1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * au1550 psc spi controller driver
4 * may work also with au1200, au1210, au1250
5 * will not work on au1000, au1100 and au1500 (no full spi controller there)
6 *
7 * Copyright (c) 2006 ATRON electronic GmbH
8 * Author: Jan Nikitenko <jan.nikitenko@gmail.com>
9 */
10
11 #include <linux/init.h>
12 #include <linux/interrupt.h>
13 #include <linux/slab.h>
14 #include <linux/errno.h>
15 #include <linux/module.h>
16 #include <linux/device.h>
17 #include <linux/platform_device.h>
18 #include <linux/resource.h>
19 #include <linux/spi/spi.h>
20 #include <linux/spi/spi_bitbang.h>
21 #include <linux/dma-mapping.h>
22 #include <linux/completion.h>
23 #include <asm/mach-au1x00/au1000.h>
24 #include <asm/mach-au1x00/au1xxx_psc.h>
25 #include <asm/mach-au1x00/au1xxx_dbdma.h>
26
27 #include <asm/mach-au1x00/au1550_spi.h>
28
29 static unsigned int usedma = 1;
30 module_param(usedma, uint, 0644);
31
32 /*
33 #define AU1550_SPI_DEBUG_LOOPBACK
34 */
35
36
37 #define AU1550_SPI_DBDMA_DESCRIPTORS 1
38 #define AU1550_SPI_DMA_RXTMP_MINSIZE 2048U
39
40 struct au1550_spi {
41 struct spi_bitbang bitbang;
42
43 volatile psc_spi_t __iomem *regs;
44 int irq;
45
46 unsigned int len;
47 unsigned int tx_count;
48 unsigned int rx_count;
49 const u8 *tx;
50 u8 *rx;
51
52 void (*rx_word)(struct au1550_spi *hw);
53 void (*tx_word)(struct au1550_spi *hw);
54 int (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
55 irqreturn_t (*irq_callback)(struct au1550_spi *hw);
56
57 struct completion master_done;
58
59 unsigned int usedma;
60 u32 dma_tx_id;
61 u32 dma_rx_id;
62 u32 dma_tx_ch;
63 u32 dma_rx_ch;
64
65 u8 *dma_rx_tmpbuf;
66 unsigned int dma_rx_tmpbuf_size;
67 u32 dma_rx_tmpbuf_addr;
68
69 struct spi_master *master;
70 struct device *dev;
71 struct au1550_spi_info *pdata;
72 struct resource *ioarea;
73 };
74
75
76 /* we use an 8-bit memory device for dma transfers to/from spi fifo */
77 static dbdev_tab_t au1550_spi_mem_dbdev = {
78 .dev_id = DBDMA_MEM_CHAN,
79 .dev_flags = DEV_FLAGS_ANYUSE|DEV_FLAGS_SYNC,
80 .dev_tsize = 0,
81 .dev_devwidth = 8,
82 .dev_physaddr = 0x00000000,
83 .dev_intlevel = 0,
84 .dev_intpolarity = 0
85 };
86
87 static int ddma_memid; /* id to above mem dma device */
88
89 static void au1550_spi_bits_handlers_set(struct au1550_spi *hw, int bpw);
90
91
92 /*
93 * compute BRG and DIV bits to setup spi clock based on main input clock rate
94 * that was specified in platform data structure
95 * according to au1550 datasheet:
96 * psc_tempclk = psc_mainclk / (2 << DIV)
97 * spiclk = psc_tempclk / (2 * (BRG + 1))
98 * BRG valid range is 4..63
99 * DIV valid range is 0..3
100 */
au1550_spi_baudcfg(struct au1550_spi * hw,unsigned int speed_hz)101 static u32 au1550_spi_baudcfg(struct au1550_spi *hw, unsigned int speed_hz)
102 {
103 u32 mainclk_hz = hw->pdata->mainclk_hz;
104 u32 div, brg;
105
106 for (div = 0; div < 4; div++) {
107 brg = mainclk_hz / speed_hz / (4 << div);
108 /* now we have BRG+1 in brg, so count with that */
109 if (brg < (4 + 1)) {
110 brg = (4 + 1); /* speed_hz too big */
111 break; /* set lowest brg (div is == 0) */
112 }
113 if (brg <= (63 + 1))
114 break; /* we have valid brg and div */
115 }
116 if (div == 4) {
117 div = 3; /* speed_hz too small */
118 brg = (63 + 1); /* set highest brg and div */
119 }
120 brg--;
121 return PSC_SPICFG_SET_BAUD(brg) | PSC_SPICFG_SET_DIV(div);
122 }
123
au1550_spi_mask_ack_all(struct au1550_spi * hw)124 static inline void au1550_spi_mask_ack_all(struct au1550_spi *hw)
125 {
126 hw->regs->psc_spimsk =
127 PSC_SPIMSK_MM | PSC_SPIMSK_RR | PSC_SPIMSK_RO
128 | PSC_SPIMSK_RU | PSC_SPIMSK_TR | PSC_SPIMSK_TO
129 | PSC_SPIMSK_TU | PSC_SPIMSK_SD | PSC_SPIMSK_MD;
130 wmb(); /* drain writebuffer */
131
132 hw->regs->psc_spievent =
133 PSC_SPIEVNT_MM | PSC_SPIEVNT_RR | PSC_SPIEVNT_RO
134 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TR | PSC_SPIEVNT_TO
135 | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD | PSC_SPIEVNT_MD;
136 wmb(); /* drain writebuffer */
137 }
138
au1550_spi_reset_fifos(struct au1550_spi * hw)139 static void au1550_spi_reset_fifos(struct au1550_spi *hw)
140 {
141 u32 pcr;
142
143 hw->regs->psc_spipcr = PSC_SPIPCR_RC | PSC_SPIPCR_TC;
144 wmb(); /* drain writebuffer */
145 do {
146 pcr = hw->regs->psc_spipcr;
147 wmb(); /* drain writebuffer */
148 } while (pcr != 0);
149 }
150
151 /*
152 * dma transfers are used for the most common spi word size of 8-bits
153 * we cannot easily change already set up dma channels' width, so if we wanted
154 * dma support for more than 8-bit words (up to 24 bits), we would need to
155 * setup dma channels from scratch on each spi transfer, based on bits_per_word
156 * instead we have pre set up 8 bit dma channels supporting spi 4 to 8 bits
157 * transfers, and 9 to 24 bits spi transfers will be done in pio irq based mode
158 * callbacks to handle dma or pio are set up in au1550_spi_bits_handlers_set()
159 */
au1550_spi_chipsel(struct spi_device * spi,int value)160 static void au1550_spi_chipsel(struct spi_device *spi, int value)
161 {
162 struct au1550_spi *hw = spi_master_get_devdata(spi->master);
163 unsigned int cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
164 u32 cfg, stat;
165
166 switch (value) {
167 case BITBANG_CS_INACTIVE:
168 if (hw->pdata->deactivate_cs)
169 hw->pdata->deactivate_cs(hw->pdata, spi->chip_select,
170 cspol);
171 break;
172
173 case BITBANG_CS_ACTIVE:
174 au1550_spi_bits_handlers_set(hw, spi->bits_per_word);
175
176 cfg = hw->regs->psc_spicfg;
177 wmb(); /* drain writebuffer */
178 hw->regs->psc_spicfg = cfg & ~PSC_SPICFG_DE_ENABLE;
179 wmb(); /* drain writebuffer */
180
181 if (spi->mode & SPI_CPOL)
182 cfg |= PSC_SPICFG_BI;
183 else
184 cfg &= ~PSC_SPICFG_BI;
185 if (spi->mode & SPI_CPHA)
186 cfg &= ~PSC_SPICFG_CDE;
187 else
188 cfg |= PSC_SPICFG_CDE;
189
190 if (spi->mode & SPI_LSB_FIRST)
191 cfg |= PSC_SPICFG_MLF;
192 else
193 cfg &= ~PSC_SPICFG_MLF;
194
195 if (hw->usedma && spi->bits_per_word <= 8)
196 cfg &= ~PSC_SPICFG_DD_DISABLE;
197 else
198 cfg |= PSC_SPICFG_DD_DISABLE;
199 cfg = PSC_SPICFG_CLR_LEN(cfg);
200 cfg |= PSC_SPICFG_SET_LEN(spi->bits_per_word);
201
202 cfg = PSC_SPICFG_CLR_BAUD(cfg);
203 cfg &= ~PSC_SPICFG_SET_DIV(3);
204 cfg |= au1550_spi_baudcfg(hw, spi->max_speed_hz);
205
206 hw->regs->psc_spicfg = cfg | PSC_SPICFG_DE_ENABLE;
207 wmb(); /* drain writebuffer */
208 do {
209 stat = hw->regs->psc_spistat;
210 wmb(); /* drain writebuffer */
211 } while ((stat & PSC_SPISTAT_DR) == 0);
212
213 if (hw->pdata->activate_cs)
214 hw->pdata->activate_cs(hw->pdata, spi->chip_select,
215 cspol);
216 break;
217 }
218 }
219
au1550_spi_setupxfer(struct spi_device * spi,struct spi_transfer * t)220 static int au1550_spi_setupxfer(struct spi_device *spi, struct spi_transfer *t)
221 {
222 struct au1550_spi *hw = spi_master_get_devdata(spi->master);
223 unsigned int bpw, hz;
224 u32 cfg, stat;
225
226 if (t) {
227 bpw = t->bits_per_word;
228 hz = t->speed_hz;
229 } else {
230 bpw = spi->bits_per_word;
231 hz = spi->max_speed_hz;
232 }
233
234 if (!hz)
235 return -EINVAL;
236
237 au1550_spi_bits_handlers_set(hw, spi->bits_per_word);
238
239 cfg = hw->regs->psc_spicfg;
240 wmb(); /* drain writebuffer */
241 hw->regs->psc_spicfg = cfg & ~PSC_SPICFG_DE_ENABLE;
242 wmb(); /* drain writebuffer */
243
244 if (hw->usedma && bpw <= 8)
245 cfg &= ~PSC_SPICFG_DD_DISABLE;
246 else
247 cfg |= PSC_SPICFG_DD_DISABLE;
248 cfg = PSC_SPICFG_CLR_LEN(cfg);
249 cfg |= PSC_SPICFG_SET_LEN(bpw);
250
251 cfg = PSC_SPICFG_CLR_BAUD(cfg);
252 cfg &= ~PSC_SPICFG_SET_DIV(3);
253 cfg |= au1550_spi_baudcfg(hw, hz);
254
255 hw->regs->psc_spicfg = cfg;
256 wmb(); /* drain writebuffer */
257
258 if (cfg & PSC_SPICFG_DE_ENABLE) {
259 do {
260 stat = hw->regs->psc_spistat;
261 wmb(); /* drain writebuffer */
262 } while ((stat & PSC_SPISTAT_DR) == 0);
263 }
264
265 au1550_spi_reset_fifos(hw);
266 au1550_spi_mask_ack_all(hw);
267 return 0;
268 }
269
270 /*
271 * for dma spi transfers, we have to setup rx channel, otherwise there is
272 * no reliable way how to recognize that spi transfer is done
273 * dma complete callbacks are called before real spi transfer is finished
274 * and if only tx dma channel is set up (and rx fifo overflow event masked)
275 * spi master done event irq is not generated unless rx fifo is empty (emptied)
276 * so we need rx tmp buffer to use for rx dma if user does not provide one
277 */
au1550_spi_dma_rxtmp_alloc(struct au1550_spi * hw,unsigned int size)278 static int au1550_spi_dma_rxtmp_alloc(struct au1550_spi *hw, unsigned int size)
279 {
280 hw->dma_rx_tmpbuf = kmalloc(size, GFP_KERNEL);
281 if (!hw->dma_rx_tmpbuf)
282 return -ENOMEM;
283 hw->dma_rx_tmpbuf_size = size;
284 hw->dma_rx_tmpbuf_addr = dma_map_single(hw->dev, hw->dma_rx_tmpbuf,
285 size, DMA_FROM_DEVICE);
286 if (dma_mapping_error(hw->dev, hw->dma_rx_tmpbuf_addr)) {
287 kfree(hw->dma_rx_tmpbuf);
288 hw->dma_rx_tmpbuf = 0;
289 hw->dma_rx_tmpbuf_size = 0;
290 return -EFAULT;
291 }
292 return 0;
293 }
294
au1550_spi_dma_rxtmp_free(struct au1550_spi * hw)295 static void au1550_spi_dma_rxtmp_free(struct au1550_spi *hw)
296 {
297 dma_unmap_single(hw->dev, hw->dma_rx_tmpbuf_addr,
298 hw->dma_rx_tmpbuf_size, DMA_FROM_DEVICE);
299 kfree(hw->dma_rx_tmpbuf);
300 hw->dma_rx_tmpbuf = 0;
301 hw->dma_rx_tmpbuf_size = 0;
302 }
303
au1550_spi_dma_txrxb(struct spi_device * spi,struct spi_transfer * t)304 static int au1550_spi_dma_txrxb(struct spi_device *spi, struct spi_transfer *t)
305 {
306 struct au1550_spi *hw = spi_master_get_devdata(spi->master);
307 dma_addr_t dma_tx_addr;
308 dma_addr_t dma_rx_addr;
309 u32 res;
310
311 hw->len = t->len;
312 hw->tx_count = 0;
313 hw->rx_count = 0;
314
315 hw->tx = t->tx_buf;
316 hw->rx = t->rx_buf;
317 dma_tx_addr = t->tx_dma;
318 dma_rx_addr = t->rx_dma;
319
320 /*
321 * check if buffers are already dma mapped, map them otherwise:
322 * - first map the TX buffer, so cache data gets written to memory
323 * - then map the RX buffer, so that cache entries (with
324 * soon-to-be-stale data) get removed
325 * use rx buffer in place of tx if tx buffer was not provided
326 * use temp rx buffer (preallocated or realloc to fit) for rx dma
327 */
328 if (t->tx_buf) {
329 if (t->tx_dma == 0) { /* if DMA_ADDR_INVALID, map it */
330 dma_tx_addr = dma_map_single(hw->dev,
331 (void *)t->tx_buf,
332 t->len, DMA_TO_DEVICE);
333 if (dma_mapping_error(hw->dev, dma_tx_addr))
334 dev_err(hw->dev, "tx dma map error\n");
335 }
336 }
337
338 if (t->rx_buf) {
339 if (t->rx_dma == 0) { /* if DMA_ADDR_INVALID, map it */
340 dma_rx_addr = dma_map_single(hw->dev,
341 (void *)t->rx_buf,
342 t->len, DMA_FROM_DEVICE);
343 if (dma_mapping_error(hw->dev, dma_rx_addr))
344 dev_err(hw->dev, "rx dma map error\n");
345 }
346 } else {
347 if (t->len > hw->dma_rx_tmpbuf_size) {
348 int ret;
349
350 au1550_spi_dma_rxtmp_free(hw);
351 ret = au1550_spi_dma_rxtmp_alloc(hw, max(t->len,
352 AU1550_SPI_DMA_RXTMP_MINSIZE));
353 if (ret < 0)
354 return ret;
355 }
356 hw->rx = hw->dma_rx_tmpbuf;
357 dma_rx_addr = hw->dma_rx_tmpbuf_addr;
358 dma_sync_single_for_device(hw->dev, dma_rx_addr,
359 t->len, DMA_FROM_DEVICE);
360 }
361
362 if (!t->tx_buf) {
363 dma_sync_single_for_device(hw->dev, dma_rx_addr,
364 t->len, DMA_BIDIRECTIONAL);
365 hw->tx = hw->rx;
366 }
367
368 /* put buffers on the ring */
369 res = au1xxx_dbdma_put_dest(hw->dma_rx_ch, virt_to_phys(hw->rx),
370 t->len, DDMA_FLAGS_IE);
371 if (!res)
372 dev_err(hw->dev, "rx dma put dest error\n");
373
374 res = au1xxx_dbdma_put_source(hw->dma_tx_ch, virt_to_phys(hw->tx),
375 t->len, DDMA_FLAGS_IE);
376 if (!res)
377 dev_err(hw->dev, "tx dma put source error\n");
378
379 au1xxx_dbdma_start(hw->dma_rx_ch);
380 au1xxx_dbdma_start(hw->dma_tx_ch);
381
382 /* by default enable nearly all events interrupt */
383 hw->regs->psc_spimsk = PSC_SPIMSK_SD;
384 wmb(); /* drain writebuffer */
385
386 /* start the transfer */
387 hw->regs->psc_spipcr = PSC_SPIPCR_MS;
388 wmb(); /* drain writebuffer */
389
390 wait_for_completion(&hw->master_done);
391
392 au1xxx_dbdma_stop(hw->dma_tx_ch);
393 au1xxx_dbdma_stop(hw->dma_rx_ch);
394
395 if (!t->rx_buf) {
396 /* using the temporal preallocated and premapped buffer */
397 dma_sync_single_for_cpu(hw->dev, dma_rx_addr, t->len,
398 DMA_FROM_DEVICE);
399 }
400 /* unmap buffers if mapped above */
401 if (t->rx_buf && t->rx_dma == 0)
402 dma_unmap_single(hw->dev, dma_rx_addr, t->len,
403 DMA_FROM_DEVICE);
404 if (t->tx_buf && t->tx_dma == 0)
405 dma_unmap_single(hw->dev, dma_tx_addr, t->len,
406 DMA_TO_DEVICE);
407
408 return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
409 }
410
au1550_spi_dma_irq_callback(struct au1550_spi * hw)411 static irqreturn_t au1550_spi_dma_irq_callback(struct au1550_spi *hw)
412 {
413 u32 stat, evnt;
414
415 stat = hw->regs->psc_spistat;
416 evnt = hw->regs->psc_spievent;
417 wmb(); /* drain writebuffer */
418 if ((stat & PSC_SPISTAT_DI) == 0) {
419 dev_err(hw->dev, "Unexpected IRQ!\n");
420 return IRQ_NONE;
421 }
422
423 if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
424 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
425 | PSC_SPIEVNT_TU | PSC_SPIEVNT_SD))
426 != 0) {
427 /*
428 * due to an spi error we consider transfer as done,
429 * so mask all events until before next transfer start
430 * and stop the possibly running dma immediately
431 */
432 au1550_spi_mask_ack_all(hw);
433 au1xxx_dbdma_stop(hw->dma_rx_ch);
434 au1xxx_dbdma_stop(hw->dma_tx_ch);
435
436 /* get number of transferred bytes */
437 hw->rx_count = hw->len - au1xxx_get_dma_residue(hw->dma_rx_ch);
438 hw->tx_count = hw->len - au1xxx_get_dma_residue(hw->dma_tx_ch);
439
440 au1xxx_dbdma_reset(hw->dma_rx_ch);
441 au1xxx_dbdma_reset(hw->dma_tx_ch);
442 au1550_spi_reset_fifos(hw);
443
444 if (evnt == PSC_SPIEVNT_RO)
445 dev_err(hw->dev,
446 "dma transfer: receive FIFO overflow!\n");
447 else
448 dev_err(hw->dev,
449 "dma transfer: unexpected SPI error (event=0x%x stat=0x%x)!\n",
450 evnt, stat);
451
452 complete(&hw->master_done);
453 return IRQ_HANDLED;
454 }
455
456 if ((evnt & PSC_SPIEVNT_MD) != 0) {
457 /* transfer completed successfully */
458 au1550_spi_mask_ack_all(hw);
459 hw->rx_count = hw->len;
460 hw->tx_count = hw->len;
461 complete(&hw->master_done);
462 }
463 return IRQ_HANDLED;
464 }
465
466
467 /* routines to handle different word sizes in pio mode */
468 #define AU1550_SPI_RX_WORD(size, mask) \
469 static void au1550_spi_rx_word_##size(struct au1550_spi *hw) \
470 { \
471 u32 fifoword = hw->regs->psc_spitxrx & (u32)(mask); \
472 wmb(); /* drain writebuffer */ \
473 if (hw->rx) { \
474 *(u##size *)hw->rx = (u##size)fifoword; \
475 hw->rx += (size) / 8; \
476 } \
477 hw->rx_count += (size) / 8; \
478 }
479
480 #define AU1550_SPI_TX_WORD(size, mask) \
481 static void au1550_spi_tx_word_##size(struct au1550_spi *hw) \
482 { \
483 u32 fifoword = 0; \
484 if (hw->tx) { \
485 fifoword = *(u##size *)hw->tx & (u32)(mask); \
486 hw->tx += (size) / 8; \
487 } \
488 hw->tx_count += (size) / 8; \
489 if (hw->tx_count >= hw->len) \
490 fifoword |= PSC_SPITXRX_LC; \
491 hw->regs->psc_spitxrx = fifoword; \
492 wmb(); /* drain writebuffer */ \
493 }
494
495 AU1550_SPI_RX_WORD(8, 0xff)
496 AU1550_SPI_RX_WORD(16, 0xffff)
497 AU1550_SPI_RX_WORD(32, 0xffffff)
498 AU1550_SPI_TX_WORD(8, 0xff)
499 AU1550_SPI_TX_WORD(16, 0xffff)
500 AU1550_SPI_TX_WORD(32, 0xffffff)
501
au1550_spi_pio_txrxb(struct spi_device * spi,struct spi_transfer * t)502 static int au1550_spi_pio_txrxb(struct spi_device *spi, struct spi_transfer *t)
503 {
504 u32 stat, mask;
505 struct au1550_spi *hw = spi_master_get_devdata(spi->master);
506
507 hw->tx = t->tx_buf;
508 hw->rx = t->rx_buf;
509 hw->len = t->len;
510 hw->tx_count = 0;
511 hw->rx_count = 0;
512
513 /* by default enable nearly all events after filling tx fifo */
514 mask = PSC_SPIMSK_SD;
515
516 /* fill the transmit FIFO */
517 while (hw->tx_count < hw->len) {
518
519 hw->tx_word(hw);
520
521 if (hw->tx_count >= hw->len) {
522 /* mask tx fifo request interrupt as we are done */
523 mask |= PSC_SPIMSK_TR;
524 }
525
526 stat = hw->regs->psc_spistat;
527 wmb(); /* drain writebuffer */
528 if (stat & PSC_SPISTAT_TF)
529 break;
530 }
531
532 /* enable event interrupts */
533 hw->regs->psc_spimsk = mask;
534 wmb(); /* drain writebuffer */
535
536 /* start the transfer */
537 hw->regs->psc_spipcr = PSC_SPIPCR_MS;
538 wmb(); /* drain writebuffer */
539
540 wait_for_completion(&hw->master_done);
541
542 return hw->rx_count < hw->tx_count ? hw->rx_count : hw->tx_count;
543 }
544
au1550_spi_pio_irq_callback(struct au1550_spi * hw)545 static irqreturn_t au1550_spi_pio_irq_callback(struct au1550_spi *hw)
546 {
547 int busy;
548 u32 stat, evnt;
549
550 stat = hw->regs->psc_spistat;
551 evnt = hw->regs->psc_spievent;
552 wmb(); /* drain writebuffer */
553 if ((stat & PSC_SPISTAT_DI) == 0) {
554 dev_err(hw->dev, "Unexpected IRQ!\n");
555 return IRQ_NONE;
556 }
557
558 if ((evnt & (PSC_SPIEVNT_MM | PSC_SPIEVNT_RO
559 | PSC_SPIEVNT_RU | PSC_SPIEVNT_TO
560 | PSC_SPIEVNT_SD))
561 != 0) {
562 /*
563 * due to an error we consider transfer as done,
564 * so mask all events until before next transfer start
565 */
566 au1550_spi_mask_ack_all(hw);
567 au1550_spi_reset_fifos(hw);
568 dev_err(hw->dev,
569 "pio transfer: unexpected SPI error (event=0x%x stat=0x%x)!\n",
570 evnt, stat);
571 complete(&hw->master_done);
572 return IRQ_HANDLED;
573 }
574
575 /*
576 * while there is something to read from rx fifo
577 * or there is a space to write to tx fifo:
578 */
579 do {
580 busy = 0;
581 stat = hw->regs->psc_spistat;
582 wmb(); /* drain writebuffer */
583
584 /*
585 * Take care to not let the Rx FIFO overflow.
586 *
587 * We only write a byte if we have read one at least. Initially,
588 * the write fifo is full, so we should read from the read fifo
589 * first.
590 * In case we miss a word from the read fifo, we should get a
591 * RO event and should back out.
592 */
593 if (!(stat & PSC_SPISTAT_RE) && hw->rx_count < hw->len) {
594 hw->rx_word(hw);
595 busy = 1;
596
597 if (!(stat & PSC_SPISTAT_TF) && hw->tx_count < hw->len)
598 hw->tx_word(hw);
599 }
600 } while (busy);
601
602 hw->regs->psc_spievent = PSC_SPIEVNT_RR | PSC_SPIEVNT_TR;
603 wmb(); /* drain writebuffer */
604
605 /*
606 * Restart the SPI transmission in case of a transmit underflow.
607 * This seems to work despite the notes in the Au1550 data book
608 * of Figure 8-4 with flowchart for SPI master operation:
609 *
610 * """Note 1: An XFR Error Interrupt occurs, unless masked,
611 * for any of the following events: Tx FIFO Underflow,
612 * Rx FIFO Overflow, or Multiple-master Error
613 * Note 2: In case of a Tx Underflow Error, all zeroes are
614 * transmitted."""
615 *
616 * By simply restarting the spi transfer on Tx Underflow Error,
617 * we assume that spi transfer was paused instead of zeroes
618 * transmittion mentioned in the Note 2 of Au1550 data book.
619 */
620 if (evnt & PSC_SPIEVNT_TU) {
621 hw->regs->psc_spievent = PSC_SPIEVNT_TU | PSC_SPIEVNT_MD;
622 wmb(); /* drain writebuffer */
623 hw->regs->psc_spipcr = PSC_SPIPCR_MS;
624 wmb(); /* drain writebuffer */
625 }
626
627 if (hw->rx_count >= hw->len) {
628 /* transfer completed successfully */
629 au1550_spi_mask_ack_all(hw);
630 complete(&hw->master_done);
631 }
632 return IRQ_HANDLED;
633 }
634
au1550_spi_txrx_bufs(struct spi_device * spi,struct spi_transfer * t)635 static int au1550_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
636 {
637 struct au1550_spi *hw = spi_master_get_devdata(spi->master);
638
639 return hw->txrx_bufs(spi, t);
640 }
641
au1550_spi_irq(int irq,void * dev)642 static irqreturn_t au1550_spi_irq(int irq, void *dev)
643 {
644 struct au1550_spi *hw = dev;
645
646 return hw->irq_callback(hw);
647 }
648
au1550_spi_bits_handlers_set(struct au1550_spi * hw,int bpw)649 static void au1550_spi_bits_handlers_set(struct au1550_spi *hw, int bpw)
650 {
651 if (bpw <= 8) {
652 if (hw->usedma) {
653 hw->txrx_bufs = &au1550_spi_dma_txrxb;
654 hw->irq_callback = &au1550_spi_dma_irq_callback;
655 } else {
656 hw->rx_word = &au1550_spi_rx_word_8;
657 hw->tx_word = &au1550_spi_tx_word_8;
658 hw->txrx_bufs = &au1550_spi_pio_txrxb;
659 hw->irq_callback = &au1550_spi_pio_irq_callback;
660 }
661 } else if (bpw <= 16) {
662 hw->rx_word = &au1550_spi_rx_word_16;
663 hw->tx_word = &au1550_spi_tx_word_16;
664 hw->txrx_bufs = &au1550_spi_pio_txrxb;
665 hw->irq_callback = &au1550_spi_pio_irq_callback;
666 } else {
667 hw->rx_word = &au1550_spi_rx_word_32;
668 hw->tx_word = &au1550_spi_tx_word_32;
669 hw->txrx_bufs = &au1550_spi_pio_txrxb;
670 hw->irq_callback = &au1550_spi_pio_irq_callback;
671 }
672 }
673
au1550_spi_setup_psc_as_spi(struct au1550_spi * hw)674 static void au1550_spi_setup_psc_as_spi(struct au1550_spi *hw)
675 {
676 u32 stat, cfg;
677
678 /* set up the PSC for SPI mode */
679 hw->regs->psc_ctrl = PSC_CTRL_DISABLE;
680 wmb(); /* drain writebuffer */
681 hw->regs->psc_sel = PSC_SEL_PS_SPIMODE;
682 wmb(); /* drain writebuffer */
683
684 hw->regs->psc_spicfg = 0;
685 wmb(); /* drain writebuffer */
686
687 hw->regs->psc_ctrl = PSC_CTRL_ENABLE;
688 wmb(); /* drain writebuffer */
689
690 do {
691 stat = hw->regs->psc_spistat;
692 wmb(); /* drain writebuffer */
693 } while ((stat & PSC_SPISTAT_SR) == 0);
694
695
696 cfg = hw->usedma ? 0 : PSC_SPICFG_DD_DISABLE;
697 cfg |= PSC_SPICFG_SET_LEN(8);
698 cfg |= PSC_SPICFG_RT_FIFO8 | PSC_SPICFG_TT_FIFO8;
699 /* use minimal allowed brg and div values as initial setting: */
700 cfg |= PSC_SPICFG_SET_BAUD(4) | PSC_SPICFG_SET_DIV(0);
701
702 #ifdef AU1550_SPI_DEBUG_LOOPBACK
703 cfg |= PSC_SPICFG_LB;
704 #endif
705
706 hw->regs->psc_spicfg = cfg;
707 wmb(); /* drain writebuffer */
708
709 au1550_spi_mask_ack_all(hw);
710
711 hw->regs->psc_spicfg |= PSC_SPICFG_DE_ENABLE;
712 wmb(); /* drain writebuffer */
713
714 do {
715 stat = hw->regs->psc_spistat;
716 wmb(); /* drain writebuffer */
717 } while ((stat & PSC_SPISTAT_DR) == 0);
718
719 au1550_spi_reset_fifos(hw);
720 }
721
722
au1550_spi_probe(struct platform_device * pdev)723 static int au1550_spi_probe(struct platform_device *pdev)
724 {
725 struct au1550_spi *hw;
726 struct spi_master *master;
727 struct resource *r;
728 int err = 0;
729
730 master = spi_alloc_master(&pdev->dev, sizeof(struct au1550_spi));
731 if (master == NULL) {
732 dev_err(&pdev->dev, "No memory for spi_master\n");
733 err = -ENOMEM;
734 goto err_nomem;
735 }
736
737 /* the spi->mode bits understood by this driver: */
738 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
739 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 24);
740
741 hw = spi_master_get_devdata(master);
742
743 hw->master = master;
744 hw->pdata = dev_get_platdata(&pdev->dev);
745 hw->dev = &pdev->dev;
746
747 if (hw->pdata == NULL) {
748 dev_err(&pdev->dev, "No platform data supplied\n");
749 err = -ENOENT;
750 goto err_no_pdata;
751 }
752
753 r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
754 if (!r) {
755 dev_err(&pdev->dev, "no IRQ\n");
756 err = -ENODEV;
757 goto err_no_iores;
758 }
759 hw->irq = r->start;
760
761 hw->usedma = 0;
762 r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
763 if (r) {
764 hw->dma_tx_id = r->start;
765 r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
766 if (r) {
767 hw->dma_rx_id = r->start;
768 if (usedma && ddma_memid) {
769 if (pdev->dev.dma_mask == NULL)
770 dev_warn(&pdev->dev, "no dma mask\n");
771 else
772 hw->usedma = 1;
773 }
774 }
775 }
776
777 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
778 if (!r) {
779 dev_err(&pdev->dev, "no mmio resource\n");
780 err = -ENODEV;
781 goto err_no_iores;
782 }
783
784 hw->ioarea = request_mem_region(r->start, sizeof(psc_spi_t),
785 pdev->name);
786 if (!hw->ioarea) {
787 dev_err(&pdev->dev, "Cannot reserve iomem region\n");
788 err = -ENXIO;
789 goto err_no_iores;
790 }
791
792 hw->regs = (psc_spi_t __iomem *)ioremap(r->start, sizeof(psc_spi_t));
793 if (!hw->regs) {
794 dev_err(&pdev->dev, "cannot ioremap\n");
795 err = -ENXIO;
796 goto err_ioremap;
797 }
798
799 platform_set_drvdata(pdev, hw);
800
801 init_completion(&hw->master_done);
802
803 hw->bitbang.master = hw->master;
804 hw->bitbang.setup_transfer = au1550_spi_setupxfer;
805 hw->bitbang.chipselect = au1550_spi_chipsel;
806 hw->bitbang.txrx_bufs = au1550_spi_txrx_bufs;
807
808 if (hw->usedma) {
809 hw->dma_tx_ch = au1xxx_dbdma_chan_alloc(ddma_memid,
810 hw->dma_tx_id, NULL, (void *)hw);
811 if (hw->dma_tx_ch == 0) {
812 dev_err(&pdev->dev,
813 "Cannot allocate tx dma channel\n");
814 err = -ENXIO;
815 goto err_no_txdma;
816 }
817 au1xxx_dbdma_set_devwidth(hw->dma_tx_ch, 8);
818 if (au1xxx_dbdma_ring_alloc(hw->dma_tx_ch,
819 AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
820 dev_err(&pdev->dev,
821 "Cannot allocate tx dma descriptors\n");
822 err = -ENXIO;
823 goto err_no_txdma_descr;
824 }
825
826
827 hw->dma_rx_ch = au1xxx_dbdma_chan_alloc(hw->dma_rx_id,
828 ddma_memid, NULL, (void *)hw);
829 if (hw->dma_rx_ch == 0) {
830 dev_err(&pdev->dev,
831 "Cannot allocate rx dma channel\n");
832 err = -ENXIO;
833 goto err_no_rxdma;
834 }
835 au1xxx_dbdma_set_devwidth(hw->dma_rx_ch, 8);
836 if (au1xxx_dbdma_ring_alloc(hw->dma_rx_ch,
837 AU1550_SPI_DBDMA_DESCRIPTORS) == 0) {
838 dev_err(&pdev->dev,
839 "Cannot allocate rx dma descriptors\n");
840 err = -ENXIO;
841 goto err_no_rxdma_descr;
842 }
843
844 err = au1550_spi_dma_rxtmp_alloc(hw,
845 AU1550_SPI_DMA_RXTMP_MINSIZE);
846 if (err < 0) {
847 dev_err(&pdev->dev,
848 "Cannot allocate initial rx dma tmp buffer\n");
849 goto err_dma_rxtmp_alloc;
850 }
851 }
852
853 au1550_spi_bits_handlers_set(hw, 8);
854
855 err = request_irq(hw->irq, au1550_spi_irq, 0, pdev->name, hw);
856 if (err) {
857 dev_err(&pdev->dev, "Cannot claim IRQ\n");
858 goto err_no_irq;
859 }
860
861 master->bus_num = pdev->id;
862 master->num_chipselect = hw->pdata->num_chipselect;
863
864 /*
865 * precompute valid range for spi freq - from au1550 datasheet:
866 * psc_tempclk = psc_mainclk / (2 << DIV)
867 * spiclk = psc_tempclk / (2 * (BRG + 1))
868 * BRG valid range is 4..63
869 * DIV valid range is 0..3
870 * round the min and max frequencies to values that would still
871 * produce valid brg and div
872 */
873 {
874 int min_div = (2 << 0) * (2 * (4 + 1));
875 int max_div = (2 << 3) * (2 * (63 + 1));
876
877 master->max_speed_hz = hw->pdata->mainclk_hz / min_div;
878 master->min_speed_hz =
879 hw->pdata->mainclk_hz / (max_div + 1) + 1;
880 }
881
882 au1550_spi_setup_psc_as_spi(hw);
883
884 err = spi_bitbang_start(&hw->bitbang);
885 if (err) {
886 dev_err(&pdev->dev, "Failed to register SPI master\n");
887 goto err_register;
888 }
889
890 dev_info(&pdev->dev,
891 "spi master registered: bus_num=%d num_chipselect=%d\n",
892 master->bus_num, master->num_chipselect);
893
894 return 0;
895
896 err_register:
897 free_irq(hw->irq, hw);
898
899 err_no_irq:
900 au1550_spi_dma_rxtmp_free(hw);
901
902 err_dma_rxtmp_alloc:
903 err_no_rxdma_descr:
904 if (hw->usedma)
905 au1xxx_dbdma_chan_free(hw->dma_rx_ch);
906
907 err_no_rxdma:
908 err_no_txdma_descr:
909 if (hw->usedma)
910 au1xxx_dbdma_chan_free(hw->dma_tx_ch);
911
912 err_no_txdma:
913 iounmap((void __iomem *)hw->regs);
914
915 err_ioremap:
916 release_mem_region(r->start, sizeof(psc_spi_t));
917
918 err_no_iores:
919 err_no_pdata:
920 spi_master_put(hw->master);
921
922 err_nomem:
923 return err;
924 }
925
au1550_spi_remove(struct platform_device * pdev)926 static int au1550_spi_remove(struct platform_device *pdev)
927 {
928 struct au1550_spi *hw = platform_get_drvdata(pdev);
929
930 dev_info(&pdev->dev, "spi master remove: bus_num=%d\n",
931 hw->master->bus_num);
932
933 spi_bitbang_stop(&hw->bitbang);
934 free_irq(hw->irq, hw);
935 iounmap((void __iomem *)hw->regs);
936 release_mem_region(hw->ioarea->start, sizeof(psc_spi_t));
937
938 if (hw->usedma) {
939 au1550_spi_dma_rxtmp_free(hw);
940 au1xxx_dbdma_chan_free(hw->dma_rx_ch);
941 au1xxx_dbdma_chan_free(hw->dma_tx_ch);
942 }
943
944 spi_master_put(hw->master);
945 return 0;
946 }
947
948 /* work with hotplug and coldplug */
949 MODULE_ALIAS("platform:au1550-spi");
950
951 static struct platform_driver au1550_spi_drv = {
952 .probe = au1550_spi_probe,
953 .remove = au1550_spi_remove,
954 .driver = {
955 .name = "au1550-spi",
956 },
957 };
958
au1550_spi_init(void)959 static int __init au1550_spi_init(void)
960 {
961 /*
962 * create memory device with 8 bits dev_devwidth
963 * needed for proper byte ordering to spi fifo
964 */
965 switch (alchemy_get_cputype()) {
966 case ALCHEMY_CPU_AU1550:
967 case ALCHEMY_CPU_AU1200:
968 case ALCHEMY_CPU_AU1300:
969 break;
970 default:
971 return -ENODEV;
972 }
973
974 if (usedma) {
975 ddma_memid = au1xxx_ddma_add_device(&au1550_spi_mem_dbdev);
976 if (!ddma_memid)
977 printk(KERN_ERR "au1550-spi: cannot add memory dbdma device\n");
978 }
979 return platform_driver_register(&au1550_spi_drv);
980 }
981 module_init(au1550_spi_init);
982
au1550_spi_exit(void)983 static void __exit au1550_spi_exit(void)
984 {
985 if (usedma && ddma_memid)
986 au1xxx_ddma_del_device(ddma_memid);
987 platform_driver_unregister(&au1550_spi_drv);
988 }
989 module_exit(au1550_spi_exit);
990
991 MODULE_DESCRIPTION("Au1550 PSC SPI Driver");
992 MODULE_AUTHOR("Jan Nikitenko <jan.nikitenko@gmail.com>");
993 MODULE_LICENSE("GPL");
994