
751 
752 	/* Check for flash end */
753 	if (offset >= ops->block_size * ops->blocks_num)
754 		return -EINVAL;
755 
756 	/* Target the C2 flash programming data register for C2 data register
757 	 * access */
758 	c2port_write_ar(dev, C2PORT_FPDAT);
759 
760 	/* Send flash block write command */
761 	c2port_write_dr(dev, C2PORT_BLOCK_WRITE);
762 
763 	/* Wait for input acknowledge */
764 	ret = c2port_poll_in_busy(dev);
765 	if (ret < 0)
766 		return ret;
767 
768 	/* Should check status before starting FLASH access sequence */
769 
770 	/* Wait for status information */
771 	ret = c2port_poll_out_ready(dev);
772 	if (ret < 0)
773 		return ret;
774 
775 	/* Read flash programming interface status */
776 	ret = c2port_read_dr(dev, &status);
777 	if (ret < 0)
778 		return ret;
779 	if (status != C2PORT_COMMAND_OK)
780 		return -EBUSY;
781 
782 	/* Send address high byte */
783 	c2port_write_dr(dev, offset >> 8);
784 	ret = c2port_poll_in_busy(dev);
785 	if (ret < 0)
786 		return ret;
787 
788 	/* Send address low byte */
789 	c2port_write_dr(dev, offset & 0x00ff);
790 	ret = c2port_poll_in_busy(dev);
791 	if (ret < 0)
792 		return ret;
793 
794 	/* Send address block size */
795 	c2port_write_dr(dev, nwrite);
796 	ret = c2port_poll_in_busy(dev);
797 	if (ret < 0)
798 		return ret;
799 
800 	/* Should check status before writing FLASH block */
801 
802 	/* Wait for status information */
803 	ret = c2port_poll_out_ready(dev);
804 	if (ret < 0)
805 		return ret;
806 
807 	/* Read flash programming interface status */
808 	ret = c2port_read_dr(dev, &status);
809 	if (ret < 0)
810 		return ret;
811 	if (status != C2PORT_COMMAND_OK)
812 		return -EBUSY;
813 
814 	/* Write flash block */
815 	for (i = 0; i < nwrite; i++) {
816 		ret = c2port_write_dr(dev, *(buffer+i));
817 		if (ret < 0)
818 			return ret;
819 
820 		ret = c2port_poll_in_busy(dev);
821 		if (ret < 0)
822 			return ret;
823 
824 	}
825 
826 	/* Wait for last flash write to complete */
827 	ret = c2port_poll_out_ready(dev);
828 	if (ret < 0)
829 		return ret;
830 
831 	return nwrite;
832 }
833 
834 static ssize_t c2port_write_flash_data(struct file *filp, struct kobject *kobj,
835 				struct bin_attribute *attr,
836 				char *buffer, loff_t offset, size_t count)
837 {
838 	struct c2port_device *c2dev = dev_get_drvdata(kobj_to_dev(kobj));
839 	int ret;
840 
841 	/* Check the device access status */
842 	if (!c2dev->access || !c2dev->flash_access)
843 		return -EBUSY;
844 
845 	mutex_lock(&c2dev->mutex);
846 	ret = __c2port_write_flash_data(c2dev, buffer, offset, count);
847 	mutex_unlock(&c2dev->mutex);
848 
849 	if (ret < 0)
850 		dev_err(c2dev->dev, "cannot write %s flash\n", c2dev->name);
851 
852 	return ret;
853 }
854 /* size is computed at run-time */
855 static BIN_ATTR(flash_data, 0644, c2port_read_flash_data,
856 		c2port_write_flash_data, 0);
857 
858 /*
859  * Class attributes
860  */
861 static struct attribute *c2port_attrs[] = {
862 	&dev_attr_name.attr,
863 	&dev_attr_flash_blocks_num.attr,
864 	&dev_attr_flash_block_size.attr,
865 	&dev_attr_flash_size.attr,
866 	&dev_attr_access.attr,
867 	&dev_attr_reset.attr,
868 	&dev_attr_dev_id.attr,
869 	&dev_attr_rev_id.attr,
870 	&dev_attr_flash_access.attr,
871 	&dev_attr_flash_erase.attr,
872 	NULL,
873 };
874 
875 static struct bin_attribute *c2port_bin_attrs[] = {
876 	&bin_attr_flash_data,
877 	NULL,
878 };
879 
880 static const struct attribute_group c2port_group = {
881 	.attrs = c2port_attrs,
882 	.bin_attrs = c2port_bin_attrs,
883 };
884 
885 static const struct attribute_group *c2port_groups[] = {
886 	&c2port_group,
887 	NULL,
888 };
889 
890 /*
891  * Exported functions
892  */
893 
894 struct c2port_device *c2port_device_register(char *name,
895 					struct c2port_ops *ops, void *devdata)
896 {
897 	struct c2port_device *c2dev;
898 	int ret;
899 
900 	if (unlikely(!ops) || unlikely(!ops->access) || \
901 		unlikely(!ops->c2d_dir) || unlikely(!ops->c2ck_set) || \
902 		unlikely(!ops->c2d_get) || unlikely(!ops->c2d_set))
903 		return ERR_PTR(-EINVAL);
904 
905 	c2dev = kmalloc(sizeof(struct c2port_device), GFP_KERNEL);
906 	if (unlikely(!c2dev))
907 		return ERR_PTR(-ENOMEM);
908 
909 	idr_preload(GFP_KERNEL);
910 	spin_lock_irq(&c2port_idr_lock);
911 	ret = idr_alloc(&c2port_idr, c2dev, 0, 0, GFP_NOWAIT);
912 	spin_unlock_irq(&c2port_idr_lock);
913 	idr_preload_end();
914 
915 	if (ret < 0)
916 		goto error_idr_alloc;
917 	c2dev->id = ret;
918 
919 	bin_attr_flash_data.size = ops->blocks_num * ops->block_size;
920 
921 	c2dev->dev = device_create(c2port_class, NULL, 0, c2dev,
922 				   "c2port%d", c2dev->id);
923 	if (IS_ERR(c2dev->dev)) {
924 		ret = PTR_ERR(c2dev->dev);
925 		goto error_device_create;
926 	}
927 	dev_set_drvdata(c2dev->dev, c2dev);
928 
929 	strncpy(c2dev->name, name, C2PORT_NAME_LEN);
930 	c2dev->ops = ops;
931 	mutex_init(&c2dev->mutex);
932 
933 	/* By default C2 port access is off */
934 	c2dev->access = c2dev->flash_access = 0;
935 	ops->access(c2dev, 0);
936 
937 	dev_info(c2dev->dev, "C2 port %s added\n", name);
938 	dev_info(c2dev->dev, "%s flash has %d blocks x %d bytes "
939 				"(%d bytes total)\n",
940 				name, ops->blocks_num, ops->block_size,
941 				ops->blocks_num * ops->block_size);
942 
943 	return c2dev;
944 
945 error_device_create:
946 	spin_lock_irq(&c2port_idr_lock);
947 	idr_remove(&c2port_idr, c2dev->id);
948 	spin_unlock_irq(&c2port_idr_lock);
949 
950 error_idr_alloc:
951 	kfree(c2dev);
952 
953 	return ERR_PTR(ret);
954 }
955 EXPORT_SYMBOL(c2port_device_register);
956 
957 void c2port_device_unregister(struct c2port_device *c2dev)
958 {
959 	if (!c2dev)
960 		return;
961 
962 	dev_info(c2dev->dev, "C2 port %s removed\n", c2dev->name);
963 
964 	spin_lock_irq(&c2port_idr_lock);
965 	idr_remove(&c2port_idr, c2dev->id);
966 	spin_unlock_irq(&c2port_idr_lock);
967 
968 	device_destroy(c2port_class, c2dev->id);
969 
970 	kfree(c2dev);
971 }
972 EXPORT_SYMBOL(c2port_device_unregister);
973 
974 /*
975  * Module stuff
976  */
977 
978 static int __init c2port_init(void)
979 {
980 	printk(KERN_INFO "Silicon Labs C2 port support v. " DRIVER_VERSION
981 		" - (C) 2007 Rodolfo Giometti\n");
982 
983 	c2port_class = class_create(THIS_MODULE, "c2port");
984 	if (IS_ERR(c2port_class)) {
985 		printk(KERN_ERR "c2port: failed to allocate class\n");
986 		return PTR_ERR(c2port_class);
987 	}
988 	c2port_class->dev_groups = c2port_groups;
989 
990 	return 0;
991 }
992 
993 static void __exit c2port_exit(void)
994 {
995 	class_destroy(c2port_class);
996 }
997 
998 module_init(c2port_init);
999 module_exit(c2port_exit);
1000 
1001 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
1002 MODULE_DESCRIPTION("Silicon Labs C2 port support v. " DRIVER_VERSION);
1003 MODULE_LICENSE("GPL");
1004