2 * Driver for Atmel AT32 and AT91 SPI Controllers
4 * Copyright (C) 2006 Atmel Corporation
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.
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/clk.h>
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/delay.h>
17 #include <linux/dma-mapping.h>
18 #include <linux/dmaengine.h>
19 #include <linux/err.h>
20 #include <linux/interrupt.h>
21 #include <linux/spi/spi.h>
22 #include <linux/slab.h>
23 #include <linux/platform_data/atmel.h>
24 #include <linux/platform_data/dma-atmel.h>
28 #include <linux/gpio.h>
29 #include <linux/pinctrl/consumer.h>
31 /* SPI register offsets */
34 #define SPI_RDR 0x0008
35 #define SPI_TDR 0x000c
37 #define SPI_IER 0x0014
38 #define SPI_IDR 0x0018
39 #define SPI_IMR 0x001c
40 #define SPI_CSR0 0x0030
41 #define SPI_CSR1 0x0034
42 #define SPI_CSR2 0x0038
43 #define SPI_CSR3 0x003c
44 #define SPI_VERSION 0x00fc
45 #define SPI_RPR 0x0100
46 #define SPI_RCR 0x0104
47 #define SPI_TPR 0x0108
48 #define SPI_TCR 0x010c
49 #define SPI_RNPR 0x0110
50 #define SPI_RNCR 0x0114
51 #define SPI_TNPR 0x0118
52 #define SPI_TNCR 0x011c
53 #define SPI_PTCR 0x0120
54 #define SPI_PTSR 0x0124
57 #define SPI_SPIEN_OFFSET 0
58 #define SPI_SPIEN_SIZE 1
59 #define SPI_SPIDIS_OFFSET 1
60 #define SPI_SPIDIS_SIZE 1
61 #define SPI_SWRST_OFFSET 7
62 #define SPI_SWRST_SIZE 1
63 #define SPI_LASTXFER_OFFSET 24
64 #define SPI_LASTXFER_SIZE 1
67 #define SPI_MSTR_OFFSET 0
68 #define SPI_MSTR_SIZE 1
69 #define SPI_PS_OFFSET 1
71 #define SPI_PCSDEC_OFFSET 2
72 #define SPI_PCSDEC_SIZE 1
73 #define SPI_FDIV_OFFSET 3
74 #define SPI_FDIV_SIZE 1
75 #define SPI_MODFDIS_OFFSET 4
76 #define SPI_MODFDIS_SIZE 1
77 #define SPI_WDRBT_OFFSET 5
78 #define SPI_WDRBT_SIZE 1
79 #define SPI_LLB_OFFSET 7
80 #define SPI_LLB_SIZE 1
81 #define SPI_PCS_OFFSET 16
82 #define SPI_PCS_SIZE 4
83 #define SPI_DLYBCS_OFFSET 24
84 #define SPI_DLYBCS_SIZE 8
86 /* Bitfields in RDR */
87 #define SPI_RD_OFFSET 0
88 #define SPI_RD_SIZE 16
90 /* Bitfields in TDR */
91 #define SPI_TD_OFFSET 0
92 #define SPI_TD_SIZE 16
95 #define SPI_RDRF_OFFSET 0
96 #define SPI_RDRF_SIZE 1
97 #define SPI_TDRE_OFFSET 1
98 #define SPI_TDRE_SIZE 1
99 #define SPI_MODF_OFFSET 2
100 #define SPI_MODF_SIZE 1
101 #define SPI_OVRES_OFFSET 3
102 #define SPI_OVRES_SIZE 1
103 #define SPI_ENDRX_OFFSET 4
104 #define SPI_ENDRX_SIZE 1
105 #define SPI_ENDTX_OFFSET 5
106 #define SPI_ENDTX_SIZE 1
107 #define SPI_RXBUFF_OFFSET 6
108 #define SPI_RXBUFF_SIZE 1
109 #define SPI_TXBUFE_OFFSET 7
110 #define SPI_TXBUFE_SIZE 1
111 #define SPI_NSSR_OFFSET 8
112 #define SPI_NSSR_SIZE 1
113 #define SPI_TXEMPTY_OFFSET 9
114 #define SPI_TXEMPTY_SIZE 1
115 #define SPI_SPIENS_OFFSET 16
116 #define SPI_SPIENS_SIZE 1
118 /* Bitfields in CSR0 */
119 #define SPI_CPOL_OFFSET 0
120 #define SPI_CPOL_SIZE 1
121 #define SPI_NCPHA_OFFSET 1
122 #define SPI_NCPHA_SIZE 1
123 #define SPI_CSAAT_OFFSET 3
124 #define SPI_CSAAT_SIZE 1
125 #define SPI_BITS_OFFSET 4
126 #define SPI_BITS_SIZE 4
127 #define SPI_SCBR_OFFSET 8
128 #define SPI_SCBR_SIZE 8
129 #define SPI_DLYBS_OFFSET 16
130 #define SPI_DLYBS_SIZE 8
131 #define SPI_DLYBCT_OFFSET 24
132 #define SPI_DLYBCT_SIZE 8
134 /* Bitfields in RCR */
135 #define SPI_RXCTR_OFFSET 0
136 #define SPI_RXCTR_SIZE 16
138 /* Bitfields in TCR */
139 #define SPI_TXCTR_OFFSET 0
140 #define SPI_TXCTR_SIZE 16
142 /* Bitfields in RNCR */
143 #define SPI_RXNCR_OFFSET 0
144 #define SPI_RXNCR_SIZE 16
146 /* Bitfields in TNCR */
147 #define SPI_TXNCR_OFFSET 0
148 #define SPI_TXNCR_SIZE 16
150 /* Bitfields in PTCR */
151 #define SPI_RXTEN_OFFSET 0
152 #define SPI_RXTEN_SIZE 1
153 #define SPI_RXTDIS_OFFSET 1
154 #define SPI_RXTDIS_SIZE 1
155 #define SPI_TXTEN_OFFSET 8
156 #define SPI_TXTEN_SIZE 1
157 #define SPI_TXTDIS_OFFSET 9
158 #define SPI_TXTDIS_SIZE 1
160 /* Constants for BITS */
161 #define SPI_BITS_8_BPT 0
162 #define SPI_BITS_9_BPT 1
163 #define SPI_BITS_10_BPT 2
164 #define SPI_BITS_11_BPT 3
165 #define SPI_BITS_12_BPT 4
166 #define SPI_BITS_13_BPT 5
167 #define SPI_BITS_14_BPT 6
168 #define SPI_BITS_15_BPT 7
169 #define SPI_BITS_16_BPT 8
171 /* Bit manipulation macros */
172 #define SPI_BIT(name) \
173 (1 << SPI_##name##_OFFSET)
174 #define SPI_BF(name, value) \
175 (((value) & ((1 << SPI_##name##_SIZE) - 1)) << SPI_##name##_OFFSET)
176 #define SPI_BFEXT(name, value) \
177 (((value) >> SPI_##name##_OFFSET) & ((1 << SPI_##name##_SIZE) - 1))
178 #define SPI_BFINS(name, value, old) \
179 (((old) & ~(((1 << SPI_##name##_SIZE) - 1) << SPI_##name##_OFFSET)) \
180 | SPI_BF(name, value))
182 /* Register access macros */
183 #define spi_readl(port, reg) \
184 __raw_readl((port)->regs + SPI_##reg)
185 #define spi_writel(port, reg, value) \
186 __raw_writel((value), (port)->regs + SPI_##reg)
188 /* use PIO for small transfers, avoiding DMA setup/teardown overhead and
189 * cache operations; better heuristics consider wordsize and bitrate.
191 #define DMA_MIN_BYTES 16
193 #define SPI_DMA_TIMEOUT (msecs_to_jiffies(1000))
195 struct atmel_spi_dma {
196 struct dma_chan *chan_rx;
197 struct dma_chan *chan_tx;
198 struct scatterlist sgrx;
199 struct scatterlist sgtx;
200 struct dma_async_tx_descriptor *data_desc_rx;
201 struct dma_async_tx_descriptor *data_desc_tx;
203 struct at_dma_slave dma_slave;
206 struct atmel_spi_caps {
209 bool has_dma_support;
213 * The core SPI transfer engine just talks to a register bank to set up
214 * DMA transfers; transfer queue progress is driven by IRQs. The clock
215 * framework provides the base clock, subdivided for each spi_device.
225 struct platform_device *pdev;
227 struct spi_transfer *current_transfer;
228 unsigned long current_remaining_bytes;
231 struct completion xfer_completion;
235 dma_addr_t buffer_dma;
237 struct atmel_spi_caps caps;
242 struct atmel_spi_dma dma;
248 /* Controller-specific per-slave state */
249 struct atmel_spi_device {
250 unsigned int npcs_pin;
254 #define BUFFER_SIZE PAGE_SIZE
255 #define INVALID_DMA_ADDRESS 0xffffffff
258 * Version 2 of the SPI controller has
260 * - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
261 * - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
263 * - SPI_CSRx.SBCR allows faster clocking
265 static bool atmel_spi_is_v2(struct atmel_spi *as)
267 return as->caps.is_spi2;
271 * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
272 * they assume that spi slave device state will not change on deselect, so
273 * that automagic deselection is OK. ("NPCSx rises if no data is to be
274 * transmitted") Not so! Workaround uses nCSx pins as GPIOs; or newer
275 * controllers have CSAAT and friends.
277 * Since the CSAAT functionality is a bit weird on newer controllers as
278 * well, we use GPIO to control nCSx pins on all controllers, updating
279 * MR.PCS to avoid confusing the controller. Using GPIOs also lets us
280 * support active-high chipselects despite the controller's belief that
281 * only active-low devices/systems exists.
283 * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
284 * right when driven with GPIO. ("Mode Fault does not allow more than one
285 * Master on Chip Select 0.") No workaround exists for that ... so for
286 * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
287 * and (c) will trigger that first erratum in some cases.
290 static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
292 struct atmel_spi_device *asd = spi->controller_state;
293 unsigned active = spi->mode & SPI_CS_HIGH;
296 if (atmel_spi_is_v2(as)) {
297 spi_writel(as, CSR0 + 4 * spi->chip_select, asd->csr);
298 /* For the low SPI version, there is a issue that PDC transfer
299 * on CS1,2,3 needs SPI_CSR0.BITS config as SPI_CSR1,2,3.BITS
301 spi_writel(as, CSR0, asd->csr);
302 if (as->caps.has_wdrbt) {
304 SPI_BF(PCS, ~(0x01 << spi->chip_select))
310 SPI_BF(PCS, ~(0x01 << spi->chip_select))
315 mr = spi_readl(as, MR);
316 gpio_set_value(asd->npcs_pin, active);
318 u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
322 /* Make sure clock polarity is correct */
323 for (i = 0; i < spi->master->num_chipselect; i++) {
324 csr = spi_readl(as, CSR0 + 4 * i);
325 if ((csr ^ cpol) & SPI_BIT(CPOL))
326 spi_writel(as, CSR0 + 4 * i,
327 csr ^ SPI_BIT(CPOL));
330 mr = spi_readl(as, MR);
331 mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
332 if (spi->chip_select != 0)
333 gpio_set_value(asd->npcs_pin, active);
334 spi_writel(as, MR, mr);
337 dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
338 asd->npcs_pin, active ? " (high)" : "",
342 static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
344 struct atmel_spi_device *asd = spi->controller_state;
345 unsigned active = spi->mode & SPI_CS_HIGH;
348 /* only deactivate *this* device; sometimes transfers to
349 * another device may be active when this routine is called.
351 mr = spi_readl(as, MR);
352 if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
353 mr = SPI_BFINS(PCS, 0xf, mr);
354 spi_writel(as, MR, mr);
357 dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
358 asd->npcs_pin, active ? " (low)" : "",
361 if (atmel_spi_is_v2(as) || spi->chip_select != 0)
362 gpio_set_value(asd->npcs_pin, !active);
365 static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock)
367 spin_lock_irqsave(&as->lock, as->flags);
370 static void atmel_spi_unlock(struct atmel_spi *as) __releases(&as->lock)
372 spin_unlock_irqrestore(&as->lock, as->flags);
375 static inline bool atmel_spi_use_dma(struct atmel_spi *as,
376 struct spi_transfer *xfer)
378 return as->use_dma && xfer->len >= DMA_MIN_BYTES;
381 static int atmel_spi_dma_slave_config(struct atmel_spi *as,
382 struct dma_slave_config *slave_config,
387 if (bits_per_word > 8) {
388 slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
389 slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
391 slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
392 slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
395 slave_config->dst_addr = (dma_addr_t)as->phybase + SPI_TDR;
396 slave_config->src_addr = (dma_addr_t)as->phybase + SPI_RDR;
397 slave_config->src_maxburst = 1;
398 slave_config->dst_maxburst = 1;
399 slave_config->device_fc = false;
401 slave_config->direction = DMA_MEM_TO_DEV;
402 if (dmaengine_slave_config(as->dma.chan_tx, slave_config)) {
403 dev_err(&as->pdev->dev,
404 "failed to configure tx dma channel\n");
408 slave_config->direction = DMA_DEV_TO_MEM;
409 if (dmaengine_slave_config(as->dma.chan_rx, slave_config)) {
410 dev_err(&as->pdev->dev,
411 "failed to configure rx dma channel\n");
418 static bool filter(struct dma_chan *chan, void *pdata)
420 struct atmel_spi_dma *sl_pdata = pdata;
421 struct at_dma_slave *sl;
426 sl = &sl_pdata->dma_slave;
427 if (sl->dma_dev == chan->device->dev) {
435 static int atmel_spi_configure_dma(struct atmel_spi *as)
437 struct dma_slave_config slave_config;
438 struct device *dev = &as->pdev->dev;
443 dma_cap_set(DMA_SLAVE, mask);
445 as->dma.chan_tx = dma_request_slave_channel_compat(mask, filter,
448 if (!as->dma.chan_tx) {
450 "DMA TX channel not available, SPI unable to use DMA\n");
455 as->dma.chan_rx = dma_request_slave_channel_compat(mask, filter,
459 if (!as->dma.chan_rx) {
461 "DMA RX channel not available, SPI unable to use DMA\n");
466 err = atmel_spi_dma_slave_config(as, &slave_config, 8);
470 dev_info(&as->pdev->dev,
471 "Using %s (tx) and %s (rx) for DMA transfers\n",
472 dma_chan_name(as->dma.chan_tx),
473 dma_chan_name(as->dma.chan_rx));
477 dma_release_channel(as->dma.chan_rx);
479 dma_release_channel(as->dma.chan_tx);
483 static void atmel_spi_stop_dma(struct atmel_spi *as)
486 as->dma.chan_rx->device->device_control(as->dma.chan_rx,
487 DMA_TERMINATE_ALL, 0);
489 as->dma.chan_tx->device->device_control(as->dma.chan_tx,
490 DMA_TERMINATE_ALL, 0);
493 static void atmel_spi_release_dma(struct atmel_spi *as)
496 dma_release_channel(as->dma.chan_rx);
498 dma_release_channel(as->dma.chan_tx);
501 /* This function is called by the DMA driver from tasklet context */
502 static void dma_callback(void *data)
504 struct spi_master *master = data;
505 struct atmel_spi *as = spi_master_get_devdata(master);
507 complete(&as->xfer_completion);
511 * Next transfer using PIO.
513 static void atmel_spi_next_xfer_pio(struct spi_master *master,
514 struct spi_transfer *xfer)
516 struct atmel_spi *as = spi_master_get_devdata(master);
517 unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
519 dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_pio\n");
521 /* Make sure data is not remaining in RDR */
523 while (spi_readl(as, SR) & SPI_BIT(RDRF)) {
529 if (xfer->bits_per_word > 8)
530 spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
532 spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));
534 spi_writel(as, TDR, 0);
537 dev_dbg(master->dev.parent,
538 " start pio xfer %p: len %u tx %p rx %p bitpw %d\n",
539 xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
540 xfer->bits_per_word);
542 /* Enable relevant interrupts */
543 spi_writel(as, IER, SPI_BIT(RDRF) | SPI_BIT(OVRES));
547 * Submit next transfer for DMA.
549 static int atmel_spi_next_xfer_dma_submit(struct spi_master *master,
550 struct spi_transfer *xfer,
553 struct atmel_spi *as = spi_master_get_devdata(master);
554 struct dma_chan *rxchan = as->dma.chan_rx;
555 struct dma_chan *txchan = as->dma.chan_tx;
556 struct dma_async_tx_descriptor *rxdesc;
557 struct dma_async_tx_descriptor *txdesc;
558 struct dma_slave_config slave_config;
562 dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_dma_submit\n");
564 /* Check that the channels are available */
565 if (!rxchan || !txchan)
568 /* release lock for DMA operations */
569 atmel_spi_unlock(as);
571 /* prepare the RX dma transfer */
572 sg_init_table(&as->dma.sgrx, 1);
574 as->dma.sgrx.dma_address = xfer->rx_dma + xfer->len - *plen;
576 as->dma.sgrx.dma_address = as->buffer_dma;
577 if (len > BUFFER_SIZE)
581 /* prepare the TX dma transfer */
582 sg_init_table(&as->dma.sgtx, 1);
584 as->dma.sgtx.dma_address = xfer->tx_dma + xfer->len - *plen;
586 as->dma.sgtx.dma_address = as->buffer_dma;
587 if (len > BUFFER_SIZE)
589 memset(as->buffer, 0, len);
592 sg_dma_len(&as->dma.sgtx) = len;
593 sg_dma_len(&as->dma.sgrx) = len;
597 if (atmel_spi_dma_slave_config(as, &slave_config, 8))
600 /* Send both scatterlists */
601 rxdesc = rxchan->device->device_prep_slave_sg(rxchan,
605 DMA_PREP_INTERRUPT | DMA_CTRL_ACK,
610 txdesc = txchan->device->device_prep_slave_sg(txchan,
614 DMA_PREP_INTERRUPT | DMA_CTRL_ACK,
619 dev_dbg(master->dev.parent,
620 " start dma xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
621 xfer, xfer->len, xfer->tx_buf, (unsigned long long)xfer->tx_dma,
622 xfer->rx_buf, (unsigned long long)xfer->rx_dma);
624 /* Enable relevant interrupts */
625 spi_writel(as, IER, SPI_BIT(OVRES));
627 /* Put the callback on the RX transfer only, that should finish last */
628 rxdesc->callback = dma_callback;
629 rxdesc->callback_param = master;
631 /* Submit and fire RX and TX with TX last so we're ready to read! */
632 cookie = rxdesc->tx_submit(rxdesc);
633 if (dma_submit_error(cookie))
635 cookie = txdesc->tx_submit(txdesc);
636 if (dma_submit_error(cookie))
638 rxchan->device->device_issue_pending(rxchan);
639 txchan->device->device_issue_pending(txchan);
646 spi_writel(as, IDR, SPI_BIT(OVRES));
647 atmel_spi_stop_dma(as);
653 static void atmel_spi_next_xfer_data(struct spi_master *master,
654 struct spi_transfer *xfer,
659 struct atmel_spi *as = spi_master_get_devdata(master);
662 /* use scratch buffer only when rx or tx data is unspecified */
664 *rx_dma = xfer->rx_dma + xfer->len - *plen;
666 *rx_dma = as->buffer_dma;
667 if (len > BUFFER_SIZE)
672 *tx_dma = xfer->tx_dma + xfer->len - *plen;
674 *tx_dma = as->buffer_dma;
675 if (len > BUFFER_SIZE)
677 memset(as->buffer, 0, len);
678 dma_sync_single_for_device(&as->pdev->dev,
679 as->buffer_dma, len, DMA_TO_DEVICE);
685 static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
686 struct spi_device *spi,
687 struct spi_transfer *xfer)
690 unsigned long bus_hz;
692 /* v1 chips start out at half the peripheral bus speed. */
693 bus_hz = clk_get_rate(as->clk);
694 if (!atmel_spi_is_v2(as))
698 * Calculate the lowest divider that satisfies the
699 * constraint, assuming div32/fdiv/mbz == 0.
702 scbr = DIV_ROUND_UP(bus_hz, xfer->speed_hz);
705 * This can happend if max_speed is null.
706 * In this case, we set the lowest possible speed
711 * If the resulting divider doesn't fit into the
712 * register bitfield, we can't satisfy the constraint.
714 if (scbr >= (1 << SPI_SCBR_SIZE)) {
716 "setup: %d Hz too slow, scbr %u; min %ld Hz\n",
717 xfer->speed_hz, scbr, bus_hz/255);
722 "setup: %d Hz too high, scbr %u; max %ld Hz\n",
723 xfer->speed_hz, scbr, bus_hz);
726 csr = spi_readl(as, CSR0 + 4 * spi->chip_select);
727 csr = SPI_BFINS(SCBR, scbr, csr);
728 spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
734 * Submit next transfer for PDC.
735 * lock is held, spi irq is blocked
737 static void atmel_spi_pdc_next_xfer(struct spi_master *master,
738 struct spi_message *msg,
739 struct spi_transfer *xfer)
741 struct atmel_spi *as = spi_master_get_devdata(master);
743 dma_addr_t tx_dma, rx_dma;
745 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
747 len = as->current_remaining_bytes;
748 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
749 as->current_remaining_bytes -= len;
751 spi_writel(as, RPR, rx_dma);
752 spi_writel(as, TPR, tx_dma);
754 if (msg->spi->bits_per_word > 8)
756 spi_writel(as, RCR, len);
757 spi_writel(as, TCR, len);
759 dev_dbg(&msg->spi->dev,
760 " start xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
761 xfer, xfer->len, xfer->tx_buf,
762 (unsigned long long)xfer->tx_dma, xfer->rx_buf,
763 (unsigned long long)xfer->rx_dma);
765 if (as->current_remaining_bytes) {
766 len = as->current_remaining_bytes;
767 atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
768 as->current_remaining_bytes -= len;
770 spi_writel(as, RNPR, rx_dma);
771 spi_writel(as, TNPR, tx_dma);
773 if (msg->spi->bits_per_word > 8)
775 spi_writel(as, RNCR, len);
776 spi_writel(as, TNCR, len);
778 dev_dbg(&msg->spi->dev,
779 " next xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
780 xfer, xfer->len, xfer->tx_buf,
781 (unsigned long long)xfer->tx_dma, xfer->rx_buf,
782 (unsigned long long)xfer->rx_dma);
785 /* REVISIT: We're waiting for ENDRX before we start the next
786 * transfer because we need to handle some difficult timing
787 * issues otherwise. If we wait for ENDTX in one transfer and
788 * then starts waiting for ENDRX in the next, it's difficult
789 * to tell the difference between the ENDRX interrupt we're
790 * actually waiting for and the ENDRX interrupt of the
793 * It should be doable, though. Just not now...
795 spi_writel(as, IER, SPI_BIT(ENDRX) | SPI_BIT(OVRES));
796 spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
800 * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
801 * - The buffer is either valid for CPU access, else NULL
802 * - If the buffer is valid, so is its DMA address
804 * This driver manages the dma address unless message->is_dma_mapped.
807 atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
809 struct device *dev = &as->pdev->dev;
811 xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
813 /* tx_buf is a const void* where we need a void * for the dma
815 void *nonconst_tx = (void *)xfer->tx_buf;
817 xfer->tx_dma = dma_map_single(dev,
818 nonconst_tx, xfer->len,
820 if (dma_mapping_error(dev, xfer->tx_dma))
824 xfer->rx_dma = dma_map_single(dev,
825 xfer->rx_buf, xfer->len,
827 if (dma_mapping_error(dev, xfer->rx_dma)) {
829 dma_unmap_single(dev,
830 xfer->tx_dma, xfer->len,
838 static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
839 struct spi_transfer *xfer)
841 if (xfer->tx_dma != INVALID_DMA_ADDRESS)
842 dma_unmap_single(master->dev.parent, xfer->tx_dma,
843 xfer->len, DMA_TO_DEVICE);
844 if (xfer->rx_dma != INVALID_DMA_ADDRESS)
845 dma_unmap_single(master->dev.parent, xfer->rx_dma,
846 xfer->len, DMA_FROM_DEVICE);
849 static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as)
851 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
856 * Must update "current_remaining_bytes" to keep track of data
860 atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
864 unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
867 if (xfer->bits_per_word > 8) {
868 rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
869 *rxp16 = spi_readl(as, RDR);
871 rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
872 *rxp = spi_readl(as, RDR);
877 if (xfer->bits_per_word > 8) {
878 as->current_remaining_bytes -= 2;
879 if (as->current_remaining_bytes < 0)
880 as->current_remaining_bytes = 0;
882 as->current_remaining_bytes--;
888 * No need for locking in this Interrupt handler: done_status is the
889 * only information modified.
892 atmel_spi_pio_interrupt(int irq, void *dev_id)
894 struct spi_master *master = dev_id;
895 struct atmel_spi *as = spi_master_get_devdata(master);
896 u32 status, pending, imr;
897 struct spi_transfer *xfer;
900 imr = spi_readl(as, IMR);
901 status = spi_readl(as, SR);
902 pending = status & imr;
904 if (pending & SPI_BIT(OVRES)) {
906 spi_writel(as, IDR, SPI_BIT(OVRES));
907 dev_warn(master->dev.parent, "overrun\n");
910 * When we get an overrun, we disregard the current
911 * transfer. Data will not be copied back from any
912 * bounce buffer and msg->actual_len will not be
913 * updated with the last xfer.
915 * We will also not process any remaning transfers in
918 as->done_status = -EIO;
921 /* Clear any overrun happening while cleaning up */
924 complete(&as->xfer_completion);
926 } else if (pending & SPI_BIT(RDRF)) {
929 if (as->current_remaining_bytes) {
931 xfer = as->current_transfer;
932 atmel_spi_pump_pio_data(as, xfer);
933 if (!as->current_remaining_bytes)
934 spi_writel(as, IDR, pending);
936 complete(&as->xfer_completion);
939 atmel_spi_unlock(as);
941 WARN_ONCE(pending, "IRQ not handled, pending = %x\n", pending);
943 spi_writel(as, IDR, pending);
950 atmel_spi_pdc_interrupt(int irq, void *dev_id)
952 struct spi_master *master = dev_id;
953 struct atmel_spi *as = spi_master_get_devdata(master);
954 u32 status, pending, imr;
957 imr = spi_readl(as, IMR);
958 status = spi_readl(as, SR);
959 pending = status & imr;
961 if (pending & SPI_BIT(OVRES)) {
965 spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
968 /* Clear any overrun happening while cleaning up */
971 as->done_status = -EIO;
973 complete(&as->xfer_completion);
975 } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
978 spi_writel(as, IDR, pending);
980 complete(&as->xfer_completion);
986 static int atmel_spi_setup(struct spi_device *spi)
988 struct atmel_spi *as;
989 struct atmel_spi_device *asd;
991 unsigned int bits = spi->bits_per_word;
992 unsigned int npcs_pin;
995 as = spi_master_get_devdata(spi->master);
997 if (spi->chip_select > spi->master->num_chipselect) {
999 "setup: invalid chipselect %u (%u defined)\n",
1000 spi->chip_select, spi->master->num_chipselect);
1004 /* see notes above re chipselect */
1005 if (!atmel_spi_is_v2(as)
1006 && spi->chip_select == 0
1007 && (spi->mode & SPI_CS_HIGH)) {
1008 dev_dbg(&spi->dev, "setup: can't be active-high\n");
1012 csr = SPI_BF(BITS, bits - 8);
1013 if (spi->mode & SPI_CPOL)
1014 csr |= SPI_BIT(CPOL);
1015 if (!(spi->mode & SPI_CPHA))
1016 csr |= SPI_BIT(NCPHA);
1018 /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
1020 * DLYBCT would add delays between words, slowing down transfers.
1021 * It could potentially be useful to cope with DMA bottlenecks, but
1022 * in those cases it's probably best to just use a lower bitrate.
1024 csr |= SPI_BF(DLYBS, 0);
1025 csr |= SPI_BF(DLYBCT, 0);
1027 /* chipselect must have been muxed as GPIO (e.g. in board setup) */
1028 npcs_pin = (unsigned int)spi->controller_data;
1030 if (gpio_is_valid(spi->cs_gpio))
1031 npcs_pin = spi->cs_gpio;
1033 asd = spi->controller_state;
1035 asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
1039 ret = gpio_request(npcs_pin, dev_name(&spi->dev));
1045 asd->npcs_pin = npcs_pin;
1046 spi->controller_state = asd;
1047 gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH));
1053 "setup: bpw %u mode 0x%x -> csr%d %08x\n",
1054 bits, spi->mode, spi->chip_select, csr);
1056 if (!atmel_spi_is_v2(as))
1057 spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
1062 static int atmel_spi_one_transfer(struct spi_master *master,
1063 struct spi_message *msg,
1064 struct spi_transfer *xfer)
1066 struct atmel_spi *as;
1067 struct spi_device *spi = msg->spi;
1070 struct atmel_spi_device *asd;
1074 as = spi_master_get_devdata(master);
1076 if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1077 dev_dbg(&spi->dev, "missing rx or tx buf\n");
1081 if (xfer->bits_per_word) {
1082 asd = spi->controller_state;
1083 bits = (asd->csr >> 4) & 0xf;
1084 if (bits != xfer->bits_per_word - 8) {
1086 "you can't yet change bits_per_word in transfers\n");
1087 return -ENOPROTOOPT;
1092 * DMA map early, for performance (empties dcache ASAP) and
1093 * better fault reporting.
1095 if ((!msg->is_dma_mapped)
1096 && (atmel_spi_use_dma(as, xfer) || as->use_pdc)) {
1097 if (atmel_spi_dma_map_xfer(as, xfer) < 0)
1101 atmel_spi_set_xfer_speed(as, msg->spi, xfer);
1103 as->done_status = 0;
1104 as->current_transfer = xfer;
1105 as->current_remaining_bytes = xfer->len;
1106 while (as->current_remaining_bytes) {
1107 reinit_completion(&as->xfer_completion);
1110 atmel_spi_pdc_next_xfer(master, msg, xfer);
1111 } else if (atmel_spi_use_dma(as, xfer)) {
1112 len = as->current_remaining_bytes;
1113 ret = atmel_spi_next_xfer_dma_submit(master,
1117 "unable to use DMA, fallback to PIO\n");
1118 atmel_spi_next_xfer_pio(master, xfer);
1120 as->current_remaining_bytes -= len;
1123 atmel_spi_next_xfer_pio(master, xfer);
1126 ret = wait_for_completion_timeout(&as->xfer_completion,
1128 if (WARN_ON(ret == 0)) {
1130 "spi trasfer timeout, err %d\n", ret);
1131 as->done_status = -EIO;
1136 if (as->done_status)
1140 if (as->done_status) {
1142 dev_warn(master->dev.parent,
1143 "overrun (%u/%u remaining)\n",
1144 spi_readl(as, TCR), spi_readl(as, RCR));
1147 * Clean up DMA registers and make sure the data
1148 * registers are empty.
1150 spi_writel(as, RNCR, 0);
1151 spi_writel(as, TNCR, 0);
1152 spi_writel(as, RCR, 0);
1153 spi_writel(as, TCR, 0);
1154 for (timeout = 1000; timeout; timeout--)
1155 if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
1158 dev_warn(master->dev.parent,
1159 "timeout waiting for TXEMPTY");
1160 while (spi_readl(as, SR) & SPI_BIT(RDRF))
1163 /* Clear any overrun happening while cleaning up */
1166 } else if (atmel_spi_use_dma(as, xfer)) {
1167 atmel_spi_stop_dma(as);
1170 if (!msg->is_dma_mapped
1171 && (atmel_spi_use_dma(as, xfer) || as->use_pdc))
1172 atmel_spi_dma_unmap_xfer(master, xfer);
1177 /* only update length if no error */
1178 msg->actual_length += xfer->len;
1181 if (!msg->is_dma_mapped
1182 && (atmel_spi_use_dma(as, xfer) || as->use_pdc))
1183 atmel_spi_dma_unmap_xfer(master, xfer);
1185 if (xfer->delay_usecs)
1186 udelay(xfer->delay_usecs);
1188 if (xfer->cs_change) {
1189 if (list_is_last(&xfer->transfer_list,
1193 as->cs_active = !as->cs_active;
1195 cs_activate(as, msg->spi);
1197 cs_deactivate(as, msg->spi);
1204 static int atmel_spi_transfer_one_message(struct spi_master *master,
1205 struct spi_message *msg)
1207 struct atmel_spi *as;
1208 struct spi_transfer *xfer;
1209 struct spi_device *spi = msg->spi;
1212 as = spi_master_get_devdata(master);
1214 dev_dbg(&spi->dev, "new message %p submitted for %s\n",
1215 msg, dev_name(&spi->dev));
1218 cs_activate(as, spi);
1220 as->cs_active = true;
1221 as->keep_cs = false;
1224 msg->actual_length = 0;
1226 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1227 ret = atmel_spi_one_transfer(master, msg, xfer);
1233 atmel_spi_disable_pdc_transfer(as);
1235 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1237 " xfer %p: len %u tx %p/%pad rx %p/%pad\n",
1239 xfer->tx_buf, &xfer->tx_dma,
1240 xfer->rx_buf, &xfer->rx_dma);
1245 cs_deactivate(as, msg->spi);
1247 atmel_spi_unlock(as);
1249 msg->status = as->done_status;
1250 spi_finalize_current_message(spi->master);
1255 static void atmel_spi_cleanup(struct spi_device *spi)
1257 struct atmel_spi_device *asd = spi->controller_state;
1258 unsigned gpio = (unsigned) spi->controller_data;
1263 spi->controller_state = NULL;
1268 static inline unsigned int atmel_get_version(struct atmel_spi *as)
1270 return spi_readl(as, VERSION) & 0x00000fff;
1273 static void atmel_get_caps(struct atmel_spi *as)
1275 unsigned int version;
1277 version = atmel_get_version(as);
1278 dev_info(&as->pdev->dev, "version: 0x%x\n", version);
1280 as->caps.is_spi2 = version > 0x121;
1281 as->caps.has_wdrbt = version >= 0x210;
1282 as->caps.has_dma_support = version >= 0x212;
1285 /*-------------------------------------------------------------------------*/
1287 static int atmel_spi_probe(struct platform_device *pdev)
1289 struct resource *regs;
1293 struct spi_master *master;
1294 struct atmel_spi *as;
1296 /* Select default pin state */
1297 pinctrl_pm_select_default_state(&pdev->dev);
1299 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1303 irq = platform_get_irq(pdev, 0);
1307 clk = devm_clk_get(&pdev->dev, "spi_clk");
1309 return PTR_ERR(clk);
1311 /* setup spi core then atmel-specific driver state */
1313 master = spi_alloc_master(&pdev->dev, sizeof(*as));
1317 /* the spi->mode bits understood by this driver: */
1318 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
1319 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
1320 master->dev.of_node = pdev->dev.of_node;
1321 master->bus_num = pdev->id;
1322 master->num_chipselect = master->dev.of_node ? 0 : 4;
1323 master->setup = atmel_spi_setup;
1324 master->transfer_one_message = atmel_spi_transfer_one_message;
1325 master->cleanup = atmel_spi_cleanup;
1326 platform_set_drvdata(pdev, master);
1328 as = spi_master_get_devdata(master);
1331 * Scratch buffer is used for throwaway rx and tx data.
1332 * It's coherent to minimize dcache pollution.
1334 as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
1335 &as->buffer_dma, GFP_KERNEL);
1339 spin_lock_init(&as->lock);
1342 as->regs = devm_ioremap_resource(&pdev->dev, regs);
1343 if (IS_ERR(as->regs)) {
1344 ret = PTR_ERR(as->regs);
1345 goto out_free_buffer;
1347 as->phybase = regs->start;
1351 init_completion(&as->xfer_completion);
1355 as->use_dma = false;
1356 as->use_pdc = false;
1357 if (as->caps.has_dma_support) {
1358 if (atmel_spi_configure_dma(as) == 0)
1364 if (as->caps.has_dma_support && !as->use_dma)
1365 dev_info(&pdev->dev, "Atmel SPI Controller using PIO only\n");
1368 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pdc_interrupt,
1369 0, dev_name(&pdev->dev), master);
1371 ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pio_interrupt,
1372 0, dev_name(&pdev->dev), master);
1375 goto out_unmap_regs;
1377 /* Initialize the hardware */
1378 ret = clk_prepare_enable(clk);
1381 spi_writel(as, CR, SPI_BIT(SWRST));
1382 spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1383 if (as->caps.has_wdrbt) {
1384 spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
1387 spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
1391 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
1392 spi_writel(as, CR, SPI_BIT(SPIEN));
1395 dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
1396 (unsigned long)regs->start, irq);
1398 ret = devm_spi_register_master(&pdev->dev, master);
1406 atmel_spi_release_dma(as);
1408 spi_writel(as, CR, SPI_BIT(SWRST));
1409 spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1410 clk_disable_unprepare(clk);
1414 dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
1417 spi_master_put(master);
1421 static int atmel_spi_remove(struct platform_device *pdev)
1423 struct spi_master *master = platform_get_drvdata(pdev);
1424 struct atmel_spi *as = spi_master_get_devdata(master);
1426 /* reset the hardware and block queue progress */
1427 spin_lock_irq(&as->lock);
1429 atmel_spi_stop_dma(as);
1430 atmel_spi_release_dma(as);
1433 spi_writel(as, CR, SPI_BIT(SWRST));
1434 spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1436 spin_unlock_irq(&as->lock);
1438 dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
1441 clk_disable_unprepare(as->clk);
1446 #ifdef CONFIG_PM_SLEEP
1447 static int atmel_spi_suspend(struct device *dev)
1449 struct spi_master *master = dev_get_drvdata(dev);
1450 struct atmel_spi *as = spi_master_get_devdata(master);
1453 /* Stop the queue running */
1454 ret = spi_master_suspend(master);
1456 dev_warn(dev, "cannot suspend master\n");
1460 clk_disable_unprepare(as->clk);
1462 pinctrl_pm_select_sleep_state(dev);
1467 static int atmel_spi_resume(struct device *dev)
1469 struct spi_master *master = dev_get_drvdata(dev);
1470 struct atmel_spi *as = spi_master_get_devdata(master);
1473 pinctrl_pm_select_default_state(dev);
1475 clk_prepare_enable(as->clk);
1477 /* Start the queue running */
1478 ret = spi_master_resume(master);
1480 dev_err(dev, "problem starting queue (%d)\n", ret);
1485 static SIMPLE_DEV_PM_OPS(atmel_spi_pm_ops, atmel_spi_suspend, atmel_spi_resume);
1487 #define ATMEL_SPI_PM_OPS (&atmel_spi_pm_ops)
1489 #define ATMEL_SPI_PM_OPS NULL
1492 #if defined(CONFIG_OF)
1493 static const struct of_device_id atmel_spi_dt_ids[] = {
1494 { .compatible = "atmel,at91rm9200-spi" },
1498 MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids);
1501 static struct platform_driver atmel_spi_driver = {
1503 .name = "atmel_spi",
1504 .owner = THIS_MODULE,
1505 .pm = ATMEL_SPI_PM_OPS,
1506 .of_match_table = of_match_ptr(atmel_spi_dt_ids),
1508 .probe = atmel_spi_probe,
1509 .remove = atmel_spi_remove,
1511 module_platform_driver(atmel_spi_driver);
1513 MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
1514 MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
1515 MODULE_LICENSE("GPL");
1516 MODULE_ALIAS("platform:atmel_spi");