Version:  2.0.40 2.2.26 2.4.37 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15

Linux/drivers/spi/spi-atmel.c

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

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