1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Driver for Atmel AT32 and AT91 SPI Controllers
4 *
5 * Copyright (C) 2006 Atmel Corporation
6 */
7
8#include <linux/kernel.h>
9#include <linux/clk.h>
10#include <linux/module.h>
11#include <linux/platform_device.h>
12#include <linux/delay.h>
13#include <linux/dma-mapping.h>
14#include <linux/dmaengine.h>
15#include <linux/err.h>
16#include <linux/interrupt.h>
17#include <linux/spi/spi.h>
18#include <linux/slab.h>
19#include <linux/of.h>
20
21#include <linux/io.h>
22#include <linux/gpio/consumer.h>
23#include <linux/pinctrl/consumer.h>
24#include <linux/pm_runtime.h>
25#include <linux/iopoll.h>
26#include <trace/events/spi.h>
27
28/* SPI register offsets */
29#define SPI_CR 0x0000
30#define SPI_MR 0x0004
31#define SPI_RDR 0x0008
32#define SPI_TDR 0x000c
33#define SPI_SR 0x0010
34#define SPI_IER 0x0014
35#define SPI_IDR 0x0018
36#define SPI_IMR 0x001c
37#define SPI_CSR0 0x0030
38#define SPI_CSR1 0x0034
39#define SPI_CSR2 0x0038
40#define SPI_CSR3 0x003c
41#define SPI_FMR 0x0040
42#define SPI_FLR 0x0044
43#define SPI_VERSION 0x00fc
44#define SPI_RPR 0x0100
45#define SPI_RCR 0x0104
46#define SPI_TPR 0x0108
47#define SPI_TCR 0x010c
48#define SPI_RNPR 0x0110
49#define SPI_RNCR 0x0114
50#define SPI_TNPR 0x0118
51#define SPI_TNCR 0x011c
52#define SPI_PTCR 0x0120
53#define SPI_PTSR 0x0124
54
55/* Bitfields in CR */
56#define SPI_SPIEN_OFFSET 0
57#define SPI_SPIEN_SIZE 1
58#define SPI_SPIDIS_OFFSET 1
59#define SPI_SPIDIS_SIZE 1
60#define SPI_SWRST_OFFSET 7
61#define SPI_SWRST_SIZE 1
62#define SPI_LASTXFER_OFFSET 24
63#define SPI_LASTXFER_SIZE 1
64#define SPI_TXFCLR_OFFSET 16
65#define SPI_TXFCLR_SIZE 1
66#define SPI_RXFCLR_OFFSET 17
67#define SPI_RXFCLR_SIZE 1
68#define SPI_FIFOEN_OFFSET 30
69#define SPI_FIFOEN_SIZE 1
70#define SPI_FIFODIS_OFFSET 31
71#define SPI_FIFODIS_SIZE 1
72
73/* Bitfields in MR */
74#define SPI_MSTR_OFFSET 0
75#define SPI_MSTR_SIZE 1
76#define SPI_PS_OFFSET 1
77#define SPI_PS_SIZE 1
78#define SPI_PCSDEC_OFFSET 2
79#define SPI_PCSDEC_SIZE 1
80#define SPI_FDIV_OFFSET 3
81#define SPI_FDIV_SIZE 1
82#define SPI_MODFDIS_OFFSET 4
83#define SPI_MODFDIS_SIZE 1
84#define SPI_WDRBT_OFFSET 5
85#define SPI_WDRBT_SIZE 1
86#define SPI_LLB_OFFSET 7
87#define SPI_LLB_SIZE 1
88#define SPI_PCS_OFFSET 16
89#define SPI_PCS_SIZE 4
90#define SPI_DLYBCS_OFFSET 24
91#define SPI_DLYBCS_SIZE 8
92
93/* Bitfields in RDR */
94#define SPI_RD_OFFSET 0
95#define SPI_RD_SIZE 16
96
97/* Bitfields in TDR */
98#define SPI_TD_OFFSET 0
99#define SPI_TD_SIZE 16
100
101/* Bitfields in SR */
102#define SPI_RDRF_OFFSET 0
103#define SPI_RDRF_SIZE 1
104#define SPI_TDRE_OFFSET 1
105#define SPI_TDRE_SIZE 1
106#define SPI_MODF_OFFSET 2
107#define SPI_MODF_SIZE 1
108#define SPI_OVRES_OFFSET 3
109#define SPI_OVRES_SIZE 1
110#define SPI_ENDRX_OFFSET 4
111#define SPI_ENDRX_SIZE 1
112#define SPI_ENDTX_OFFSET 5
113#define SPI_ENDTX_SIZE 1
114#define SPI_RXBUFF_OFFSET 6
115#define SPI_RXBUFF_SIZE 1
116#define SPI_TXBUFE_OFFSET 7
117#define SPI_TXBUFE_SIZE 1
118#define SPI_NSSR_OFFSET 8
119#define SPI_NSSR_SIZE 1
120#define SPI_TXEMPTY_OFFSET 9
121#define SPI_TXEMPTY_SIZE 1
122#define SPI_SPIENS_OFFSET 16
123#define SPI_SPIENS_SIZE 1
124#define SPI_TXFEF_OFFSET 24
125#define SPI_TXFEF_SIZE 1
126#define SPI_TXFFF_OFFSET 25
127#define SPI_TXFFF_SIZE 1
128#define SPI_TXFTHF_OFFSET 26
129#define SPI_TXFTHF_SIZE 1
130#define SPI_RXFEF_OFFSET 27
131#define SPI_RXFEF_SIZE 1
132#define SPI_RXFFF_OFFSET 28
133#define SPI_RXFFF_SIZE 1
134#define SPI_RXFTHF_OFFSET 29
135#define SPI_RXFTHF_SIZE 1
136#define SPI_TXFPTEF_OFFSET 30
137#define SPI_TXFPTEF_SIZE 1
138#define SPI_RXFPTEF_OFFSET 31
139#define SPI_RXFPTEF_SIZE 1
140
141/* Bitfields in CSR0 */
142#define SPI_CPOL_OFFSET 0
143#define SPI_CPOL_SIZE 1
144#define SPI_NCPHA_OFFSET 1
145#define SPI_NCPHA_SIZE 1
146#define SPI_CSAAT_OFFSET 3
147#define SPI_CSAAT_SIZE 1
148#define SPI_BITS_OFFSET 4
149#define SPI_BITS_SIZE 4
150#define SPI_SCBR_OFFSET 8
151#define SPI_SCBR_SIZE 8
152#define SPI_DLYBS_OFFSET 16
153#define SPI_DLYBS_SIZE 8
154#define SPI_DLYBCT_OFFSET 24
155#define SPI_DLYBCT_SIZE 8
156
157/* Bitfields in RCR */
158#define SPI_RXCTR_OFFSET 0
159#define SPI_RXCTR_SIZE 16
160
161/* Bitfields in TCR */
162#define SPI_TXCTR_OFFSET 0
163#define SPI_TXCTR_SIZE 16
164
165/* Bitfields in RNCR */
166#define SPI_RXNCR_OFFSET 0
167#define SPI_RXNCR_SIZE 16
168
169/* Bitfields in TNCR */
170#define SPI_TXNCR_OFFSET 0
171#define SPI_TXNCR_SIZE 16
172
173/* Bitfields in PTCR */
174#define SPI_RXTEN_OFFSET 0
175#define SPI_RXTEN_SIZE 1
176#define SPI_RXTDIS_OFFSET 1
177#define SPI_RXTDIS_SIZE 1
178#define SPI_TXTEN_OFFSET 8
179#define SPI_TXTEN_SIZE 1
180#define SPI_TXTDIS_OFFSET 9
181#define SPI_TXTDIS_SIZE 1
182
183/* Bitfields in FMR */
184#define SPI_TXRDYM_OFFSET 0
185#define SPI_TXRDYM_SIZE 2
186#define SPI_RXRDYM_OFFSET 4
187#define SPI_RXRDYM_SIZE 2
188#define SPI_TXFTHRES_OFFSET 16
189#define SPI_TXFTHRES_SIZE 6
190#define SPI_RXFTHRES_OFFSET 24
191#define SPI_RXFTHRES_SIZE 6
192
193/* Bitfields in FLR */
194#define SPI_TXFL_OFFSET 0
195#define SPI_TXFL_SIZE 6
196#define SPI_RXFL_OFFSET 16
197#define SPI_RXFL_SIZE 6
198
199/* Constants for BITS */
200#define SPI_BITS_8_BPT 0
201#define SPI_BITS_9_BPT 1
202#define SPI_BITS_10_BPT 2
203#define SPI_BITS_11_BPT 3
204#define SPI_BITS_12_BPT 4
205#define SPI_BITS_13_BPT 5
206#define SPI_BITS_14_BPT 6
207#define SPI_BITS_15_BPT 7
208#define SPI_BITS_16_BPT 8
209#define SPI_ONE_DATA 0
210#define SPI_TWO_DATA 1
211#define SPI_FOUR_DATA 2
212
213/* Bit manipulation macros */
214#define SPI_BIT(name) \
215 (1 << SPI_##name##_OFFSET)
216#define SPI_BF(name, value) \
217 (((value) & ((1 << SPI_##name##_SIZE) - 1)) << SPI_##name##_OFFSET)
218#define SPI_BFEXT(name, value) \
219 (((value) >> SPI_##name##_OFFSET) & ((1 << SPI_##name##_SIZE) - 1))
220#define SPI_BFINS(name, value, old) \
221 (((old) & ~(((1 << SPI_##name##_SIZE) - 1) << SPI_##name##_OFFSET)) \
222 | SPI_BF(name, value))
223
224/* Register access macros */
225#define spi_readl(port, reg) \
226 readl_relaxed((port)->regs + SPI_##reg)
227#define spi_writel(port, reg, value) \
228 writel_relaxed((value), (port)->regs + SPI_##reg)
229#define spi_writew(port, reg, value) \
230 writew_relaxed((value), (port)->regs + SPI_##reg)
231
232/* use PIO for small transfers, avoiding DMA setup/teardown overhead and
233 * cache operations; better heuristics consider wordsize and bitrate.
234 */
235#define DMA_MIN_BYTES 16
236
237#define AUTOSUSPEND_TIMEOUT 2000
238
239struct atmel_spi_caps {
240 bool is_spi2;
241 bool has_wdrbt;
242 bool has_dma_support;
243 bool has_pdc_support;
244};
245
246/*
247 * The core SPI transfer engine just talks to a register bank to set up
248 * DMA transfers; transfer queue progress is driven by IRQs. The clock
249 * framework provides the base clock, subdivided for each spi_device.
250 */
251struct atmel_spi {
252 spinlock_t lock;
253 unsigned long flags;
254
255 phys_addr_t phybase;
256 void __iomem *regs;
257 int irq;
258 struct clk *clk;
259 struct platform_device *pdev;
260 unsigned long spi_clk;
261
262 struct spi_transfer *current_transfer;
263 int current_remaining_bytes;
264 int done_status;
265 dma_addr_t dma_addr_rx_bbuf;
266 dma_addr_t dma_addr_tx_bbuf;
267 void *addr_rx_bbuf;
268 void *addr_tx_bbuf;
269
270 struct completion xfer_completion;
271
272 struct atmel_spi_caps caps;
273
274 bool use_dma;
275 bool use_pdc;
276
277 bool keep_cs;
278
279 u32 fifo_size;
280 bool last_polarity;
281 u8 native_cs_free;
282 u8 native_cs_for_gpio;
283};
284
285/* Controller-specific per-slave state */
286struct atmel_spi_device {
287 u32 csr;
288};
289
290#define SPI_MAX_DMA_XFER 65535 /* true for both PDC and DMA */
291#define INVALID_DMA_ADDRESS 0xffffffff
292
293/*
294 * This frequency can be anything supported by the controller, but to avoid
295 * unnecessary delay, the highest possible frequency is chosen.
296 *
297 * This frequency is the highest possible which is not interfering with other
298 * chip select registers (see Note for Serial Clock Bit Rate configuration in
299 * Atmel-11121F-ATARM-SAMA5D3-Series-Datasheet_02-Feb-16, page 1283)
300 */
301#define DUMMY_MSG_FREQUENCY 0x02
302/*
303 * 8 bits is the minimum data the controller is capable of sending.
304 *
305 * This message can be anything as it should not be treated by any SPI device.
306 */
307#define DUMMY_MSG 0xAA
308
309/*
310 * Version 2 of the SPI controller has
311 * - CR.LASTXFER
312 * - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
313 * - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
314 * - SPI_CSRx.CSAAT
315 * - SPI_CSRx.SBCR allows faster clocking
316 */
317static bool atmel_spi_is_v2(struct atmel_spi *as)
318{
319 return as->caps.is_spi2;
320}
321
322/*
323 * Send a dummy message.
324 *
325 * This is sometimes needed when using a CS GPIO to force clock transition when
326 * switching between devices with different polarities.
327 */
328static void atmel_spi_send_dummy(struct atmel_spi *as, struct spi_device *spi, int chip_select)
329{
330 u32 status;
331 u32 csr;
332
333 /*
334 * Set a clock frequency to allow sending message on SPI bus.
335 * The frequency here can be anything, but is needed for
336 * the controller to send the data.
337 */
338 csr = spi_readl(as, CSR0 + 4 * chip_select);
339 csr = SPI_BFINS(SCBR, DUMMY_MSG_FREQUENCY, csr);
340 spi_writel(as, CSR0 + 4 * chip_select, csr);
341
342 /*
343 * Read all data coming from SPI bus, needed to be able to send
344 * the message.
345 */
346 spi_readl(as, RDR);
347 while (spi_readl(as, SR) & SPI_BIT(RDRF)) {
348 spi_readl(as, RDR);
349 cpu_relax();
350 }
351
352 spi_writel(as, TDR, DUMMY_MSG);
353
354 readl_poll_timeout_atomic(as->regs + SPI_SR, status,
355 (status & SPI_BIT(TXEMPTY)), 1, 1000);
356}
357
358
359/*
360 * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
361 * they assume that spi slave device state will not change on deselect, so
362 * that automagic deselection is OK. ("NPCSx rises if no data is to be
363 * transmitted") Not so! Workaround uses nCSx pins as GPIOs; or newer
364 * controllers have CSAAT and friends.
365 *
366 * Even controller newer than ar91rm9200, using GPIOs can make sens as
367 * it lets us support active-high chipselects despite the controller's
368 * belief that only active-low devices/systems exists.
369 *
370 * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
371 * right when driven with GPIO. ("Mode Fault does not allow more than one
372 * Master on Chip Select 0.") No workaround exists for that ... so for
373 * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
374 * and (c) will trigger that first erratum in some cases.
375 *
376 * When changing the clock polarity, the SPI controller waits for the next
377 * transmission to enforce the default clock state. This may be an issue when
378 * using a GPIO as Chip Select: the clock level is applied only when the first
379 * packet is sent, once the CS has already been asserted. The workaround is to
380 * avoid this by sending a first (dummy) message before toggling the CS state.
381 */
382static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
383{
384 struct atmel_spi_device *asd = spi->controller_state;
385 bool new_polarity;
386 int chip_select;
387 u32 mr;
388
389 if (spi_get_csgpiod(spi, idx: 0))
390 chip_select = as->native_cs_for_gpio;
391 else
392 chip_select = spi_get_chipselect(spi, idx: 0);
393
394 if (atmel_spi_is_v2(as)) {
395 spi_writel(as, CSR0 + 4 * chip_select, asd->csr);
396 /* For the low SPI version, there is a issue that PDC transfer
397 * on CS1,2,3 needs SPI_CSR0.BITS config as SPI_CSR1,2,3.BITS
398 */
399 spi_writel(as, CSR0, asd->csr);
400 if (as->caps.has_wdrbt) {
401 spi_writel(as, MR,
402 SPI_BF(PCS, ~(0x01 << chip_select))
403 | SPI_BIT(WDRBT)
404 | SPI_BIT(MODFDIS)
405 | SPI_BIT(MSTR));
406 } else {
407 spi_writel(as, MR,
408 SPI_BF(PCS, ~(0x01 << chip_select))
409 | SPI_BIT(MODFDIS)
410 | SPI_BIT(MSTR));
411 }
412
413 mr = spi_readl(as, MR);
414
415 /*
416 * Ensures the clock polarity is valid before we actually
417 * assert the CS to avoid spurious clock edges to be
418 * processed by the spi devices.
419 */
420 if (spi_get_csgpiod(spi, idx: 0)) {
421 new_polarity = (asd->csr & SPI_BIT(CPOL)) != 0;
422 if (new_polarity != as->last_polarity) {
423 /*
424 * Need to disable the GPIO before sending the dummy
425 * message because it is already set by the spi core.
426 */
427 gpiod_set_value_cansleep(desc: spi_get_csgpiod(spi, idx: 0), value: 0);
428 atmel_spi_send_dummy(as, spi, chip_select);
429 as->last_polarity = new_polarity;
430 gpiod_set_value_cansleep(desc: spi_get_csgpiod(spi, idx: 0), value: 1);
431 }
432 }
433 } else {
434 u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
435 int i;
436 u32 csr;
437
438 /* Make sure clock polarity is correct */
439 for (i = 0; i < spi->controller->num_chipselect; i++) {
440 csr = spi_readl(as, CSR0 + 4 * i);
441 if ((csr ^ cpol) & SPI_BIT(CPOL))
442 spi_writel(as, CSR0 + 4 * i,
443 csr ^ SPI_BIT(CPOL));
444 }
445
446 mr = spi_readl(as, MR);
447 mr = SPI_BFINS(PCS, ~(1 << chip_select), mr);
448 spi_writel(as, MR, mr);
449 }
450
451 dev_dbg(&spi->dev, "activate NPCS, mr %08x\n", mr);
452}
453
454static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
455{
456 int chip_select;
457 u32 mr;
458
459 if (spi_get_csgpiod(spi, idx: 0))
460 chip_select = as->native_cs_for_gpio;
461 else
462 chip_select = spi_get_chipselect(spi, idx: 0);
463
464 /* only deactivate *this* device; sometimes transfers to
465 * another device may be active when this routine is called.
466 */
467 mr = spi_readl(as, MR);
468 if (~SPI_BFEXT(PCS, mr) & (1 << chip_select)) {
469 mr = SPI_BFINS(PCS, 0xf, mr);
470 spi_writel(as, MR, mr);
471 }
472
473 dev_dbg(&spi->dev, "DEactivate NPCS, mr %08x\n", mr);
474
475 if (!spi_get_csgpiod(spi, idx: 0))
476 spi_writel(as, CR, SPI_BIT(LASTXFER));
477}
478
479static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock)
480{
481 spin_lock_irqsave(&as->lock, as->flags);
482}
483
484static void atmel_spi_unlock(struct atmel_spi *as) __releases(&as->lock)
485{
486 spin_unlock_irqrestore(lock: &as->lock, flags: as->flags);
487}
488
489static inline bool atmel_spi_is_vmalloc_xfer(struct spi_transfer *xfer)
490{
491 return is_vmalloc_addr(x: xfer->tx_buf) || is_vmalloc_addr(x: xfer->rx_buf);
492}
493
494static inline bool atmel_spi_use_dma(struct atmel_spi *as,
495 struct spi_transfer *xfer)
496{
497 return as->use_dma && xfer->len >= DMA_MIN_BYTES;
498}
499
500static bool atmel_spi_can_dma(struct spi_controller *host,
501 struct spi_device *spi,
502 struct spi_transfer *xfer)
503{
504 struct atmel_spi *as = spi_controller_get_devdata(ctlr: host);
505
506 if (IS_ENABLED(CONFIG_SOC_SAM_V4_V5))
507 return atmel_spi_use_dma(as, xfer) &&
508 !atmel_spi_is_vmalloc_xfer(xfer);
509 else
510 return atmel_spi_use_dma(as, xfer);
511
512}
513
514static int atmel_spi_dma_slave_config(struct atmel_spi *as, u8 bits_per_word)
515{
516 struct spi_controller *host = platform_get_drvdata(pdev: as->pdev);
517 struct dma_slave_config slave_config;
518 int err = 0;
519
520 if (bits_per_word > 8) {
521 slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
522 slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
523 } else {
524 slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
525 slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
526 }
527
528 slave_config.dst_addr = (dma_addr_t)as->phybase + SPI_TDR;
529 slave_config.src_addr = (dma_addr_t)as->phybase + SPI_RDR;
530 slave_config.src_maxburst = 1;
531 slave_config.dst_maxburst = 1;
532 slave_config.device_fc = false;
533
534 /*
535 * This driver uses fixed peripheral select mode (PS bit set to '0' in
536 * the Mode Register).
537 * So according to the datasheet, when FIFOs are available (and
538 * enabled), the Transmit FIFO operates in Multiple Data Mode.
539 * In this mode, up to 2 data, not 4, can be written into the Transmit
540 * Data Register in a single access.
541 * However, the first data has to be written into the lowest 16 bits and
542 * the second data into the highest 16 bits of the Transmit
543 * Data Register. For 8bit data (the most frequent case), it would
544 * require to rework tx_buf so each data would actually fit 16 bits.
545 * So we'd rather write only one data at the time. Hence the transmit
546 * path works the same whether FIFOs are available (and enabled) or not.
547 */
548 if (dmaengine_slave_config(chan: host->dma_tx, config: &slave_config)) {
549 dev_err(&as->pdev->dev,
550 "failed to configure tx dma channel\n");
551 err = -EINVAL;
552 }
553
554 /*
555 * This driver configures the spi controller for host mode (MSTR bit
556 * set to '1' in the Mode Register).
557 * So according to the datasheet, when FIFOs are available (and
558 * enabled), the Receive FIFO operates in Single Data Mode.
559 * So the receive path works the same whether FIFOs are available (and
560 * enabled) or not.
561 */
562 if (dmaengine_slave_config(chan: host->dma_rx, config: &slave_config)) {
563 dev_err(&as->pdev->dev,
564 "failed to configure rx dma channel\n");
565 err = -EINVAL;
566 }
567
568 return err;
569}
570
571static int atmel_spi_configure_dma(struct spi_controller *host,
572 struct atmel_spi *as)
573{
574 struct device *dev = &as->pdev->dev;
575 int err;
576
577 host->dma_tx = dma_request_chan(dev, name: "tx");
578 if (IS_ERR(ptr: host->dma_tx)) {
579 err = PTR_ERR(ptr: host->dma_tx);
580 dev_dbg(dev, "No TX DMA channel, DMA is disabled\n");
581 goto error_clear;
582 }
583
584 host->dma_rx = dma_request_chan(dev, name: "rx");
585 if (IS_ERR(ptr: host->dma_rx)) {
586 err = PTR_ERR(ptr: host->dma_rx);
587 /*
588 * No reason to check EPROBE_DEFER here since we have already
589 * requested tx channel.
590 */
591 dev_dbg(dev, "No RX DMA channel, DMA is disabled\n");
592 goto error;
593 }
594
595 err = atmel_spi_dma_slave_config(as, bits_per_word: 8);
596 if (err)
597 goto error;
598
599 dev_info(&as->pdev->dev,
600 "Using %s (tx) and %s (rx) for DMA transfers\n",
601 dma_chan_name(host->dma_tx),
602 dma_chan_name(host->dma_rx));
603
604 return 0;
605error:
606 if (!IS_ERR(ptr: host->dma_rx))
607 dma_release_channel(chan: host->dma_rx);
608 if (!IS_ERR(ptr: host->dma_tx))
609 dma_release_channel(chan: host->dma_tx);
610error_clear:
611 host->dma_tx = host->dma_rx = NULL;
612 return err;
613}
614
615static void atmel_spi_stop_dma(struct spi_controller *host)
616{
617 if (host->dma_rx)
618 dmaengine_terminate_all(chan: host->dma_rx);
619 if (host->dma_tx)
620 dmaengine_terminate_all(chan: host->dma_tx);
621}
622
623static void atmel_spi_release_dma(struct spi_controller *host)
624{
625 if (host->dma_rx) {
626 dma_release_channel(chan: host->dma_rx);
627 host->dma_rx = NULL;
628 }
629 if (host->dma_tx) {
630 dma_release_channel(chan: host->dma_tx);
631 host->dma_tx = NULL;
632 }
633}
634
635/* This function is called by the DMA driver from tasklet context */
636static void dma_callback(void *data)
637{
638 struct spi_controller *host = data;
639 struct atmel_spi *as = spi_controller_get_devdata(ctlr: host);
640
641 if (is_vmalloc_addr(x: as->current_transfer->rx_buf) &&
642 IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
643 memcpy(as->current_transfer->rx_buf, as->addr_rx_bbuf,
644 as->current_transfer->len);
645 }
646 complete(&as->xfer_completion);
647}
648
649/*
650 * Next transfer using PIO without FIFO.
651 */
652static void atmel_spi_next_xfer_single(struct spi_controller *host,
653 struct spi_transfer *xfer)
654{
655 struct atmel_spi *as = spi_controller_get_devdata(ctlr: host);
656 unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
657
658 dev_vdbg(host->dev.parent, "atmel_spi_next_xfer_pio\n");
659
660 /* Make sure data is not remaining in RDR */
661 spi_readl(as, RDR);
662 while (spi_readl(as, SR) & SPI_BIT(RDRF)) {
663 spi_readl(as, RDR);
664 cpu_relax();
665 }
666
667 if (xfer->bits_per_word > 8)
668 spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
669 else
670 spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));
671
672 dev_dbg(host->dev.parent,
673 " start pio xfer %p: len %u tx %p rx %p bitpw %d\n",
674 xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
675 xfer->bits_per_word);
676
677 /* Enable relevant interrupts */
678 spi_writel(as, IER, SPI_BIT(RDRF) | SPI_BIT(OVRES));
679}
680
681/*
682 * Next transfer using PIO with FIFO.
683 */
684static void atmel_spi_next_xfer_fifo(struct spi_controller *host,
685 struct spi_transfer *xfer)
686{
687 struct atmel_spi *as = spi_controller_get_devdata(ctlr: host);
688 u32 current_remaining_data, num_data;
689 u32 offset = xfer->len - as->current_remaining_bytes;
690 const u16 *words = (const u16 *)((u8 *)xfer->tx_buf + offset);
691 const u8 *bytes = (const u8 *)((u8 *)xfer->tx_buf + offset);
692 u16 td0, td1;
693 u32 fifomr;
694
695 dev_vdbg(host->dev.parent, "atmel_spi_next_xfer_fifo\n");
696
697 /* Compute the number of data to transfer in the current iteration */
698 current_remaining_data = ((xfer->bits_per_word > 8) ?
699 ((u32)as->current_remaining_bytes >> 1) :
700 (u32)as->current_remaining_bytes);
701 num_data = min(current_remaining_data, as->fifo_size);
702
703 /* Flush RX and TX FIFOs */
704 spi_writel(as, CR, SPI_BIT(RXFCLR) | SPI_BIT(TXFCLR));
705 while (spi_readl(as, FLR))
706 cpu_relax();
707
708 /* Set RX FIFO Threshold to the number of data to transfer */
709 fifomr = spi_readl(as, FMR);
710 spi_writel(as, FMR, SPI_BFINS(RXFTHRES, num_data, fifomr));
711
712 /* Clear FIFO flags in the Status Register, especially RXFTHF */
713 (void)spi_readl(as, SR);
714
715 /* Fill TX FIFO */
716 while (num_data >= 2) {
717 if (xfer->bits_per_word > 8) {
718 td0 = *words++;
719 td1 = *words++;
720 } else {
721 td0 = *bytes++;
722 td1 = *bytes++;
723 }
724
725 spi_writel(as, TDR, (td1 << 16) | td0);
726 num_data -= 2;
727 }
728
729 if (num_data) {
730 if (xfer->bits_per_word > 8)
731 td0 = *words++;
732 else
733 td0 = *bytes++;
734
735 spi_writew(as, TDR, td0);
736 num_data--;
737 }
738
739 dev_dbg(host->dev.parent,
740 " start fifo xfer %p: len %u tx %p rx %p bitpw %d\n",
741 xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
742 xfer->bits_per_word);
743
744 /*
745 * Enable RX FIFO Threshold Flag interrupt to be notified about
746 * transfer completion.
747 */
748 spi_writel(as, IER, SPI_BIT(RXFTHF) | SPI_BIT(OVRES));
749}
750
751/*
752 * Next transfer using PIO.
753 */
754static void atmel_spi_next_xfer_pio(struct spi_controller *host,
755 struct spi_transfer *xfer)
756{
757 struct atmel_spi *as = spi_controller_get_devdata(ctlr: host);
758
759 if (as->fifo_size)
760 atmel_spi_next_xfer_fifo(host, xfer);
761 else
762 atmel_spi_next_xfer_single(host, xfer);
763}
764
765/*
766 * Submit next transfer for DMA.
767 */
768static int atmel_spi_next_xfer_dma_submit(struct spi_controller *host,
769 struct spi_transfer *xfer,
770 u32 *plen)
771{
772 struct atmel_spi *as = spi_controller_get_devdata(ctlr: host);
773 struct dma_chan *rxchan = host->dma_rx;
774 struct dma_chan *txchan = host->dma_tx;
775 struct dma_async_tx_descriptor *rxdesc;
776 struct dma_async_tx_descriptor *txdesc;
777 dma_cookie_t cookie;
778
779 dev_vdbg(host->dev.parent, "atmel_spi_next_xfer_dma_submit\n");
780
781 /* Check that the channels are available */
782 if (!rxchan || !txchan)
783 return -ENODEV;
784
785
786 *plen = xfer->len;
787
788 if (atmel_spi_dma_slave_config(as, bits_per_word: xfer->bits_per_word))
789 goto err_exit;
790
791 /* Send both scatterlists */
792 if (atmel_spi_is_vmalloc_xfer(xfer) &&
793 IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
794 rxdesc = dmaengine_prep_slave_single(chan: rxchan,
795 buf: as->dma_addr_rx_bbuf,
796 len: xfer->len,
797 dir: DMA_DEV_TO_MEM,
798 flags: DMA_PREP_INTERRUPT |
799 DMA_CTRL_ACK);
800 } else {
801 rxdesc = dmaengine_prep_slave_sg(chan: rxchan,
802 sgl: xfer->rx_sg.sgl,
803 sg_len: xfer->rx_sg.nents,
804 dir: DMA_DEV_TO_MEM,
805 flags: DMA_PREP_INTERRUPT |
806 DMA_CTRL_ACK);
807 }
808 if (!rxdesc)
809 goto err_dma;
810
811 if (atmel_spi_is_vmalloc_xfer(xfer) &&
812 IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
813 memcpy(as->addr_tx_bbuf, xfer->tx_buf, xfer->len);
814 txdesc = dmaengine_prep_slave_single(chan: txchan,
815 buf: as->dma_addr_tx_bbuf,
816 len: xfer->len, dir: DMA_MEM_TO_DEV,
817 flags: DMA_PREP_INTERRUPT |
818 DMA_CTRL_ACK);
819 } else {
820 txdesc = dmaengine_prep_slave_sg(chan: txchan,
821 sgl: xfer->tx_sg.sgl,
822 sg_len: xfer->tx_sg.nents,
823 dir: DMA_MEM_TO_DEV,
824 flags: DMA_PREP_INTERRUPT |
825 DMA_CTRL_ACK);
826 }
827 if (!txdesc)
828 goto err_dma;
829
830 dev_dbg(host->dev.parent,
831 " start dma xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
832 xfer, xfer->len, xfer->tx_buf, (unsigned long long)xfer->tx_dma,
833 xfer->rx_buf, (unsigned long long)xfer->rx_dma);
834
835 /* Enable relevant interrupts */
836 spi_writel(as, IER, SPI_BIT(OVRES));
837
838 /* Put the callback on the RX transfer only, that should finish last */
839 rxdesc->callback = dma_callback;
840 rxdesc->callback_param = host;
841
842 /* Submit and fire RX and TX with TX last so we're ready to read! */
843 cookie = rxdesc->tx_submit(rxdesc);
844 if (dma_submit_error(cookie))
845 goto err_dma;
846 cookie = txdesc->tx_submit(txdesc);
847 if (dma_submit_error(cookie))
848 goto err_dma;
849 rxchan->device->device_issue_pending(rxchan);
850 txchan->device->device_issue_pending(txchan);
851
852 return 0;
853
854err_dma:
855 spi_writel(as, IDR, SPI_BIT(OVRES));
856 atmel_spi_stop_dma(host);
857err_exit:
858 return -ENOMEM;
859}
860
861static void atmel_spi_next_xfer_data(struct spi_controller *host,
862 struct spi_transfer *xfer,
863 dma_addr_t *tx_dma,
864 dma_addr_t *rx_dma,
865 u32 *plen)
866{
867 *rx_dma = xfer->rx_dma + xfer->len - *plen;
868 *tx_dma = xfer->tx_dma + xfer->len - *plen;
869 if (*plen > host->max_dma_len)
870 *plen = host->max_dma_len;
871}
872
873static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
874 struct spi_device *spi,
875 struct spi_transfer *xfer)
876{
877 u32 scbr, csr;
878 unsigned long bus_hz;
879 int chip_select;
880
881 if (spi_get_csgpiod(spi, idx: 0))
882 chip_select = as->native_cs_for_gpio;
883 else
884 chip_select = spi_get_chipselect(spi, idx: 0);
885
886 /* v1 chips start out at half the peripheral bus speed. */
887 bus_hz = as->spi_clk;
888 if (!atmel_spi_is_v2(as))
889 bus_hz /= 2;
890
891 /*
892 * Calculate the lowest divider that satisfies the
893 * constraint, assuming div32/fdiv/mbz == 0.
894 */
895 scbr = DIV_ROUND_UP(bus_hz, xfer->speed_hz);
896
897 /*
898 * If the resulting divider doesn't fit into the
899 * register bitfield, we can't satisfy the constraint.
900 */
901 if (scbr >= (1 << SPI_SCBR_SIZE)) {
902 dev_err(&spi->dev,
903 "setup: %d Hz too slow, scbr %u; min %ld Hz\n",
904 xfer->speed_hz, scbr, bus_hz/255);
905 return -EINVAL;
906 }
907 if (scbr == 0) {
908 dev_err(&spi->dev,
909 "setup: %d Hz too high, scbr %u; max %ld Hz\n",
910 xfer->speed_hz, scbr, bus_hz);
911 return -EINVAL;
912 }
913 csr = spi_readl(as, CSR0 + 4 * chip_select);
914 csr = SPI_BFINS(SCBR, scbr, csr);
915 spi_writel(as, CSR0 + 4 * chip_select, csr);
916 xfer->effective_speed_hz = bus_hz / scbr;
917
918 return 0;
919}
920
921/*
922 * Submit next transfer for PDC.
923 * lock is held, spi irq is blocked
924 */
925static void atmel_spi_pdc_next_xfer(struct spi_controller *host,
926 struct spi_transfer *xfer)
927{
928 struct atmel_spi *as = spi_controller_get_devdata(ctlr: host);
929 u32 len;
930 dma_addr_t tx_dma, rx_dma;
931
932 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
933
934 len = as->current_remaining_bytes;
935 atmel_spi_next_xfer_data(host, xfer, tx_dma: &tx_dma, rx_dma: &rx_dma, plen: &len);
936 as->current_remaining_bytes -= len;
937
938 spi_writel(as, RPR, rx_dma);
939 spi_writel(as, TPR, tx_dma);
940
941 if (xfer->bits_per_word > 8)
942 len >>= 1;
943 spi_writel(as, RCR, len);
944 spi_writel(as, TCR, len);
945
946 dev_dbg(&host->dev,
947 " start xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
948 xfer, xfer->len, xfer->tx_buf,
949 (unsigned long long)xfer->tx_dma, xfer->rx_buf,
950 (unsigned long long)xfer->rx_dma);
951
952 if (as->current_remaining_bytes) {
953 len = as->current_remaining_bytes;
954 atmel_spi_next_xfer_data(host, xfer, tx_dma: &tx_dma, rx_dma: &rx_dma, plen: &len);
955 as->current_remaining_bytes -= len;
956
957 spi_writel(as, RNPR, rx_dma);
958 spi_writel(as, TNPR, tx_dma);
959
960 if (xfer->bits_per_word > 8)
961 len >>= 1;
962 spi_writel(as, RNCR, len);
963 spi_writel(as, TNCR, len);
964
965 dev_dbg(&host->dev,
966 " next xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
967 xfer, xfer->len, xfer->tx_buf,
968 (unsigned long long)xfer->tx_dma, xfer->rx_buf,
969 (unsigned long long)xfer->rx_dma);
970 }
971
972 /* REVISIT: We're waiting for RXBUFF before we start the next
973 * transfer because we need to handle some difficult timing
974 * issues otherwise. If we wait for TXBUFE in one transfer and
975 * then starts waiting for RXBUFF in the next, it's difficult
976 * to tell the difference between the RXBUFF interrupt we're
977 * actually waiting for and the RXBUFF interrupt of the
978 * previous transfer.
979 *
980 * It should be doable, though. Just not now...
981 */
982 spi_writel(as, IER, SPI_BIT(RXBUFF) | SPI_BIT(OVRES));
983 spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
984}
985
986/*
987 * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
988 * - The buffer is either valid for CPU access, else NULL
989 * - If the buffer is valid, so is its DMA address
990 *
991 * This driver manages the dma address unless message->is_dma_mapped.
992 */
993static int
994atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
995{
996 struct device *dev = &as->pdev->dev;
997
998 xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
999 if (xfer->tx_buf) {
1000 /* tx_buf is a const void* where we need a void * for the dma
1001 * mapping */
1002 void *nonconst_tx = (void *)xfer->tx_buf;
1003
1004 xfer->tx_dma = dma_map_single(dev,
1005 nonconst_tx, xfer->len,
1006 DMA_TO_DEVICE);
1007 if (dma_mapping_error(dev, dma_addr: xfer->tx_dma))
1008 return -ENOMEM;
1009 }
1010 if (xfer->rx_buf) {
1011 xfer->rx_dma = dma_map_single(dev,
1012 xfer->rx_buf, xfer->len,
1013 DMA_FROM_DEVICE);
1014 if (dma_mapping_error(dev, dma_addr: xfer->rx_dma)) {
1015 if (xfer->tx_buf)
1016 dma_unmap_single(dev,
1017 xfer->tx_dma, xfer->len,
1018 DMA_TO_DEVICE);
1019 return -ENOMEM;
1020 }
1021 }
1022 return 0;
1023}
1024
1025static void atmel_spi_dma_unmap_xfer(struct spi_controller *host,
1026 struct spi_transfer *xfer)
1027{
1028 if (xfer->tx_dma != INVALID_DMA_ADDRESS)
1029 dma_unmap_single(host->dev.parent, xfer->tx_dma,
1030 xfer->len, DMA_TO_DEVICE);
1031 if (xfer->rx_dma != INVALID_DMA_ADDRESS)
1032 dma_unmap_single(host->dev.parent, xfer->rx_dma,
1033 xfer->len, DMA_FROM_DEVICE);
1034}
1035
1036static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as)
1037{
1038 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
1039}
1040
1041static void
1042atmel_spi_pump_single_data(struct atmel_spi *as, struct spi_transfer *xfer)
1043{
1044 u8 *rxp;
1045 u16 *rxp16;
1046 unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
1047
1048 if (xfer->bits_per_word > 8) {
1049 rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
1050 *rxp16 = spi_readl(as, RDR);
1051 } else {
1052 rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
1053 *rxp = spi_readl(as, RDR);
1054 }
1055 if (xfer->bits_per_word > 8) {
1056 if (as->current_remaining_bytes > 2)
1057 as->current_remaining_bytes -= 2;
1058 else
1059 as->current_remaining_bytes = 0;
1060 } else {
1061 as->current_remaining_bytes--;
1062 }
1063}
1064
1065static void
1066atmel_spi_pump_fifo_data(struct atmel_spi *as, struct spi_transfer *xfer)
1067{
1068 u32 fifolr = spi_readl(as, FLR);
1069 u32 num_bytes, num_data = SPI_BFEXT(RXFL, fifolr);
1070 u32 offset = xfer->len - as->current_remaining_bytes;
1071 u16 *words = (u16 *)((u8 *)xfer->rx_buf + offset);
1072 u8 *bytes = (u8 *)((u8 *)xfer->rx_buf + offset);
1073 u16 rd; /* RD field is the lowest 16 bits of RDR */
1074
1075 /* Update the number of remaining bytes to transfer */
1076 num_bytes = ((xfer->bits_per_word > 8) ?
1077 (num_data << 1) :
1078 num_data);
1079
1080 if (as->current_remaining_bytes > num_bytes)
1081 as->current_remaining_bytes -= num_bytes;
1082 else
1083 as->current_remaining_bytes = 0;
1084
1085 /* Handle odd number of bytes when data are more than 8bit width */
1086 if (xfer->bits_per_word > 8)
1087 as->current_remaining_bytes &= ~0x1;
1088
1089 /* Read data */
1090 while (num_data) {
1091 rd = spi_readl(as, RDR);
1092 if (xfer->bits_per_word > 8)
1093 *words++ = rd;
1094 else
1095 *bytes++ = rd;
1096 num_data--;
1097 }
1098}
1099
1100/* Called from IRQ
1101 *
1102 * Must update "current_remaining_bytes" to keep track of data
1103 * to transfer.
1104 */
1105static void
1106atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
1107{
1108 if (as->fifo_size)
1109 atmel_spi_pump_fifo_data(as, xfer);
1110 else
1111 atmel_spi_pump_single_data(as, xfer);
1112}
1113
1114/* Interrupt
1115 *
1116 */
1117static irqreturn_t
1118atmel_spi_pio_interrupt(int irq, void *dev_id)
1119{
1120 struct spi_controller *host = dev_id;
1121 struct atmel_spi *as = spi_controller_get_devdata(ctlr: host);
1122 u32 status, pending, imr;
1123 struct spi_transfer *xfer;
1124 int ret = IRQ_NONE;
1125
1126 imr = spi_readl(as, IMR);
1127 status = spi_readl(as, SR);
1128 pending = status & imr;
1129
1130 if (pending & SPI_BIT(OVRES)) {
1131 ret = IRQ_HANDLED;
1132 spi_writel(as, IDR, SPI_BIT(OVRES));
1133 dev_warn(host->dev.parent, "overrun\n");
1134
1135 /*
1136 * When we get an overrun, we disregard the current
1137 * transfer. Data will not be copied back from any
1138 * bounce buffer and msg->actual_len will not be
1139 * updated with the last xfer.
1140 *
1141 * We will also not process any remaning transfers in
1142 * the message.
1143 */
1144 as->done_status = -EIO;
1145 smp_wmb();
1146
1147 /* Clear any overrun happening while cleaning up */
1148 spi_readl(as, SR);
1149
1150 complete(&as->xfer_completion);
1151
1152 } else if (pending & (SPI_BIT(RDRF) | SPI_BIT(RXFTHF))) {
1153 atmel_spi_lock(as);
1154
1155 if (as->current_remaining_bytes) {
1156 ret = IRQ_HANDLED;
1157 xfer = as->current_transfer;
1158 atmel_spi_pump_pio_data(as, xfer);
1159 if (!as->current_remaining_bytes)
1160 spi_writel(as, IDR, pending);
1161
1162 complete(&as->xfer_completion);
1163 }
1164
1165 atmel_spi_unlock(as);
1166 } else {
1167 WARN_ONCE(pending, "IRQ not handled, pending = %x\n", pending);
1168 ret = IRQ_HANDLED;
1169 spi_writel(as, IDR, pending);
1170 }
1171
1172 return ret;
1173}
1174
1175static irqreturn_t
1176atmel_spi_pdc_interrupt(int irq, void *dev_id)
1177{
1178 struct spi_controller *host = dev_id;
1179 struct atmel_spi *as = spi_controller_get_devdata(ctlr: host);
1180 u32 status, pending, imr;
1181 int ret = IRQ_NONE;
1182
1183 imr = spi_readl(as, IMR);
1184 status = spi_readl(as, SR);
1185 pending = status & imr;
1186
1187 if (pending & SPI_BIT(OVRES)) {
1188
1189 ret = IRQ_HANDLED;
1190
1191 spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
1192 | SPI_BIT(OVRES)));
1193
1194 /* Clear any overrun happening while cleaning up */
1195 spi_readl(as, SR);
1196
1197 as->done_status = -EIO;
1198
1199 complete(&as->xfer_completion);
1200
1201 } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
1202 ret = IRQ_HANDLED;
1203
1204 spi_writel(as, IDR, pending);
1205
1206 complete(&as->xfer_completion);
1207 }
1208
1209 return ret;
1210}
1211
1212static int atmel_word_delay_csr(struct spi_device *spi, struct atmel_spi *as)
1213{
1214 struct spi_delay *delay = &spi->word_delay;
1215 u32 value = delay->value;
1216
1217 switch (delay->unit) {
1218 case SPI_DELAY_UNIT_NSECS:
1219 value /= 1000;
1220 break;
1221 case SPI_DELAY_UNIT_USECS:
1222 break;
1223 default:
1224 return -EINVAL;
1225 }
1226
1227 return (as->spi_clk / 1000000 * value) >> 5;
1228}
1229
1230static void initialize_native_cs_for_gpio(struct atmel_spi *as)
1231{
1232 int i;
1233 struct spi_controller *host = platform_get_drvdata(pdev: as->pdev);
1234
1235 if (!as->native_cs_free)
1236 return; /* already initialized */
1237
1238 if (!host->cs_gpiods)
1239 return; /* No CS GPIO */
1240
1241 /*
1242 * On the first version of the controller (AT91RM9200), CS0
1243 * can't be used associated with GPIO
1244 */
1245 if (atmel_spi_is_v2(as))
1246 i = 0;
1247 else
1248 i = 1;
1249
1250 for (; i < 4; i++)
1251 if (host->cs_gpiods[i])
1252 as->native_cs_free |= BIT(i);
1253
1254 if (as->native_cs_free)
1255 as->native_cs_for_gpio = ffs(as->native_cs_free);
1256}
1257
1258static int atmel_spi_setup(struct spi_device *spi)
1259{
1260 struct atmel_spi *as;
1261 struct atmel_spi_device *asd;
1262 u32 csr;
1263 unsigned int bits = spi->bits_per_word;
1264 int chip_select;
1265 int word_delay_csr;
1266
1267 as = spi_controller_get_devdata(ctlr: spi->controller);
1268
1269 /* see notes above re chipselect */
1270 if (!spi_get_csgpiod(spi, idx: 0) && (spi->mode & SPI_CS_HIGH)) {
1271 dev_warn(&spi->dev, "setup: non GPIO CS can't be active-high\n");
1272 return -EINVAL;
1273 }
1274
1275 /* Setup() is called during spi_register_controller(aka
1276 * spi_register_master) but after all membmers of the cs_gpiod
1277 * array have been filled, so we can looked for which native
1278 * CS will be free for using with GPIO
1279 */
1280 initialize_native_cs_for_gpio(as);
1281
1282 if (spi_get_csgpiod(spi, idx: 0) && as->native_cs_free) {
1283 dev_err(&spi->dev,
1284 "No native CS available to support this GPIO CS\n");
1285 return -EBUSY;
1286 }
1287
1288 if (spi_get_csgpiod(spi, idx: 0))
1289 chip_select = as->native_cs_for_gpio;
1290 else
1291 chip_select = spi_get_chipselect(spi, idx: 0);
1292
1293 csr = SPI_BF(BITS, bits - 8);
1294 if (spi->mode & SPI_CPOL)
1295 csr |= SPI_BIT(CPOL);
1296 if (!(spi->mode & SPI_CPHA))
1297 csr |= SPI_BIT(NCPHA);
1298
1299 if (!spi_get_csgpiod(spi, idx: 0))
1300 csr |= SPI_BIT(CSAAT);
1301 csr |= SPI_BF(DLYBS, 0);
1302
1303 word_delay_csr = atmel_word_delay_csr(spi, as);
1304 if (word_delay_csr < 0)
1305 return word_delay_csr;
1306
1307 /* DLYBCT adds delays between words. This is useful for slow devices
1308 * that need a bit of time to setup the next transfer.
1309 */
1310 csr |= SPI_BF(DLYBCT, word_delay_csr);
1311
1312 asd = spi->controller_state;
1313 if (!asd) {
1314 asd = kzalloc(size: sizeof(struct atmel_spi_device), GFP_KERNEL);
1315 if (!asd)
1316 return -ENOMEM;
1317
1318 spi->controller_state = asd;
1319 }
1320
1321 asd->csr = csr;
1322
1323 dev_dbg(&spi->dev,
1324 "setup: bpw %u mode 0x%x -> csr%d %08x\n",
1325 bits, spi->mode, spi_get_chipselect(spi, 0), csr);
1326
1327 if (!atmel_spi_is_v2(as))
1328 spi_writel(as, CSR0 + 4 * chip_select, csr);
1329
1330 return 0;
1331}
1332
1333static void atmel_spi_set_cs(struct spi_device *spi, bool enable)
1334{
1335 struct atmel_spi *as = spi_controller_get_devdata(ctlr: spi->controller);
1336 /* the core doesn't really pass us enable/disable, but CS HIGH vs CS LOW
1337 * since we already have routines for activate/deactivate translate
1338 * high/low to active/inactive
1339 */
1340 enable = (!!(spi->mode & SPI_CS_HIGH) == enable);
1341
1342 if (enable) {
1343 cs_activate(as, spi);
1344 } else {
1345 cs_deactivate(as, spi);
1346 }
1347
1348}
1349
1350static int atmel_spi_one_transfer(struct spi_controller *host,
1351 struct spi_device *spi,
1352 struct spi_transfer *xfer)
1353{
1354 struct atmel_spi *as;
1355 u8 bits;
1356 u32 len;
1357 struct atmel_spi_device *asd;
1358 int timeout;
1359 int ret;
1360 unsigned int dma_timeout;
1361 long ret_timeout;
1362
1363 as = spi_controller_get_devdata(ctlr: host);
1364
1365 asd = spi->controller_state;
1366 bits = (asd->csr >> 4) & 0xf;
1367 if (bits != xfer->bits_per_word - 8) {
1368 dev_dbg(&spi->dev,
1369 "you can't yet change bits_per_word in transfers\n");
1370 return -ENOPROTOOPT;
1371 }
1372
1373 /*
1374 * DMA map early, for performance (empties dcache ASAP) and
1375 * better fault reporting.
1376 */
1377 if ((!host->cur_msg->is_dma_mapped)
1378 && as->use_pdc) {
1379 if (atmel_spi_dma_map_xfer(as, xfer) < 0)
1380 return -ENOMEM;
1381 }
1382
1383 atmel_spi_set_xfer_speed(as, spi, xfer);
1384
1385 as->done_status = 0;
1386 as->current_transfer = xfer;
1387 as->current_remaining_bytes = xfer->len;
1388 while (as->current_remaining_bytes) {
1389 reinit_completion(x: &as->xfer_completion);
1390
1391 if (as->use_pdc) {
1392 atmel_spi_lock(as);
1393 atmel_spi_pdc_next_xfer(host, xfer);
1394 atmel_spi_unlock(as);
1395 } else if (atmel_spi_use_dma(as, xfer)) {
1396 len = as->current_remaining_bytes;
1397 ret = atmel_spi_next_xfer_dma_submit(host,
1398 xfer, plen: &len);
1399 if (ret) {
1400 dev_err(&spi->dev,
1401 "unable to use DMA, fallback to PIO\n");
1402 as->done_status = ret;
1403 break;
1404 } else {
1405 as->current_remaining_bytes -= len;
1406 if (as->current_remaining_bytes < 0)
1407 as->current_remaining_bytes = 0;
1408 }
1409 } else {
1410 atmel_spi_lock(as);
1411 atmel_spi_next_xfer_pio(host, xfer);
1412 atmel_spi_unlock(as);
1413 }
1414
1415 dma_timeout = msecs_to_jiffies(m: spi_controller_xfer_timeout(ctlr: host, xfer));
1416 ret_timeout = wait_for_completion_timeout(x: &as->xfer_completion, timeout: dma_timeout);
1417 if (!ret_timeout) {
1418 dev_err(&spi->dev, "spi transfer timeout\n");
1419 as->done_status = -EIO;
1420 }
1421
1422 if (as->done_status)
1423 break;
1424 }
1425
1426 if (as->done_status) {
1427 if (as->use_pdc) {
1428 dev_warn(host->dev.parent,
1429 "overrun (%u/%u remaining)\n",
1430 spi_readl(as, TCR), spi_readl(as, RCR));
1431
1432 /*
1433 * Clean up DMA registers and make sure the data
1434 * registers are empty.
1435 */
1436 spi_writel(as, RNCR, 0);
1437 spi_writel(as, TNCR, 0);
1438 spi_writel(as, RCR, 0);
1439 spi_writel(as, TCR, 0);
1440 for (timeout = 1000; timeout; timeout--)
1441 if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
1442 break;
1443 if (!timeout)
1444 dev_warn(host->dev.parent,
1445 "timeout waiting for TXEMPTY");
1446 while (spi_readl(as, SR) & SPI_BIT(RDRF))
1447 spi_readl(as, RDR);
1448
1449 /* Clear any overrun happening while cleaning up */
1450 spi_readl(as, SR);
1451
1452 } else if (atmel_spi_use_dma(as, xfer)) {
1453 atmel_spi_stop_dma(host);
1454 }
1455 }
1456
1457 if (!host->cur_msg->is_dma_mapped
1458 && as->use_pdc)
1459 atmel_spi_dma_unmap_xfer(host, xfer);
1460
1461 if (as->use_pdc)
1462 atmel_spi_disable_pdc_transfer(as);
1463
1464 return as->done_status;
1465}
1466
1467static void atmel_spi_cleanup(struct spi_device *spi)
1468{
1469 struct atmel_spi_device *asd = spi->controller_state;
1470
1471 if (!asd)
1472 return;
1473
1474 spi->controller_state = NULL;
1475 kfree(objp: asd);
1476}
1477
1478static inline unsigned int atmel_get_version(struct atmel_spi *as)
1479{
1480 return spi_readl(as, VERSION) & 0x00000fff;
1481}
1482
1483static void atmel_get_caps(struct atmel_spi *as)
1484{
1485 unsigned int version;
1486
1487 version = atmel_get_version(as);
1488
1489 as->caps.is_spi2 = version > 0x121;
1490 as->caps.has_wdrbt = version >= 0x210;
1491 as->caps.has_dma_support = version >= 0x212;
1492 as->caps.has_pdc_support = version < 0x212;
1493}
1494
1495static void atmel_spi_init(struct atmel_spi *as)
1496{
1497 spi_writel(as, CR, SPI_BIT(SWRST));
1498 spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1499
1500 /* It is recommended to enable FIFOs first thing after reset */
1501 if (as->fifo_size)
1502 spi_writel(as, CR, SPI_BIT(FIFOEN));
1503
1504 if (as->caps.has_wdrbt) {
1505 spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
1506 | SPI_BIT(MSTR));
1507 } else {
1508 spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
1509 }
1510
1511 if (as->use_pdc)
1512 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
1513 spi_writel(as, CR, SPI_BIT(SPIEN));
1514}
1515
1516static int atmel_spi_probe(struct platform_device *pdev)
1517{
1518 struct resource *regs;
1519 int irq;
1520 struct clk *clk;
1521 int ret;
1522 struct spi_controller *host;
1523 struct atmel_spi *as;
1524
1525 /* Select default pin state */
1526 pinctrl_pm_select_default_state(dev: &pdev->dev);
1527
1528 irq = platform_get_irq(pdev, 0);
1529 if (irq < 0)
1530 return irq;
1531
1532 clk = devm_clk_get(dev: &pdev->dev, id: "spi_clk");
1533 if (IS_ERR(ptr: clk))
1534 return PTR_ERR(ptr: clk);
1535
1536 /* setup spi core then atmel-specific driver state */
1537 host = spi_alloc_host(dev: &pdev->dev, size: sizeof(*as));
1538 if (!host)
1539 return -ENOMEM;
1540
1541 /* the spi->mode bits understood by this driver: */
1542 host->use_gpio_descriptors = true;
1543 host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
1544 host->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
1545 host->dev.of_node = pdev->dev.of_node;
1546 host->bus_num = pdev->id;
1547 host->num_chipselect = 4;
1548 host->setup = atmel_spi_setup;
1549 host->flags = (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX |
1550 SPI_CONTROLLER_GPIO_SS);
1551 host->transfer_one = atmel_spi_one_transfer;
1552 host->set_cs = atmel_spi_set_cs;
1553 host->cleanup = atmel_spi_cleanup;
1554 host->auto_runtime_pm = true;
1555 host->max_dma_len = SPI_MAX_DMA_XFER;
1556 host->can_dma = atmel_spi_can_dma;
1557 platform_set_drvdata(pdev, data: host);
1558
1559 as = spi_controller_get_devdata(ctlr: host);
1560
1561 spin_lock_init(&as->lock);
1562
1563 as->pdev = pdev;
1564 as->regs = devm_platform_get_and_ioremap_resource(pdev, index: 0, res: &regs);
1565 if (IS_ERR(ptr: as->regs)) {
1566 ret = PTR_ERR(ptr: as->regs);
1567 goto out_unmap_regs;
1568 }
1569 as->phybase = regs->start;
1570 as->irq = irq;
1571 as->clk = clk;
1572
1573 init_completion(x: &as->xfer_completion);
1574
1575 atmel_get_caps(as);
1576
1577 as->use_dma = false;
1578 as->use_pdc = false;
1579 if (as->caps.has_dma_support) {
1580 ret = atmel_spi_configure_dma(host, as);
1581 if (ret == 0) {
1582 as->use_dma = true;
1583 } else if (ret == -EPROBE_DEFER) {
1584 goto out_unmap_regs;
1585 }
1586 } else if (as->caps.has_pdc_support) {
1587 as->use_pdc = true;
1588 }
1589
1590 if (IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
1591 as->addr_rx_bbuf = dma_alloc_coherent(dev: &pdev->dev,
1592 SPI_MAX_DMA_XFER,
1593 dma_handle: &as->dma_addr_rx_bbuf,
1594 GFP_KERNEL | GFP_DMA);
1595 if (!as->addr_rx_bbuf) {
1596 as->use_dma = false;
1597 } else {
1598 as->addr_tx_bbuf = dma_alloc_coherent(dev: &pdev->dev,
1599 SPI_MAX_DMA_XFER,
1600 dma_handle: &as->dma_addr_tx_bbuf,
1601 GFP_KERNEL | GFP_DMA);
1602 if (!as->addr_tx_bbuf) {
1603 as->use_dma = false;
1604 dma_free_coherent(dev: &pdev->dev, SPI_MAX_DMA_XFER,
1605 cpu_addr: as->addr_rx_bbuf,
1606 dma_handle: as->dma_addr_rx_bbuf);
1607 }
1608 }
1609 if (!as->use_dma)
1610 dev_info(host->dev.parent,
1611 " can not allocate dma coherent memory\n");
1612 }
1613
1614 if (as->caps.has_dma_support && !as->use_dma)
1615 dev_info(&pdev->dev, "Atmel SPI Controller using PIO only\n");
1616
1617 if (as->use_pdc) {
1618 ret = devm_request_irq(dev: &pdev->dev, irq, handler: atmel_spi_pdc_interrupt,
1619 irqflags: 0, devname: dev_name(dev: &pdev->dev), dev_id: host);
1620 } else {
1621 ret = devm_request_irq(dev: &pdev->dev, irq, handler: atmel_spi_pio_interrupt,
1622 irqflags: 0, devname: dev_name(dev: &pdev->dev), dev_id: host);
1623 }
1624 if (ret)
1625 goto out_unmap_regs;
1626
1627 /* Initialize the hardware */
1628 ret = clk_prepare_enable(clk);
1629 if (ret)
1630 goto out_free_irq;
1631
1632 as->spi_clk = clk_get_rate(clk);
1633
1634 as->fifo_size = 0;
1635 if (!of_property_read_u32(np: pdev->dev.of_node, propname: "atmel,fifo-size",
1636 out_value: &as->fifo_size)) {
1637 dev_info(&pdev->dev, "Using FIFO (%u data)\n", as->fifo_size);
1638 }
1639
1640 atmel_spi_init(as);
1641
1642 pm_runtime_set_autosuspend_delay(dev: &pdev->dev, AUTOSUSPEND_TIMEOUT);
1643 pm_runtime_use_autosuspend(dev: &pdev->dev);
1644 pm_runtime_set_active(dev: &pdev->dev);
1645 pm_runtime_enable(dev: &pdev->dev);
1646
1647 ret = devm_spi_register_controller(dev: &pdev->dev, ctlr: host);
1648 if (ret)
1649 goto out_free_dma;
1650
1651 /* go! */
1652 dev_info(&pdev->dev, "Atmel SPI Controller version 0x%x at 0x%08lx (irq %d)\n",
1653 atmel_get_version(as), (unsigned long)regs->start,
1654 irq);
1655
1656 return 0;
1657
1658out_free_dma:
1659 pm_runtime_disable(dev: &pdev->dev);
1660 pm_runtime_set_suspended(dev: &pdev->dev);
1661
1662 if (as->use_dma)
1663 atmel_spi_release_dma(host);
1664
1665 spi_writel(as, CR, SPI_BIT(SWRST));
1666 spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1667 clk_disable_unprepare(clk);
1668out_free_irq:
1669out_unmap_regs:
1670 spi_controller_put(ctlr: host);
1671 return ret;
1672}
1673
1674static void atmel_spi_remove(struct platform_device *pdev)
1675{
1676 struct spi_controller *host = platform_get_drvdata(pdev);
1677 struct atmel_spi *as = spi_controller_get_devdata(ctlr: host);
1678
1679 pm_runtime_get_sync(dev: &pdev->dev);
1680
1681 /* reset the hardware and block queue progress */
1682 if (as->use_dma) {
1683 atmel_spi_stop_dma(host);
1684 atmel_spi_release_dma(host);
1685 if (IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
1686 dma_free_coherent(dev: &pdev->dev, SPI_MAX_DMA_XFER,
1687 cpu_addr: as->addr_tx_bbuf,
1688 dma_handle: as->dma_addr_tx_bbuf);
1689 dma_free_coherent(dev: &pdev->dev, SPI_MAX_DMA_XFER,
1690 cpu_addr: as->addr_rx_bbuf,
1691 dma_handle: as->dma_addr_rx_bbuf);
1692 }
1693 }
1694
1695 spin_lock_irq(lock: &as->lock);
1696 spi_writel(as, CR, SPI_BIT(SWRST));
1697 spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1698 spi_readl(as, SR);
1699 spin_unlock_irq(lock: &as->lock);
1700
1701 clk_disable_unprepare(clk: as->clk);
1702
1703 pm_runtime_put_noidle(dev: &pdev->dev);
1704 pm_runtime_disable(dev: &pdev->dev);
1705}
1706
1707static int atmel_spi_runtime_suspend(struct device *dev)
1708{
1709 struct spi_controller *host = dev_get_drvdata(dev);
1710 struct atmel_spi *as = spi_controller_get_devdata(ctlr: host);
1711
1712 clk_disable_unprepare(clk: as->clk);
1713 pinctrl_pm_select_sleep_state(dev);
1714
1715 return 0;
1716}
1717
1718static int atmel_spi_runtime_resume(struct device *dev)
1719{
1720 struct spi_controller *host = dev_get_drvdata(dev);
1721 struct atmel_spi *as = spi_controller_get_devdata(ctlr: host);
1722
1723 pinctrl_pm_select_default_state(dev);
1724
1725 return clk_prepare_enable(clk: as->clk);
1726}
1727
1728static int atmel_spi_suspend(struct device *dev)
1729{
1730 struct spi_controller *host = dev_get_drvdata(dev);
1731 int ret;
1732
1733 /* Stop the queue running */
1734 ret = spi_controller_suspend(ctlr: host);
1735 if (ret)
1736 return ret;
1737
1738 if (!pm_runtime_suspended(dev))
1739 atmel_spi_runtime_suspend(dev);
1740
1741 return 0;
1742}
1743
1744static int atmel_spi_resume(struct device *dev)
1745{
1746 struct spi_controller *host = dev_get_drvdata(dev);
1747 struct atmel_spi *as = spi_controller_get_devdata(ctlr: host);
1748 int ret;
1749
1750 ret = clk_prepare_enable(clk: as->clk);
1751 if (ret)
1752 return ret;
1753
1754 atmel_spi_init(as);
1755
1756 clk_disable_unprepare(clk: as->clk);
1757
1758 if (!pm_runtime_suspended(dev)) {
1759 ret = atmel_spi_runtime_resume(dev);
1760 if (ret)
1761 return ret;
1762 }
1763
1764 /* Start the queue running */
1765 return spi_controller_resume(ctlr: host);
1766}
1767
1768static const struct dev_pm_ops atmel_spi_pm_ops = {
1769 SYSTEM_SLEEP_PM_OPS(atmel_spi_suspend, atmel_spi_resume)
1770 RUNTIME_PM_OPS(atmel_spi_runtime_suspend,
1771 atmel_spi_runtime_resume, NULL)
1772};
1773
1774static const struct of_device_id atmel_spi_dt_ids[] = {
1775 { .compatible = "atmel,at91rm9200-spi" },
1776 { /* sentinel */ }
1777};
1778
1779MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids);
1780
1781static struct platform_driver atmel_spi_driver = {
1782 .driver = {
1783 .name = "atmel_spi",
1784 .pm = pm_ptr(&atmel_spi_pm_ops),
1785 .of_match_table = atmel_spi_dt_ids,
1786 },
1787 .probe = atmel_spi_probe,
1788 .remove_new = atmel_spi_remove,
1789};
1790module_platform_driver(atmel_spi_driver);
1791
1792MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
1793MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
1794MODULE_LICENSE("GPL");
1795MODULE_ALIAS("platform:atmel_spi");
1796

source code of linux/drivers/spi/spi-atmel.c