xref: /openbmc/linux/drivers/spi/spi-rspi.c (revision ab73b751)
1 /*
2  * SH RSPI driver
3  *
4  * Copyright (C) 2012  Renesas Solutions Corp.
5  *
6  * Based on spi-sh.c:
7  * Copyright (C) 2011 Renesas Solutions Corp.
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; version 2 of the License.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
21  *
22  */
23 
24 #include <linux/module.h>
25 #include <linux/kernel.h>
26 #include <linux/sched.h>
27 #include <linux/errno.h>
28 #include <linux/list.h>
29 #include <linux/workqueue.h>
30 #include <linux/interrupt.h>
31 #include <linux/platform_device.h>
32 #include <linux/io.h>
33 #include <linux/clk.h>
34 #include <linux/dmaengine.h>
35 #include <linux/dma-mapping.h>
36 #include <linux/sh_dma.h>
37 #include <linux/spi/spi.h>
38 #include <linux/spi/rspi.h>
39 
40 #define RSPI_SPCR		0x00
41 #define RSPI_SSLP		0x01
42 #define RSPI_SPPCR		0x02
43 #define RSPI_SPSR		0x03
44 #define RSPI_SPDR		0x04
45 #define RSPI_SPSCR		0x08
46 #define RSPI_SPSSR		0x09
47 #define RSPI_SPBR		0x0a
48 #define RSPI_SPDCR		0x0b
49 #define RSPI_SPCKD		0x0c
50 #define RSPI_SSLND		0x0d
51 #define RSPI_SPND		0x0e
52 #define RSPI_SPCR2		0x0f
53 #define RSPI_SPCMD0		0x10
54 #define RSPI_SPCMD1		0x12
55 #define RSPI_SPCMD2		0x14
56 #define RSPI_SPCMD3		0x16
57 #define RSPI_SPCMD4		0x18
58 #define RSPI_SPCMD5		0x1a
59 #define RSPI_SPCMD6		0x1c
60 #define RSPI_SPCMD7		0x1e
61 
62 /* SPCR */
63 #define SPCR_SPRIE		0x80
64 #define SPCR_SPE		0x40
65 #define SPCR_SPTIE		0x20
66 #define SPCR_SPEIE		0x10
67 #define SPCR_MSTR		0x08
68 #define SPCR_MODFEN		0x04
69 #define SPCR_TXMD		0x02
70 #define SPCR_SPMS		0x01
71 
72 /* SSLP */
73 #define SSLP_SSL1P		0x02
74 #define SSLP_SSL0P		0x01
75 
76 /* SPPCR */
77 #define SPPCR_MOIFE		0x20
78 #define SPPCR_MOIFV		0x10
79 #define SPPCR_SPOM		0x04
80 #define SPPCR_SPLP2		0x02
81 #define SPPCR_SPLP		0x01
82 
83 /* SPSR */
84 #define SPSR_SPRF		0x80
85 #define SPSR_SPTEF		0x20
86 #define SPSR_PERF		0x08
87 #define SPSR_MODF		0x04
88 #define SPSR_IDLNF		0x02
89 #define SPSR_OVRF		0x01
90 
91 /* SPSCR */
92 #define SPSCR_SPSLN_MASK	0x07
93 
94 /* SPSSR */
95 #define SPSSR_SPECM_MASK	0x70
96 #define SPSSR_SPCP_MASK		0x07
97 
98 /* SPDCR */
99 #define SPDCR_SPLW		0x20
100 #define SPDCR_SPRDTD		0x10
101 #define SPDCR_SLSEL1		0x08
102 #define SPDCR_SLSEL0		0x04
103 #define SPDCR_SLSEL_MASK	0x0c
104 #define SPDCR_SPFC1		0x02
105 #define SPDCR_SPFC0		0x01
106 
107 /* SPCKD */
108 #define SPCKD_SCKDL_MASK	0x07
109 
110 /* SSLND */
111 #define SSLND_SLNDL_MASK	0x07
112 
113 /* SPND */
114 #define SPND_SPNDL_MASK		0x07
115 
116 /* SPCR2 */
117 #define SPCR2_PTE		0x08
118 #define SPCR2_SPIE		0x04
119 #define SPCR2_SPOE		0x02
120 #define SPCR2_SPPE		0x01
121 
122 /* SPCMDn */
123 #define SPCMD_SCKDEN		0x8000
124 #define SPCMD_SLNDEN		0x4000
125 #define SPCMD_SPNDEN		0x2000
126 #define SPCMD_LSBF		0x1000
127 #define SPCMD_SPB_MASK		0x0f00
128 #define SPCMD_SPB_8_TO_16(bit)	(((bit - 1) << 8) & SPCMD_SPB_MASK)
129 #define SPCMD_SPB_20BIT		0x0000
130 #define SPCMD_SPB_24BIT		0x0100
131 #define SPCMD_SPB_32BIT		0x0200
132 #define SPCMD_SSLKP		0x0080
133 #define SPCMD_SSLA_MASK		0x0030
134 #define SPCMD_BRDV_MASK		0x000c
135 #define SPCMD_CPOL		0x0002
136 #define SPCMD_CPHA		0x0001
137 
138 struct rspi_data {
139 	void __iomem *addr;
140 	u32 max_speed_hz;
141 	struct spi_master *master;
142 	struct list_head queue;
143 	struct work_struct ws;
144 	wait_queue_head_t wait;
145 	spinlock_t lock;
146 	struct clk *clk;
147 	unsigned char spsr;
148 
149 	/* for dmaengine */
150 	struct sh_dmae_slave dma_tx;
151 	struct sh_dmae_slave dma_rx;
152 	struct dma_chan *chan_tx;
153 	struct dma_chan *chan_rx;
154 	int irq;
155 
156 	unsigned dma_width_16bit:1;
157 	unsigned dma_callbacked:1;
158 };
159 
160 static void rspi_write8(struct rspi_data *rspi, u8 data, u16 offset)
161 {
162 	iowrite8(data, rspi->addr + offset);
163 }
164 
165 static void rspi_write16(struct rspi_data *rspi, u16 data, u16 offset)
166 {
167 	iowrite16(data, rspi->addr + offset);
168 }
169 
170 static u8 rspi_read8(struct rspi_data *rspi, u16 offset)
171 {
172 	return ioread8(rspi->addr + offset);
173 }
174 
175 static u16 rspi_read16(struct rspi_data *rspi, u16 offset)
176 {
177 	return ioread16(rspi->addr + offset);
178 }
179 
180 static unsigned char rspi_calc_spbr(struct rspi_data *rspi)
181 {
182 	int tmp;
183 	unsigned char spbr;
184 
185 	tmp = clk_get_rate(rspi->clk) / (2 * rspi->max_speed_hz) - 1;
186 	spbr = clamp(tmp, 0, 255);
187 
188 	return spbr;
189 }
190 
191 static void rspi_enable_irq(struct rspi_data *rspi, u8 enable)
192 {
193 	rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) | enable, RSPI_SPCR);
194 }
195 
196 static void rspi_disable_irq(struct rspi_data *rspi, u8 disable)
197 {
198 	rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) & ~disable, RSPI_SPCR);
199 }
200 
201 static int rspi_wait_for_interrupt(struct rspi_data *rspi, u8 wait_mask,
202 				   u8 enable_bit)
203 {
204 	int ret;
205 
206 	rspi->spsr = rspi_read8(rspi, RSPI_SPSR);
207 	rspi_enable_irq(rspi, enable_bit);
208 	ret = wait_event_timeout(rspi->wait, rspi->spsr & wait_mask, HZ);
209 	if (ret == 0 && !(rspi->spsr & wait_mask))
210 		return -ETIMEDOUT;
211 
212 	return 0;
213 }
214 
215 static void rspi_assert_ssl(struct rspi_data *rspi)
216 {
217 	rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) | SPCR_SPE, RSPI_SPCR);
218 }
219 
220 static void rspi_negate_ssl(struct rspi_data *rspi)
221 {
222 	rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) & ~SPCR_SPE, RSPI_SPCR);
223 }
224 
225 static int rspi_set_config_register(struct rspi_data *rspi, int access_size)
226 {
227 	/* Sets output mode(CMOS) and MOSI signal(from previous transfer) */
228 	rspi_write8(rspi, 0x00, RSPI_SPPCR);
229 
230 	/* Sets transfer bit rate */
231 	rspi_write8(rspi, rspi_calc_spbr(rspi), RSPI_SPBR);
232 
233 	/* Sets number of frames to be used: 1 frame */
234 	rspi_write8(rspi, 0x00, RSPI_SPDCR);
235 
236 	/* Sets RSPCK, SSL, next-access delay value */
237 	rspi_write8(rspi, 0x00, RSPI_SPCKD);
238 	rspi_write8(rspi, 0x00, RSPI_SSLND);
239 	rspi_write8(rspi, 0x00, RSPI_SPND);
240 
241 	/* Sets parity, interrupt mask */
242 	rspi_write8(rspi, 0x00, RSPI_SPCR2);
243 
244 	/* Sets SPCMD */
245 	rspi_write16(rspi, SPCMD_SPB_8_TO_16(access_size) | SPCMD_SSLKP,
246 		     RSPI_SPCMD0);
247 
248 	/* Sets RSPI mode */
249 	rspi_write8(rspi, SPCR_MSTR, RSPI_SPCR);
250 
251 	return 0;
252 }
253 
254 static int rspi_send_pio(struct rspi_data *rspi, struct spi_message *mesg,
255 			 struct spi_transfer *t)
256 {
257 	int remain = t->len;
258 	u8 *data;
259 
260 	data = (u8 *)t->tx_buf;
261 	while (remain > 0) {
262 		rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) | SPCR_TXMD,
263 			    RSPI_SPCR);
264 
265 		if (rspi_wait_for_interrupt(rspi, SPSR_SPTEF, SPCR_SPTIE) < 0) {
266 			dev_err(&rspi->master->dev,
267 				"%s: tx empty timeout\n", __func__);
268 			return -ETIMEDOUT;
269 		}
270 
271 		rspi_write16(rspi, *data, RSPI_SPDR);
272 		data++;
273 		remain--;
274 	}
275 
276 	/* Waiting for the last transmition */
277 	rspi_wait_for_interrupt(rspi, SPSR_SPTEF, SPCR_SPTIE);
278 
279 	return 0;
280 }
281 
282 static void rspi_dma_complete(void *arg)
283 {
284 	struct rspi_data *rspi = arg;
285 
286 	rspi->dma_callbacked = 1;
287 	wake_up_interruptible(&rspi->wait);
288 }
289 
290 static int rspi_dma_map_sg(struct scatterlist *sg, void *buf, unsigned len,
291 			   struct dma_chan *chan,
292 			   enum dma_transfer_direction dir)
293 {
294 	sg_init_table(sg, 1);
295 	sg_set_buf(sg, buf, len);
296 	sg_dma_len(sg) = len;
297 	return dma_map_sg(chan->device->dev, sg, 1, dir);
298 }
299 
300 static void rspi_dma_unmap_sg(struct scatterlist *sg, struct dma_chan *chan,
301 			      enum dma_transfer_direction dir)
302 {
303 	dma_unmap_sg(chan->device->dev, sg, 1, dir);
304 }
305 
306 static void rspi_memory_to_8bit(void *buf, const void *data, unsigned len)
307 {
308 	u16 *dst = buf;
309 	const u8 *src = data;
310 
311 	while (len) {
312 		*dst++ = (u16)(*src++);
313 		len--;
314 	}
315 }
316 
317 static void rspi_memory_from_8bit(void *buf, const void *data, unsigned len)
318 {
319 	u8 *dst = buf;
320 	const u16 *src = data;
321 
322 	while (len) {
323 		*dst++ = (u8)*src++;
324 		len--;
325 	}
326 }
327 
328 static int rspi_send_dma(struct rspi_data *rspi, struct spi_transfer *t)
329 {
330 	struct scatterlist sg;
331 	void *buf = NULL;
332 	struct dma_async_tx_descriptor *desc;
333 	unsigned len;
334 	int ret = 0;
335 
336 	if (rspi->dma_width_16bit) {
337 		/*
338 		 * If DMAC bus width is 16-bit, the driver allocates a dummy
339 		 * buffer. And, the driver converts original data into the
340 		 * DMAC data as the following format:
341 		 *  original data: 1st byte, 2nd byte ...
342 		 *  DMAC data:     1st byte, dummy, 2nd byte, dummy ...
343 		 */
344 		len = t->len * 2;
345 		buf = kmalloc(len, GFP_KERNEL);
346 		if (!buf)
347 			return -ENOMEM;
348 		rspi_memory_to_8bit(buf, t->tx_buf, t->len);
349 	} else {
350 		len = t->len;
351 		buf = (void *)t->tx_buf;
352 	}
353 
354 	if (!rspi_dma_map_sg(&sg, buf, len, rspi->chan_tx, DMA_TO_DEVICE)) {
355 		ret = -EFAULT;
356 		goto end_nomap;
357 	}
358 	desc = dmaengine_prep_slave_sg(rspi->chan_tx, &sg, 1, DMA_TO_DEVICE,
359 				       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
360 	if (!desc) {
361 		ret = -EIO;
362 		goto end;
363 	}
364 
365 	/*
366 	 * DMAC needs SPTIE, but if SPTIE is set, this IRQ routine will be
367 	 * called. So, this driver disables the IRQ while DMA transfer.
368 	 */
369 	disable_irq(rspi->irq);
370 
371 	rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) | SPCR_TXMD, RSPI_SPCR);
372 	rspi_enable_irq(rspi, SPCR_SPTIE);
373 	rspi->dma_callbacked = 0;
374 
375 	desc->callback = rspi_dma_complete;
376 	desc->callback_param = rspi;
377 	dmaengine_submit(desc);
378 	dma_async_issue_pending(rspi->chan_tx);
379 
380 	ret = wait_event_interruptible_timeout(rspi->wait,
381 					       rspi->dma_callbacked, HZ);
382 	if (ret > 0 && rspi->dma_callbacked)
383 		ret = 0;
384 	else if (!ret)
385 		ret = -ETIMEDOUT;
386 	rspi_disable_irq(rspi, SPCR_SPTIE);
387 
388 	enable_irq(rspi->irq);
389 
390 end:
391 	rspi_dma_unmap_sg(&sg, rspi->chan_tx, DMA_TO_DEVICE);
392 end_nomap:
393 	if (rspi->dma_width_16bit)
394 		kfree(buf);
395 
396 	return ret;
397 }
398 
399 static void rspi_receive_init(struct rspi_data *rspi)
400 {
401 	unsigned char spsr;
402 
403 	spsr = rspi_read8(rspi, RSPI_SPSR);
404 	if (spsr & SPSR_SPRF)
405 		rspi_read16(rspi, RSPI_SPDR);	/* dummy read */
406 	if (spsr & SPSR_OVRF)
407 		rspi_write8(rspi, rspi_read8(rspi, RSPI_SPSR) & ~SPSR_OVRF,
408 			    RSPI_SPCR);
409 }
410 
411 static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg,
412 			    struct spi_transfer *t)
413 {
414 	int remain = t->len;
415 	u8 *data;
416 
417 	rspi_receive_init(rspi);
418 
419 	data = (u8 *)t->rx_buf;
420 	while (remain > 0) {
421 		rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) & ~SPCR_TXMD,
422 			    RSPI_SPCR);
423 
424 		if (rspi_wait_for_interrupt(rspi, SPSR_SPTEF, SPCR_SPTIE) < 0) {
425 			dev_err(&rspi->master->dev,
426 				"%s: tx empty timeout\n", __func__);
427 			return -ETIMEDOUT;
428 		}
429 		/* dummy write for generate clock */
430 		rspi_write16(rspi, 0x00, RSPI_SPDR);
431 
432 		if (rspi_wait_for_interrupt(rspi, SPSR_SPRF, SPCR_SPRIE) < 0) {
433 			dev_err(&rspi->master->dev,
434 				"%s: receive timeout\n", __func__);
435 			return -ETIMEDOUT;
436 		}
437 		/* SPDR allows 16 or 32-bit access only */
438 		*data = (u8)rspi_read16(rspi, RSPI_SPDR);
439 
440 		data++;
441 		remain--;
442 	}
443 
444 	return 0;
445 }
446 
447 static int rspi_receive_dma(struct rspi_data *rspi, struct spi_transfer *t)
448 {
449 	struct scatterlist sg, sg_dummy;
450 	void *dummy = NULL, *rx_buf = NULL;
451 	struct dma_async_tx_descriptor *desc, *desc_dummy;
452 	unsigned len;
453 	int ret = 0;
454 
455 	if (rspi->dma_width_16bit) {
456 		/*
457 		 * If DMAC bus width is 16-bit, the driver allocates a dummy
458 		 * buffer. And, finally the driver converts the DMAC data into
459 		 * actual data as the following format:
460 		 *  DMAC data:   1st byte, dummy, 2nd byte, dummy ...
461 		 *  actual data: 1st byte, 2nd byte ...
462 		 */
463 		len = t->len * 2;
464 		rx_buf = kmalloc(len, GFP_KERNEL);
465 		if (!rx_buf)
466 			return -ENOMEM;
467 	 } else {
468 		len = t->len;
469 		rx_buf = t->rx_buf;
470 	}
471 
472 	/* prepare dummy transfer to generate SPI clocks */
473 	dummy = kzalloc(len, GFP_KERNEL);
474 	if (!dummy) {
475 		ret = -ENOMEM;
476 		goto end_nomap;
477 	}
478 	if (!rspi_dma_map_sg(&sg_dummy, dummy, len, rspi->chan_tx,
479 			     DMA_TO_DEVICE)) {
480 		ret = -EFAULT;
481 		goto end_nomap;
482 	}
483 	desc_dummy = dmaengine_prep_slave_sg(rspi->chan_tx, &sg_dummy, 1,
484 			DMA_TO_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
485 	if (!desc_dummy) {
486 		ret = -EIO;
487 		goto end_dummy_mapped;
488 	}
489 
490 	/* prepare receive transfer */
491 	if (!rspi_dma_map_sg(&sg, rx_buf, len, rspi->chan_rx,
492 			     DMA_FROM_DEVICE)) {
493 		ret = -EFAULT;
494 		goto end_dummy_mapped;
495 
496 	}
497 	desc = dmaengine_prep_slave_sg(rspi->chan_rx, &sg, 1, DMA_FROM_DEVICE,
498 				       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
499 	if (!desc) {
500 		ret = -EIO;
501 		goto end;
502 	}
503 
504 	rspi_receive_init(rspi);
505 
506 	/*
507 	 * DMAC needs SPTIE, but if SPTIE is set, this IRQ routine will be
508 	 * called. So, this driver disables the IRQ while DMA transfer.
509 	 */
510 	disable_irq(rspi->irq);
511 
512 	rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) & ~SPCR_TXMD, RSPI_SPCR);
513 	rspi_enable_irq(rspi, SPCR_SPTIE | SPCR_SPRIE);
514 	rspi->dma_callbacked = 0;
515 
516 	desc->callback = rspi_dma_complete;
517 	desc->callback_param = rspi;
518 	dmaengine_submit(desc);
519 	dma_async_issue_pending(rspi->chan_rx);
520 
521 	desc_dummy->callback = NULL;	/* No callback */
522 	dmaengine_submit(desc_dummy);
523 	dma_async_issue_pending(rspi->chan_tx);
524 
525 	ret = wait_event_interruptible_timeout(rspi->wait,
526 					       rspi->dma_callbacked, HZ);
527 	if (ret > 0 && rspi->dma_callbacked)
528 		ret = 0;
529 	else if (!ret)
530 		ret = -ETIMEDOUT;
531 	rspi_disable_irq(rspi, SPCR_SPTIE | SPCR_SPRIE);
532 
533 	enable_irq(rspi->irq);
534 
535 end:
536 	rspi_dma_unmap_sg(&sg, rspi->chan_rx, DMA_FROM_DEVICE);
537 end_dummy_mapped:
538 	rspi_dma_unmap_sg(&sg_dummy, rspi->chan_tx, DMA_TO_DEVICE);
539 end_nomap:
540 	if (rspi->dma_width_16bit) {
541 		if (!ret)
542 			rspi_memory_from_8bit(t->rx_buf, rx_buf, t->len);
543 		kfree(rx_buf);
544 	}
545 	kfree(dummy);
546 
547 	return ret;
548 }
549 
550 static int rspi_is_dma(struct rspi_data *rspi, struct spi_transfer *t)
551 {
552 	if (t->tx_buf && rspi->chan_tx)
553 		return 1;
554 	/* If the module receives data by DMAC, it also needs TX DMAC */
555 	if (t->rx_buf && rspi->chan_tx && rspi->chan_rx)
556 		return 1;
557 
558 	return 0;
559 }
560 
561 static void rspi_work(struct work_struct *work)
562 {
563 	struct rspi_data *rspi = container_of(work, struct rspi_data, ws);
564 	struct spi_message *mesg;
565 	struct spi_transfer *t;
566 	unsigned long flags;
567 	int ret;
568 
569 	spin_lock_irqsave(&rspi->lock, flags);
570 	while (!list_empty(&rspi->queue)) {
571 		mesg = list_entry(rspi->queue.next, struct spi_message, queue);
572 		list_del_init(&mesg->queue);
573 		spin_unlock_irqrestore(&rspi->lock, flags);
574 
575 		rspi_assert_ssl(rspi);
576 
577 		list_for_each_entry(t, &mesg->transfers, transfer_list) {
578 			if (t->tx_buf) {
579 				if (rspi_is_dma(rspi, t))
580 					ret = rspi_send_dma(rspi, t);
581 				else
582 					ret = rspi_send_pio(rspi, mesg, t);
583 				if (ret < 0)
584 					goto error;
585 			}
586 			if (t->rx_buf) {
587 				if (rspi_is_dma(rspi, t))
588 					ret = rspi_receive_dma(rspi, t);
589 				else
590 					ret = rspi_receive_pio(rspi, mesg, t);
591 				if (ret < 0)
592 					goto error;
593 			}
594 			mesg->actual_length += t->len;
595 		}
596 		rspi_negate_ssl(rspi);
597 
598 		mesg->status = 0;
599 		mesg->complete(mesg->context);
600 
601 		spin_lock_irqsave(&rspi->lock, flags);
602 	}
603 
604 	return;
605 
606 error:
607 	mesg->status = ret;
608 	mesg->complete(mesg->context);
609 }
610 
611 static int rspi_setup(struct spi_device *spi)
612 {
613 	struct rspi_data *rspi = spi_master_get_devdata(spi->master);
614 
615 	if (!spi->bits_per_word)
616 		spi->bits_per_word = 8;
617 	rspi->max_speed_hz = spi->max_speed_hz;
618 
619 	rspi_set_config_register(rspi, 8);
620 
621 	return 0;
622 }
623 
624 static int rspi_transfer(struct spi_device *spi, struct spi_message *mesg)
625 {
626 	struct rspi_data *rspi = spi_master_get_devdata(spi->master);
627 	unsigned long flags;
628 
629 	mesg->actual_length = 0;
630 	mesg->status = -EINPROGRESS;
631 
632 	spin_lock_irqsave(&rspi->lock, flags);
633 	list_add_tail(&mesg->queue, &rspi->queue);
634 	schedule_work(&rspi->ws);
635 	spin_unlock_irqrestore(&rspi->lock, flags);
636 
637 	return 0;
638 }
639 
640 static void rspi_cleanup(struct spi_device *spi)
641 {
642 }
643 
644 static irqreturn_t rspi_irq(int irq, void *_sr)
645 {
646 	struct rspi_data *rspi = (struct rspi_data *)_sr;
647 	unsigned long spsr;
648 	irqreturn_t ret = IRQ_NONE;
649 	unsigned char disable_irq = 0;
650 
651 	rspi->spsr = spsr = rspi_read8(rspi, RSPI_SPSR);
652 	if (spsr & SPSR_SPRF)
653 		disable_irq |= SPCR_SPRIE;
654 	if (spsr & SPSR_SPTEF)
655 		disable_irq |= SPCR_SPTIE;
656 
657 	if (disable_irq) {
658 		ret = IRQ_HANDLED;
659 		rspi_disable_irq(rspi, disable_irq);
660 		wake_up(&rspi->wait);
661 	}
662 
663 	return ret;
664 }
665 
666 static bool rspi_filter(struct dma_chan *chan, void *filter_param)
667 {
668 	chan->private = filter_param;
669 	return true;
670 }
671 
672 static void __devinit rspi_request_dma(struct rspi_data *rspi,
673 				       struct platform_device *pdev)
674 {
675 	struct rspi_plat_data *rspi_pd = pdev->dev.platform_data;
676 	dma_cap_mask_t mask;
677 
678 	if (!rspi_pd)
679 		return;
680 
681 	rspi->dma_width_16bit = rspi_pd->dma_width_16bit;
682 
683 	/* If the module receives data by DMAC, it also needs TX DMAC */
684 	if (rspi_pd->dma_rx_id && rspi_pd->dma_tx_id) {
685 		dma_cap_zero(mask);
686 		dma_cap_set(DMA_SLAVE, mask);
687 		rspi->dma_rx.slave_id = rspi_pd->dma_rx_id;
688 		rspi->chan_rx = dma_request_channel(mask, rspi_filter,
689 						    &rspi->dma_rx);
690 		if (rspi->chan_rx)
691 			dev_info(&pdev->dev, "Use DMA when rx.\n");
692 	}
693 	if (rspi_pd->dma_tx_id) {
694 		dma_cap_zero(mask);
695 		dma_cap_set(DMA_SLAVE, mask);
696 		rspi->dma_tx.slave_id = rspi_pd->dma_tx_id;
697 		rspi->chan_tx = dma_request_channel(mask, rspi_filter,
698 						    &rspi->dma_tx);
699 		if (rspi->chan_tx)
700 			dev_info(&pdev->dev, "Use DMA when tx\n");
701 	}
702 }
703 
704 static void __devexit rspi_release_dma(struct rspi_data *rspi)
705 {
706 	if (rspi->chan_tx)
707 		dma_release_channel(rspi->chan_tx);
708 	if (rspi->chan_rx)
709 		dma_release_channel(rspi->chan_rx);
710 }
711 
712 static int __devexit rspi_remove(struct platform_device *pdev)
713 {
714 	struct rspi_data *rspi = dev_get_drvdata(&pdev->dev);
715 
716 	spi_unregister_master(rspi->master);
717 	rspi_release_dma(rspi);
718 	free_irq(platform_get_irq(pdev, 0), rspi);
719 	clk_put(rspi->clk);
720 	iounmap(rspi->addr);
721 	spi_master_put(rspi->master);
722 
723 	return 0;
724 }
725 
726 static int __devinit rspi_probe(struct platform_device *pdev)
727 {
728 	struct resource *res;
729 	struct spi_master *master;
730 	struct rspi_data *rspi;
731 	int ret, irq;
732 	char clk_name[16];
733 
734 	/* get base addr */
735 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
736 	if (unlikely(res == NULL)) {
737 		dev_err(&pdev->dev, "invalid resource\n");
738 		return -EINVAL;
739 	}
740 
741 	irq = platform_get_irq(pdev, 0);
742 	if (irq < 0) {
743 		dev_err(&pdev->dev, "platform_get_irq error\n");
744 		return -ENODEV;
745 	}
746 
747 	master = spi_alloc_master(&pdev->dev, sizeof(struct rspi_data));
748 	if (master == NULL) {
749 		dev_err(&pdev->dev, "spi_alloc_master error.\n");
750 		return -ENOMEM;
751 	}
752 
753 	rspi = spi_master_get_devdata(master);
754 	dev_set_drvdata(&pdev->dev, rspi);
755 
756 	rspi->master = master;
757 	rspi->addr = ioremap(res->start, resource_size(res));
758 	if (rspi->addr == NULL) {
759 		dev_err(&pdev->dev, "ioremap error.\n");
760 		ret = -ENOMEM;
761 		goto error1;
762 	}
763 
764 	snprintf(clk_name, sizeof(clk_name), "rspi%d", pdev->id);
765 	rspi->clk = clk_get(&pdev->dev, clk_name);
766 	if (IS_ERR(rspi->clk)) {
767 		dev_err(&pdev->dev, "cannot get clock\n");
768 		ret = PTR_ERR(rspi->clk);
769 		goto error2;
770 	}
771 	clk_enable(rspi->clk);
772 
773 	INIT_LIST_HEAD(&rspi->queue);
774 	spin_lock_init(&rspi->lock);
775 	INIT_WORK(&rspi->ws, rspi_work);
776 	init_waitqueue_head(&rspi->wait);
777 
778 	master->num_chipselect = 2;
779 	master->bus_num = pdev->id;
780 	master->setup = rspi_setup;
781 	master->transfer = rspi_transfer;
782 	master->cleanup = rspi_cleanup;
783 
784 	ret = request_irq(irq, rspi_irq, 0, dev_name(&pdev->dev), rspi);
785 	if (ret < 0) {
786 		dev_err(&pdev->dev, "request_irq error\n");
787 		goto error3;
788 	}
789 
790 	rspi->irq = irq;
791 	rspi_request_dma(rspi, pdev);
792 
793 	ret = spi_register_master(master);
794 	if (ret < 0) {
795 		dev_err(&pdev->dev, "spi_register_master error.\n");
796 		goto error4;
797 	}
798 
799 	dev_info(&pdev->dev, "probed\n");
800 
801 	return 0;
802 
803 error4:
804 	rspi_release_dma(rspi);
805 	free_irq(irq, rspi);
806 error3:
807 	clk_put(rspi->clk);
808 error2:
809 	iounmap(rspi->addr);
810 error1:
811 	spi_master_put(master);
812 
813 	return ret;
814 }
815 
816 static struct platform_driver rspi_driver = {
817 	.probe =	rspi_probe,
818 	.remove =	__devexit_p(rspi_remove),
819 	.driver		= {
820 		.name = "rspi",
821 		.owner	= THIS_MODULE,
822 	},
823 };
824 module_platform_driver(rspi_driver);
825 
826 MODULE_DESCRIPTION("Renesas RSPI bus driver");
827 MODULE_LICENSE("GPL v2");
828 MODULE_AUTHOR("Yoshihiro Shimoda");
829 MODULE_ALIAS("platform:rspi");
830