1 /*
2 * Driver for Atmel AT32 and AT91 SPI Controllers
3 *
4 * Copyright (C) 2006 Atmel Corporation
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11 #include <linux/kernel.h>
12 #include <linux/clk.h>
13 #include <linux/module.h>
14 #include <linux/platform_device.h>
15 #include <linux/delay.h>
16 #include <linux/dma-mapping.h>
17 #include <linux/dmaengine.h>
18 #include <linux/err.h>
19 #include <linux/interrupt.h>
20 #include <linux/spi/spi.h>
21 #include <linux/slab.h>
22 #include <linux/platform_data/dma-atmel.h>
23 #include <linux/of.h>
24
25 #include <linux/io.h>
26 #include <linux/gpio.h>
27 #include <linux/pinctrl/consumer.h>
28 #include <linux/pm_runtime.h>
29
30 /* SPI register offsets */
31 #define SPI_CR 0x0000
32 #define SPI_MR 0x0004
33 #define SPI_RDR 0x0008
34 #define SPI_TDR 0x000c
35 #define SPI_SR 0x0010
36 #define SPI_IER 0x0014
37 #define SPI_IDR 0x0018
38 #define SPI_IMR 0x001c
39 #define SPI_CSR0 0x0030
40 #define SPI_CSR1 0x0034
41 #define SPI_CSR2 0x0038
42 #define SPI_CSR3 0x003c
43 #define SPI_FMR 0x0040
44 #define SPI_FLR 0x0044
45 #define SPI_VERSION 0x00fc
46 #define SPI_RPR 0x0100
47 #define SPI_RCR 0x0104
48 #define SPI_TPR 0x0108
49 #define SPI_TCR 0x010c
50 #define SPI_RNPR 0x0110
51 #define SPI_RNCR 0x0114
52 #define SPI_TNPR 0x0118
53 #define SPI_TNCR 0x011c
54 #define SPI_PTCR 0x0120
55 #define SPI_PTSR 0x0124
56
57 /* Bitfields in CR */
58 #define SPI_SPIEN_OFFSET 0
59 #define SPI_SPIEN_SIZE 1
60 #define SPI_SPIDIS_OFFSET 1
61 #define SPI_SPIDIS_SIZE 1
62 #define SPI_SWRST_OFFSET 7
63 #define SPI_SWRST_SIZE 1
64 #define SPI_LASTXFER_OFFSET 24
65 #define SPI_LASTXFER_SIZE 1
66 #define SPI_TXFCLR_OFFSET 16
67 #define SPI_TXFCLR_SIZE 1
68 #define SPI_RXFCLR_OFFSET 17
69 #define SPI_RXFCLR_SIZE 1
70 #define SPI_FIFOEN_OFFSET 30
71 #define SPI_FIFOEN_SIZE 1
72 #define SPI_FIFODIS_OFFSET 31
73 #define SPI_FIFODIS_SIZE 1
74
75 /* Bitfields in MR */
76 #define SPI_MSTR_OFFSET 0
77 #define SPI_MSTR_SIZE 1
78 #define SPI_PS_OFFSET 1
79 #define SPI_PS_SIZE 1
80 #define SPI_PCSDEC_OFFSET 2
81 #define SPI_PCSDEC_SIZE 1
82 #define SPI_FDIV_OFFSET 3
83 #define SPI_FDIV_SIZE 1
84 #define SPI_MODFDIS_OFFSET 4
85 #define SPI_MODFDIS_SIZE 1
86 #define SPI_WDRBT_OFFSET 5
87 #define SPI_WDRBT_SIZE 1
88 #define SPI_LLB_OFFSET 7
89 #define SPI_LLB_SIZE 1
90 #define SPI_PCS_OFFSET 16
91 #define SPI_PCS_SIZE 4
92 #define SPI_DLYBCS_OFFSET 24
93 #define SPI_DLYBCS_SIZE 8
94
95 /* Bitfields in RDR */
96 #define SPI_RD_OFFSET 0
97 #define SPI_RD_SIZE 16
98
99 /* Bitfields in TDR */
100 #define SPI_TD_OFFSET 0
101 #define SPI_TD_SIZE 16
102
103 /* Bitfields in SR */
104 #define SPI_RDRF_OFFSET 0
105 #define SPI_RDRF_SIZE 1
106 #define SPI_TDRE_OFFSET 1
107 #define SPI_TDRE_SIZE 1
108 #define SPI_MODF_OFFSET 2
109 #define SPI_MODF_SIZE 1
110 #define SPI_OVRES_OFFSET 3
111 #define SPI_OVRES_SIZE 1
112 #define SPI_ENDRX_OFFSET 4
113 #define SPI_ENDRX_SIZE 1
114 #define SPI_ENDTX_OFFSET 5
115 #define SPI_ENDTX_SIZE 1
116 #define SPI_RXBUFF_OFFSET 6
117 #define SPI_RXBUFF_SIZE 1
118 #define SPI_TXBUFE_OFFSET 7
119 #define SPI_TXBUFE_SIZE 1
120 #define SPI_NSSR_OFFSET 8
121 #define SPI_NSSR_SIZE 1
122 #define SPI_TXEMPTY_OFFSET 9
123 #define SPI_TXEMPTY_SIZE 1
124 #define SPI_SPIENS_OFFSET 16
125 #define SPI_SPIENS_SIZE 1
126 #define SPI_TXFEF_OFFSET 24
127 #define SPI_TXFEF_SIZE 1
128 #define SPI_TXFFF_OFFSET 25
129 #define SPI_TXFFF_SIZE 1
130 #define SPI_TXFTHF_OFFSET 26
131 #define SPI_TXFTHF_SIZE 1
132 #define SPI_RXFEF_OFFSET 27
133 #define SPI_RXFEF_SIZE 1
134 #define SPI_RXFFF_OFFSET 28
135 #define SPI_RXFFF_SIZE 1
136 #define SPI_RXFTHF_OFFSET 29
137 #define SPI_RXFTHF_SIZE 1
138 #define SPI_TXFPTEF_OFFSET 30
139 #define SPI_TXFPTEF_SIZE 1
140 #define SPI_RXFPTEF_OFFSET 31
141 #define SPI_RXFPTEF_SIZE 1
142
143 /* Bitfields in CSR0 */
144 #define SPI_CPOL_OFFSET 0
145 #define SPI_CPOL_SIZE 1
146 #define SPI_NCPHA_OFFSET 1
147 #define SPI_NCPHA_SIZE 1
148 #define SPI_CSAAT_OFFSET 3
149 #define SPI_CSAAT_SIZE 1
150 #define SPI_BITS_OFFSET 4
151 #define SPI_BITS_SIZE 4
152 #define SPI_SCBR_OFFSET 8
153 #define SPI_SCBR_SIZE 8
154 #define SPI_DLYBS_OFFSET 16
155 #define SPI_DLYBS_SIZE 8
156 #define SPI_DLYBCT_OFFSET 24
157 #define SPI_DLYBCT_SIZE 8
158
159 /* Bitfields in RCR */
160 #define SPI_RXCTR_OFFSET 0
161 #define SPI_RXCTR_SIZE 16
162
163 /* Bitfields in TCR */
164 #define SPI_TXCTR_OFFSET 0
165 #define SPI_TXCTR_SIZE 16
166
167 /* Bitfields in RNCR */
168 #define SPI_RXNCR_OFFSET 0
169 #define SPI_RXNCR_SIZE 16
170
171 /* Bitfields in TNCR */
172 #define SPI_TXNCR_OFFSET 0
173 #define SPI_TXNCR_SIZE 16
174
175 /* Bitfields in PTCR */
176 #define SPI_RXTEN_OFFSET 0
177 #define SPI_RXTEN_SIZE 1
178 #define SPI_RXTDIS_OFFSET 1
179 #define SPI_RXTDIS_SIZE 1
180 #define SPI_TXTEN_OFFSET 8
181 #define SPI_TXTEN_SIZE 1
182 #define SPI_TXTDIS_OFFSET 9
183 #define SPI_TXTDIS_SIZE 1
184
185 /* Bitfields in FMR */
186 #define SPI_TXRDYM_OFFSET 0
187 #define SPI_TXRDYM_SIZE 2
188 #define SPI_RXRDYM_OFFSET 4
189 #define SPI_RXRDYM_SIZE 2
190 #define SPI_TXFTHRES_OFFSET 16
191 #define SPI_TXFTHRES_SIZE 6
192 #define SPI_RXFTHRES_OFFSET 24
193 #define SPI_RXFTHRES_SIZE 6
194
195 /* Bitfields in FLR */
196 #define SPI_TXFL_OFFSET 0
197 #define SPI_TXFL_SIZE 6
198 #define SPI_RXFL_OFFSET 16
199 #define SPI_RXFL_SIZE 6
200
201 /* Constants for BITS */
202 #define SPI_BITS_8_BPT 0
203 #define SPI_BITS_9_BPT 1
204 #define SPI_BITS_10_BPT 2
205 #define SPI_BITS_11_BPT 3
206 #define SPI_BITS_12_BPT 4
207 #define SPI_BITS_13_BPT 5
208 #define SPI_BITS_14_BPT 6
209 #define SPI_BITS_15_BPT 7
210 #define SPI_BITS_16_BPT 8
211 #define SPI_ONE_DATA 0
212 #define SPI_TWO_DATA 1
213 #define SPI_FOUR_DATA 2
214
215 /* Bit manipulation macros */
216 #define SPI_BIT(name) \
217 (1 << SPI_##name##_OFFSET)
218 #define SPI_BF(name, value) \
219 (((value) & ((1 << SPI_##name##_SIZE) - 1)) << SPI_##name##_OFFSET)
220 #define SPI_BFEXT(name, value) \
221 (((value) >> SPI_##name##_OFFSET) & ((1 << SPI_##name##_SIZE) - 1))
222 #define SPI_BFINS(name, value, old) \
223 (((old) & ~(((1 << SPI_##name##_SIZE) - 1) << SPI_##name##_OFFSET)) \
224 | SPI_BF(name, value))
225
226 /* Register access macros */
227 #ifdef CONFIG_AVR32
228 #define spi_readl(port, reg) \
229 __raw_readl((port)->regs + SPI_##reg)
230 #define spi_writel(port, reg, value) \
231 __raw_writel((value), (port)->regs + SPI_##reg)
232
233 #define spi_readw(port, reg) \
234 __raw_readw((port)->regs + SPI_##reg)
235 #define spi_writew(port, reg, value) \
236 __raw_writew((value), (port)->regs + SPI_##reg)
237
238 #define spi_readb(port, reg) \
239 __raw_readb((port)->regs + SPI_##reg)
240 #define spi_writeb(port, reg, value) \
241 __raw_writeb((value), (port)->regs + SPI_##reg)
242 #else
243 #define spi_readl(port, reg) \
244 readl_relaxed((port)->regs + SPI_##reg)
245 #define spi_writel(port, reg, value) \
246 writel_relaxed((value), (port)->regs + SPI_##reg)
247
248 #define spi_readw(port, reg) \
249 readw_relaxed((port)->regs + SPI_##reg)
250 #define spi_writew(port, reg, value) \
251 writew_relaxed((value), (port)->regs + SPI_##reg)
252
253 #define spi_readb(port, reg) \
254 readb_relaxed((port)->regs + SPI_##reg)
255 #define spi_writeb(port, reg, value) \
256 writeb_relaxed((value), (port)->regs + SPI_##reg)
257 #endif
258 /* use PIO for small transfers, avoiding DMA setup/teardown overhead and
259 * cache operations; better heuristics consider wordsize and bitrate.
260 */
261 #define DMA_MIN_BYTES 16
262
263 #define SPI_DMA_TIMEOUT (msecs_to_jiffies(1000))
264
265 #define AUTOSUSPEND_TIMEOUT 2000
266
267 struct atmel_spi_dma {
268 struct dma_chan *chan_rx;
269 struct dma_chan *chan_tx;
270 struct scatterlist sgrx;
271 struct scatterlist sgtx;
272 struct dma_async_tx_descriptor *data_desc_rx;
273 struct dma_async_tx_descriptor *data_desc_tx;
274
275 struct at_dma_slave dma_slave;
276 };
277
278 struct atmel_spi_caps {
279 bool is_spi2;
280 bool has_wdrbt;
281 bool has_dma_support;
282 };
283
284 /*
285 * The core SPI transfer engine just talks to a register bank to set up
286 * DMA transfers; transfer queue progress is driven by IRQs. The clock
287 * framework provides the base clock, subdivided for each spi_device.
288 */
289 struct atmel_spi {
290 spinlock_t lock;
291 unsigned long flags;
292
293 phys_addr_t phybase;
294 void __iomem *regs;
295 int irq;
296 struct clk *clk;
297 struct platform_device *pdev;
298
299 struct spi_transfer *current_transfer;
300 int current_remaining_bytes;
301 int done_status;
302
303 struct completion xfer_completion;
304
305 /* scratch buffer */
306 void *buffer;
307 dma_addr_t buffer_dma;
308
309 struct atmel_spi_caps caps;
310
311 bool use_dma;
312 bool use_pdc;
313 bool use_cs_gpios;
314 /* dmaengine data */
315 struct atmel_spi_dma dma;
316
317 bool keep_cs;
318
319 u32 fifo_size;
320 };
321
322 /* Controller-specific per-slave state */
323 struct atmel_spi_device {
324 unsigned int npcs_pin;
325 u32 csr;
326 };
327
328 #define BUFFER_SIZE PAGE_SIZE
329 #define INVALID_DMA_ADDRESS 0xffffffff
330
331 /*
332 * Version 2 of the SPI controller has
333 * - CR.LASTXFER
334 * - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
335 * - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
336 * - SPI_CSRx.CSAAT
337 * - SPI_CSRx.SBCR allows faster clocking
338 */
atmel_spi_is_v2(struct atmel_spi * as)339 static bool atmel_spi_is_v2(struct atmel_spi *as)
340 {
341 return as->caps.is_spi2;
342 }
343
344 /*
345 * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
346 * they assume that spi slave device state will not change on deselect, so
347 * that automagic deselection is OK. ("NPCSx rises if no data is to be
348 * transmitted") Not so! Workaround uses nCSx pins as GPIOs; or newer
349 * controllers have CSAAT and friends.
350 *
351 * Since the CSAAT functionality is a bit weird on newer controllers as
352 * well, we use GPIO to control nCSx pins on all controllers, updating
353 * MR.PCS to avoid confusing the controller. Using GPIOs also lets us
354 * support active-high chipselects despite the controller's belief that
355 * only active-low devices/systems exists.
356 *
357 * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
358 * right when driven with GPIO. ("Mode Fault does not allow more than one
359 * Master on Chip Select 0.") No workaround exists for that ... so for
360 * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
361 * and (c) will trigger that first erratum in some cases.
362 */
363
cs_activate(struct atmel_spi * as,struct spi_device * spi)364 static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
365 {
366 struct atmel_spi_device *asd = spi->controller_state;
367 unsigned active = spi->mode & SPI_CS_HIGH;
368 u32 mr;
369
370 if (atmel_spi_is_v2(as)) {
371 spi_writel(as, CSR0 + 4 * spi->chip_select, asd->csr);
372 /* For the low SPI version, there is a issue that PDC transfer
373 * on CS1,2,3 needs SPI_CSR0.BITS config as SPI_CSR1,2,3.BITS
374 */
375 spi_writel(as, CSR0, asd->csr);
376 if (as->caps.has_wdrbt) {
377 spi_writel(as, MR,
378 SPI_BF(PCS, ~(0x01 << spi->chip_select))
379 | SPI_BIT(WDRBT)
380 | SPI_BIT(MODFDIS)
381 | SPI_BIT(MSTR));
382 } else {
383 spi_writel(as, MR,
384 SPI_BF(PCS, ~(0x01 << spi->chip_select))
385 | SPI_BIT(MODFDIS)
386 | SPI_BIT(MSTR));
387 }
388
389 mr = spi_readl(as, MR);
390 if (as->use_cs_gpios)
391 gpio_set_value(asd->npcs_pin, active);
392 } else {
393 u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
394 int i;
395 u32 csr;
396
397 /* Make sure clock polarity is correct */
398 for (i = 0; i < spi->master->num_chipselect; i++) {
399 csr = spi_readl(as, CSR0 + 4 * i);
400 if ((csr ^ cpol) & SPI_BIT(CPOL))
401 spi_writel(as, CSR0 + 4 * i,
402 csr ^ SPI_BIT(CPOL));
403 }
404
405 mr = spi_readl(as, MR);
406 mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
407 if (as->use_cs_gpios && spi->chip_select != 0)
408 gpio_set_value(asd->npcs_pin, active);
409 spi_writel(as, MR, mr);
410 }
411
412 dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
413 asd->npcs_pin, active ? " (high)" : "",
414 mr);
415 }
416
cs_deactivate(struct atmel_spi * as,struct spi_device * spi)417 static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
418 {
419 struct atmel_spi_device *asd = spi->controller_state;
420 unsigned active = spi->mode & SPI_CS_HIGH;
421 u32 mr;
422
423 /* only deactivate *this* device; sometimes transfers to
424 * another device may be active when this routine is called.
425 */
426 mr = spi_readl(as, MR);
427 if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
428 mr = SPI_BFINS(PCS, 0xf, mr);
429 spi_writel(as, MR, mr);
430 }
431
432 dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
433 asd->npcs_pin, active ? " (low)" : "",
434 mr);
435
436 if (!as->use_cs_gpios)
437 spi_writel(as, CR, SPI_BIT(LASTXFER));
438 else if (atmel_spi_is_v2(as) || spi->chip_select != 0)
439 gpio_set_value(asd->npcs_pin, !active);
440 }
441
atmel_spi_lock(struct atmel_spi * as)442 static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock)
443 {
444 spin_lock_irqsave(&as->lock, as->flags);
445 }
446
atmel_spi_unlock(struct atmel_spi * as)447 static void atmel_spi_unlock(struct atmel_spi *as) __releases(&as->lock)
448 {
449 spin_unlock_irqrestore(&as->lock, as->flags);
450 }
451
atmel_spi_use_dma(struct atmel_spi * as,struct spi_transfer * xfer)452 static inline bool atmel_spi_use_dma(struct atmel_spi *as,
453 struct spi_transfer *xfer)
454 {
455 return as->use_dma && xfer->len >= DMA_MIN_BYTES;
456 }
457
atmel_spi_dma_slave_config(struct atmel_spi * as,struct dma_slave_config * slave_config,u8 bits_per_word)458 static int atmel_spi_dma_slave_config(struct atmel_spi *as,
459 struct dma_slave_config *slave_config,
460 u8 bits_per_word)
461 {
462 int err = 0;
463
464 if (bits_per_word > 8) {
465 slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
466 slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
467 } else {
468 slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
469 slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
470 }
471
472 slave_config->dst_addr = (dma_addr_t)as->phybase + SPI_TDR;
473 slave_config->src_addr = (dma_addr_t)as->phybase + SPI_RDR;
474 slave_config->src_maxburst = 1;
475 slave_config->dst_maxburst = 1;
476 slave_config->device_fc = false;
477
478 /*
479 * This driver uses fixed peripheral select mode (PS bit set to '0' in
480 * the Mode Register).
481 * So according to the datasheet, when FIFOs are available (and
482 * enabled), the Transmit FIFO operates in Multiple Data Mode.
483 * In this mode, up to 2 data, not 4, can be written into the Transmit
484 * Data Register in a single access.
485 * However, the first data has to be written into the lowest 16 bits and
486 * the second data into the highest 16 bits of the Transmit
487 * Data Register. For 8bit data (the most frequent case), it would
488 * require to rework tx_buf so each data would actualy fit 16 bits.
489 * So we'd rather write only one data at the time. Hence the transmit
490 * path works the same whether FIFOs are available (and enabled) or not.
491 */
492 slave_config->direction = DMA_MEM_TO_DEV;
493 if (dmaengine_slave_config(as->dma.chan_tx, slave_config)) {
494 dev_err(&as->pdev->dev,
495 "failed to configure tx dma channel\n");
496 err = -EINVAL;
497 }
498
499 /*
500 * This driver configures the spi controller for master mode (MSTR bit
501 * set to '1' in the Mode Register).
502 * So according to the datasheet, when FIFOs are available (and
503 * enabled), the Receive FIFO operates in Single Data Mode.
504 * So the receive path works the same whether FIFOs are available (and
505 * enabled) or not.
506 */
507 slave_config->direction = DMA_DEV_TO_MEM;
508 if (dmaengine_slave_config(as->dma.chan_rx, slave_config)) {
509 dev_err(&as->pdev->dev,
510 "failed to configure rx dma channel\n");
511 err = -EINVAL;
512 }
513
514 return err;
515 }
516
atmel_spi_configure_dma(struct atmel_spi * as)517 static int atmel_spi_configure_dma(struct atmel_spi *as)
518 {
519 struct dma_slave_config slave_config;
520 struct device *dev = &as->pdev->dev;
521 int err;
522
523 dma_cap_mask_t mask;
524 dma_cap_zero(mask);
525 dma_cap_set(DMA_SLAVE, mask);
526
527 as->dma.chan_tx = dma_request_slave_channel_reason(dev, "tx");
528 if (IS_ERR(as->dma.chan_tx)) {
529 err = PTR_ERR(as->dma.chan_tx);
530 if (err == -EPROBE_DEFER) {
531 dev_warn(dev, "no DMA channel available at the moment\n");
532 return err;
533 }
534 dev_err(dev,
535 "DMA TX channel not available, SPI unable to use DMA\n");
536 err = -EBUSY;
537 goto error;
538 }
539
540 /*
541 * No reason to check EPROBE_DEFER here since we have already requested
542 * tx channel. If it fails here, it's for another reason.
543 */
544 as->dma.chan_rx = dma_request_slave_channel(dev, "rx");
545
546 if (!as->dma.chan_rx) {
547 dev_err(dev,
548 "DMA RX channel not available, SPI unable to use DMA\n");
549 err = -EBUSY;
550 goto error;
551 }
552
553 err = atmel_spi_dma_slave_config(as, &slave_config, 8);
554 if (err)
555 goto error;
556
557 dev_info(&as->pdev->dev,
558 "Using %s (tx) and %s (rx) for DMA transfers\n",
559 dma_chan_name(as->dma.chan_tx),
560 dma_chan_name(as->dma.chan_rx));
561 return 0;
562 error:
563 if (as->dma.chan_rx)
564 dma_release_channel(as->dma.chan_rx);
565 if (!IS_ERR(as->dma.chan_tx))
566 dma_release_channel(as->dma.chan_tx);
567 return err;
568 }
569
atmel_spi_stop_dma(struct atmel_spi * as)570 static void atmel_spi_stop_dma(struct atmel_spi *as)
571 {
572 if (as->dma.chan_rx)
573 dmaengine_terminate_all(as->dma.chan_rx);
574 if (as->dma.chan_tx)
575 dmaengine_terminate_all(as->dma.chan_tx);
576 }
577
atmel_spi_release_dma(struct atmel_spi * as)578 static void atmel_spi_release_dma(struct atmel_spi *as)
579 {
580 if (as->dma.chan_rx)
581 dma_release_channel(as->dma.chan_rx);
582 if (as->dma.chan_tx)
583 dma_release_channel(as->dma.chan_tx);
584 }
585
586 /* This function is called by the DMA driver from tasklet context */
dma_callback(void * data)587 static void dma_callback(void *data)
588 {
589 struct spi_master *master = data;
590 struct atmel_spi *as = spi_master_get_devdata(master);
591
592 complete(&as->xfer_completion);
593 }
594
595 /*
596 * Next transfer using PIO without FIFO.
597 */
atmel_spi_next_xfer_single(struct spi_master * master,struct spi_transfer * xfer)598 static void atmel_spi_next_xfer_single(struct spi_master *master,
599 struct spi_transfer *xfer)
600 {
601 struct atmel_spi *as = spi_master_get_devdata(master);
602 unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
603
604 dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_pio\n");
605
606 /* Make sure data is not remaining in RDR */
607 spi_readl(as, RDR);
608 while (spi_readl(as, SR) & SPI_BIT(RDRF)) {
609 spi_readl(as, RDR);
610 cpu_relax();
611 }
612
613 if (xfer->tx_buf) {
614 if (xfer->bits_per_word > 8)
615 spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
616 else
617 spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));
618 } else {
619 spi_writel(as, TDR, 0);
620 }
621
622 dev_dbg(master->dev.parent,
623 " start pio xfer %p: len %u tx %p rx %p bitpw %d\n",
624 xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
625 xfer->bits_per_word);
626
627 /* Enable relevant interrupts */
628 spi_writel(as, IER, SPI_BIT(RDRF) | SPI_BIT(OVRES));
629 }
630
631 /*
632 * Next transfer using PIO with FIFO.
633 */
atmel_spi_next_xfer_fifo(struct spi_master * master,struct spi_transfer * xfer)634 static void atmel_spi_next_xfer_fifo(struct spi_master *master,
635 struct spi_transfer *xfer)
636 {
637 struct atmel_spi *as = spi_master_get_devdata(master);
638 u32 current_remaining_data, num_data;
639 u32 offset = xfer->len - as->current_remaining_bytes;
640 const u16 *words = (const u16 *)((u8 *)xfer->tx_buf + offset);
641 const u8 *bytes = (const u8 *)((u8 *)xfer->tx_buf + offset);
642 u16 td0, td1;
643 u32 fifomr;
644
645 dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_fifo\n");
646
647 /* Compute the number of data to transfer in the current iteration */
648 current_remaining_data = ((xfer->bits_per_word > 8) ?
649 ((u32)as->current_remaining_bytes >> 1) :
650 (u32)as->current_remaining_bytes);
651 num_data = min(current_remaining_data, as->fifo_size);
652
653 /* Flush RX and TX FIFOs */
654 spi_writel(as, CR, SPI_BIT(RXFCLR) | SPI_BIT(TXFCLR));
655 while (spi_readl(as, FLR))
656 cpu_relax();
657
658 /* Set RX FIFO Threshold to the number of data to transfer */
659 fifomr = spi_readl(as, FMR);
660 spi_writel(as, FMR, SPI_BFINS(RXFTHRES, num_data, fifomr));
661
662 /* Clear FIFO flags in the Status Register, especially RXFTHF */
663 (void)spi_readl(as, SR);
664
665 /* Fill TX FIFO */
666 while (num_data >= 2) {
667 if (xfer->tx_buf) {
668 if (xfer->bits_per_word > 8) {
669 td0 = *words++;
670 td1 = *words++;
671 } else {
672 td0 = *bytes++;
673 td1 = *bytes++;
674 }
675 } else {
676 td0 = 0;
677 td1 = 0;
678 }
679
680 spi_writel(as, TDR, (td1 << 16) | td0);
681 num_data -= 2;
682 }
683
684 if (num_data) {
685 if (xfer->tx_buf) {
686 if (xfer->bits_per_word > 8)
687 td0 = *words++;
688 else
689 td0 = *bytes++;
690 } else {
691 td0 = 0;
692 }
693
694 spi_writew(as, TDR, td0);
695 num_data--;
696 }
697
698 dev_dbg(master->dev.parent,
699 " start fifo xfer %p: len %u tx %p rx %p bitpw %d\n",
700 xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
701 xfer->bits_per_word);
702
703 /*
704 * Enable RX FIFO Threshold Flag interrupt to be notified about
705 * transfer completion.
706 */
707 spi_writel(as, IER, SPI_BIT(RXFTHF) | SPI_BIT(OVRES));
708 }
709
710 /*
711 * Next transfer using PIO.
712 */
atmel_spi_next_xfer_pio(struct spi_master * master,struct spi_transfer * xfer)713 static void atmel_spi_next_xfer_pio(struct spi_master *master,
714 struct spi_transfer *xfer)
715 {
716 struct atmel_spi *as = spi_master_get_devdata(master);
717
718 if (as->fifo_size)
719 atmel_spi_next_xfer_fifo(master, xfer);
720 else
721 atmel_spi_next_xfer_single(master, xfer);
722 }
723
724 /*
725 * Submit next transfer for DMA.
726 */
atmel_spi_next_xfer_dma_submit(struct spi_master * master,struct spi_transfer * xfer,u32 * plen)727 static int atmel_spi_next_xfer_dma_submit(struct spi_master *master,
728 struct spi_transfer *xfer,
729 u32 *plen)
730 {
731 struct atmel_spi *as = spi_master_get_devdata(master);
732 struct dma_chan *rxchan = as->dma.chan_rx;
733 struct dma_chan *txchan = as->dma.chan_tx;
734 struct dma_async_tx_descriptor *rxdesc;
735 struct dma_async_tx_descriptor *txdesc;
736 struct dma_slave_config slave_config;
737 dma_cookie_t cookie;
738 u32 len = *plen;
739
740 dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_dma_submit\n");
741
742 /* Check that the channels are available */
743 if (!rxchan || !txchan)
744 return -ENODEV;
745
746 /* release lock for DMA operations */
747 atmel_spi_unlock(as);
748
749 /* prepare the RX dma transfer */
750 sg_init_table(&as->dma.sgrx, 1);
751 if (xfer->rx_buf) {
752 as->dma.sgrx.dma_address = xfer->rx_dma + xfer->len - *plen;
753 } else {
754 as->dma.sgrx.dma_address = as->buffer_dma;
755 if (len > BUFFER_SIZE)
756 len = BUFFER_SIZE;
757 }
758
759 /* prepare the TX dma transfer */
760 sg_init_table(&as->dma.sgtx, 1);
761 if (xfer->tx_buf) {
762 as->dma.sgtx.dma_address = xfer->tx_dma + xfer->len - *plen;
763 } else {
764 as->dma.sgtx.dma_address = as->buffer_dma;
765 if (len > BUFFER_SIZE)
766 len = BUFFER_SIZE;
767 memset(as->buffer, 0, len);
768 }
769
770 sg_dma_len(&as->dma.sgtx) = len;
771 sg_dma_len(&as->dma.sgrx) = len;
772
773 *plen = len;
774
775 if (atmel_spi_dma_slave_config(as, &slave_config,
776 xfer->bits_per_word))
777 goto err_exit;
778
779 /* Send both scatterlists */
780 rxdesc = dmaengine_prep_slave_sg(rxchan, &as->dma.sgrx, 1,
781 DMA_FROM_DEVICE,
782 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
783 if (!rxdesc)
784 goto err_dma;
785
786 txdesc = dmaengine_prep_slave_sg(txchan, &as->dma.sgtx, 1,
787 DMA_TO_DEVICE,
788 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
789 if (!txdesc)
790 goto err_dma;
791
792 dev_dbg(master->dev.parent,
793 " start dma xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
794 xfer, xfer->len, xfer->tx_buf, (unsigned long long)xfer->tx_dma,
795 xfer->rx_buf, (unsigned long long)xfer->rx_dma);
796
797 /* Enable relevant interrupts */
798 spi_writel(as, IER, SPI_BIT(OVRES));
799
800 /* Put the callback on the RX transfer only, that should finish last */
801 rxdesc->callback = dma_callback;
802 rxdesc->callback_param = master;
803
804 /* Submit and fire RX and TX with TX last so we're ready to read! */
805 cookie = rxdesc->tx_submit(rxdesc);
806 if (dma_submit_error(cookie))
807 goto err_dma;
808 cookie = txdesc->tx_submit(txdesc);
809 if (dma_submit_error(cookie))
810 goto err_dma;
811 rxchan->device->device_issue_pending(rxchan);
812 txchan->device->device_issue_pending(txchan);
813
814 /* take back lock */
815 atmel_spi_lock(as);
816 return 0;
817
818 err_dma:
819 spi_writel(as, IDR, SPI_BIT(OVRES));
820 atmel_spi_stop_dma(as);
821 err_exit:
822 atmel_spi_lock(as);
823 return -ENOMEM;
824 }
825
atmel_spi_next_xfer_data(struct spi_master * master,struct spi_transfer * xfer,dma_addr_t * tx_dma,dma_addr_t * rx_dma,u32 * plen)826 static void atmel_spi_next_xfer_data(struct spi_master *master,
827 struct spi_transfer *xfer,
828 dma_addr_t *tx_dma,
829 dma_addr_t *rx_dma,
830 u32 *plen)
831 {
832 struct atmel_spi *as = spi_master_get_devdata(master);
833 u32 len = *plen;
834
835 /* use scratch buffer only when rx or tx data is unspecified */
836 if (xfer->rx_buf)
837 *rx_dma = xfer->rx_dma + xfer->len - *plen;
838 else {
839 *rx_dma = as->buffer_dma;
840 if (len > BUFFER_SIZE)
841 len = BUFFER_SIZE;
842 }
843
844 if (xfer->tx_buf)
845 *tx_dma = xfer->tx_dma + xfer->len - *plen;
846 else {
847 *tx_dma = as->buffer_dma;
848 if (len > BUFFER_SIZE)
849 len = BUFFER_SIZE;
850 memset(as->buffer, 0, len);
851 dma_sync_single_for_device(&as->pdev->dev,
852 as->buffer_dma, len, DMA_TO_DEVICE);
853 }
854
855 *plen = len;
856 }
857
atmel_spi_set_xfer_speed(struct atmel_spi * as,struct spi_device * spi,struct spi_transfer * xfer)858 static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
859 struct spi_device *spi,
860 struct spi_transfer *xfer)
861 {
862 u32 scbr, csr;
863 unsigned long bus_hz;
864
865 /* v1 chips start out at half the peripheral bus speed. */
866 bus_hz = clk_get_rate(as->clk);
867 if (!atmel_spi_is_v2(as))
868 bus_hz /= 2;
869
870 /*
871 * Calculate the lowest divider that satisfies the
872 * constraint, assuming div32/fdiv/mbz == 0.
873 */
874 scbr = DIV_ROUND_UP(bus_hz, xfer->speed_hz);
875
876 /*
877 * If the resulting divider doesn't fit into the
878 * register bitfield, we can't satisfy the constraint.
879 */
880 if (scbr >= (1 << SPI_SCBR_SIZE)) {
881 dev_err(&spi->dev,
882 "setup: %d Hz too slow, scbr %u; min %ld Hz\n",
883 xfer->speed_hz, scbr, bus_hz/255);
884 return -EINVAL;
885 }
886 if (scbr == 0) {
887 dev_err(&spi->dev,
888 "setup: %d Hz too high, scbr %u; max %ld Hz\n",
889 xfer->speed_hz, scbr, bus_hz);
890 return -EINVAL;
891 }
892 csr = spi_readl(as, CSR0 + 4 * spi->chip_select);
893 csr = SPI_BFINS(SCBR, scbr, csr);
894 spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
895
896 return 0;
897 }
898
899 /*
900 * Submit next transfer for PDC.
901 * lock is held, spi irq is blocked
902 */
atmel_spi_pdc_next_xfer(struct spi_master * master,struct spi_message * msg,struct spi_transfer * xfer)903 static void atmel_spi_pdc_next_xfer(struct spi_master *master,
904 struct spi_message *msg,
905 struct spi_transfer *xfer)
906 {
907 struct atmel_spi *as = spi_master_get_devdata(master);
908 u32 len;
909 dma_addr_t tx_dma, rx_dma;
910
911 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
912
913 len = as->current_remaining_bytes;
914 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
915 as->current_remaining_bytes -= len;
916
917 spi_writel(as, RPR, rx_dma);
918 spi_writel(as, TPR, tx_dma);
919
920 if (msg->spi->bits_per_word > 8)
921 len >>= 1;
922 spi_writel(as, RCR, len);
923 spi_writel(as, TCR, len);
924
925 dev_dbg(&msg->spi->dev,
926 " start xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
927 xfer, xfer->len, xfer->tx_buf,
928 (unsigned long long)xfer->tx_dma, xfer->rx_buf,
929 (unsigned long long)xfer->rx_dma);
930
931 if (as->current_remaining_bytes) {
932 len = as->current_remaining_bytes;
933 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
934 as->current_remaining_bytes -= len;
935
936 spi_writel(as, RNPR, rx_dma);
937 spi_writel(as, TNPR, tx_dma);
938
939 if (msg->spi->bits_per_word > 8)
940 len >>= 1;
941 spi_writel(as, RNCR, len);
942 spi_writel(as, TNCR, len);
943
944 dev_dbg(&msg->spi->dev,
945 " next xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
946 xfer, xfer->len, xfer->tx_buf,
947 (unsigned long long)xfer->tx_dma, xfer->rx_buf,
948 (unsigned long long)xfer->rx_dma);
949 }
950
951 /* REVISIT: We're waiting for RXBUFF before we start the next
952 * transfer because we need to handle some difficult timing
953 * issues otherwise. If we wait for TXBUFE in one transfer and
954 * then starts waiting for RXBUFF in the next, it's difficult
955 * to tell the difference between the RXBUFF interrupt we're
956 * actually waiting for and the RXBUFF interrupt of the
957 * previous transfer.
958 *
959 * It should be doable, though. Just not now...
960 */
961 spi_writel(as, IER, SPI_BIT(RXBUFF) | SPI_BIT(OVRES));
962 spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
963 }
964
965 /*
966 * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
967 * - The buffer is either valid for CPU access, else NULL
968 * - If the buffer is valid, so is its DMA address
969 *
970 * This driver manages the dma address unless message->is_dma_mapped.
971 */
972 static int
atmel_spi_dma_map_xfer(struct atmel_spi * as,struct spi_transfer * xfer)973 atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
974 {
975 struct device *dev = &as->pdev->dev;
976
977 xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
978 if (xfer->tx_buf) {
979 /* tx_buf is a const void* where we need a void * for the dma
980 * mapping */
981 void *nonconst_tx = (void *)xfer->tx_buf;
982
983 xfer->tx_dma = dma_map_single(dev,
984 nonconst_tx, xfer->len,
985 DMA_TO_DEVICE);
986 if (dma_mapping_error(dev, xfer->tx_dma))
987 return -ENOMEM;
988 }
989 if (xfer->rx_buf) {
990 xfer->rx_dma = dma_map_single(dev,
991 xfer->rx_buf, xfer->len,
992 DMA_FROM_DEVICE);
993 if (dma_mapping_error(dev, xfer->rx_dma)) {
994 if (xfer->tx_buf)
995 dma_unmap_single(dev,
996 xfer->tx_dma, xfer->len,
997 DMA_TO_DEVICE);
998 return -ENOMEM;
999 }
1000 }
1001 return 0;
1002 }
1003
atmel_spi_dma_unmap_xfer(struct spi_master * master,struct spi_transfer * xfer)1004 static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
1005 struct spi_transfer *xfer)
1006 {
1007 if (xfer->tx_dma != INVALID_DMA_ADDRESS)
1008 dma_unmap_single(master->dev.parent, xfer->tx_dma,
1009 xfer->len, DMA_TO_DEVICE);
1010 if (xfer->rx_dma != INVALID_DMA_ADDRESS)
1011 dma_unmap_single(master->dev.parent, xfer->rx_dma,
1012 xfer->len, DMA_FROM_DEVICE);
1013 }
1014
atmel_spi_disable_pdc_transfer(struct atmel_spi * as)1015 static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as)
1016 {
1017 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
1018 }
1019
1020 static void
atmel_spi_pump_single_data(struct atmel_spi * as,struct spi_transfer * xfer)1021 atmel_spi_pump_single_data(struct atmel_spi *as, struct spi_transfer *xfer)
1022 {
1023 u8 *rxp;
1024 u16 *rxp16;
1025 unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
1026
1027 if (xfer->rx_buf) {
1028 if (xfer->bits_per_word > 8) {
1029 rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
1030 *rxp16 = spi_readl(as, RDR);
1031 } else {
1032 rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
1033 *rxp = spi_readl(as, RDR);
1034 }
1035 } else {
1036 spi_readl(as, RDR);
1037 }
1038 if (xfer->bits_per_word > 8) {
1039 if (as->current_remaining_bytes > 2)
1040 as->current_remaining_bytes -= 2;
1041 else
1042 as->current_remaining_bytes = 0;
1043 } else {
1044 as->current_remaining_bytes--;
1045 }
1046 }
1047
1048 static void
atmel_spi_pump_fifo_data(struct atmel_spi * as,struct spi_transfer * xfer)1049 atmel_spi_pump_fifo_data(struct atmel_spi *as, struct spi_transfer *xfer)
1050 {
1051 u32 fifolr = spi_readl(as, FLR);
1052 u32 num_bytes, num_data = SPI_BFEXT(RXFL, fifolr);
1053 u32 offset = xfer->len - as->current_remaining_bytes;
1054 u16 *words = (u16 *)((u8 *)xfer->rx_buf + offset);
1055 u8 *bytes = (u8 *)((u8 *)xfer->rx_buf + offset);
1056 u16 rd; /* RD field is the lowest 16 bits of RDR */
1057
1058 /* Update the number of remaining bytes to transfer */
1059 num_bytes = ((xfer->bits_per_word > 8) ?
1060 (num_data << 1) :
1061 num_data);
1062
1063 if (as->current_remaining_bytes > num_bytes)
1064 as->current_remaining_bytes -= num_bytes;
1065 else
1066 as->current_remaining_bytes = 0;
1067
1068 /* Handle odd number of bytes when data are more than 8bit width */
1069 if (xfer->bits_per_word > 8)
1070 as->current_remaining_bytes &= ~0x1;
1071
1072 /* Read data */
1073 while (num_data) {
1074 rd = spi_readl(as, RDR);
1075 if (xfer->rx_buf) {
1076 if (xfer->bits_per_word > 8)
1077 *words++ = rd;
1078 else
1079 *bytes++ = rd;
1080 }
1081 num_data--;
1082 }
1083 }
1084
1085 /* Called from IRQ
1086 *
1087 * Must update "current_remaining_bytes" to keep track of data
1088 * to transfer.
1089 */
1090 static void
atmel_spi_pump_pio_data(struct atmel_spi * as,struct spi_transfer * xfer)1091 atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
1092 {
1093 if (as->fifo_size)
1094 atmel_spi_pump_fifo_data(as, xfer);
1095 else
1096 atmel_spi_pump_single_data(as, xfer);
1097 }
1098
1099 /* Interrupt
1100 *
1101 * No need for locking in this Interrupt handler: done_status is the
1102 * only information modified.
1103 */
1104 static irqreturn_t
atmel_spi_pio_interrupt(int irq,void * dev_id)1105 atmel_spi_pio_interrupt(int irq, void *dev_id)
1106 {
1107 struct spi_master *master = dev_id;
1108 struct atmel_spi *as = spi_master_get_devdata(master);
1109 u32 status, pending, imr;
1110 struct spi_transfer *xfer;
1111 int ret = IRQ_NONE;
1112
1113 imr = spi_readl(as, IMR);
1114 status = spi_readl(as, SR);
1115 pending = status & imr;
1116
1117 if (pending & SPI_BIT(OVRES)) {
1118 ret = IRQ_HANDLED;
1119 spi_writel(as, IDR, SPI_BIT(OVRES));
1120 dev_warn(master->dev.parent, "overrun\n");
1121
1122 /*
1123 * When we get an overrun, we disregard the current
1124 * transfer. Data will not be copied back from any
1125 * bounce buffer and msg->actual_len will not be
1126 * updated with the last xfer.
1127 *
1128 * We will also not process any remaning transfers in
1129 * the message.
1130 */
1131 as->done_status = -EIO;
1132 smp_wmb();
1133
1134 /* Clear any overrun happening while cleaning up */
1135 spi_readl(as, SR);
1136
1137 complete(&as->xfer_completion);
1138
1139 } else if (pending & (SPI_BIT(RDRF) | SPI_BIT(RXFTHF))) {
1140 atmel_spi_lock(as);
1141
1142 if (as->current_remaining_bytes) {
1143 ret = IRQ_HANDLED;
1144 xfer = as->current_transfer;
1145 atmel_spi_pump_pio_data(as, xfer);
1146 if (!as->current_remaining_bytes)
1147 spi_writel(as, IDR, pending);
1148
1149 complete(&as->xfer_completion);
1150 }
1151
1152 atmel_spi_unlock(as);
1153 } else {
1154 WARN_ONCE(pending, "IRQ not handled, pending = %x\n", pending);
1155 ret = IRQ_HANDLED;
1156 spi_writel(as, IDR, pending);
1157 }
1158
1159 return ret;
1160 }
1161
1162 static irqreturn_t
atmel_spi_pdc_interrupt(int irq,void * dev_id)1163 atmel_spi_pdc_interrupt(int irq, void *dev_id)
1164 {
1165 struct spi_master *master = dev_id;
1166 struct atmel_spi *as = spi_master_get_devdata(master);
1167 u32 status, pending, imr;
1168 int ret = IRQ_NONE;
1169
1170 imr = spi_readl(as, IMR);
1171 status = spi_readl(as, SR);
1172 pending = status & imr;
1173
1174 if (pending & SPI_BIT(OVRES)) {
1175
1176 ret = IRQ_HANDLED;
1177
1178 spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
1179 | SPI_BIT(OVRES)));
1180
1181 /* Clear any overrun happening while cleaning up */
1182 spi_readl(as, SR);
1183
1184 as->done_status = -EIO;
1185
1186 complete(&as->xfer_completion);
1187
1188 } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
1189 ret = IRQ_HANDLED;
1190
1191 spi_writel(as, IDR, pending);
1192
1193 complete(&as->xfer_completion);
1194 }
1195
1196 return ret;
1197 }
1198
atmel_spi_setup(struct spi_device * spi)1199 static int atmel_spi_setup(struct spi_device *spi)
1200 {
1201 struct atmel_spi *as;
1202 struct atmel_spi_device *asd;
1203 u32 csr;
1204 unsigned int bits = spi->bits_per_word;
1205 unsigned int npcs_pin;
1206 int ret;
1207
1208 as = spi_master_get_devdata(spi->master);
1209
1210 /* see notes above re chipselect */
1211 if (!as->use_cs_gpios && (spi->mode & SPI_CS_HIGH)) {
1212 dev_warn(&spi->dev, "setup: non GPIO CS can't be active-high\n");
1213 return -EINVAL;
1214 }
1215
1216 csr = SPI_BF(BITS, bits - 8);
1217 if (spi->mode & SPI_CPOL)
1218 csr |= SPI_BIT(CPOL);
1219 if (!(spi->mode & SPI_CPHA))
1220 csr |= SPI_BIT(NCPHA);
1221 if (!as->use_cs_gpios)
1222 csr |= SPI_BIT(CSAAT);
1223
1224 /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
1225 *
1226 * DLYBCT would add delays between words, slowing down transfers.
1227 * It could potentially be useful to cope with DMA bottlenecks, but
1228 * in those cases it's probably best to just use a lower bitrate.
1229 */
1230 csr |= SPI_BF(DLYBS, 0);
1231 csr |= SPI_BF(DLYBCT, 0);
1232
1233 /* chipselect must have been muxed as GPIO (e.g. in board setup) */
1234 npcs_pin = (unsigned long)spi->controller_data;
1235
1236 if (!as->use_cs_gpios)
1237 npcs_pin = spi->chip_select;
1238 else if (gpio_is_valid(spi->cs_gpio))
1239 npcs_pin = spi->cs_gpio;
1240
1241 asd = spi->controller_state;
1242 if (!asd) {
1243 asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
1244 if (!asd)
1245 return -ENOMEM;
1246
1247 if (as->use_cs_gpios) {
1248 ret = gpio_request(npcs_pin, dev_name(&spi->dev));
1249 if (ret) {
1250 kfree(asd);
1251 return ret;
1252 }
1253
1254 gpio_direction_output(npcs_pin,
1255 !(spi->mode & SPI_CS_HIGH));
1256 }
1257
1258 asd->npcs_pin = npcs_pin;
1259 spi->controller_state = asd;
1260 }
1261
1262 asd->csr = csr;
1263
1264 dev_dbg(&spi->dev,
1265 "setup: bpw %u mode 0x%x -> csr%d %08x\n",
1266 bits, spi->mode, spi->chip_select, csr);
1267
1268 if (!atmel_spi_is_v2(as))
1269 spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
1270
1271 return 0;
1272 }
1273
atmel_spi_one_transfer(struct spi_master * master,struct spi_message * msg,struct spi_transfer * xfer)1274 static int atmel_spi_one_transfer(struct spi_master *master,
1275 struct spi_message *msg,
1276 struct spi_transfer *xfer)
1277 {
1278 struct atmel_spi *as;
1279 struct spi_device *spi = msg->spi;
1280 u8 bits;
1281 u32 len;
1282 struct atmel_spi_device *asd;
1283 int timeout;
1284 int ret;
1285 unsigned long dma_timeout;
1286
1287 as = spi_master_get_devdata(master);
1288
1289 if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1290 dev_dbg(&spi->dev, "missing rx or tx buf\n");
1291 return -EINVAL;
1292 }
1293
1294 asd = spi->controller_state;
1295 bits = (asd->csr >> 4) & 0xf;
1296 if (bits != xfer->bits_per_word - 8) {
1297 dev_dbg(&spi->dev,
1298 "you can't yet change bits_per_word in transfers\n");
1299 return -ENOPROTOOPT;
1300 }
1301
1302 /*
1303 * DMA map early, for performance (empties dcache ASAP) and
1304 * better fault reporting.
1305 */
1306 if ((!msg->is_dma_mapped)
1307 && (atmel_spi_use_dma(as, xfer) || as->use_pdc)) {
1308 if (atmel_spi_dma_map_xfer(as, xfer) < 0)
1309 return -ENOMEM;
1310 }
1311
1312 atmel_spi_set_xfer_speed(as, msg->spi, xfer);
1313
1314 as->done_status = 0;
1315 as->current_transfer = xfer;
1316 as->current_remaining_bytes = xfer->len;
1317 while (as->current_remaining_bytes) {
1318 reinit_completion(&as->xfer_completion);
1319
1320 if (as->use_pdc) {
1321 atmel_spi_pdc_next_xfer(master, msg, xfer);
1322 } else if (atmel_spi_use_dma(as, xfer)) {
1323 len = as->current_remaining_bytes;
1324 ret = atmel_spi_next_xfer_dma_submit(master,
1325 xfer, &len);
1326 if (ret) {
1327 dev_err(&spi->dev,
1328 "unable to use DMA, fallback to PIO\n");
1329 atmel_spi_next_xfer_pio(master, xfer);
1330 } else {
1331 as->current_remaining_bytes -= len;
1332 if (as->current_remaining_bytes < 0)
1333 as->current_remaining_bytes = 0;
1334 }
1335 } else {
1336 atmel_spi_next_xfer_pio(master, xfer);
1337 }
1338
1339 /* interrupts are disabled, so free the lock for schedule */
1340 atmel_spi_unlock(as);
1341 dma_timeout = wait_for_completion_timeout(&as->xfer_completion,
1342 SPI_DMA_TIMEOUT);
1343 atmel_spi_lock(as);
1344 if (WARN_ON(dma_timeout == 0)) {
1345 dev_err(&spi->dev, "spi transfer timeout\n");
1346 as->done_status = -EIO;
1347 }
1348
1349 if (as->done_status)
1350 break;
1351 }
1352
1353 if (as->done_status) {
1354 if (as->use_pdc) {
1355 dev_warn(master->dev.parent,
1356 "overrun (%u/%u remaining)\n",
1357 spi_readl(as, TCR), spi_readl(as, RCR));
1358
1359 /*
1360 * Clean up DMA registers and make sure the data
1361 * registers are empty.
1362 */
1363 spi_writel(as, RNCR, 0);
1364 spi_writel(as, TNCR, 0);
1365 spi_writel(as, RCR, 0);
1366 spi_writel(as, TCR, 0);
1367 for (timeout = 1000; timeout; timeout--)
1368 if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
1369 break;
1370 if (!timeout)
1371 dev_warn(master->dev.parent,
1372 "timeout waiting for TXEMPTY");
1373 while (spi_readl(as, SR) & SPI_BIT(RDRF))
1374 spi_readl(as, RDR);
1375
1376 /* Clear any overrun happening while cleaning up */
1377 spi_readl(as, SR);
1378
1379 } else if (atmel_spi_use_dma(as, xfer)) {
1380 atmel_spi_stop_dma(as);
1381 }
1382
1383 if (!msg->is_dma_mapped
1384 && (atmel_spi_use_dma(as, xfer) || as->use_pdc))
1385 atmel_spi_dma_unmap_xfer(master, xfer);
1386
1387 return 0;
1388
1389 } else {
1390 /* only update length if no error */
1391 msg->actual_length += xfer->len;
1392 }
1393
1394 if (!msg->is_dma_mapped
1395 && (atmel_spi_use_dma(as, xfer) || as->use_pdc))
1396 atmel_spi_dma_unmap_xfer(master, xfer);
1397
1398 if (xfer->delay_usecs)
1399 udelay(xfer->delay_usecs);
1400
1401 if (xfer->cs_change) {
1402 if (list_is_last(&xfer->transfer_list,
1403 &msg->transfers)) {
1404 as->keep_cs = true;
1405 } else {
1406 cs_deactivate(as, msg->spi);
1407 udelay(10);
1408 cs_activate(as, msg->spi);
1409 }
1410 }
1411
1412 return 0;
1413 }
1414
atmel_spi_transfer_one_message(struct spi_master * master,struct spi_message * msg)1415 static int atmel_spi_transfer_one_message(struct spi_master *master,
1416 struct spi_message *msg)
1417 {
1418 struct atmel_spi *as;
1419 struct spi_transfer *xfer;
1420 struct spi_device *spi = msg->spi;
1421 int ret = 0;
1422
1423 as = spi_master_get_devdata(master);
1424
1425 dev_dbg(&spi->dev, "new message %p submitted for %s\n",
1426 msg, dev_name(&spi->dev));
1427
1428 atmel_spi_lock(as);
1429 cs_activate(as, spi);
1430
1431 as->keep_cs = false;
1432
1433 msg->status = 0;
1434 msg->actual_length = 0;
1435
1436 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1437 ret = atmel_spi_one_transfer(master, msg, xfer);
1438 if (ret)
1439 goto msg_done;
1440 }
1441
1442 if (as->use_pdc)
1443 atmel_spi_disable_pdc_transfer(as);
1444
1445 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1446 dev_dbg(&spi->dev,
1447 " xfer %p: len %u tx %p/%pad rx %p/%pad\n",
1448 xfer, xfer->len,
1449 xfer->tx_buf, &xfer->tx_dma,
1450 xfer->rx_buf, &xfer->rx_dma);
1451 }
1452
1453 msg_done:
1454 if (!as->keep_cs)
1455 cs_deactivate(as, msg->spi);
1456
1457 atmel_spi_unlock(as);
1458
1459 msg->status = as->done_status;
1460 spi_finalize_current_message(spi->master);
1461
1462 return ret;
1463 }
1464
atmel_spi_cleanup(struct spi_device * spi)1465 static void atmel_spi_cleanup(struct spi_device *spi)
1466 {
1467 struct atmel_spi_device *asd = spi->controller_state;
1468 unsigned gpio = (unsigned long) spi->controller_data;
1469
1470 if (!asd)
1471 return;
1472
1473 spi->controller_state = NULL;
1474 gpio_free(gpio);
1475 kfree(asd);
1476 }
1477
atmel_get_version(struct atmel_spi * as)1478 static inline unsigned int atmel_get_version(struct atmel_spi *as)
1479 {
1480 return spi_readl(as, VERSION) & 0x00000fff;
1481 }
1482
atmel_get_caps(struct atmel_spi * as)1483 static void atmel_get_caps(struct atmel_spi *as)
1484 {
1485 unsigned int version;
1486
1487 version = atmel_get_version(as);
1488 dev_info(&as->pdev->dev, "version: 0x%x\n", version);
1489
1490 as->caps.is_spi2 = version > 0x121;
1491 as->caps.has_wdrbt = version >= 0x210;
1492 as->caps.has_dma_support = version >= 0x212;
1493 }
1494
1495 /*-------------------------------------------------------------------------*/
1496
atmel_spi_probe(struct platform_device * pdev)1497 static int atmel_spi_probe(struct platform_device *pdev)
1498 {
1499 struct resource *regs;
1500 int irq;
1501 struct clk *clk;
1502 int ret;
1503 struct spi_master *master;
1504 struct atmel_spi *as;
1505
1506 /* Select default pin state */
1507 pinctrl_pm_select_default_state(&pdev->dev);
1508
1509 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1510 if (!regs)
1511 return -ENXIO;
1512
1513 irq = platform_get_irq(pdev, 0);
1514 if (irq < 0)
1515 return irq;
1516
1517 clk = devm_clk_get(&pdev->dev, "spi_clk");
1518 if (IS_ERR(clk))
1519 return PTR_ERR(clk);
1520
1521 /* setup spi core then atmel-specific driver state */
1522 ret = -ENOMEM;
1523 master = spi_alloc_master(&pdev->dev, sizeof(*as));
1524 if (!master)
1525 goto out_free;
1526
1527 /* the spi->mode bits understood by this driver: */
1528 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
1529 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
1530 master->dev.of_node = pdev->dev.of_node;
1531 master->bus_num = pdev->id;
1532 master->num_chipselect = master->dev.of_node ? 0 : 4;
1533 master->setup = atmel_spi_setup;
1534 master->transfer_one_message = atmel_spi_transfer_one_message;
1535 master->cleanup = atmel_spi_cleanup;
1536 master->auto_runtime_pm = true;
1537 platform_set_drvdata(pdev, master);
1538
1539 as = spi_master_get_devdata(master);
1540
1541 /*
1542 * Scratch buffer is used for throwaway rx and tx data.
1543 * It's coherent to minimize dcache pollution.
1544 */
1545 as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
1546 &as->buffer_dma, GFP_KERNEL);
1547 if (!as->buffer)
1548 goto out_free;
1549
1550 spin_lock_init(&as->lock);
1551
1552 as->pdev = pdev;
1553 as->regs = devm_ioremap_resource(&pdev->dev, regs);
1554 if (IS_ERR(as->regs)) {
1555 ret = PTR_ERR(as->regs);
1556 goto out_free_buffer;
1557 }
1558 as->phybase = regs->start;
1559 as->irq = irq;
1560 as->clk = clk;
1561
1562 init_completion(&as->xfer_completion);
1563
1564 atmel_get_caps(as);
1565
1566 as->use_cs_gpios = true;
1567 if (atmel_spi_is_v2(as) &&
1568 pdev->dev.of_node &&
1569 !of_get_property(pdev->dev.of_node, "cs-gpios", NULL)) {
1570 as->use_cs_gpios = false;
1571 master->num_chipselect = 4;
1572 }
1573
1574 as->use_dma = false;
1575 as->use_pdc = false;
1576 if (as->caps.has_dma_support) {
1577 ret = atmel_spi_configure_dma(as);
1578 if (ret == 0)
1579 as->use_dma = true;
1580 else if (ret == -EPROBE_DEFER)
1581 return ret;
1582 } else {
1583 as->use_pdc = true;
1584 }
1585
1586 if (as->caps.has_dma_support && !as->use_dma)
1587 dev_info(&pdev->dev, "Atmel SPI Controller using PIO only\n");
1588
1589 if (as->use_pdc) {
1590 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pdc_interrupt,
1591 0, dev_name(&pdev->dev), master);
1592 } else {
1593 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pio_interrupt,
1594 0, dev_name(&pdev->dev), master);
1595 }
1596 if (ret)
1597 goto out_unmap_regs;
1598
1599 /* Initialize the hardware */
1600 ret = clk_prepare_enable(clk);
1601 if (ret)
1602 goto out_free_irq;
1603 spi_writel(as, CR, SPI_BIT(SWRST));
1604 spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1605 if (as->caps.has_wdrbt) {
1606 spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
1607 | SPI_BIT(MSTR));
1608 } else {
1609 spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
1610 }
1611
1612 if (as->use_pdc)
1613 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
1614 spi_writel(as, CR, SPI_BIT(SPIEN));
1615
1616 as->fifo_size = 0;
1617 if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size",
1618 &as->fifo_size)) {
1619 dev_info(&pdev->dev, "Using FIFO (%u data)\n", as->fifo_size);
1620 spi_writel(as, CR, SPI_BIT(FIFOEN));
1621 }
1622
1623 /* go! */
1624 dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
1625 (unsigned long)regs->start, irq);
1626
1627 pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
1628 pm_runtime_use_autosuspend(&pdev->dev);
1629 pm_runtime_set_active(&pdev->dev);
1630 pm_runtime_enable(&pdev->dev);
1631
1632 ret = devm_spi_register_master(&pdev->dev, master);
1633 if (ret)
1634 goto out_free_dma;
1635
1636 return 0;
1637
1638 out_free_dma:
1639 pm_runtime_disable(&pdev->dev);
1640 pm_runtime_set_suspended(&pdev->dev);
1641
1642 if (as->use_dma)
1643 atmel_spi_release_dma(as);
1644
1645 spi_writel(as, CR, SPI_BIT(SWRST));
1646 spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1647 clk_disable_unprepare(clk);
1648 out_free_irq:
1649 out_unmap_regs:
1650 out_free_buffer:
1651 dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
1652 as->buffer_dma);
1653 out_free:
1654 spi_master_put(master);
1655 return ret;
1656 }
1657
atmel_spi_remove(struct platform_device * pdev)1658 static int atmel_spi_remove(struct platform_device *pdev)
1659 {
1660 struct spi_master *master = platform_get_drvdata(pdev);
1661 struct atmel_spi *as = spi_master_get_devdata(master);
1662
1663 pm_runtime_get_sync(&pdev->dev);
1664
1665 /* reset the hardware and block queue progress */
1666 if (as->use_dma) {
1667 atmel_spi_stop_dma(as);
1668 atmel_spi_release_dma(as);
1669 }
1670
1671 spin_lock_irq(&as->lock);
1672 spi_writel(as, CR, SPI_BIT(SWRST));
1673 spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1674 spi_readl(as, SR);
1675 spin_unlock_irq(&as->lock);
1676
1677 dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
1678 as->buffer_dma);
1679
1680 clk_disable_unprepare(as->clk);
1681
1682 pm_runtime_put_noidle(&pdev->dev);
1683 pm_runtime_disable(&pdev->dev);
1684
1685 return 0;
1686 }
1687
1688 #ifdef CONFIG_PM
atmel_spi_runtime_suspend(struct device * dev)1689 static int atmel_spi_runtime_suspend(struct device *dev)
1690 {
1691 struct spi_master *master = dev_get_drvdata(dev);
1692 struct atmel_spi *as = spi_master_get_devdata(master);
1693
1694 clk_disable_unprepare(as->clk);
1695 pinctrl_pm_select_sleep_state(dev);
1696
1697 return 0;
1698 }
1699
atmel_spi_runtime_resume(struct device * dev)1700 static int atmel_spi_runtime_resume(struct device *dev)
1701 {
1702 struct spi_master *master = dev_get_drvdata(dev);
1703 struct atmel_spi *as = spi_master_get_devdata(master);
1704
1705 pinctrl_pm_select_default_state(dev);
1706
1707 return clk_prepare_enable(as->clk);
1708 }
1709
1710 #ifdef CONFIG_PM_SLEEP
atmel_spi_suspend(struct device * dev)1711 static int atmel_spi_suspend(struct device *dev)
1712 {
1713 struct spi_master *master = dev_get_drvdata(dev);
1714 int ret;
1715
1716 /* Stop the queue running */
1717 ret = spi_master_suspend(master);
1718 if (ret) {
1719 dev_warn(dev, "cannot suspend master\n");
1720 return ret;
1721 }
1722
1723 if (!pm_runtime_suspended(dev))
1724 atmel_spi_runtime_suspend(dev);
1725
1726 return 0;
1727 }
1728
atmel_spi_resume(struct device * dev)1729 static int atmel_spi_resume(struct device *dev)
1730 {
1731 struct spi_master *master = dev_get_drvdata(dev);
1732 int ret;
1733
1734 if (!pm_runtime_suspended(dev)) {
1735 ret = atmel_spi_runtime_resume(dev);
1736 if (ret)
1737 return ret;
1738 }
1739
1740 /* Start the queue running */
1741 ret = spi_master_resume(master);
1742 if (ret)
1743 dev_err(dev, "problem starting queue (%d)\n", ret);
1744
1745 return ret;
1746 }
1747 #endif
1748
1749 static const struct dev_pm_ops atmel_spi_pm_ops = {
1750 SET_SYSTEM_SLEEP_PM_OPS(atmel_spi_suspend, atmel_spi_resume)
1751 SET_RUNTIME_PM_OPS(atmel_spi_runtime_suspend,
1752 atmel_spi_runtime_resume, NULL)
1753 };
1754 #define ATMEL_SPI_PM_OPS (&atmel_spi_pm_ops)
1755 #else
1756 #define ATMEL_SPI_PM_OPS NULL
1757 #endif
1758
1759 #if defined(CONFIG_OF)
1760 static const struct of_device_id atmel_spi_dt_ids[] = {
1761 { .compatible = "atmel,at91rm9200-spi" },
1762 { /* sentinel */ }
1763 };
1764
1765 MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids);
1766 #endif
1767
1768 static struct platform_driver atmel_spi_driver = {
1769 .driver = {
1770 .name = "atmel_spi",
1771 .pm = ATMEL_SPI_PM_OPS,
1772 .of_match_table = of_match_ptr(atmel_spi_dt_ids),
1773 },
1774 .probe = atmel_spi_probe,
1775 .remove = atmel_spi_remove,
1776 };
1777 module_platform_driver(atmel_spi_driver);
1778
1779 MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
1780 MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
1781 MODULE_LICENSE("GPL");
1782 MODULE_ALIAS("platform:atmel_spi");
1783