tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Driver for Nvidia TEGRA spi controller.
3 *
4 * Copyright (C) 2010 Google, Inc.
5 *
6 * Author:
7 * Erik Gilling <konkers@android.com>
8 *
9 * This software is licensed under the terms of the GNU General Public
10 * License version 2, as published by the Free Software Foundation, and
11 * may be copied, distributed, and modified under those terms.
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 */
19
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/init.h>
23#include <linux/err.h>
24#include <linux/platform_device.h>
25#include <linux/io.h>
26#include <linux/dma-mapping.h>
27#include <linux/dmapool.h>
28#include <linux/clk.h>
29#include <linux/interrupt.h>
30#include <linux/delay.h>
31
32#include <linux/spi/spi.h>
33
34#include <mach/dma.h>
35
36#define SLINK_COMMAND 0x000
37#define SLINK_BIT_LENGTH(x) (((x) & 0x1f) << 0)
38#define SLINK_WORD_SIZE(x) (((x) & 0x1f) << 5)
39#define SLINK_BOTH_EN (1 << 10)
40#define SLINK_CS_SW (1 << 11)
41#define SLINK_CS_VALUE (1 << 12)
42#define SLINK_CS_POLARITY (1 << 13)
43#define SLINK_IDLE_SDA_DRIVE_LOW (0 << 16)
44#define SLINK_IDLE_SDA_DRIVE_HIGH (1 << 16)
45#define SLINK_IDLE_SDA_PULL_LOW (2 << 16)
46#define SLINK_IDLE_SDA_PULL_HIGH (3 << 16)
47#define SLINK_IDLE_SDA_MASK (3 << 16)
48#define SLINK_CS_POLARITY1 (1 << 20)
49#define SLINK_CK_SDA (1 << 21)
50#define SLINK_CS_POLARITY2 (1 << 22)
51#define SLINK_CS_POLARITY3 (1 << 23)
52#define SLINK_IDLE_SCLK_DRIVE_LOW (0 << 24)
53#define SLINK_IDLE_SCLK_DRIVE_HIGH (1 << 24)
54#define SLINK_IDLE_SCLK_PULL_LOW (2 << 24)
55#define SLINK_IDLE_SCLK_PULL_HIGH (3 << 24)
56#define SLINK_IDLE_SCLK_MASK (3 << 24)
57#define SLINK_M_S (1 << 28)
58#define SLINK_WAIT (1 << 29)
59#define SLINK_GO (1 << 30)
60#define SLINK_ENB (1 << 31)
61
62#define SLINK_COMMAND2 0x004
63#define SLINK_LSBFE (1 << 0)
64#define SLINK_SSOE (1 << 1)
65#define SLINK_SPIE (1 << 4)
66#define SLINK_BIDIROE (1 << 6)
67#define SLINK_MODFEN (1 << 7)
68#define SLINK_INT_SIZE(x) (((x) & 0x1f) << 8)
69#define SLINK_CS_ACTIVE_BETWEEN (1 << 17)
70#define SLINK_SS_EN_CS(x) (((x) & 0x3) << 18)
71#define SLINK_SS_SETUP(x) (((x) & 0x3) << 20)
72#define SLINK_FIFO_REFILLS_0 (0 << 22)
73#define SLINK_FIFO_REFILLS_1 (1 << 22)
74#define SLINK_FIFO_REFILLS_2 (2 << 22)
75#define SLINK_FIFO_REFILLS_3 (3 << 22)
76#define SLINK_FIFO_REFILLS_MASK (3 << 22)
77#define SLINK_WAIT_PACK_INT(x) (((x) & 0x7) << 26)
78#define SLINK_SPC0 (1 << 29)
79#define SLINK_TXEN (1 << 30)
80#define SLINK_RXEN (1 << 31)
81
82#define SLINK_STATUS 0x008
83#define SLINK_COUNT(val) (((val) >> 0) & 0x1f)
84#define SLINK_WORD(val) (((val) >> 5) & 0x1f)
85#define SLINK_BLK_CNT(val) (((val) >> 0) & 0xffff)
86#define SLINK_MODF (1 << 16)
87#define SLINK_RX_UNF (1 << 18)
88#define SLINK_TX_OVF (1 << 19)
89#define SLINK_TX_FULL (1 << 20)
90#define SLINK_TX_EMPTY (1 << 21)
91#define SLINK_RX_FULL (1 << 22)
92#define SLINK_RX_EMPTY (1 << 23)
93#define SLINK_TX_UNF (1 << 24)
94#define SLINK_RX_OVF (1 << 25)
95#define SLINK_TX_FLUSH (1 << 26)
96#define SLINK_RX_FLUSH (1 << 27)
97#define SLINK_SCLK (1 << 28)
98#define SLINK_ERR (1 << 29)
99#define SLINK_RDY (1 << 30)
100#define SLINK_BSY (1 << 31)
101
102#define SLINK_MAS_DATA 0x010
103#define SLINK_SLAVE_DATA 0x014
104
105#define SLINK_DMA_CTL 0x018
106#define SLINK_DMA_BLOCK_SIZE(x) (((x) & 0xffff) << 0)
107#define SLINK_TX_TRIG_1 (0 << 16)
108#define SLINK_TX_TRIG_4 (1 << 16)
109#define SLINK_TX_TRIG_8 (2 << 16)
110#define SLINK_TX_TRIG_16 (3 << 16)
111#define SLINK_TX_TRIG_MASK (3 << 16)
112#define SLINK_RX_TRIG_1 (0 << 18)
113#define SLINK_RX_TRIG_4 (1 << 18)
114#define SLINK_RX_TRIG_8 (2 << 18)
115#define SLINK_RX_TRIG_16 (3 << 18)
116#define SLINK_RX_TRIG_MASK (3 << 18)
117#define SLINK_PACKED (1 << 20)
118#define SLINK_PACK_SIZE_4 (0 << 21)
119#define SLINK_PACK_SIZE_8 (1 << 21)
120#define SLINK_PACK_SIZE_16 (2 << 21)
121#define SLINK_PACK_SIZE_32 (3 << 21)
122#define SLINK_PACK_SIZE_MASK (3 << 21)
123#define SLINK_IE_TXC (1 << 26)
124#define SLINK_IE_RXC (1 << 27)
125#define SLINK_DMA_EN (1 << 31)
126
127#define SLINK_STATUS2 0x01c
128#define SLINK_TX_FIFO_EMPTY_COUNT(val) (((val) & 0x3f) >> 0)
129#define SLINK_RX_FIFO_FULL_COUNT(val) (((val) & 0x3f) >> 16)
130
131#define SLINK_TX_FIFO 0x100
132#define SLINK_RX_FIFO 0x180
133
134static const unsigned long spi_tegra_req_sels[] = {
135 TEGRA_DMA_REQ_SEL_SL2B1,
136 TEGRA_DMA_REQ_SEL_SL2B2,
137 TEGRA_DMA_REQ_SEL_SL2B3,
138 TEGRA_DMA_REQ_SEL_SL2B4,
139};
140
141#define BB_LEN 32
142
143struct spi_tegra_data {
144 struct spi_master *master;
145 struct platform_device *pdev;
146 spinlock_t lock;
147
148 struct clk *clk;
149 void __iomem *base;
150 unsigned long phys;
151
152 u32 cur_speed;
153
154 struct list_head queue;
155 struct spi_transfer *cur;
156 unsigned cur_pos;
157 unsigned cur_len;
158 unsigned cur_bytes_per_word;
159
160 /* The tegra spi controller has a bug which causes the first word
161 * in PIO transactions to be garbage. Since packed DMA transactions
162 * require transfers to be 4 byte aligned we need a bounce buffer
163 * for the generic case.
164 */
165 struct tegra_dma_req rx_dma_req;
166 struct tegra_dma_channel *rx_dma;
167 u32 *rx_bb;
168 dma_addr_t rx_bb_phys;
169};
170
171
172static inline unsigned long spi_tegra_readl(struct spi_tegra_data *tspi,
173 unsigned long reg)
174{
175 return readl(tspi->base + reg);
176}
177
178static inline void spi_tegra_writel(struct spi_tegra_data *tspi,
179 unsigned long val,
180 unsigned long reg)
181{
182 writel(val, tspi->base + reg);
183}
184
185static void spi_tegra_go(struct spi_tegra_data *tspi)
186{
187 unsigned long val;
188
189 wmb();
190
191 val = spi_tegra_readl(tspi, SLINK_DMA_CTL);
192 val &= ~SLINK_DMA_BLOCK_SIZE(~0) & ~SLINK_DMA_EN;
193 val |= SLINK_DMA_BLOCK_SIZE(tspi->rx_dma_req.size / 4 - 1);
194 spi_tegra_writel(tspi, val, SLINK_DMA_CTL);
195
196 tegra_dma_enqueue_req(tspi->rx_dma, &tspi->rx_dma_req);
197
198 val |= SLINK_DMA_EN;
199 spi_tegra_writel(tspi, val, SLINK_DMA_CTL);
200}
201
202static unsigned spi_tegra_fill_tx_fifo(struct spi_tegra_data *tspi,
203 struct spi_transfer *t)
204{
205 unsigned len = min(t->len - tspi->cur_pos, BB_LEN *
206 tspi->cur_bytes_per_word);
207 u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_pos;
208 int i, j;
209 unsigned long val;
210
211 val = spi_tegra_readl(tspi, SLINK_COMMAND);
212 val &= ~SLINK_WORD_SIZE(~0);
213 val |= SLINK_WORD_SIZE(len / tspi->cur_bytes_per_word - 1);
214 spi_tegra_writel(tspi, val, SLINK_COMMAND);
215
216 for (i = 0; i < len; i += tspi->cur_bytes_per_word) {
217 val = 0;
218 for (j = 0; j < tspi->cur_bytes_per_word; j++)
219 val |= tx_buf[i + j] << j * 8;
220
221 spi_tegra_writel(tspi, val, SLINK_TX_FIFO);
222 }
223
224 tspi->rx_dma_req.size = len / tspi->cur_bytes_per_word * 4;
225
226 return len;
227}
228
229static unsigned spi_tegra_drain_rx_fifo(struct spi_tegra_data *tspi,
230 struct spi_transfer *t)
231{
232 unsigned len = tspi->cur_len;
233 u8 *rx_buf = (u8 *)t->rx_buf + tspi->cur_pos;
234 int i, j;
235 unsigned long val;
236
237 for (i = 0; i < len; i += tspi->cur_bytes_per_word) {
238 val = tspi->rx_bb[i / tspi->cur_bytes_per_word];
239 for (j = 0; j < tspi->cur_bytes_per_word; j++)
240 rx_buf[i + j] = (val >> (j * 8)) & 0xff;
241 }
242
243 return len;
244}
245
246static void spi_tegra_start_transfer(struct spi_device *spi,
247 struct spi_transfer *t)
248{
249 struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master);
250 u32 speed;
251 u8 bits_per_word;
252 unsigned long val;
253
254 speed = t->speed_hz ? t->speed_hz : spi->max_speed_hz;
255 bits_per_word = t->bits_per_word ? t->bits_per_word :
256 spi->bits_per_word;
257
258 tspi->cur_bytes_per_word = (bits_per_word - 1) / 8 + 1;
259
260 if (speed != tspi->cur_speed)
261 clk_set_rate(tspi->clk, speed);
262
263 if (tspi->cur_speed == 0)
264 clk_enable(tspi->clk);
265
266 tspi->cur_speed = speed;
267
268 val = spi_tegra_readl(tspi, SLINK_COMMAND2);
269 val &= ~SLINK_SS_EN_CS(~0) | SLINK_RXEN | SLINK_TXEN;
270 if (t->rx_buf)
271 val |= SLINK_RXEN;
272 if (t->tx_buf)
273 val |= SLINK_TXEN;
274 val |= SLINK_SS_EN_CS(spi->chip_select);
275 val |= SLINK_SPIE;
276 spi_tegra_writel(tspi, val, SLINK_COMMAND2);
277
278 val = spi_tegra_readl(tspi, SLINK_COMMAND);
279 val &= ~SLINK_BIT_LENGTH(~0);
280 val |= SLINK_BIT_LENGTH(bits_per_word - 1);
281
282 /* FIXME: should probably control CS manually so that we can be sure
283 * it does not go low between transfer and to support delay_usecs
284 * correctly.
285 */
286 val &= ~SLINK_IDLE_SCLK_MASK & ~SLINK_CK_SDA & ~SLINK_CS_SW;
287
288 if (spi->mode & SPI_CPHA)
289 val |= SLINK_CK_SDA;
290
291 if (spi->mode & SPI_CPOL)
292 val |= SLINK_IDLE_SCLK_DRIVE_HIGH;
293 else
294 val |= SLINK_IDLE_SCLK_DRIVE_LOW;
295
296 val |= SLINK_M_S;
297
298 spi_tegra_writel(tspi, val, SLINK_COMMAND);
299
300 spi_tegra_writel(tspi, SLINK_RX_FLUSH | SLINK_TX_FLUSH, SLINK_STATUS);
301
302 tspi->cur = t;
303 tspi->cur_pos = 0;
304 tspi->cur_len = spi_tegra_fill_tx_fifo(tspi, t);
305
306 spi_tegra_go(tspi);
307}
308
309static void spi_tegra_start_message(struct spi_device *spi,
310 struct spi_message *m)
311{
312 struct spi_transfer *t;
313
314 m->actual_length = 0;
315 m->status = 0;
316
317 t = list_first_entry(&m->transfers, struct spi_transfer, transfer_list);
318 spi_tegra_start_transfer(spi, t);
319}
320
321static void tegra_spi_rx_dma_complete(struct tegra_dma_req *req)
322{
323 struct spi_tegra_data *tspi = req->dev;
324 unsigned long flags;
325 struct spi_message *m;
326 struct spi_device *spi;
327 int timeout = 0;
328 unsigned long val;
329
330 /* the SPI controller may come back with both the BSY and RDY bits
331 * set. In this case we need to wait for the BSY bit to clear so
332 * that we are sure the DMA is finished. 1000 reads was empirically
333 * determined to be long enough.
334 */
335 while (timeout++ < 1000) {
336 if (!(spi_tegra_readl(tspi, SLINK_STATUS) & SLINK_BSY))
337 break;
338 }
339
340 spin_lock_irqsave(&tspi->lock, flags);
341
342 val = spi_tegra_readl(tspi, SLINK_STATUS);
343 val |= SLINK_RDY;
344 spi_tegra_writel(tspi, val, SLINK_STATUS);
345
346 m = list_first_entry(&tspi->queue, struct spi_message, queue);
347
348 if (timeout >= 1000)
349 m->status = -EIO;
350
351 spi = m->state;
352
353 tspi->cur_pos += spi_tegra_drain_rx_fifo(tspi, tspi->cur);
354 m->actual_length += tspi->cur_pos;
355
356 if (tspi->cur_pos < tspi->cur->len) {
357 tspi->cur_len = spi_tegra_fill_tx_fifo(tspi, tspi->cur);
358 spi_tegra_go(tspi);
359 } else if (!list_is_last(&tspi->cur->transfer_list,
360 &m->transfers)) {
361 tspi->cur = list_first_entry(&tspi->cur->transfer_list,
362 struct spi_transfer,
363 transfer_list);
364 spi_tegra_start_transfer(spi, tspi->cur);
365 } else {
366 list_del(&m->queue);
367
368 m->complete(m->context);
369
370 if (!list_empty(&tspi->queue)) {
371 m = list_first_entry(&tspi->queue, struct spi_message,
372 queue);
373 spi = m->state;
374 spi_tegra_start_message(spi, m);
375 } else {
376 clk_disable(tspi->clk);
377 tspi->cur_speed = 0;
378 }
379 }
380
381 spin_unlock_irqrestore(&tspi->lock, flags);
382}
383
384static int spi_tegra_setup(struct spi_device *spi)
385{
386 struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master);
387 unsigned long cs_bit;
388 unsigned long val;
389 unsigned long flags;
390
391 dev_dbg(&spi->dev, "setup %d bpw, %scpol, %scpha, %dHz\n",
392 spi->bits_per_word,
393 spi->mode & SPI_CPOL ? "" : "~",
394 spi->mode & SPI_CPHA ? "" : "~",
395 spi->max_speed_hz);
396
397
398 switch (spi->chip_select) {
399 case 0:
400 cs_bit = SLINK_CS_POLARITY;
401 break;
402
403 case 1:
404 cs_bit = SLINK_CS_POLARITY1;
405 break;
406
407 case 2:
408 cs_bit = SLINK_CS_POLARITY2;
409 break;
410
411 case 4:
412 cs_bit = SLINK_CS_POLARITY3;
413 break;
414
415 default:
416 return -EINVAL;
417 }
418
419 spin_lock_irqsave(&tspi->lock, flags);
420
421 val = spi_tegra_readl(tspi, SLINK_COMMAND);
422 if (spi->mode & SPI_CS_HIGH)
423 val |= cs_bit;
424 else
425 val &= ~cs_bit;
426 spi_tegra_writel(tspi, val, SLINK_COMMAND);
427
428 spin_unlock_irqrestore(&tspi->lock, flags);
429
430 return 0;
431}
432
433static int spi_tegra_transfer(struct spi_device *spi, struct spi_message *m)
434{
435 struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master);
436 struct spi_transfer *t;
437 unsigned long flags;
438 int was_empty;
439
440 if (list_empty(&m->transfers) || !m->complete)
441 return -EINVAL;
442
443 list_for_each_entry(t, &m->transfers, transfer_list) {
444 if (t->bits_per_word < 0 || t->bits_per_word > 32)
445 return -EINVAL;
446
447 if (t->len == 0)
448 return -EINVAL;
449
450 if (!t->rx_buf && !t->tx_buf)
451 return -EINVAL;
452 }
453
454 m->state = spi;
455
456 spin_lock_irqsave(&tspi->lock, flags);
457 was_empty = list_empty(&tspi->queue);
458 list_add_tail(&m->queue, &tspi->queue);
459
460 if (was_empty)
461 spi_tegra_start_message(spi, m);
462
463 spin_unlock_irqrestore(&tspi->lock, flags);
464
465 return 0;
466}
467
468static int __devinit spi_tegra_probe(struct platform_device *pdev)
469{
470 struct spi_master *master;
471 struct spi_tegra_data *tspi;
472 struct resource *r;
473 int ret;
474
475 master = spi_alloc_master(&pdev->dev, sizeof *tspi);
476 if (master == NULL) {
477 dev_err(&pdev->dev, "master allocation failed\n");
478 return -ENOMEM;
479 }
480
481 /* the spi->mode bits understood by this driver: */
482 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
483
484 master->bus_num = pdev->id;
485
486 master->setup = spi_tegra_setup;
487 master->transfer = spi_tegra_transfer;
488 master->num_chipselect = 4;
489
490 dev_set_drvdata(&pdev->dev, master);
491 tspi = spi_master_get_devdata(master);
492 tspi->master = master;
493 tspi->pdev = pdev;
494 spin_lock_init(&tspi->lock);
495
496 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
497 if (r == NULL) {
498 ret = -ENODEV;
499 goto err0;
500 }
501
502 if (!request_mem_region(r->start, resource_size(r),
503 dev_name(&pdev->dev))) {
504 ret = -EBUSY;
505 goto err0;
506 }
507
508 tspi->phys = r->start;
509 tspi->base = ioremap(r->start, resource_size(r));
510 if (!tspi->base) {
511 dev_err(&pdev->dev, "can't ioremap iomem\n");
512 ret = -ENOMEM;
513 goto err1;
514 }
515
516 tspi->clk = clk_get(&pdev->dev, NULL);
517 if (IS_ERR(tspi->clk)) {
518 dev_err(&pdev->dev, "can not get clock\n");
519 ret = PTR_ERR(tspi->clk);
520 goto err2;
521 }
522
523 INIT_LIST_HEAD(&tspi->queue);
524
525 tspi->rx_dma = tegra_dma_allocate_channel(TEGRA_DMA_MODE_ONESHOT);
526 if (!tspi->rx_dma) {
527 dev_err(&pdev->dev, "can not allocate rx dma channel\n");
528 ret = -ENODEV;
529 goto err3;
530 }
531
532 tspi->rx_bb = dma_alloc_coherent(&pdev->dev, sizeof(u32) * BB_LEN,
533 &tspi->rx_bb_phys, GFP_KERNEL);
534 if (!tspi->rx_bb) {
535 dev_err(&pdev->dev, "can not allocate rx bounce buffer\n");
536 ret = -ENOMEM;
537 goto err4;
538 }
539
540 tspi->rx_dma_req.complete = tegra_spi_rx_dma_complete;
541 tspi->rx_dma_req.to_memory = 1;
542 tspi->rx_dma_req.dest_addr = tspi->rx_bb_phys;
543 tspi->rx_dma_req.dest_bus_width = 32;
544 tspi->rx_dma_req.source_addr = tspi->phys + SLINK_RX_FIFO;
545 tspi->rx_dma_req.source_bus_width = 32;
546 tspi->rx_dma_req.source_wrap = 4;
547 tspi->rx_dma_req.req_sel = spi_tegra_req_sels[pdev->id];
548 tspi->rx_dma_req.dev = tspi;
549
550 master->dev.of_node = pdev->dev.of_node;
551 ret = spi_register_master(master);
552
553 if (ret < 0)
554 goto err5;
555
556 return ret;
557
558err5:
559 dma_free_coherent(&pdev->dev, sizeof(u32) * BB_LEN,
560 tspi->rx_bb, tspi->rx_bb_phys);
561err4:
562 tegra_dma_free_channel(tspi->rx_dma);
563err3:
564 clk_put(tspi->clk);
565err2:
566 iounmap(tspi->base);
567err1:
568 release_mem_region(r->start, resource_size(r));
569err0:
570 spi_master_put(master);
571 return ret;
572}
573
574static int __devexit spi_tegra_remove(struct platform_device *pdev)
575{
576 struct spi_master *master;
577 struct spi_tegra_data *tspi;
578 struct resource *r;
579
580 master = dev_get_drvdata(&pdev->dev);
581 tspi = spi_master_get_devdata(master);
582
583 spi_unregister_master(master);
584 tegra_dma_free_channel(tspi->rx_dma);
585
586 dma_free_coherent(&pdev->dev, sizeof(u32) * BB_LEN,
587 tspi->rx_bb, tspi->rx_bb_phys);
588
589 clk_put(tspi->clk);
590 iounmap(tspi->base);
591
592 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
593 release_mem_region(r->start, resource_size(r));
594
595 return 0;
596}
597
598MODULE_ALIAS("platform:spi_tegra");
599
600#ifdef CONFIG_OF
601static struct of_device_id spi_tegra_of_match_table[] __devinitdata = {
602 { .compatible = "nvidia,tegra20-spi", },
603 {}
604};
605MODULE_DEVICE_TABLE(of, spi_tegra_of_match_table);
606#else /* CONFIG_OF */
607#define spi_tegra_of_match_table NULL
608#endif /* CONFIG_OF */
609
610static struct platform_driver spi_tegra_driver = {
611 .driver = {
612 .name = "spi_tegra",
613 .owner = THIS_MODULE,
614 .of_match_table = spi_tegra_of_match_table,
615 },
616 .probe = spi_tegra_probe,
617 .remove = __devexit_p(spi_tegra_remove),
618};
619module_platform_driver(spi_tegra_driver);
620
621MODULE_LICENSE("GPL");