xref: /netbsd-src/sys/dev/spi/spiflash.c (revision 181254a7b1bdde6873432bffef2d2decc4b5c22f)
1 /* $NetBSD: spiflash.c,v 1.23 2019/09/14 15:12:12 tnn Exp $ */
2 
3 /*-
4  * Copyright (c) 2006 Urbana-Champaign Independent Media Center.
5  * Copyright (c) 2006 Garrett D'Amore.
6  * All rights reserved.
7  *
8  * Portions of this code were written by Garrett D'Amore for the
9  * Champaign-Urbana Community Wireless Network Project.
10  *
11  * Redistribution and use in source and binary forms, with or
12  * without modification, are permitted provided that the following
13  * conditions are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above
17  *    copyright notice, this list of conditions and the following
18  *    disclaimer in the documentation and/or other materials provided
19  *    with the distribution.
20  * 3. All advertising materials mentioning features or use of this
21  *    software must display the following acknowledgements:
22  *      This product includes software developed by the Urbana-Champaign
23  *      Independent Media Center.
24  *	This product includes software developed by Garrett D'Amore.
25  * 4. Urbana-Champaign Independent Media Center's name and Garrett
26  *    D'Amore's name may not be used to endorse or promote products
27  *    derived from this software without specific prior written permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE URBANA-CHAMPAIGN INDEPENDENT
30  * MEDIA CENTER AND GARRETT D'AMORE ``AS IS'' AND ANY EXPRESS OR
31  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
32  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33  * ARE DISCLAIMED.  IN NO EVENT SHALL THE URBANA-CHAMPAIGN INDEPENDENT
34  * MEDIA CENTER OR GARRETT D'AMORE BE LIABLE FOR ANY DIRECT, INDIRECT,
35  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42  */
43 
44 #include <sys/cdefs.h>
45 __KERNEL_RCSID(0, "$NetBSD: spiflash.c,v 1.23 2019/09/14 15:12:12 tnn Exp $");
46 
47 #include <sys/param.h>
48 #include <sys/conf.h>
49 #include <sys/proc.h>
50 #include <sys/systm.h>
51 #include <sys/device.h>
52 #include <sys/kernel.h>
53 #include <sys/file.h>
54 #include <sys/ioctl.h>
55 #include <sys/disk.h>
56 #include <sys/disklabel.h>
57 #include <sys/buf.h>
58 #include <sys/bufq.h>
59 #include <sys/uio.h>
60 #include <sys/kthread.h>
61 #include <sys/malloc.h>
62 #include <sys/errno.h>
63 
64 #include <dev/spi/spivar.h>
65 #include <dev/spi/spiflash.h>
66 
67 /*
68  * This is an MI block driver for SPI flash devices.  It could probably be
69  * converted to some more generic framework, if someone wanted to create one
70  * for NOR flashes.  Note that some flashes have the ability to handle
71  * interrupts.
72  */
73 
74 struct spiflash_softc {
75 	struct disk		sc_dk;
76 
77 	struct spiflash_hw_if	sc_hw;
78 	void			*sc_cookie;
79 
80 	const char		*sc_name;
81 	struct spi_handle	*sc_handle;
82 	int			sc_device_size;
83 	int			sc_write_size;
84 	int			sc_erase_size;
85 	int			sc_read_size;
86 	int			sc_device_blks;
87 
88 	struct bufq_state	*sc_waitq;
89 	struct bufq_state	*sc_workq;
90 	struct bufq_state	*sc_doneq;
91 	lwp_t			*sc_thread;
92 };
93 
94 #define	sc_getname	sc_hw.sf_getname
95 #define	sc_gethandle	sc_hw.sf_gethandle
96 #define	sc_getsize	sc_hw.sf_getsize
97 #define	sc_getflags	sc_hw.sf_getflags
98 #define	sc_erase	sc_hw.sf_erase
99 #define	sc_write	sc_hw.sf_write
100 #define	sc_read		sc_hw.sf_read
101 #define	sc_getstatus	sc_hw.sf_getstatus
102 #define	sc_setstatus	sc_hw.sf_setstatus
103 
104 struct spiflash_attach_args {
105 	const struct spiflash_hw_if	*hw;
106 	void				*cookie;
107 };
108 
109 #define	STATIC
110 STATIC int spiflash_match(device_t , cfdata_t , void *);
111 STATIC void spiflash_attach(device_t , device_t , void *);
112 STATIC int spiflash_print(void *, const char *);
113 STATIC int spiflash_common_erase(spiflash_handle_t, size_t, size_t);
114 STATIC int spiflash_common_write(spiflash_handle_t, size_t, size_t,
115     const uint8_t *);
116 STATIC int spiflash_common_read(spiflash_handle_t, size_t, size_t, uint8_t *);
117 STATIC void spiflash_process_done(spiflash_handle_t, int);
118 STATIC void spiflash_process_read(spiflash_handle_t);
119 STATIC void spiflash_process_write(spiflash_handle_t);
120 STATIC void spiflash_thread(void *);
121 STATIC int spiflash_nsectors(spiflash_handle_t, struct buf *);
122 STATIC int spiflash_nsectors(spiflash_handle_t, struct buf *);
123 STATIC int spiflash_sector(spiflash_handle_t, struct buf *);
124 
125 CFATTACH_DECL_NEW(spiflash, sizeof(struct spiflash_softc),
126 	      spiflash_match, spiflash_attach, NULL, NULL);
127 
128 #ifdef	SPIFLASH_DEBUG
129 #define	DPRINTF(x)	do { printf x; } while (0/*CONSTCOND*/)
130 #else
131 #define	DPRINTF(x)	do {  } while (0/*CONSTCOND*/)
132 #endif
133 
134 extern struct cfdriver spiflash_cd;
135 
136 dev_type_open(spiflash_open);
137 dev_type_close(spiflash_close);
138 dev_type_read(spiflash_read);
139 dev_type_write(spiflash_write);
140 dev_type_ioctl(spiflash_ioctl);
141 dev_type_strategy(spiflash_strategy);
142 
143 const struct bdevsw spiflash_bdevsw = {
144 	.d_open = spiflash_open,
145 	.d_close = spiflash_close,
146 	.d_strategy = spiflash_strategy,
147 	.d_ioctl = spiflash_ioctl,
148 	.d_dump = nodump,
149 	.d_psize = nosize,
150 	.d_discard = nodiscard,
151 	.d_flag = D_DISK,
152 };
153 
154 const struct cdevsw spiflash_cdevsw = {
155 	.d_open = spiflash_open,
156 	.d_close = spiflash_close,
157 	.d_read = spiflash_read,
158 	.d_write = spiflash_write,
159 	.d_ioctl = spiflash_ioctl,
160 	.d_stop = nostop,
161 	.d_tty = notty,
162 	.d_poll = nopoll,
163 	.d_mmap = nommap,
164 	.d_kqfilter = nokqfilter,
165 	.d_discard = nodiscard,
166 	.d_flag = D_DISK,
167 };
168 
169 static struct dkdriver spiflash_dkdriver = {
170 	.d_strategy = spiflash_strategy
171 };
172 
173 spiflash_handle_t
174 spiflash_attach_mi(const struct spiflash_hw_if *hw, void *cookie,
175     device_t dev)
176 {
177 	struct spiflash_attach_args sfa;
178 	sfa.hw = hw;
179 	sfa.cookie = cookie;
180 
181 	return (spiflash_handle_t)config_found(dev, &sfa, spiflash_print);
182 }
183 
184 int
185 spiflash_print(void *aux, const char *pnp)
186 {
187 	if (pnp != NULL)
188 		printf("spiflash at %s\n", pnp);
189 
190 	return UNCONF;
191 }
192 
193 int
194 spiflash_match(device_t parent, cfdata_t cf, void *aux)
195 {
196 
197 	return 1;
198 }
199 
200 void
201 spiflash_attach(device_t parent, device_t self, void *aux)
202 {
203 	struct spiflash_softc *sc = device_private(self);
204 	struct spiflash_attach_args *sfa = aux;
205 	void *cookie = sfa->cookie;
206 
207 	sc->sc_hw = *sfa->hw;
208 	sc->sc_cookie = cookie;
209 	sc->sc_name = sc->sc_getname(cookie);
210 	sc->sc_handle = sc->sc_gethandle(cookie);
211 	sc->sc_device_size = sc->sc_getsize(cookie, SPIFLASH_SIZE_DEVICE);
212 	sc->sc_erase_size = sc->sc_getsize(cookie, SPIFLASH_SIZE_ERASE);
213 	sc->sc_write_size = sc->sc_getsize(cookie, SPIFLASH_SIZE_WRITE);
214 	sc->sc_read_size = sc->sc_getsize(cookie, SPIFLASH_SIZE_READ);
215 	sc->sc_device_blks = sc->sc_device_size / DEV_BSIZE;
216 
217 	if (sc->sc_read == NULL)
218 		sc->sc_read = spiflash_common_read;
219 	if (sc->sc_write == NULL)
220 		sc->sc_write = spiflash_common_write;
221 	if (sc->sc_erase == NULL)
222 		sc->sc_erase = spiflash_common_erase;
223 
224 	aprint_naive(": SPI flash\n");
225 	aprint_normal(": %s SPI flash\n", sc->sc_name);
226 	/* XXX: note that this has to change for boot-sectored flash */
227 	aprint_normal_dev(self, "%d KB, %d sectors of %d KB each\n",
228 	    sc->sc_device_size / 1024,
229 	    sc->sc_device_size / sc->sc_erase_size,
230 	    sc->sc_erase_size / 1024);
231 
232 	/* first-come first-served strategy works best for us */
233 	bufq_alloc(&sc->sc_waitq, "fcfs", BUFQ_SORT_RAWBLOCK);
234 	bufq_alloc(&sc->sc_workq, "fcfs", BUFQ_SORT_RAWBLOCK);
235 	bufq_alloc(&sc->sc_doneq, "fcfs", BUFQ_SORT_RAWBLOCK);
236 
237 	disk_init(&sc->sc_dk, device_xname(self), &spiflash_dkdriver);
238 	disk_attach(&sc->sc_dk);
239 
240 	/* arrange to allocate the kthread */
241 	kthread_create(PRI_NONE, 0, NULL, spiflash_thread, sc,
242 	    &sc->sc_thread, "spiflash");
243 }
244 
245 int
246 spiflash_open(dev_t dev, int flags, int mode, struct lwp *l)
247 {
248 	spiflash_handle_t sc;
249 
250 	sc = device_lookup_private(&spiflash_cd, DISKUNIT(dev));
251 	if (sc == NULL)
252 		return ENXIO;
253 
254 	/*
255 	 * XXX: We need to handle partitions here.  The problem is
256 	 * that it isn't entirely clear to me how to deal with this.
257 	 * There are devices that could be used "in the raw" with a
258 	 * NetBSD label, but then you get into devices that have other
259 	 * kinds of data on them -- some have VxWorks data, some have
260 	 * RedBoot data, and some have other contraints -- for example
261 	 * some devices might have a portion that is read-only,
262 	 * whereas others might have a portion that is read-write.
263 	 *
264 	 * For now we just permit access to the entire device.
265 	 */
266 	return 0;
267 }
268 
269 int
270 spiflash_close(dev_t dev, int flags, int mode, struct lwp *l)
271 {
272 	spiflash_handle_t sc;
273 
274 	sc = device_lookup_private(&spiflash_cd, DISKUNIT(dev));
275 	if (sc == NULL)
276 		return ENXIO;
277 
278 	return 0;
279 }
280 
281 int
282 spiflash_read(dev_t dev, struct uio *uio, int ioflag)
283 {
284 
285 	return physio(spiflash_strategy, NULL, dev, B_READ, minphys, uio);
286 }
287 
288 int
289 spiflash_write(dev_t dev, struct uio *uio, int ioflag)
290 {
291 
292 	return physio(spiflash_strategy, NULL, dev, B_WRITE, minphys, uio);
293 }
294 
295 int
296 spiflash_ioctl(dev_t dev, u_long cmd, void *data, int flags, struct lwp *l)
297 {
298 	spiflash_handle_t sc;
299 
300 	sc = device_lookup_private(&spiflash_cd, DISKUNIT(dev));
301 	if (sc == NULL)
302 		return ENXIO;
303 
304 	return EINVAL;
305 }
306 
307 void
308 spiflash_strategy(struct buf *bp)
309 {
310 	spiflash_handle_t sc;
311 	int	s;
312 
313 	bp->b_resid = bp->b_bcount;
314 
315 	sc = device_lookup_private(&spiflash_cd, DISKUNIT(bp->b_dev));
316 	if (sc == NULL) {
317 		bp->b_error = ENXIO;
318 		biodone(bp);
319 		return;
320 	}
321 
322 	if (((bp->b_bcount % sc->sc_write_size) != 0) ||
323 	    (bp->b_blkno < 0)) {
324 		bp->b_error = EINVAL;
325 		biodone(bp);
326 		return;
327 	}
328 
329 	/* no work? */
330 	if (bp->b_bcount == 0) {
331 		biodone(bp);
332 		return;
333 	}
334 
335 	if (bounds_check_with_mediasize(bp, DEV_BSIZE,
336 		sc->sc_device_blks) <= 0) {
337 		biodone(bp);
338 		return;
339 	}
340 
341 	/* all ready, hand off to thread for async processing */
342 	s = splbio();
343 	bufq_put(sc->sc_waitq, bp);
344 	wakeup(&sc->sc_thread);
345 	splx(s);
346 }
347 
348 void
349 spiflash_process_done(spiflash_handle_t sc, int err)
350 {
351 	struct buf	*bp;
352 	int		cnt = 0;
353 	int		flag = 0;
354 
355 	while ((bp = bufq_get(sc->sc_doneq)) != NULL) {
356 		flag = bp->b_flags & B_READ;
357 		if ((bp->b_error = err) == 0)
358 			bp->b_resid = 0;
359 		cnt += bp->b_bcount - bp->b_resid;
360 		biodone(bp);
361 	}
362 	disk_unbusy(&sc->sc_dk, cnt, flag);
363 }
364 
365 void
366 spiflash_process_read(spiflash_handle_t sc)
367 {
368 	struct buf	*bp;
369 	int		err = 0;
370 
371 	disk_busy(&sc->sc_dk);
372 	while ((bp = bufq_get(sc->sc_workq)) != NULL) {
373 		size_t addr = bp->b_blkno * DEV_BSIZE;
374 		uint8_t *data = bp->b_data;
375 		int cnt = bp->b_resid;
376 
377 		bufq_put(sc->sc_doneq, bp);
378 
379 		DPRINTF(("read from addr %x, cnt %d\n", (unsigned)addr, cnt));
380 
381 		if ((err = sc->sc_read(sc, addr, cnt, data)) != 0) {
382 			/* error occurred, fail all pending workq bufs */
383 			bufq_move(sc->sc_doneq, sc->sc_workq);
384 			break;
385 		}
386 
387 		bp->b_resid -= cnt;
388 		data += cnt;
389 		addr += cnt;
390 	}
391 	spiflash_process_done(sc, err);
392 }
393 
394 void
395 spiflash_process_write(spiflash_handle_t sc)
396 {
397 	int	len;
398 	size_t	base;
399 	daddr_t	blkno;
400 	uint8_t	*save;
401 	int	err = 0, neederase = 0;
402 	struct buf *bp;
403 
404 	/*
405 	 * due to other considerations, we are guaranteed that
406 	 * we will only have multiple buffers if they are all in
407 	 * the same erase sector.  Therefore we never need to look
408 	 * beyond the first block to determine how much data we need
409 	 * to save.
410 	 */
411 
412 	bp = bufq_peek(sc->sc_workq);
413 	len = spiflash_nsectors(sc, bp)  * sc->sc_erase_size;
414 	blkno = bp->b_blkno;
415 	base = (blkno * DEV_BSIZE) & ~ (sc->sc_erase_size - 1);
416 
417 	/* get ourself a scratch buffer */
418 	save = malloc(len, M_DEVBUF, M_WAITOK);
419 
420 	disk_busy(&sc->sc_dk);
421 	/* read in as much of the data as we need */
422 	DPRINTF(("reading in %d bytes\n", len));
423 	if ((err = sc->sc_read(sc, base, len, save)) != 0) {
424 		bufq_move(sc->sc_doneq, sc->sc_workq);
425 		spiflash_process_done(sc, err);
426 		return;
427 	}
428 
429 	/*
430 	 * now coalesce the writes into the save area, but also
431 	 * check to see if we need to do an erase
432 	 */
433 	while ((bp = bufq_get(sc->sc_workq)) != NULL) {
434 		uint8_t	*data, *dst;
435 		int resid = bp->b_resid;
436 
437 		DPRINTF(("coalesce write, blkno %x, count %d, resid %d\n",
438 			    (unsigned)bp->b_blkno, bp->b_bcount, resid));
439 
440 		data = bp->b_data;
441 		dst = save + (bp->b_blkno * DEV_BSIZE) - base;
442 
443 		/*
444 		 * NOR flash bits.  We can clear a bit, but we cannot
445 		 * set a bit, without erasing.  This should help reduce
446 		 * unnecessary erases.
447 		 */
448 		while (resid) {
449 			if ((*data) & ~(*dst))
450 				neederase = 1;
451 			*dst++ = *data++;
452 			resid--;
453 		}
454 
455 		bufq_put(sc->sc_doneq, bp);
456 	}
457 
458 	/*
459 	 * do the erase, if we need to.
460 	 */
461 	if (neederase) {
462 		DPRINTF(("erasing from %zx - %zx\n", base, base + len));
463 		if ((err = sc->sc_erase(sc, base, len)) != 0) {
464 			spiflash_process_done(sc, err);
465 			return;
466 		}
467 	}
468 
469 	/*
470 	 * now write our save area, and finish up.
471 	 */
472 	DPRINTF(("flashing %d bytes to %zx from %p\n", len, base, save));
473 	err = sc->sc_write(sc, base, len, save);
474 	spiflash_process_done(sc, err);
475 }
476 
477 
478 int
479 spiflash_nsectors(spiflash_handle_t sc, struct buf *bp)
480 {
481 	unsigned	addr, sector;
482 
483 	addr = bp->b_blkno * DEV_BSIZE;
484 	sector = addr / sc->sc_erase_size;
485 
486 	addr += bp->b_bcount;
487 	addr--;
488 	return (((addr / sc->sc_erase_size)  - sector) + 1);
489 }
490 
491 int
492 spiflash_sector(spiflash_handle_t sc, struct buf *bp)
493 {
494 	unsigned	addr, sector;
495 
496 	addr = bp->b_blkno * DEV_BSIZE;
497 	sector = addr / sc->sc_erase_size;
498 
499 	/* if it spans multiple blocks, error it */
500 	addr += bp->b_bcount;
501 	addr--;
502 	if (sector != (addr / sc->sc_erase_size))
503 		return -1;
504 
505 	return sector;
506 }
507 
508 void
509 spiflash_thread(void *arg)
510 {
511 	spiflash_handle_t sc = arg;
512 	struct buf	*bp;
513 	int		sector;
514 
515 	(void)splbio();
516 	for (;;) {
517 		if ((bp = bufq_get(sc->sc_waitq)) == NULL) {
518 			tsleep(&sc->sc_thread, PRIBIO, "spiflash_thread", 0);
519 			continue;
520 		}
521 
522 		bufq_put(sc->sc_workq, bp);
523 
524 		if (bp->b_flags & B_READ) {
525 			/* just do the read */
526 			spiflash_process_read(sc);
527 			continue;
528 		}
529 
530 		/*
531 		 * Because writing a flash filesystem is particularly
532 		 * painful, involving erase, modify, write, we prefer
533 		 * to coalesce writes to the same sector together.
534 		 */
535 
536 		sector = spiflash_sector(sc, bp);
537 
538 		/*
539 		 * if the write spans multiple sectors, skip
540 		 * coalescing.  (It would be nice if we could break
541 		 * these up.  minphys is honored for read/write, but
542 		 * not necessarily for bread.)
543 		 */
544 		if (sector < 0)
545 			goto dowrite;
546 
547 		while ((bp = bufq_peek(sc->sc_waitq)) != NULL) {
548 			/* can't deal with read requests! */
549 			if (bp->b_flags & B_READ)
550 				break;
551 
552 			/* is it for the same sector? */
553 			if (spiflash_sector(sc, bp) != sector)
554 				break;
555 
556 			bp = bufq_get(sc->sc_waitq);
557 			bufq_put(sc->sc_workq, bp);
558 		}
559 
560 	dowrite:
561 		spiflash_process_write(sc);
562 	}
563 }
564 /*
565  * SPI flash common implementation.
566  */
567 
568 /*
569  * Most devices take on the order of 1 second for each block that they
570  * delete.
571  */
572 int
573 spiflash_common_erase(spiflash_handle_t sc, size_t start, size_t size)
574 {
575 	int		rv;
576 
577 	if ((start % sc->sc_erase_size) || (size % sc->sc_erase_size))
578 		return EINVAL;
579 
580 	/* the second test is to test against wrap */
581 	if ((start > sc->sc_device_size) ||
582 	    ((start + size) > sc->sc_device_size))
583 		return EINVAL;
584 
585 	/*
586 	 * XXX: check protection status?  Requires master table mapping
587 	 * sectors to status bits, and so forth.
588 	 */
589 
590 	while (size) {
591 		if ((rv = spiflash_write_enable(sc)) != 0) {
592 			spiflash_write_disable(sc);
593 			return rv;
594 		}
595 		if ((rv = spiflash_cmd(sc, SPIFLASH_CMD_ERASE, 3, start, 0,
596 			 NULL, NULL)) != 0) {
597 			spiflash_write_disable(sc);
598 			return rv;
599 		}
600 
601 		/*
602 		 * The devices I have all say typical for sector erase
603 		 * is ~1sec.  We check ten times that often.  (There
604 		 * is no way to interrupt on this.)
605 		 */
606 		if ((rv = spiflash_wait(sc, hz / 10)) != 0)
607 			return rv;
608 
609 		start += sc->sc_erase_size;
610 		size -= sc->sc_erase_size;
611 
612 		/* NB: according to the docs I have, the write enable
613 		 * is automatically cleared upon completion of an erase
614 		 * command, so there is no need to explicitly disable it.
615 		 */
616 	}
617 
618 	return 0;
619 }
620 
621 int
622 spiflash_common_write(spiflash_handle_t sc, size_t start, size_t size,
623     const uint8_t *data)
624 {
625 	int		rv;
626 
627 	if ((start % sc->sc_write_size) || (size % sc->sc_write_size))
628 		return EINVAL;
629 
630 	while (size) {
631 		int cnt;
632 
633 		if ((rv = spiflash_write_enable(sc)) != 0) {
634 			spiflash_write_disable(sc);
635 			return rv;
636 		}
637 
638 		cnt = uimin(size, sc->sc_write_size);
639 		if ((rv = spiflash_cmd(sc, SPIFLASH_CMD_PROGRAM, 3, start,
640 			 cnt, data, NULL)) != 0) {
641 			spiflash_write_disable(sc);
642 			return rv;
643 		}
644 
645 		/*
646 		 * It seems that most devices can write bits fairly
647 		 * quickly.  For example, one part I have access to
648 		 * takes ~5msec to process the entire 256 byte page.
649 		 * Probably this should be modified to cope with
650 		 * device-specific timing, and maybe also take into
651 		 * account systems with higher values of HZ (which
652 		 * could benefit from sleeping.)
653 		 */
654 		if ((rv = spiflash_wait(sc, 0)) != 0)
655 			return rv;
656 
657 		data += cnt;
658 		start += cnt;
659 		size -= cnt;
660 	}
661 
662 	return 0;
663 }
664 
665 int
666 spiflash_common_read(spiflash_handle_t sc, size_t start, size_t size,
667     uint8_t *data)
668 {
669 	int		rv;
670 
671 	while (size) {
672 		int cnt;
673 
674 		if (sc->sc_read_size > 0)
675 			cnt = uimin(size, sc->sc_read_size);
676 		else
677 			cnt = size;
678 
679 		if ((rv = spiflash_cmd(sc, SPIFLASH_CMD_READ, 3, start,
680 			 cnt, NULL, data)) != 0) {
681 			return rv;
682 		}
683 
684 		data += cnt;
685 		start += cnt;
686 		size -= cnt;
687 	}
688 
689 	return 0;
690 }
691 
692 /* read status register */
693 int
694 spiflash_read_status(spiflash_handle_t sc, uint8_t *sr)
695 {
696 
697 	return spiflash_cmd(sc, SPIFLASH_CMD_RDSR, 0, 0, 1, NULL, sr);
698 }
699 
700 int
701 spiflash_write_enable(spiflash_handle_t sc)
702 {
703 
704 	return spiflash_cmd(sc, SPIFLASH_CMD_WREN, 0, 0, 0, NULL, NULL);
705 }
706 
707 int
708 spiflash_write_disable(spiflash_handle_t sc)
709 {
710 
711 	return spiflash_cmd(sc, SPIFLASH_CMD_WRDI, 0, 0, 0, NULL, NULL);
712 }
713 
714 int
715 spiflash_cmd(spiflash_handle_t sc, uint8_t cmd,
716     size_t addrlen, uint32_t addr,
717     size_t cnt, const uint8_t *wdata, uint8_t *rdata)
718 {
719 	struct spi_transfer	trans;
720 	struct spi_chunk	chunk1, chunk2;
721 	char buf[4];
722 	int i;
723 
724 	buf[0] = cmd;
725 
726 	if (addrlen > 3)
727 		return EINVAL;
728 
729 	for (i = addrlen; i > 0; i--) {
730 		buf[i] = addr & 0xff;
731 		addr >>= 8;
732 	}
733 	spi_transfer_init(&trans);
734 	spi_chunk_init(&chunk1, addrlen + 1, buf, NULL);
735 	spi_transfer_add(&trans, &chunk1);
736 	if (cnt) {
737 		spi_chunk_init(&chunk2, cnt, wdata, rdata);
738 		spi_transfer_add(&trans, &chunk2);
739 	}
740 
741 	spi_transfer(sc->sc_handle, &trans);
742 	spi_wait(&trans);
743 
744 	if (trans.st_flags & SPI_F_ERROR)
745 		return trans.st_errno;
746 	return 0;
747 }
748 
749 int
750 spiflash_wait(spiflash_handle_t sc, int tmo)
751 {
752 	int	rv;
753 	uint8_t	sr;
754 
755 	for (;;) {
756 		if ((rv = spiflash_read_status(sc, &sr)) != 0)
757 			return rv;
758 
759 		if ((sr & SPIFLASH_SR_BUSY) == 0)
760 			break;
761 		/*
762 		 * The devices I have all say typical for sector
763 		 * erase is ~1sec.  We check time times that often.
764 		 * (There is no way to interrupt on this.)
765 		 */
766 		if (tmo)
767 			tsleep(&sr, PWAIT, "spiflash_wait", tmo);
768 	}
769 	return 0;
770 }
771