1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2009 Texas Instruments.
4 * Copyright (C) 2010 EF Johnson Technologies
5 */
6
7 #include <linux/interrupt.h>
8 #include <linux/io.h>
9 #include <linux/gpio/consumer.h>
10 #include <linux/module.h>
11 #include <linux/delay.h>
12 #include <linux/platform_device.h>
13 #include <linux/err.h>
14 #include <linux/clk.h>
15 #include <linux/dmaengine.h>
16 #include <linux/dma-mapping.h>
17 #include <linux/of.h>
18 #include <linux/of_device.h>
19 #include <linux/spi/spi.h>
20 #include <linux/spi/spi_bitbang.h>
21 #include <linux/slab.h>
22
23 #include <linux/platform_data/spi-davinci.h>
24
25 #define CS_DEFAULT 0xFF
26
27 #define SPIFMT_PHASE_MASK BIT(16)
28 #define SPIFMT_POLARITY_MASK BIT(17)
29 #define SPIFMT_DISTIMER_MASK BIT(18)
30 #define SPIFMT_SHIFTDIR_MASK BIT(20)
31 #define SPIFMT_WAITENA_MASK BIT(21)
32 #define SPIFMT_PARITYENA_MASK BIT(22)
33 #define SPIFMT_ODD_PARITY_MASK BIT(23)
34 #define SPIFMT_WDELAY_MASK 0x3f000000u
35 #define SPIFMT_WDELAY_SHIFT 24
36 #define SPIFMT_PRESCALE_SHIFT 8
37
38 /* SPIPC0 */
39 #define SPIPC0_DIFUN_MASK BIT(11) /* MISO */
40 #define SPIPC0_DOFUN_MASK BIT(10) /* MOSI */
41 #define SPIPC0_CLKFUN_MASK BIT(9) /* CLK */
42 #define SPIPC0_SPIENA_MASK BIT(8) /* nREADY */
43
44 #define SPIINT_MASKALL 0x0101035F
45 #define SPIINT_MASKINT 0x0000015F
46 #define SPI_INTLVL_1 0x000001FF
47 #define SPI_INTLVL_0 0x00000000
48
49 /* SPIDAT1 (upper 16 bit defines) */
50 #define SPIDAT1_CSHOLD_MASK BIT(12)
51 #define SPIDAT1_WDEL BIT(10)
52
53 /* SPIGCR1 */
54 #define SPIGCR1_CLKMOD_MASK BIT(1)
55 #define SPIGCR1_MASTER_MASK BIT(0)
56 #define SPIGCR1_POWERDOWN_MASK BIT(8)
57 #define SPIGCR1_LOOPBACK_MASK BIT(16)
58 #define SPIGCR1_SPIENA_MASK BIT(24)
59
60 /* SPIBUF */
61 #define SPIBUF_TXFULL_MASK BIT(29)
62 #define SPIBUF_RXEMPTY_MASK BIT(31)
63
64 /* SPIDELAY */
65 #define SPIDELAY_C2TDELAY_SHIFT 24
66 #define SPIDELAY_C2TDELAY_MASK (0xFF << SPIDELAY_C2TDELAY_SHIFT)
67 #define SPIDELAY_T2CDELAY_SHIFT 16
68 #define SPIDELAY_T2CDELAY_MASK (0xFF << SPIDELAY_T2CDELAY_SHIFT)
69 #define SPIDELAY_T2EDELAY_SHIFT 8
70 #define SPIDELAY_T2EDELAY_MASK (0xFF << SPIDELAY_T2EDELAY_SHIFT)
71 #define SPIDELAY_C2EDELAY_SHIFT 0
72 #define SPIDELAY_C2EDELAY_MASK 0xFF
73
74 /* Error Masks */
75 #define SPIFLG_DLEN_ERR_MASK BIT(0)
76 #define SPIFLG_TIMEOUT_MASK BIT(1)
77 #define SPIFLG_PARERR_MASK BIT(2)
78 #define SPIFLG_DESYNC_MASK BIT(3)
79 #define SPIFLG_BITERR_MASK BIT(4)
80 #define SPIFLG_OVRRUN_MASK BIT(6)
81 #define SPIFLG_BUF_INIT_ACTIVE_MASK BIT(24)
82 #define SPIFLG_ERROR_MASK (SPIFLG_DLEN_ERR_MASK \
83 | SPIFLG_TIMEOUT_MASK | SPIFLG_PARERR_MASK \
84 | SPIFLG_DESYNC_MASK | SPIFLG_BITERR_MASK \
85 | SPIFLG_OVRRUN_MASK)
86
87 #define SPIINT_DMA_REQ_EN BIT(16)
88
89 /* SPI Controller registers */
90 #define SPIGCR0 0x00
91 #define SPIGCR1 0x04
92 #define SPIINT 0x08
93 #define SPILVL 0x0c
94 #define SPIFLG 0x10
95 #define SPIPC0 0x14
96 #define SPIDAT1 0x3c
97 #define SPIBUF 0x40
98 #define SPIDELAY 0x48
99 #define SPIDEF 0x4c
100 #define SPIFMT0 0x50
101
102 #define DMA_MIN_BYTES 16
103
104 /* SPI Controller driver's private data. */
105 struct davinci_spi {
106 struct spi_bitbang bitbang;
107 struct clk *clk;
108
109 u8 version;
110 resource_size_t pbase;
111 void __iomem *base;
112 u32 irq;
113 struct completion done;
114
115 const void *tx;
116 void *rx;
117 int rcount;
118 int wcount;
119
120 struct dma_chan *dma_rx;
121 struct dma_chan *dma_tx;
122
123 struct davinci_spi_platform_data pdata;
124
125 void (*get_rx)(u32 rx_data, struct davinci_spi *);
126 u32 (*get_tx)(struct davinci_spi *);
127
128 u8 *bytes_per_word;
129
130 u8 prescaler_limit;
131 };
132
133 static struct davinci_spi_config davinci_spi_default_cfg;
134
davinci_spi_rx_buf_u8(u32 data,struct davinci_spi * dspi)135 static void davinci_spi_rx_buf_u8(u32 data, struct davinci_spi *dspi)
136 {
137 if (dspi->rx) {
138 u8 *rx = dspi->rx;
139 *rx++ = (u8)data;
140 dspi->rx = rx;
141 }
142 }
143
davinci_spi_rx_buf_u16(u32 data,struct davinci_spi * dspi)144 static void davinci_spi_rx_buf_u16(u32 data, struct davinci_spi *dspi)
145 {
146 if (dspi->rx) {
147 u16 *rx = dspi->rx;
148 *rx++ = (u16)data;
149 dspi->rx = rx;
150 }
151 }
152
davinci_spi_tx_buf_u8(struct davinci_spi * dspi)153 static u32 davinci_spi_tx_buf_u8(struct davinci_spi *dspi)
154 {
155 u32 data = 0;
156
157 if (dspi->tx) {
158 const u8 *tx = dspi->tx;
159
160 data = *tx++;
161 dspi->tx = tx;
162 }
163 return data;
164 }
165
davinci_spi_tx_buf_u16(struct davinci_spi * dspi)166 static u32 davinci_spi_tx_buf_u16(struct davinci_spi *dspi)
167 {
168 u32 data = 0;
169
170 if (dspi->tx) {
171 const u16 *tx = dspi->tx;
172
173 data = *tx++;
174 dspi->tx = tx;
175 }
176 return data;
177 }
178
set_io_bits(void __iomem * addr,u32 bits)179 static inline void set_io_bits(void __iomem *addr, u32 bits)
180 {
181 u32 v = ioread32(addr);
182
183 v |= bits;
184 iowrite32(v, addr);
185 }
186
clear_io_bits(void __iomem * addr,u32 bits)187 static inline void clear_io_bits(void __iomem *addr, u32 bits)
188 {
189 u32 v = ioread32(addr);
190
191 v &= ~bits;
192 iowrite32(v, addr);
193 }
194
195 /*
196 * Interface to control the chip select signal
197 */
davinci_spi_chipselect(struct spi_device * spi,int value)198 static void davinci_spi_chipselect(struct spi_device *spi, int value)
199 {
200 struct davinci_spi *dspi;
201 struct davinci_spi_config *spicfg = spi->controller_data;
202 u8 chip_sel = spi->chip_select;
203 u16 spidat1 = CS_DEFAULT;
204
205 dspi = spi_master_get_devdata(spi->master);
206
207 /* program delay transfers if tx_delay is non zero */
208 if (spicfg && spicfg->wdelay)
209 spidat1 |= SPIDAT1_WDEL;
210
211 /*
212 * Board specific chip select logic decides the polarity and cs
213 * line for the controller
214 */
215 if (spi->cs_gpiod) {
216 /*
217 * FIXME: is this code ever executed? This host does not
218 * set SPI_MASTER_GPIO_SS so this chipselect callback should
219 * not get called from the SPI core when we are using
220 * GPIOs for chip select.
221 */
222 if (value == BITBANG_CS_ACTIVE)
223 gpiod_set_value(spi->cs_gpiod, 1);
224 else
225 gpiod_set_value(spi->cs_gpiod, 0);
226 } else {
227 if (value == BITBANG_CS_ACTIVE) {
228 if (!(spi->mode & SPI_CS_WORD))
229 spidat1 |= SPIDAT1_CSHOLD_MASK;
230 spidat1 &= ~(0x1 << chip_sel);
231 }
232 }
233
234 iowrite16(spidat1, dspi->base + SPIDAT1 + 2);
235 }
236
237 /**
238 * davinci_spi_get_prescale - Calculates the correct prescale value
239 * @maxspeed_hz: the maximum rate the SPI clock can run at
240 *
241 * This function calculates the prescale value that generates a clock rate
242 * less than or equal to the specified maximum.
243 *
244 * Returns: calculated prescale value for easy programming into SPI registers
245 * or negative error number if valid prescalar cannot be updated.
246 */
davinci_spi_get_prescale(struct davinci_spi * dspi,u32 max_speed_hz)247 static inline int davinci_spi_get_prescale(struct davinci_spi *dspi,
248 u32 max_speed_hz)
249 {
250 int ret;
251
252 /* Subtract 1 to match what will be programmed into SPI register. */
253 ret = DIV_ROUND_UP(clk_get_rate(dspi->clk), max_speed_hz) - 1;
254
255 if (ret < dspi->prescaler_limit || ret > 255)
256 return -EINVAL;
257
258 return ret;
259 }
260
261 /**
262 * davinci_spi_setup_transfer - This functions will determine transfer method
263 * @spi: spi device on which data transfer to be done
264 * @t: spi transfer in which transfer info is filled
265 *
266 * This function determines data transfer method (8/16/32 bit transfer).
267 * It will also set the SPI Clock Control register according to
268 * SPI slave device freq.
269 */
davinci_spi_setup_transfer(struct spi_device * spi,struct spi_transfer * t)270 static int davinci_spi_setup_transfer(struct spi_device *spi,
271 struct spi_transfer *t)
272 {
273
274 struct davinci_spi *dspi;
275 struct davinci_spi_config *spicfg;
276 u8 bits_per_word = 0;
277 u32 hz = 0, spifmt = 0;
278 int prescale;
279
280 dspi = spi_master_get_devdata(spi->master);
281 spicfg = spi->controller_data;
282 if (!spicfg)
283 spicfg = &davinci_spi_default_cfg;
284
285 if (t) {
286 bits_per_word = t->bits_per_word;
287 hz = t->speed_hz;
288 }
289
290 /* if bits_per_word is not set then set it default */
291 if (!bits_per_word)
292 bits_per_word = spi->bits_per_word;
293
294 /*
295 * Assign function pointer to appropriate transfer method
296 * 8bit, 16bit or 32bit transfer
297 */
298 if (bits_per_word <= 8) {
299 dspi->get_rx = davinci_spi_rx_buf_u8;
300 dspi->get_tx = davinci_spi_tx_buf_u8;
301 dspi->bytes_per_word[spi->chip_select] = 1;
302 } else {
303 dspi->get_rx = davinci_spi_rx_buf_u16;
304 dspi->get_tx = davinci_spi_tx_buf_u16;
305 dspi->bytes_per_word[spi->chip_select] = 2;
306 }
307
308 if (!hz)
309 hz = spi->max_speed_hz;
310
311 /* Set up SPIFMTn register, unique to this chipselect. */
312
313 prescale = davinci_spi_get_prescale(dspi, hz);
314 if (prescale < 0)
315 return prescale;
316
317 spifmt = (prescale << SPIFMT_PRESCALE_SHIFT) | (bits_per_word & 0x1f);
318
319 if (spi->mode & SPI_LSB_FIRST)
320 spifmt |= SPIFMT_SHIFTDIR_MASK;
321
322 if (spi->mode & SPI_CPOL)
323 spifmt |= SPIFMT_POLARITY_MASK;
324
325 if (!(spi->mode & SPI_CPHA))
326 spifmt |= SPIFMT_PHASE_MASK;
327
328 /*
329 * Assume wdelay is used only on SPI peripherals that has this field
330 * in SPIFMTn register and when it's configured from board file or DT.
331 */
332 if (spicfg->wdelay)
333 spifmt |= ((spicfg->wdelay << SPIFMT_WDELAY_SHIFT)
334 & SPIFMT_WDELAY_MASK);
335
336 /*
337 * Version 1 hardware supports two basic SPI modes:
338 * - Standard SPI mode uses 4 pins, with chipselect
339 * - 3 pin SPI is a 4 pin variant without CS (SPI_NO_CS)
340 * (distinct from SPI_3WIRE, with just one data wire;
341 * or similar variants without MOSI or without MISO)
342 *
343 * Version 2 hardware supports an optional handshaking signal,
344 * so it can support two more modes:
345 * - 5 pin SPI variant is standard SPI plus SPI_READY
346 * - 4 pin with enable is (SPI_READY | SPI_NO_CS)
347 */
348
349 if (dspi->version == SPI_VERSION_2) {
350
351 u32 delay = 0;
352
353 if (spicfg->odd_parity)
354 spifmt |= SPIFMT_ODD_PARITY_MASK;
355
356 if (spicfg->parity_enable)
357 spifmt |= SPIFMT_PARITYENA_MASK;
358
359 if (spicfg->timer_disable) {
360 spifmt |= SPIFMT_DISTIMER_MASK;
361 } else {
362 delay |= (spicfg->c2tdelay << SPIDELAY_C2TDELAY_SHIFT)
363 & SPIDELAY_C2TDELAY_MASK;
364 delay |= (spicfg->t2cdelay << SPIDELAY_T2CDELAY_SHIFT)
365 & SPIDELAY_T2CDELAY_MASK;
366 }
367
368 if (spi->mode & SPI_READY) {
369 spifmt |= SPIFMT_WAITENA_MASK;
370 delay |= (spicfg->t2edelay << SPIDELAY_T2EDELAY_SHIFT)
371 & SPIDELAY_T2EDELAY_MASK;
372 delay |= (spicfg->c2edelay << SPIDELAY_C2EDELAY_SHIFT)
373 & SPIDELAY_C2EDELAY_MASK;
374 }
375
376 iowrite32(delay, dspi->base + SPIDELAY);
377 }
378
379 iowrite32(spifmt, dspi->base + SPIFMT0);
380
381 return 0;
382 }
383
davinci_spi_of_setup(struct spi_device * spi)384 static int davinci_spi_of_setup(struct spi_device *spi)
385 {
386 struct davinci_spi_config *spicfg = spi->controller_data;
387 struct device_node *np = spi->dev.of_node;
388 struct davinci_spi *dspi = spi_master_get_devdata(spi->master);
389 u32 prop;
390
391 if (spicfg == NULL && np) {
392 spicfg = kzalloc(sizeof(*spicfg), GFP_KERNEL);
393 if (!spicfg)
394 return -ENOMEM;
395 *spicfg = davinci_spi_default_cfg;
396 /* override with dt configured values */
397 if (!of_property_read_u32(np, "ti,spi-wdelay", &prop))
398 spicfg->wdelay = (u8)prop;
399 spi->controller_data = spicfg;
400
401 if (dspi->dma_rx && dspi->dma_tx)
402 spicfg->io_type = SPI_IO_TYPE_DMA;
403 }
404
405 return 0;
406 }
407
408 /**
409 * davinci_spi_setup - This functions will set default transfer method
410 * @spi: spi device on which data transfer to be done
411 *
412 * This functions sets the default transfer method.
413 */
davinci_spi_setup(struct spi_device * spi)414 static int davinci_spi_setup(struct spi_device *spi)
415 {
416 struct davinci_spi *dspi;
417 struct device_node *np = spi->dev.of_node;
418 bool internal_cs = true;
419
420 dspi = spi_master_get_devdata(spi->master);
421
422 if (!(spi->mode & SPI_NO_CS)) {
423 if (np && spi->cs_gpiod)
424 internal_cs = false;
425
426 if (internal_cs)
427 set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select);
428 }
429
430 if (spi->mode & SPI_READY)
431 set_io_bits(dspi->base + SPIPC0, SPIPC0_SPIENA_MASK);
432
433 if (spi->mode & SPI_LOOP)
434 set_io_bits(dspi->base + SPIGCR1, SPIGCR1_LOOPBACK_MASK);
435 else
436 clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_LOOPBACK_MASK);
437
438 return davinci_spi_of_setup(spi);
439 }
440
davinci_spi_cleanup(struct spi_device * spi)441 static void davinci_spi_cleanup(struct spi_device *spi)
442 {
443 struct davinci_spi_config *spicfg = spi->controller_data;
444
445 spi->controller_data = NULL;
446 if (spi->dev.of_node)
447 kfree(spicfg);
448 }
449
davinci_spi_can_dma(struct spi_master * master,struct spi_device * spi,struct spi_transfer * xfer)450 static bool davinci_spi_can_dma(struct spi_master *master,
451 struct spi_device *spi,
452 struct spi_transfer *xfer)
453 {
454 struct davinci_spi_config *spicfg = spi->controller_data;
455 bool can_dma = false;
456
457 if (spicfg)
458 can_dma = (spicfg->io_type == SPI_IO_TYPE_DMA) &&
459 (xfer->len >= DMA_MIN_BYTES) &&
460 !is_vmalloc_addr(xfer->rx_buf) &&
461 !is_vmalloc_addr(xfer->tx_buf);
462
463 return can_dma;
464 }
465
davinci_spi_check_error(struct davinci_spi * dspi,int int_status)466 static int davinci_spi_check_error(struct davinci_spi *dspi, int int_status)
467 {
468 struct device *sdev = dspi->bitbang.master->dev.parent;
469
470 if (int_status & SPIFLG_TIMEOUT_MASK) {
471 dev_err(sdev, "SPI Time-out Error\n");
472 return -ETIMEDOUT;
473 }
474 if (int_status & SPIFLG_DESYNC_MASK) {
475 dev_err(sdev, "SPI Desynchronization Error\n");
476 return -EIO;
477 }
478 if (int_status & SPIFLG_BITERR_MASK) {
479 dev_err(sdev, "SPI Bit error\n");
480 return -EIO;
481 }
482
483 if (dspi->version == SPI_VERSION_2) {
484 if (int_status & SPIFLG_DLEN_ERR_MASK) {
485 dev_err(sdev, "SPI Data Length Error\n");
486 return -EIO;
487 }
488 if (int_status & SPIFLG_PARERR_MASK) {
489 dev_err(sdev, "SPI Parity Error\n");
490 return -EIO;
491 }
492 if (int_status & SPIFLG_OVRRUN_MASK) {
493 dev_err(sdev, "SPI Data Overrun error\n");
494 return -EIO;
495 }
496 if (int_status & SPIFLG_BUF_INIT_ACTIVE_MASK) {
497 dev_err(sdev, "SPI Buffer Init Active\n");
498 return -EBUSY;
499 }
500 }
501
502 return 0;
503 }
504
505 /**
506 * davinci_spi_process_events - check for and handle any SPI controller events
507 * @dspi: the controller data
508 *
509 * This function will check the SPIFLG register and handle any events that are
510 * detected there
511 */
davinci_spi_process_events(struct davinci_spi * dspi)512 static int davinci_spi_process_events(struct davinci_spi *dspi)
513 {
514 u32 buf, status, errors = 0, spidat1;
515
516 buf = ioread32(dspi->base + SPIBUF);
517
518 if (dspi->rcount > 0 && !(buf & SPIBUF_RXEMPTY_MASK)) {
519 dspi->get_rx(buf & 0xFFFF, dspi);
520 dspi->rcount--;
521 }
522
523 status = ioread32(dspi->base + SPIFLG);
524
525 if (unlikely(status & SPIFLG_ERROR_MASK)) {
526 errors = status & SPIFLG_ERROR_MASK;
527 goto out;
528 }
529
530 if (dspi->wcount > 0 && !(buf & SPIBUF_TXFULL_MASK)) {
531 spidat1 = ioread32(dspi->base + SPIDAT1);
532 dspi->wcount--;
533 spidat1 &= ~0xFFFF;
534 spidat1 |= 0xFFFF & dspi->get_tx(dspi);
535 iowrite32(spidat1, dspi->base + SPIDAT1);
536 }
537
538 out:
539 return errors;
540 }
541
davinci_spi_dma_rx_callback(void * data)542 static void davinci_spi_dma_rx_callback(void *data)
543 {
544 struct davinci_spi *dspi = (struct davinci_spi *)data;
545
546 dspi->rcount = 0;
547
548 if (!dspi->wcount && !dspi->rcount)
549 complete(&dspi->done);
550 }
551
davinci_spi_dma_tx_callback(void * data)552 static void davinci_spi_dma_tx_callback(void *data)
553 {
554 struct davinci_spi *dspi = (struct davinci_spi *)data;
555
556 dspi->wcount = 0;
557
558 if (!dspi->wcount && !dspi->rcount)
559 complete(&dspi->done);
560 }
561
562 /**
563 * davinci_spi_bufs - functions which will handle transfer data
564 * @spi: spi device on which data transfer to be done
565 * @t: spi transfer in which transfer info is filled
566 *
567 * This function will put data to be transferred into data register
568 * of SPI controller and then wait until the completion will be marked
569 * by the IRQ Handler.
570 */
davinci_spi_bufs(struct spi_device * spi,struct spi_transfer * t)571 static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
572 {
573 struct davinci_spi *dspi;
574 int data_type, ret = -ENOMEM;
575 u32 tx_data, spidat1;
576 u32 errors = 0;
577 struct davinci_spi_config *spicfg;
578 struct davinci_spi_platform_data *pdata;
579 unsigned uninitialized_var(rx_buf_count);
580
581 dspi = spi_master_get_devdata(spi->master);
582 pdata = &dspi->pdata;
583 spicfg = (struct davinci_spi_config *)spi->controller_data;
584 if (!spicfg)
585 spicfg = &davinci_spi_default_cfg;
586
587 /* convert len to words based on bits_per_word */
588 data_type = dspi->bytes_per_word[spi->chip_select];
589
590 dspi->tx = t->tx_buf;
591 dspi->rx = t->rx_buf;
592 dspi->wcount = t->len / data_type;
593 dspi->rcount = dspi->wcount;
594
595 spidat1 = ioread32(dspi->base + SPIDAT1);
596
597 clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
598 set_io_bits(dspi->base + SPIGCR1, SPIGCR1_SPIENA_MASK);
599
600 reinit_completion(&dspi->done);
601
602 if (!davinci_spi_can_dma(spi->master, spi, t)) {
603 if (spicfg->io_type != SPI_IO_TYPE_POLL)
604 set_io_bits(dspi->base + SPIINT, SPIINT_MASKINT);
605 /* start the transfer */
606 dspi->wcount--;
607 tx_data = dspi->get_tx(dspi);
608 spidat1 &= 0xFFFF0000;
609 spidat1 |= tx_data & 0xFFFF;
610 iowrite32(spidat1, dspi->base + SPIDAT1);
611 } else {
612 struct dma_slave_config dma_rx_conf = {
613 .direction = DMA_DEV_TO_MEM,
614 .src_addr = (unsigned long)dspi->pbase + SPIBUF,
615 .src_addr_width = data_type,
616 .src_maxburst = 1,
617 };
618 struct dma_slave_config dma_tx_conf = {
619 .direction = DMA_MEM_TO_DEV,
620 .dst_addr = (unsigned long)dspi->pbase + SPIDAT1,
621 .dst_addr_width = data_type,
622 .dst_maxburst = 1,
623 };
624 struct dma_async_tx_descriptor *rxdesc;
625 struct dma_async_tx_descriptor *txdesc;
626
627 dmaengine_slave_config(dspi->dma_rx, &dma_rx_conf);
628 dmaengine_slave_config(dspi->dma_tx, &dma_tx_conf);
629
630 rxdesc = dmaengine_prep_slave_sg(dspi->dma_rx,
631 t->rx_sg.sgl, t->rx_sg.nents, DMA_DEV_TO_MEM,
632 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
633 if (!rxdesc)
634 goto err_desc;
635
636 if (!t->tx_buf) {
637 /* To avoid errors when doing rx-only transfers with
638 * many SG entries (> 20), use the rx buffer as the
639 * dummy tx buffer so that dma reloads are done at the
640 * same time for rx and tx.
641 */
642 t->tx_sg.sgl = t->rx_sg.sgl;
643 t->tx_sg.nents = t->rx_sg.nents;
644 }
645
646 txdesc = dmaengine_prep_slave_sg(dspi->dma_tx,
647 t->tx_sg.sgl, t->tx_sg.nents, DMA_MEM_TO_DEV,
648 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
649 if (!txdesc)
650 goto err_desc;
651
652 rxdesc->callback = davinci_spi_dma_rx_callback;
653 rxdesc->callback_param = (void *)dspi;
654 txdesc->callback = davinci_spi_dma_tx_callback;
655 txdesc->callback_param = (void *)dspi;
656
657 if (pdata->cshold_bug)
658 iowrite16(spidat1 >> 16, dspi->base + SPIDAT1 + 2);
659
660 dmaengine_submit(rxdesc);
661 dmaengine_submit(txdesc);
662
663 dma_async_issue_pending(dspi->dma_rx);
664 dma_async_issue_pending(dspi->dma_tx);
665
666 set_io_bits(dspi->base + SPIINT, SPIINT_DMA_REQ_EN);
667 }
668
669 /* Wait for the transfer to complete */
670 if (spicfg->io_type != SPI_IO_TYPE_POLL) {
671 if (wait_for_completion_timeout(&dspi->done, HZ) == 0)
672 errors = SPIFLG_TIMEOUT_MASK;
673 } else {
674 while (dspi->rcount > 0 || dspi->wcount > 0) {
675 errors = davinci_spi_process_events(dspi);
676 if (errors)
677 break;
678 cpu_relax();
679 }
680 }
681
682 clear_io_bits(dspi->base + SPIINT, SPIINT_MASKALL);
683 if (davinci_spi_can_dma(spi->master, spi, t))
684 clear_io_bits(dspi->base + SPIINT, SPIINT_DMA_REQ_EN);
685
686 clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_SPIENA_MASK);
687 set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
688
689 /*
690 * Check for bit error, desync error,parity error,timeout error and
691 * receive overflow errors
692 */
693 if (errors) {
694 ret = davinci_spi_check_error(dspi, errors);
695 WARN(!ret, "%s: error reported but no error found!\n",
696 dev_name(&spi->dev));
697 return ret;
698 }
699
700 if (dspi->rcount != 0 || dspi->wcount != 0) {
701 dev_err(&spi->dev, "SPI data transfer error\n");
702 return -EIO;
703 }
704
705 return t->len;
706
707 err_desc:
708 return ret;
709 }
710
711 /**
712 * dummy_thread_fn - dummy thread function
713 * @irq: IRQ number for this SPI Master
714 * @context_data: structure for SPI Master controller davinci_spi
715 *
716 * This is to satisfy the request_threaded_irq() API so that the irq
717 * handler is called in interrupt context.
718 */
dummy_thread_fn(s32 irq,void * data)719 static irqreturn_t dummy_thread_fn(s32 irq, void *data)
720 {
721 return IRQ_HANDLED;
722 }
723
724 /**
725 * davinci_spi_irq - Interrupt handler for SPI Master Controller
726 * @irq: IRQ number for this SPI Master
727 * @context_data: structure for SPI Master controller davinci_spi
728 *
729 * ISR will determine that interrupt arrives either for READ or WRITE command.
730 * According to command it will do the appropriate action. It will check
731 * transfer length and if it is not zero then dispatch transfer command again.
732 * If transfer length is zero then it will indicate the COMPLETION so that
733 * davinci_spi_bufs function can go ahead.
734 */
davinci_spi_irq(s32 irq,void * data)735 static irqreturn_t davinci_spi_irq(s32 irq, void *data)
736 {
737 struct davinci_spi *dspi = data;
738 int status;
739
740 status = davinci_spi_process_events(dspi);
741 if (unlikely(status != 0))
742 clear_io_bits(dspi->base + SPIINT, SPIINT_MASKINT);
743
744 if ((!dspi->rcount && !dspi->wcount) || status)
745 complete(&dspi->done);
746
747 return IRQ_HANDLED;
748 }
749
davinci_spi_request_dma(struct davinci_spi * dspi)750 static int davinci_spi_request_dma(struct davinci_spi *dspi)
751 {
752 struct device *sdev = dspi->bitbang.master->dev.parent;
753
754 dspi->dma_rx = dma_request_chan(sdev, "rx");
755 if (IS_ERR(dspi->dma_rx))
756 return PTR_ERR(dspi->dma_rx);
757
758 dspi->dma_tx = dma_request_chan(sdev, "tx");
759 if (IS_ERR(dspi->dma_tx)) {
760 dma_release_channel(dspi->dma_rx);
761 return PTR_ERR(dspi->dma_tx);
762 }
763
764 return 0;
765 }
766
767 #if defined(CONFIG_OF)
768
769 /* OF SPI data structure */
770 struct davinci_spi_of_data {
771 u8 version;
772 u8 prescaler_limit;
773 };
774
775 static const struct davinci_spi_of_data dm6441_spi_data = {
776 .version = SPI_VERSION_1,
777 .prescaler_limit = 2,
778 };
779
780 static const struct davinci_spi_of_data da830_spi_data = {
781 .version = SPI_VERSION_2,
782 .prescaler_limit = 2,
783 };
784
785 static const struct davinci_spi_of_data keystone_spi_data = {
786 .version = SPI_VERSION_1,
787 .prescaler_limit = 0,
788 };
789
790 static const struct of_device_id davinci_spi_of_match[] = {
791 {
792 .compatible = "ti,dm6441-spi",
793 .data = &dm6441_spi_data,
794 },
795 {
796 .compatible = "ti,da830-spi",
797 .data = &da830_spi_data,
798 },
799 {
800 .compatible = "ti,keystone-spi",
801 .data = &keystone_spi_data,
802 },
803 { },
804 };
805 MODULE_DEVICE_TABLE(of, davinci_spi_of_match);
806
807 /**
808 * spi_davinci_get_pdata - Get platform data from DTS binding
809 * @pdev: ptr to platform data
810 * @dspi: ptr to driver data
811 *
812 * Parses and populates pdata in dspi from device tree bindings.
813 *
814 * NOTE: Not all platform data params are supported currently.
815 */
spi_davinci_get_pdata(struct platform_device * pdev,struct davinci_spi * dspi)816 static int spi_davinci_get_pdata(struct platform_device *pdev,
817 struct davinci_spi *dspi)
818 {
819 struct device_node *node = pdev->dev.of_node;
820 struct davinci_spi_of_data *spi_data;
821 struct davinci_spi_platform_data *pdata;
822 unsigned int num_cs, intr_line = 0;
823 const struct of_device_id *match;
824
825 pdata = &dspi->pdata;
826
827 match = of_match_device(davinci_spi_of_match, &pdev->dev);
828 if (!match)
829 return -ENODEV;
830
831 spi_data = (struct davinci_spi_of_data *)match->data;
832
833 pdata->version = spi_data->version;
834 pdata->prescaler_limit = spi_data->prescaler_limit;
835 /*
836 * default num_cs is 1 and all chipsel are internal to the chip
837 * indicated by chip_sel being NULL or cs_gpios being NULL or
838 * set to -ENOENT. num-cs includes internal as well as gpios.
839 * indicated by chip_sel being NULL. GPIO based CS is not
840 * supported yet in DT bindings.
841 */
842 num_cs = 1;
843 of_property_read_u32(node, "num-cs", &num_cs);
844 pdata->num_chipselect = num_cs;
845 of_property_read_u32(node, "ti,davinci-spi-intr-line", &intr_line);
846 pdata->intr_line = intr_line;
847 return 0;
848 }
849 #else
spi_davinci_get_pdata(struct platform_device * pdev,struct davinci_spi * dspi)850 static int spi_davinci_get_pdata(struct platform_device *pdev,
851 struct davinci_spi *dspi)
852 {
853 return -ENODEV;
854 }
855 #endif
856
857 /**
858 * davinci_spi_probe - probe function for SPI Master Controller
859 * @pdev: platform_device structure which contains plateform specific data
860 *
861 * According to Linux Device Model this function will be invoked by Linux
862 * with platform_device struct which contains the device specific info.
863 * This function will map the SPI controller's memory, register IRQ,
864 * Reset SPI controller and setting its registers to default value.
865 * It will invoke spi_bitbang_start to create work queue so that client driver
866 * can register transfer method to work queue.
867 */
davinci_spi_probe(struct platform_device * pdev)868 static int davinci_spi_probe(struct platform_device *pdev)
869 {
870 struct spi_master *master;
871 struct davinci_spi *dspi;
872 struct davinci_spi_platform_data *pdata;
873 struct resource *r;
874 int ret = 0;
875 u32 spipc0;
876
877 master = spi_alloc_master(&pdev->dev, sizeof(struct davinci_spi));
878 if (master == NULL) {
879 ret = -ENOMEM;
880 goto err;
881 }
882
883 platform_set_drvdata(pdev, master);
884
885 dspi = spi_master_get_devdata(master);
886
887 if (dev_get_platdata(&pdev->dev)) {
888 pdata = dev_get_platdata(&pdev->dev);
889 dspi->pdata = *pdata;
890 } else {
891 /* update dspi pdata with that from the DT */
892 ret = spi_davinci_get_pdata(pdev, dspi);
893 if (ret < 0)
894 goto free_master;
895 }
896
897 /* pdata in dspi is now updated and point pdata to that */
898 pdata = &dspi->pdata;
899
900 dspi->bytes_per_word = devm_kcalloc(&pdev->dev,
901 pdata->num_chipselect,
902 sizeof(*dspi->bytes_per_word),
903 GFP_KERNEL);
904 if (dspi->bytes_per_word == NULL) {
905 ret = -ENOMEM;
906 goto free_master;
907 }
908
909 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
910 if (r == NULL) {
911 ret = -ENOENT;
912 goto free_master;
913 }
914
915 dspi->pbase = r->start;
916
917 dspi->base = devm_ioremap_resource(&pdev->dev, r);
918 if (IS_ERR(dspi->base)) {
919 ret = PTR_ERR(dspi->base);
920 goto free_master;
921 }
922
923 init_completion(&dspi->done);
924
925 ret = platform_get_irq(pdev, 0);
926 if (ret == 0)
927 ret = -EINVAL;
928 if (ret < 0)
929 goto free_master;
930 dspi->irq = ret;
931
932 ret = devm_request_threaded_irq(&pdev->dev, dspi->irq, davinci_spi_irq,
933 dummy_thread_fn, 0, dev_name(&pdev->dev), dspi);
934 if (ret)
935 goto free_master;
936
937 dspi->bitbang.master = master;
938
939 dspi->clk = devm_clk_get(&pdev->dev, NULL);
940 if (IS_ERR(dspi->clk)) {
941 ret = -ENODEV;
942 goto free_master;
943 }
944 ret = clk_prepare_enable(dspi->clk);
945 if (ret)
946 goto free_master;
947
948 master->use_gpio_descriptors = true;
949 master->dev.of_node = pdev->dev.of_node;
950 master->bus_num = pdev->id;
951 master->num_chipselect = pdata->num_chipselect;
952 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 16);
953 master->flags = SPI_MASTER_MUST_RX;
954 master->setup = davinci_spi_setup;
955 master->cleanup = davinci_spi_cleanup;
956 master->can_dma = davinci_spi_can_dma;
957
958 dspi->bitbang.chipselect = davinci_spi_chipselect;
959 dspi->bitbang.setup_transfer = davinci_spi_setup_transfer;
960 dspi->prescaler_limit = pdata->prescaler_limit;
961 dspi->version = pdata->version;
962
963 dspi->bitbang.flags = SPI_NO_CS | SPI_LSB_FIRST | SPI_LOOP | SPI_CS_WORD;
964 if (dspi->version == SPI_VERSION_2)
965 dspi->bitbang.flags |= SPI_READY;
966
967 dspi->bitbang.txrx_bufs = davinci_spi_bufs;
968
969 ret = davinci_spi_request_dma(dspi);
970 if (ret == -EPROBE_DEFER) {
971 goto free_clk;
972 } else if (ret) {
973 dev_info(&pdev->dev, "DMA is not supported (%d)\n", ret);
974 dspi->dma_rx = NULL;
975 dspi->dma_tx = NULL;
976 }
977
978 dspi->get_rx = davinci_spi_rx_buf_u8;
979 dspi->get_tx = davinci_spi_tx_buf_u8;
980
981 /* Reset In/OUT SPI module */
982 iowrite32(0, dspi->base + SPIGCR0);
983 udelay(100);
984 iowrite32(1, dspi->base + SPIGCR0);
985
986 /* Set up SPIPC0. CS and ENA init is done in davinci_spi_setup */
987 spipc0 = SPIPC0_DIFUN_MASK | SPIPC0_DOFUN_MASK | SPIPC0_CLKFUN_MASK;
988 iowrite32(spipc0, dspi->base + SPIPC0);
989
990 if (pdata->intr_line)
991 iowrite32(SPI_INTLVL_1, dspi->base + SPILVL);
992 else
993 iowrite32(SPI_INTLVL_0, dspi->base + SPILVL);
994
995 iowrite32(CS_DEFAULT, dspi->base + SPIDEF);
996
997 /* master mode default */
998 set_io_bits(dspi->base + SPIGCR1, SPIGCR1_CLKMOD_MASK);
999 set_io_bits(dspi->base + SPIGCR1, SPIGCR1_MASTER_MASK);
1000 set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
1001
1002 ret = spi_bitbang_start(&dspi->bitbang);
1003 if (ret)
1004 goto free_dma;
1005
1006 dev_info(&pdev->dev, "Controller at 0x%p\n", dspi->base);
1007
1008 return ret;
1009
1010 free_dma:
1011 if (dspi->dma_rx) {
1012 dma_release_channel(dspi->dma_rx);
1013 dma_release_channel(dspi->dma_tx);
1014 }
1015 free_clk:
1016 clk_disable_unprepare(dspi->clk);
1017 free_master:
1018 spi_master_put(master);
1019 err:
1020 return ret;
1021 }
1022
1023 /**
1024 * davinci_spi_remove - remove function for SPI Master Controller
1025 * @pdev: platform_device structure which contains plateform specific data
1026 *
1027 * This function will do the reverse action of davinci_spi_probe function
1028 * It will free the IRQ and SPI controller's memory region.
1029 * It will also call spi_bitbang_stop to destroy the work queue which was
1030 * created by spi_bitbang_start.
1031 */
davinci_spi_remove(struct platform_device * pdev)1032 static int davinci_spi_remove(struct platform_device *pdev)
1033 {
1034 struct davinci_spi *dspi;
1035 struct spi_master *master;
1036
1037 master = platform_get_drvdata(pdev);
1038 dspi = spi_master_get_devdata(master);
1039
1040 spi_bitbang_stop(&dspi->bitbang);
1041
1042 clk_disable_unprepare(dspi->clk);
1043 spi_master_put(master);
1044
1045 if (dspi->dma_rx) {
1046 dma_release_channel(dspi->dma_rx);
1047 dma_release_channel(dspi->dma_tx);
1048 }
1049
1050 return 0;
1051 }
1052
1053 static struct platform_driver davinci_spi_driver = {
1054 .driver = {
1055 .name = "spi_davinci",
1056 .of_match_table = of_match_ptr(davinci_spi_of_match),
1057 },
1058 .probe = davinci_spi_probe,
1059 .remove = davinci_spi_remove,
1060 };
1061 module_platform_driver(davinci_spi_driver);
1062
1063 MODULE_DESCRIPTION("TI DaVinci SPI Master Controller Driver");
1064 MODULE_LICENSE("GPL");
1065