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[mirror_ubuntu-bionic-kernel.git] / drivers / spi / spi-au1550.c
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63bd2359 1/*
ca632f55 2 * au1550 psc spi controller driver
63bd2359
JN		 3 * may work also with au1200, au1210, au1250
4 * will not work on au1000, au1100 and au1500 (no full spi controller there)
5 *
6 * Copyright (c) 2006 ATRON electronic GmbH
7 * Author: Jan Nikitenko <jan.nikitenko@gmail.com>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 */
23
24#include <linux/init.h>
25#include <linux/interrupt.h>
5a0e3ad6 26#include <linux/slab.h>
63bd2359 27#include <linux/errno.h>
d7614de4 28#include <linux/module.h>
63bd2359
JN		 29#include <linux/device.h>
30#include <linux/platform_device.h>
3a93a159 31#include <linux/resource.h>
63bd2359
JN		 32#include <linux/spi/spi.h>
33#include <linux/spi/spi_bitbang.h>
34#include <linux/dma-mapping.h>
35#include <linux/completion.h>
36#include <asm/mach-au1x00/au1000.h>
37#include <asm/mach-au1x00/au1xxx_psc.h>
38#include <asm/mach-au1x00/au1xxx_dbdma.h>
39
40#include <asm/mach-au1x00/au1550_spi.h>
41
42static unsigned usedma = 1;
43module_param(usedma, uint, 0644);
44
45/*
46#define AU1550_SPI_DEBUG_LOOPBACK
47*/
48
49
50#define AU1550_SPI_DBDMA_DESCRIPTORS 1
51#define AU1550_SPI_DMA_RXTMP_MINSIZE 2048U
52
53struct au1550_spi {
54 struct spi_bitbang bitbang;
55
56 volatile psc_spi_t __iomem *regs;
57 int irq;
63bd2359
JN		 58
59 unsigned len;
60 unsigned tx_count;
61 unsigned rx_count;
62 const u8 *tx;
63 u8 *rx;
64
65 void (*rx_word)(struct au1550_spi *hw);
66 void (*tx_word)(struct au1550_spi *hw);
67 int (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
68 irqreturn_t (*irq_callback)(struct au1550_spi *hw);
69
70 struct completion master_done;
71
72 unsigned usedma;
73 u32 dma_tx_id;
74 u32 dma_rx_id;
75 u32 dma_tx_ch;
76 u32 dma_rx_ch;
77
78 u8 *dma_rx_tmpbuf;
79 unsigned dma_rx_tmpbuf_size;
80 u32 dma_rx_tmpbuf_addr;
81
82 struct spi_master *master;
83 struct device *dev;
84 struct au1550_spi_info *pdata;
3a93a159 85 struct resource *ioarea;
63bd2359
JN		 86};
87
88
89/* we use an 8-bit memory device for dma transfers to/from spi fifo */
90static dbdev_tab_t au1550_spi_mem_dbdev =
91{
92 .dev_id = DBDMA_MEM_CHAN,
93 .dev_flags = DEV_FLAGS_ANYUSE|DEV_FLAGS_SYNC,
94 .dev_tsize = 0,
95 .dev_devwidth = 8,
96 .dev_physaddr = 0x00000000,
97 .dev_intlevel = 0,
98 .dev_intpolarity = 0
99};
100
3a93a159
ML		 101static int ddma_memid; /* id to above mem dma device */
102
63bd2359
JN		 103static void au1550_spi_bits_handlers_set(struct au1550_spi *hw, int bpw);
104
105
40369e1c 106/*
63bd2359
JN		 107 * compute BRG and DIV bits to setup spi clock based on main input clock rate
108 * that was specified in platform data structure
109 * according to au1550 datasheet:
110 * psc_tempclk = psc_mainclk / (2 << DIV)
111 * spiclk = psc_tempclk / (2 * (BRG + 1))
112 * BRG valid range is 4..63
113 * DIV valid range is 0..3
114 */
115static u32 au1550_spi_baudcfg(struct au1550_spi *hw, unsigned speed_hz)
116{
117 u32 mainclk_hz = hw->pdata->mainclk_hz;
118 u32 div, brg;
119
120 for (div = 0; div < 4; div++) {
121 brg = mainclk_hz / speed_hz / (4 << div);
122 /* now we have BRG+1 in brg, so count with that */
123 if (brg < (4 + 1)) {
124 brg = (4 + 1); /* speed_hz too big */
125 break; /* set lowest brg (div is == 0) */
126 }
127 if (brg <= (63 + 1))
128 break; /* we have valid brg and div */
129 }
130 if (div == 4) {
131 div = 3; /* speed_hz too small */
132 brg = (63 + 1); /* set highest brg and div */
133 }
134 brg--;
135 return PSC_SPICFG_SET_BAUD(brg) | PSC_SPICFG_SET_DIV(div);
136}
137
138static inline void au1550_spi_mask_ack_all(struct au1550_spi *hw)
139{
140 hw->regs->psc_spimsk =
141 PSC_SPIMSK_MM | PSC_SPIMSK_RR | PSC_SPIMSK_RO
142 | PSC_SPIMSK_RU | PSC_SPIMSK_TR | PSC_SPIMSK_TO
143 | PSC_SPIMSK_TU | PSC_SPIMSK_SD | PSC_SPIMSK_MD;
144 au_sync();
145
146 hw->regs->psc_spievent =
147 PSC_SPIEVNT_MM | PSC_SPIEVNT_RR | PSC_SPIEVNT_RO
148 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TR | PSC_SPIEVNT_TO
149 | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD | PSC_SPIEVNT_MD;
150 au_sync();
151}
152
153static void au1550_spi_reset_fifos(struct au1550_spi *hw)
154{
155 u32 pcr;
156
157 hw->regs->psc_spipcr = PSC_SPIPCR_RC | PSC_SPIPCR_TC;
158 au_sync();
159 do {
160 pcr = hw->regs->psc_spipcr;
161 au_sync();
162 } while (pcr != 0);
163}
164
165/*
166 * dma transfers are used for the most common spi word size of 8-bits
167 * we cannot easily change already set up dma channels' width, so if we wanted
168 * dma support for more than 8-bit words (up to 24 bits), we would need to
169 * setup dma channels from scratch on each spi transfer, based on bits_per_word
170 * instead we have pre set up 8 bit dma channels supporting spi 4 to 8 bits
171 * transfers, and 9 to 24 bits spi transfers will be done in pio irq based mode
172 * callbacks to handle dma or pio are set up in au1550_spi_bits_handlers_set()
173 */
174static void au1550_spi_chipsel(struct spi_device *spi, int value)
175{
176 struct au1550_spi *hw = spi_master_get_devdata(spi->master);
177 unsigned cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
178 u32 cfg, stat;
179
180 switch (value) {
181 case BITBANG_CS_INACTIVE:
182 if (hw->pdata->deactivate_cs)
183 hw->pdata->deactivate_cs(hw->pdata, spi->chip_select,
184 cspol);
185 break;
186
187 case BITBANG_CS_ACTIVE:
188 au1550_spi_bits_handlers_set(hw, spi->bits_per_word);
189
190 cfg = hw->regs->psc_spicfg;
191 au_sync();
192 hw->regs->psc_spicfg = cfg & ~PSC_SPICFG_DE_ENABLE;
193 au_sync();
194
195 if (spi->mode & SPI_CPOL)
196 cfg |= PSC_SPICFG_BI;
197 else
198 cfg &= ~PSC_SPICFG_BI;
199 if (spi->mode & SPI_CPHA)
200 cfg &= ~PSC_SPICFG_CDE;
201 else
202 cfg |= PSC_SPICFG_CDE;
203
204 if (spi->mode & SPI_LSB_FIRST)
205 cfg |= PSC_SPICFG_MLF;
206 else
207 cfg &= ~PSC_SPICFG_MLF;
208
209 if (hw->usedma && spi->bits_per_word <= 8)
210 cfg &= ~PSC_SPICFG_DD_DISABLE;
211 else
212 cfg |= PSC_SPICFG_DD_DISABLE;
213 cfg = PSC_SPICFG_CLR_LEN(cfg);
214 cfg |= PSC_SPICFG_SET_LEN(spi->bits_per_word);
215
216 cfg = PSC_SPICFG_CLR_BAUD(cfg);
217 cfg &= ~PSC_SPICFG_SET_DIV(3);
218 cfg |= au1550_spi_baudcfg(hw, spi->max_speed_hz);
219
220 hw->regs->psc_spicfg = cfg | PSC_SPICFG_DE_ENABLE;
221 au_sync();
222 do {
223 stat = hw->regs->psc_spistat;
224 au_sync();
225 } while ((stat & PSC_SPISTAT_DR) == 0);
226
227 if (hw->pdata->activate_cs)
228 hw->pdata->activate_cs(hw->pdata, spi->chip_select,
229 cspol);
230 break;
231 }
232}
233
234static int au1550_spi_setupxfer(struct spi_device *spi, struct spi_transfer *t)
235{
236 struct au1550_spi *hw = spi_master_get_devdata(spi->master);
237 unsigned bpw, hz;
238 u32 cfg, stat;
239
04ba24b3
JN		 240 bpw = spi->bits_per_word;
241 hz = spi->max_speed_hz;
242 if (t) {
243 if (t->bits_per_word)
244 bpw = t->bits_per_word;
245 if (t->speed_hz)
246 hz = t->speed_hz;
247 }
63bd2359 248
0dd26e53 249 if (!hz)
63bd2359 250 return -EINVAL;
63bd2359
JN		 251
252 au1550_spi_bits_handlers_set(hw, spi->bits_per_word);
253
254 cfg = hw->regs->psc_spicfg;
255 au_sync();
256 hw->regs->psc_spicfg = cfg & ~PSC_SPICFG_DE_ENABLE;
257 au_sync();
258
259 if (hw->usedma && bpw <= 8)
260 cfg &= ~PSC_SPICFG_DD_DISABLE;
261 else
262 cfg |= PSC_SPICFG_DD_DISABLE;
263 cfg = PSC_SPICFG_CLR_LEN(cfg);
264 cfg |= PSC_SPICFG_SET_LEN(bpw);
265
266 cfg = PSC_SPICFG_CLR_BAUD(cfg);
267 cfg &= ~PSC_SPICFG_SET_DIV(3);
268 cfg |= au1550_spi_baudcfg(hw, hz);
269
270 hw->regs->psc_spicfg = cfg;
271 au_sync();
272
273 if (cfg & PSC_SPICFG_DE_ENABLE) {
274 do {
275 stat = hw->regs->psc_spistat;
276 au_sync();
277 } while ((stat & PSC_SPISTAT_DR) == 0);
278 }
279
280 au1550_spi_reset_fifos(hw);
281 au1550_spi_mask_ack_all(hw);
282 return 0;
283}
284
63bd2359
JN		 285/*
286 * for dma spi transfers, we have to setup rx channel, otherwise there is
287 * no reliable way how to recognize that spi transfer is done
288 * dma complete callbacks are called before real spi transfer is finished
289 * and if only tx dma channel is set up (and rx fifo overflow event masked)
290 * spi master done event irq is not generated unless rx fifo is empty (emptied)
291 * so we need rx tmp buffer to use for rx dma if user does not provide one
292 */
293static int au1550_spi_dma_rxtmp_alloc(struct au1550_spi *hw, unsigned size)
294{
295 hw->dma_rx_tmpbuf = kmalloc(size, GFP_KERNEL);
296 if (!hw->dma_rx_tmpbuf)
297 return -ENOMEM;
298 hw->dma_rx_tmpbuf_size = size;
299 hw->dma_rx_tmpbuf_addr = dma_map_single(hw->dev, hw->dma_rx_tmpbuf,
300 size, DMA_FROM_DEVICE);
8d8bb39b 301 if (dma_mapping_error(hw->dev, hw->dma_rx_tmpbuf_addr)) {
63bd2359
JN		 302 kfree(hw->dma_rx_tmpbuf);
303 hw->dma_rx_tmpbuf = 0;
304 hw->dma_rx_tmpbuf_size = 0;
305 return -EFAULT;
306 }
307 return 0;
308}
309
310static void au1550_spi_dma_rxtmp_free(struct au1550_spi *hw)
311{
312 dma_unmap_single(hw->dev, hw->dma_rx_tmpbuf_addr,
313 hw->dma_rx_tmpbuf_size, DMA_FROM_DEVICE);
314 kfree(hw->dma_rx_tmpbuf);
315 hw->dma_rx_tmpbuf = 0;
316 hw->dma_rx_tmpbuf_size = 0;
317}
318
319static int au1550_spi_dma_txrxb(struct spi_device *spi, struct spi_transfer *t)
320{
321 struct au1550_spi *hw = spi_master_get_devdata(spi->master);
322 dma_addr_t dma_tx_addr;
323 dma_addr_t dma_rx_addr;
324 u32 res;
325
326 hw->len = t->len;
327 hw->tx_count = 0;
328 hw->rx_count = 0;
329
330 hw->tx = t->tx_buf;
331 hw->rx = t->rx_buf;
332 dma_tx_addr = t->tx_dma;
333 dma_rx_addr = t->rx_dma;
334
335 /*
4e253d23
JN		 336 * check if buffers are already dma mapped, map them otherwise:
337 * - first map the TX buffer, so cache data gets written to memory
338 * - then map the RX buffer, so that cache entries (with
339 * soon-to-be-stale data) get removed
63bd2359
JN		 340 * use rx buffer in place of tx if tx buffer was not provided
341 * use temp rx buffer (preallocated or realloc to fit) for rx dma
342 */
4e253d23
JN		 343 if (t->tx_buf) {
344 if (t->tx_dma == 0) { /* if DMA_ADDR_INVALID, map it */
345 dma_tx_addr = dma_map_single(hw->dev,
346 (void *)t->tx_buf,
347 t->len, DMA_TO_DEVICE);
348 if (dma_mapping_error(hw->dev, dma_tx_addr))
349 dev_err(hw->dev, "tx dma map error\n");
350 }
351 }
352
63bd2359
JN		 353 if (t->rx_buf) {
354 if (t->rx_dma == 0) { /* if DMA_ADDR_INVALID, map it */
355 dma_rx_addr = dma_map_single(hw->dev,
356 (void *)t->rx_buf,
357 t->len, DMA_FROM_DEVICE);
8d8bb39b 358 if (dma_mapping_error(hw->dev, dma_rx_addr))
63bd2359
JN		 359 dev_err(hw->dev, "rx dma map error\n");
360 }
361 } else {
362 if (t->len > hw->dma_rx_tmpbuf_size) {
363 int ret;
364
365 au1550_spi_dma_rxtmp_free(hw);
366 ret = au1550_spi_dma_rxtmp_alloc(hw, max(t->len,
367 AU1550_SPI_DMA_RXTMP_MINSIZE));
368 if (ret < 0)
369 return ret;
370 }
371 hw->rx = hw->dma_rx_tmpbuf;
372 dma_rx_addr = hw->dma_rx_tmpbuf_addr;
373 dma_sync_single_for_device(hw->dev, dma_rx_addr,
374 t->len, DMA_FROM_DEVICE);
375 }
4e253d23
JN		 376
377 if (!t->tx_buf) {
63bd2359
JN		 378 dma_sync_single_for_device(hw->dev, dma_rx_addr,
379 t->len, DMA_BIDIRECTIONAL);
380 hw->tx = hw->rx;
381 }
382
383 /* put buffers on the ring */
963accbc 384 res = au1xxx_dbdma_put_dest(hw->dma_rx_ch, virt_to_phys(hw->rx),
ea071cc7 385 t->len, DDMA_FLAGS_IE);
63bd2359
JN		 386 if (!res)
387 dev_err(hw->dev, "rx dma put dest error\n");
388
963accbc 389 res = au1xxx_dbdma_put_source(hw->dma_tx_ch, virt_to_phys(hw->tx),
ea071cc7 390 t->len, DDMA_FLAGS_IE);
63bd2359
JN		 391 if (!res)
392 dev_err(hw->dev, "tx dma put source error\n");
393
394 au1xxx_dbdma_start(hw->dma_rx_ch);
395 au1xxx_dbdma_start(hw->dma_tx_ch);
396
397 /* by default enable nearly all events interrupt */
398 hw->regs->psc_spimsk = PSC_SPIMSK_SD;
399 au_sync();
400
401 /* start the transfer */
402 hw->regs->psc_spipcr = PSC_SPIPCR_MS;
403 au_sync();
404
405 wait_for_completion(&hw->master_done);
406
407 au1xxx_dbdma_stop(hw->dma_tx_ch);
408 au1xxx_dbdma_stop(hw->dma_rx_ch);
409
410 if (!t->rx_buf) {
411 /* using the temporal preallocated and premapped buffer */
412 dma_sync_single_for_cpu(hw->dev, dma_rx_addr, t->len,
413 DMA_FROM_DEVICE);
414 }
415 /* unmap buffers if mapped above */
416 if (t->rx_buf && t->rx_dma == 0 )
417 dma_unmap_single(hw->dev, dma_rx_addr, t->len,
418 DMA_FROM_DEVICE);
419 if (t->tx_buf && t->tx_dma == 0 )
420 dma_unmap_single(hw->dev, dma_tx_addr, t->len,
421 DMA_TO_DEVICE);
422
423 return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
424}
425
426static irqreturn_t au1550_spi_dma_irq_callback(struct au1550_spi *hw)
427{
428 u32 stat, evnt;
429
430 stat = hw->regs->psc_spistat;
431 evnt = hw->regs->psc_spievent;
432 au_sync();
433 if ((stat & PSC_SPISTAT_DI) == 0) {
434 dev_err(hw->dev, "Unexpected IRQ!\n");
435 return IRQ_NONE;
436 }
437
438 if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
439 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
440 | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD))
441 != 0) {
442 /*
443 * due to an spi error we consider transfer as done,
444 * so mask all events until before next transfer start
886db6ac 445 * and stop the possibly running dma immediately
63bd2359
JN		 446 */
447 au1550_spi_mask_ack_all(hw);
448 au1xxx_dbdma_stop(hw->dma_rx_ch);
449 au1xxx_dbdma_stop(hw->dma_tx_ch);
450
25985edc 451 /* get number of transferred bytes */
63bd2359
JN		 452 hw->rx_count = hw->len - au1xxx_get_dma_residue(hw->dma_rx_ch);
453 hw->tx_count = hw->len - au1xxx_get_dma_residue(hw->dma_tx_ch);
454
455 au1xxx_dbdma_reset(hw->dma_rx_ch);
456 au1xxx_dbdma_reset(hw->dma_tx_ch);
457 au1550_spi_reset_fifos(hw);
458
bbe48ecc
JN		 459 if (evnt == PSC_SPIEVNT_RO)
460 dev_err(hw->dev,
461 "dma transfer: receive FIFO overflow!\n");
462 else
463 dev_err(hw->dev,
464 "dma transfer: unexpected SPI error "
465 "(event=0x%x stat=0x%x)!\n", evnt, stat);
63bd2359
JN		 466
467 complete(&hw->master_done);
468 return IRQ_HANDLED;
469 }
470
471 if ((evnt & PSC_SPIEVNT_MD) != 0) {
472 /* transfer completed successfully */
473 au1550_spi_mask_ack_all(hw);
474 hw->rx_count = hw->len;
475 hw->tx_count = hw->len;
476 complete(&hw->master_done);
477 }
478 return IRQ_HANDLED;
479}
480
481
482/* routines to handle different word sizes in pio mode */
483#define AU1550_SPI_RX_WORD(size, mask) \
484static void au1550_spi_rx_word_##size(struct au1550_spi *hw) \
485{ \
486 u32 fifoword = hw->regs->psc_spitxrx & (u32)(mask); \
487 au_sync(); \
488 if (hw->rx) { \
489 *(u##size *)hw->rx = (u##size)fifoword; \
490 hw->rx += (size) / 8; \
491 } \
492 hw->rx_count += (size) / 8; \
493}
494
495#define AU1550_SPI_TX_WORD(size, mask) \
496static void au1550_spi_tx_word_##size(struct au1550_spi *hw) \
497{ \
498 u32 fifoword = 0; \
499 if (hw->tx) { \
500 fifoword = *(u##size *)hw->tx & (u32)(mask); \
501 hw->tx += (size) / 8; \
502 } \
503 hw->tx_count += (size) / 8; \
504 if (hw->tx_count >= hw->len) \
505 fifoword |= PSC_SPITXRX_LC; \
506 hw->regs->psc_spitxrx = fifoword; \
507 au_sync(); \
508}
509
510AU1550_SPI_RX_WORD(8,0xff)
511AU1550_SPI_RX_WORD(16,0xffff)
512AU1550_SPI_RX_WORD(32,0xffffff)
513AU1550_SPI_TX_WORD(8,0xff)
514AU1550_SPI_TX_WORD(16,0xffff)
515AU1550_SPI_TX_WORD(32,0xffffff)
516
517static int au1550_spi_pio_txrxb(struct spi_device *spi, struct spi_transfer *t)
518{
519 u32 stat, mask;
520 struct au1550_spi *hw = spi_master_get_devdata(spi->master);
521
522 hw->tx = t->tx_buf;
523 hw->rx = t->rx_buf;
524 hw->len = t->len;
525 hw->tx_count = 0;
526 hw->rx_count = 0;
527
528 /* by default enable nearly all events after filling tx fifo */
529 mask = PSC_SPIMSK_SD;
530
531 /* fill the transmit FIFO */
532 while (hw->tx_count < hw->len) {
533
534 hw->tx_word(hw);
535
536 if (hw->tx_count >= hw->len) {
537 /* mask tx fifo request interrupt as we are done */
538 mask |= PSC_SPIMSK_TR;
539 }
540
541 stat = hw->regs->psc_spistat;
542 au_sync();
543 if (stat & PSC_SPISTAT_TF)
544 break;
545 }
546
547 /* enable event interrupts */
548 hw->regs->psc_spimsk = mask;
549 au_sync();
550
551 /* start the transfer */
552 hw->regs->psc_spipcr = PSC_SPIPCR_MS;
553 au_sync();
554
555 wait_for_completion(&hw->master_done);
556
557 return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
558}
559
560static irqreturn_t au1550_spi_pio_irq_callback(struct au1550_spi *hw)
561{
562 int busy;
563 u32 stat, evnt;
564
565 stat = hw->regs->psc_spistat;
566 evnt = hw->regs->psc_spievent;
567 au_sync();
568 if ((stat & PSC_SPISTAT_DI) == 0) {
569 dev_err(hw->dev, "Unexpected IRQ!\n");
570 return IRQ_NONE;
571 }
572
573 if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
574 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
bbe48ecc 575 | PSC_SPIEVNT_SD))
63bd2359 576 != 0) {
63bd2359
JN		 577 /*
578 * due to an error we consider transfer as done,
579 * so mask all events until before next transfer start
580 */
581 au1550_spi_mask_ack_all(hw);
582 au1550_spi_reset_fifos(hw);
bbe48ecc
JN		 583 dev_err(hw->dev,
584 "pio transfer: unexpected SPI error "
585 "(event=0x%x stat=0x%x)!\n", evnt, stat);
63bd2359
JN		 586 complete(&hw->master_done);
587 return IRQ_HANDLED;
588 }
589
590 /*
591 * while there is something to read from rx fifo
592 * or there is a space to write to tx fifo:
593 */
594 do {
595 busy = 0;
596 stat = hw->regs->psc_spistat;
597 au_sync();
598
bbe48ecc
JN		 599 /*
600 * Take care to not let the Rx FIFO overflow.
601 *
602 * We only write a byte if we have read one at least. Initially,
603 * the write fifo is full, so we should read from the read fifo
604 * first.
605 * In case we miss a word from the read fifo, we should get a
606 * RO event and should back out.
607 */
608 if (!(stat & PSC_SPISTAT_RE) && hw->rx_count < hw->len) {
63bd2359 609 hw->rx_word(hw);
63bd2359 610 busy = 1;
63bd2359 611
bbe48ecc
JN		 612 if (!(stat & PSC_SPISTAT_TF) && hw->tx_count < hw->len)
613 hw->tx_word(hw);
63bd2359
JN		 614 }
615 } while (busy);
616
bbe48ecc 617 hw->regs->psc_spievent = PSC_SPIEVNT_RR | PSC_SPIEVNT_TR;
63bd2359
JN		 618 au_sync();
619
bbe48ecc
JN		 620 /*
621 * Restart the SPI transmission in case of a transmit underflow.
622 * This seems to work despite the notes in the Au1550 data book
623 * of Figure 8-4 with flowchart for SPI master operation:
624 *
625 * """Note 1: An XFR Error Interrupt occurs, unless masked,
626 * for any of the following events: Tx FIFO Underflow,
627 * Rx FIFO Overflow, or Multiple-master Error
628 * Note 2: In case of a Tx Underflow Error, all zeroes are
629 * transmitted."""
630 *
631 * By simply restarting the spi transfer on Tx Underflow Error,
632 * we assume that spi transfer was paused instead of zeroes
633 * transmittion mentioned in the Note 2 of Au1550 data book.
634 */
635 if (evnt & PSC_SPIEVNT_TU) {
636 hw->regs->psc_spievent = PSC_SPIEVNT_TU | PSC_SPIEVNT_MD;
637 au_sync();
638 hw->regs->psc_spipcr = PSC_SPIPCR_MS;
639 au_sync();
640 }
641
642 if (hw->rx_count >= hw->len) {
63bd2359
JN		 643 /* transfer completed successfully */
644 au1550_spi_mask_ack_all(hw);
645 complete(&hw->master_done);
646 }
647 return IRQ_HANDLED;
648}
649
650static int au1550_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
651{
652 struct au1550_spi *hw = spi_master_get_devdata(spi->master);
653 return hw->txrx_bufs(spi, t);
654}
655
40369e1c 656static irqreturn_t au1550_spi_irq(int irq, void *dev)
63bd2359
JN		 657{
658 struct au1550_spi *hw = dev;
659 return hw->irq_callback(hw);
660}
661
662static void au1550_spi_bits_handlers_set(struct au1550_spi *hw, int bpw)
663{
664 if (bpw <= 8) {
665 if (hw->usedma) {
666 hw->txrx_bufs = &au1550_spi_dma_txrxb;
667 hw->irq_callback = &au1550_spi_dma_irq_callback;
668 } else {
669 hw->rx_word = &au1550_spi_rx_word_8;
670 hw->tx_word = &au1550_spi_tx_word_8;
671 hw->txrx_bufs = &au1550_spi_pio_txrxb;
672 hw->irq_callback = &au1550_spi_pio_irq_callback;
673 }
674 } else if (bpw <= 16) {
675 hw->rx_word = &au1550_spi_rx_word_16;
676 hw->tx_word = &au1550_spi_tx_word_16;
677 hw->txrx_bufs = &au1550_spi_pio_txrxb;
678 hw->irq_callback = &au1550_spi_pio_irq_callback;
679 } else {
680 hw->rx_word = &au1550_spi_rx_word_32;
681 hw->tx_word = &au1550_spi_tx_word_32;
682 hw->txrx_bufs = &au1550_spi_pio_txrxb;
683 hw->irq_callback = &au1550_spi_pio_irq_callback;
684 }
685}
686
2deff8d6 687static void au1550_spi_setup_psc_as_spi(struct au1550_spi *hw)
63bd2359
JN		 688{
689 u32 stat, cfg;
690
691 /* set up the PSC for SPI mode */
692 hw->regs->psc_ctrl = PSC_CTRL_DISABLE;
693 au_sync();
694 hw->regs->psc_sel = PSC_SEL_PS_SPIMODE;
695 au_sync();
696
697 hw->regs->psc_spicfg = 0;
698 au_sync();
699
700 hw->regs->psc_ctrl = PSC_CTRL_ENABLE;
701 au_sync();
702
703 do {
704 stat = hw->regs->psc_spistat;
705 au_sync();
706 } while ((stat & PSC_SPISTAT_SR) == 0);
707
708
709 cfg = hw->usedma ? 0 : PSC_SPICFG_DD_DISABLE;
710 cfg |= PSC_SPICFG_SET_LEN(8);
711 cfg |= PSC_SPICFG_RT_FIFO8 | PSC_SPICFG_TT_FIFO8;
712 /* use minimal allowed brg and div values as initial setting: */
713 cfg |= PSC_SPICFG_SET_BAUD(4) | PSC_SPICFG_SET_DIV(0);
714
715#ifdef AU1550_SPI_DEBUG_LOOPBACK
716 cfg |= PSC_SPICFG_LB;
717#endif
718
719 hw->regs->psc_spicfg = cfg;
720 au_sync();
721
722 au1550_spi_mask_ack_all(hw);
723
724 hw->regs->psc_spicfg |= PSC_SPICFG_DE_ENABLE;
725 au_sync();
726
727 do {
728 stat = hw->regs->psc_spistat;
729 au_sync();
730 } while ((stat & PSC_SPISTAT_DR) == 0);
bbe48ecc
JN		 731
732 au1550_spi_reset_fifos(hw);
63bd2359
JN		 733}
734
735
2deff8d6 736static int au1550_spi_probe(struct platform_device *pdev)
63bd2359
JN		 737{
738 struct au1550_spi *hw;
739 struct spi_master *master;
3a93a159 740 struct resource *r;
63bd2359
JN		 741 int err = 0;
742
743 master = spi_alloc_master(&pdev->dev, sizeof(struct au1550_spi));
744 if (master == NULL) {
745 dev_err(&pdev->dev, "No memory for spi_master\n");
746 err = -ENOMEM;
747 goto err_nomem;
748 }
749
e7db06b5
DB		 750 /* the spi->mode bits understood by this driver: */
751 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
24778be2 752 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 24);
e7db06b5 753
63bd2359
JN		 754 hw = spi_master_get_devdata(master);
755
94c69f76 756 hw->master = master;
8074cf06 757 hw->pdata = dev_get_platdata(&pdev->dev);
63bd2359
JN		 758 hw->dev = &pdev->dev;
759
760 if (hw->pdata == NULL) {
761 dev_err(&pdev->dev, "No platform data supplied\n");
762 err = -ENOENT;
763 goto err_no_pdata;
764 }
765
3a93a159
ML		 766 r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
767 if (!r) {
768 dev_err(&pdev->dev, "no IRQ\n");
769 err = -ENODEV;
770 goto err_no_iores;
771 }
772 hw->irq = r->start;
773
774 hw->usedma = 0;
775 r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
776 if (r) {
777 hw->dma_tx_id = r->start;
778 r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
779 if (r) {
780 hw->dma_rx_id = r->start;
781 if (usedma && ddma_memid) {
782 if (pdev->dev.dma_mask == NULL)
783 dev_warn(&pdev->dev, "no dma mask\n");
784 else
785 hw->usedma = 1;
786 }
787 }
788 }
63bd2359 789
3a93a159
ML		 790 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
791 if (!r) {
792 dev_err(&pdev->dev, "no mmio resource\n");
793 err = -ENODEV;
794 goto err_no_iores;
63bd2359
JN		 795 }
796
3a93a159
ML		 797 hw->ioarea = request_mem_region(r->start, sizeof(psc_spi_t),
798 pdev->name);
799 if (!hw->ioarea) {
63bd2359
JN		 800 dev_err(&pdev->dev, "Cannot reserve iomem region\n");
801 err = -ENXIO;
802 goto err_no_iores;
803 }
804
3a93a159
ML		 805 hw->regs = (psc_spi_t __iomem *)ioremap(r->start, sizeof(psc_spi_t));
806 if (!hw->regs) {
807 dev_err(&pdev->dev, "cannot ioremap\n");
808 err = -ENXIO;
809 goto err_ioremap;
63bd2359
JN		 810 }
811
3a93a159 812 platform_set_drvdata(pdev, hw);
63bd2359 813
3a93a159
ML		 814 init_completion(&hw->master_done);
815
816 hw->bitbang.master = hw->master;
817 hw->bitbang.setup_transfer = au1550_spi_setupxfer;
818 hw->bitbang.chipselect = au1550_spi_chipsel;
3a93a159
ML		 819 hw->bitbang.txrx_bufs = au1550_spi_txrx_bufs;
820
821 if (hw->usedma) {
822 hw->dma_tx_ch = au1xxx_dbdma_chan_alloc(ddma_memid,
63bd2359
JN		 823 hw->dma_tx_id, NULL, (void *)hw);
824 if (hw->dma_tx_ch == 0) {
825 dev_err(&pdev->dev,
826 "Cannot allocate tx dma channel\n");
827 err = -ENXIO;
828 goto err_no_txdma;
829 }
830 au1xxx_dbdma_set_devwidth(hw->dma_tx_ch, 8);
831 if (au1xxx_dbdma_ring_alloc(hw->dma_tx_ch,
832 AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
833 dev_err(&pdev->dev,
834 "Cannot allocate tx dma descriptors\n");
835 err = -ENXIO;
836 goto err_no_txdma_descr;
837 }
838
839
840 hw->dma_rx_ch = au1xxx_dbdma_chan_alloc(hw->dma_rx_id,
3a93a159 841 ddma_memid, NULL, (void *)hw);
63bd2359
JN		 842 if (hw->dma_rx_ch == 0) {
843 dev_err(&pdev->dev,
844 "Cannot allocate rx dma channel\n");
845 err = -ENXIO;
846 goto err_no_rxdma;
847 }
848 au1xxx_dbdma_set_devwidth(hw->dma_rx_ch, 8);
849 if (au1xxx_dbdma_ring_alloc(hw->dma_rx_ch,
850 AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
851 dev_err(&pdev->dev,
852 "Cannot allocate rx dma descriptors\n");
853 err = -ENXIO;
854 goto err_no_rxdma_descr;
855 }
856
857 err = au1550_spi_dma_rxtmp_alloc(hw,
858 AU1550_SPI_DMA_RXTMP_MINSIZE);
859 if (err < 0) {
860 dev_err(&pdev->dev,
861 "Cannot allocate initial rx dma tmp buffer\n");
862 goto err_dma_rxtmp_alloc;
863 }
864 }
865
866 au1550_spi_bits_handlers_set(hw, 8);
867
868 err = request_irq(hw->irq, au1550_spi_irq, 0, pdev->name, hw);
869 if (err) {
870 dev_err(&pdev->dev, "Cannot claim IRQ\n");
871 goto err_no_irq;
872 }
873
3a93a159 874 master->bus_num = pdev->id;
63bd2359
JN		 875 master->num_chipselect = hw->pdata->num_chipselect;
876
877 /*
878 * precompute valid range for spi freq - from au1550 datasheet:
879 * psc_tempclk = psc_mainclk / (2 << DIV)
880 * spiclk = psc_tempclk / (2 * (BRG + 1))
881 * BRG valid range is 4..63
882 * DIV valid range is 0..3
883 * round the min and max frequencies to values that would still
884 * produce valid brg and div
885 */
886 {
887 int min_div = (2 << 0) * (2 * (4 + 1));
888 int max_div = (2 << 3) * (2 * (63 + 1));
0dd26e53
AL		 889 master->max_speed_hz = hw->pdata->mainclk_hz / min_div;
890 master->min_speed_hz =
891 hw->pdata->mainclk_hz / (max_div + 1) + 1;
63bd2359
JN		 892 }
893
894 au1550_spi_setup_psc_as_spi(hw);
895
896 err = spi_bitbang_start(&hw->bitbang);
897 if (err) {
898 dev_err(&pdev->dev, "Failed to register SPI master\n");
899 goto err_register;
900 }
901
902 dev_info(&pdev->dev,
903 "spi master registered: bus_num=%d num_chipselect=%d\n",
904 master->bus_num, master->num_chipselect);
905
906 return 0;
907
908err_register:
909 free_irq(hw->irq, hw);
910
911err_no_irq:
912 au1550_spi_dma_rxtmp_free(hw);
913
914err_dma_rxtmp_alloc:
915err_no_rxdma_descr:
916 if (hw->usedma)
917 au1xxx_dbdma_chan_free(hw->dma_rx_ch);
918
919err_no_rxdma:
920err_no_txdma_descr:
921 if (hw->usedma)
922 au1xxx_dbdma_chan_free(hw->dma_tx_ch);
923
924err_no_txdma:
3a93a159
ML		 925 iounmap((void __iomem *)hw->regs);
926
927err_ioremap:
928 release_resource(hw->ioarea);
929 kfree(hw->ioarea);
63bd2359
JN		 930
931err_no_iores:
932err_no_pdata:
933 spi_master_put(hw->master);
934
935err_nomem:
936 return err;
937}
938
2deff8d6 939static int au1550_spi_remove(struct platform_device *pdev)
63bd2359
JN		 940{
941 struct au1550_spi *hw = platform_get_drvdata(pdev);
942
943 dev_info(&pdev->dev, "spi master remove: bus_num=%d\n",
944 hw->master->bus_num);
945
946 spi_bitbang_stop(&hw->bitbang);
947 free_irq(hw->irq, hw);
3a93a159
ML		 948 iounmap((void __iomem *)hw->regs);
949 release_resource(hw->ioarea);
950 kfree(hw->ioarea);
63bd2359
JN		 951
952 if (hw->usedma) {
953 au1550_spi_dma_rxtmp_free(hw);
954 au1xxx_dbdma_chan_free(hw->dma_rx_ch);
955 au1xxx_dbdma_chan_free(hw->dma_tx_ch);
956 }
957
63bd2359
JN		 958 spi_master_put(hw->master);
959 return 0;
960}
961
7e38c3c4
KS		 962/* work with hotplug and coldplug */
963MODULE_ALIAS("platform:au1550-spi");
964
63bd2359 965static struct platform_driver au1550_spi_drv = {
75dab1bf 966 .probe = au1550_spi_probe,
2deff8d6 967 .remove = au1550_spi_remove,
63bd2359
JN		 968 .driver = {
969 .name = "au1550-spi",
970 .owner = THIS_MODULE,
971 },
972};
973
974static int __init au1550_spi_init(void)
975{
3a93a159
ML		 976 /*
977 * create memory device with 8 bits dev_devwidth
978 * needed for proper byte ordering to spi fifo
979 */
970e268d
ML		 980 switch (alchemy_get_cputype()) {
981 case ALCHEMY_CPU_AU1550:
982 case ALCHEMY_CPU_AU1200:
983 case ALCHEMY_CPU_AU1300:
984 break;
985 default:
986 return -ENODEV;
987 }
988
3a93a159
ML		 989 if (usedma) {
990 ddma_memid = au1xxx_ddma_add_device(&au1550_spi_mem_dbdev);
991 if (!ddma_memid)
992 printk(KERN_ERR "au1550-spi: cannot add memory"
993 "dbdma device\n");
994 }
75dab1bf 995 return platform_driver_register(&au1550_spi_drv);
63bd2359
JN		 996}
997module_init(au1550_spi_init);
998
999static void __exit au1550_spi_exit(void)
1000{
3a93a159
ML		 1001 if (usedma && ddma_memid)
1002 au1xxx_ddma_del_device(ddma_memid);
63bd2359
JN		 1003 platform_driver_unregister(&au1550_spi_drv);
1004}
1005module_exit(au1550_spi_exit);
1006
1007MODULE_DESCRIPTION("Au1550 PSC SPI Driver");
1008MODULE_AUTHOR("Jan Nikitenko <jan.nikitenko@gmail.com>");
1009MODULE_LICENSE("GPL");
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