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Linux 5.1.15
[linux/fpc-iii.git] / drivers / spi / spi-xilinx.c
blob63fedc49ae9ce43e6db5080e7d0778f3dc320088
1 /*
2 * Xilinx SPI controller driver (master mode only)
3 *
4 * Author: MontaVista Software, Inc.
5 * source@mvista.com
6 *
7 * Copyright (c) 2010 Secret Lab Technologies, Ltd.
8 * Copyright (c) 2009 Intel Corporation
9 * 2002-2007 (c) MontaVista Software, Inc.
10
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
14 */
15
16 #include <linux/module.h>
17 #include <linux/interrupt.h>
18 #include <linux/of.h>
19 #include <linux/platform_device.h>
20 #include <linux/spi/spi.h>
21 #include <linux/spi/spi_bitbang.h>
22 #include <linux/spi/xilinx_spi.h>
23 #include <linux/io.h>
24
25 #define XILINX_SPI_MAX_CS 32
26
27 #define XILINX_SPI_NAME "xilinx_spi"
28
29 /* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
30 * Product Specification", DS464
31 */
32 #define XSPI_CR_OFFSET 0x60 /* Control Register */
33
34 #define XSPI_CR_LOOP 0x01
35 #define XSPI_CR_ENABLE 0x02
36 #define XSPI_CR_MASTER_MODE 0x04
37 #define XSPI_CR_CPOL 0x08
38 #define XSPI_CR_CPHA 0x10
39 #define XSPI_CR_MODE_MASK (XSPI_CR_CPHA | XSPI_CR_CPOL | \
40 XSPI_CR_LSB_FIRST | XSPI_CR_LOOP)
41 #define XSPI_CR_TXFIFO_RESET 0x20
42 #define XSPI_CR_RXFIFO_RESET 0x40
43 #define XSPI_CR_MANUAL_SSELECT 0x80
44 #define XSPI_CR_TRANS_INHIBIT 0x100
45 #define XSPI_CR_LSB_FIRST 0x200
46
47 #define XSPI_SR_OFFSET 0x64 /* Status Register */
48
49 #define XSPI_SR_RX_EMPTY_MASK 0x01 /* Receive FIFO is empty */
50 #define XSPI_SR_RX_FULL_MASK 0x02 /* Receive FIFO is full */
51 #define XSPI_SR_TX_EMPTY_MASK 0x04 /* Transmit FIFO is empty */
52 #define XSPI_SR_TX_FULL_MASK 0x08 /* Transmit FIFO is full */
53 #define XSPI_SR_MODE_FAULT_MASK 0x10 /* Mode fault error */
54
55 #define XSPI_TXD_OFFSET 0x68 /* Data Transmit Register */
56 #define XSPI_RXD_OFFSET 0x6c /* Data Receive Register */
57
58 #define XSPI_SSR_OFFSET 0x70 /* 32-bit Slave Select Register */
59
60 /* Register definitions as per "OPB IPIF (v3.01c) Product Specification", DS414
61 * IPIF registers are 32 bit
62 */
63 #define XIPIF_V123B_DGIER_OFFSET 0x1c /* IPIF global int enable reg */
64 #define XIPIF_V123B_GINTR_ENABLE 0x80000000
65
66 #define XIPIF_V123B_IISR_OFFSET 0x20 /* IPIF interrupt status reg */
67 #define XIPIF_V123B_IIER_OFFSET 0x28 /* IPIF interrupt enable reg */
68
69 #define XSPI_INTR_MODE_FAULT 0x01 /* Mode fault error */
70 #define XSPI_INTR_SLAVE_MODE_FAULT 0x02 /* Selected as slave while
71 * disabled */
72 #define XSPI_INTR_TX_EMPTY 0x04 /* TxFIFO is empty */
73 #define XSPI_INTR_TX_UNDERRUN 0x08 /* TxFIFO was underrun */
74 #define XSPI_INTR_RX_FULL 0x10 /* RxFIFO is full */
75 #define XSPI_INTR_RX_OVERRUN 0x20 /* RxFIFO was overrun */
76 #define XSPI_INTR_TX_HALF_EMPTY 0x40 /* TxFIFO is half empty */
77
78 #define XIPIF_V123B_RESETR_OFFSET 0x40 /* IPIF reset register */
79 #define XIPIF_V123B_RESET_MASK 0x0a /* the value to write */
80
81 struct xilinx_spi {
82 /* bitbang has to be first */
83 struct spi_bitbang bitbang;
84 struct completion done;
85 void __iomem *regs; /* virt. address of the control registers */
86
87 int irq;
88
89 u8 *rx_ptr; /* pointer in the Tx buffer */
90 const u8 *tx_ptr; /* pointer in the Rx buffer */
91 u8 bytes_per_word;
92 int buffer_size; /* buffer size in words */
93 u32 cs_inactive; /* Level of the CS pins when inactive*/
94 unsigned int (*read_fn)(void __iomem *);
95 void (*write_fn)(u32, void __iomem *);
96 };
97
98 static void xspi_write32(u32 val, void __iomem *addr)
99 {
100 iowrite32(val, addr);
101 }
102
103 static unsigned int xspi_read32(void __iomem *addr)
104 {
105 return ioread32(addr);
106 }
107
108 static void xspi_write32_be(u32 val, void __iomem *addr)
109 {
110 iowrite32be(val, addr);
111 }
112
113 static unsigned int xspi_read32_be(void __iomem *addr)
114 {
115 return ioread32be(addr);
116 }
117
118 static void xilinx_spi_tx(struct xilinx_spi *xspi)
119 {
120 u32 data = 0;
121
122 if (!xspi->tx_ptr) {
123 xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
124 return;
125 }
126
127 switch (xspi->bytes_per_word) {
128 case 1:
129 data = *(u8 *)(xspi->tx_ptr);
130 break;
131 case 2:
132 data = *(u16 *)(xspi->tx_ptr);
133 break;
134 case 4:
135 data = *(u32 *)(xspi->tx_ptr);
136 break;
137 }
138
139 xspi->write_fn(data, xspi->regs + XSPI_TXD_OFFSET);
140 xspi->tx_ptr += xspi->bytes_per_word;
141 }
142
143 static void xilinx_spi_rx(struct xilinx_spi *xspi)
144 {
145 u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
146
147 if (!xspi->rx_ptr)
148 return;
149
150 switch (xspi->bytes_per_word) {
151 case 1:
152 *(u8 *)(xspi->rx_ptr) = data;
153 break;
154 case 2:
155 *(u16 *)(xspi->rx_ptr) = data;
156 break;
157 case 4:
158 *(u32 *)(xspi->rx_ptr) = data;
159 break;
160 }
161
162 xspi->rx_ptr += xspi->bytes_per_word;
163 }
164
165 static void xspi_init_hw(struct xilinx_spi *xspi)
166 {
167 void __iomem *regs_base = xspi->regs;
168
169 /* Reset the SPI device */
170 xspi->write_fn(XIPIF_V123B_RESET_MASK,
171 regs_base + XIPIF_V123B_RESETR_OFFSET);
172 /* Enable the transmit empty interrupt, which we use to determine
173 * progress on the transmission.
174 */
175 xspi->write_fn(XSPI_INTR_TX_EMPTY,
176 regs_base + XIPIF_V123B_IIER_OFFSET);
177 /* Disable the global IPIF interrupt */
178 xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET);
179 /* Deselect the slave on the SPI bus */
180 xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET);
181 /* Disable the transmitter, enable Manual Slave Select Assertion,
182 * put SPI controller into master mode, and enable it */
183 xspi->write_fn(XSPI_CR_MANUAL_SSELECT | XSPI_CR_MASTER_MODE |
184 XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET | XSPI_CR_RXFIFO_RESET,
185 regs_base + XSPI_CR_OFFSET);
186 }
187
188 static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
189 {
190 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
191 u16 cr;
192 u32 cs;
193
194 if (is_on == BITBANG_CS_INACTIVE) {
195 /* Deselect the slave on the SPI bus */
196 xspi->write_fn(xspi->cs_inactive, xspi->regs + XSPI_SSR_OFFSET);
197 return;
198 }
199
200 /* Set the SPI clock phase and polarity */
201 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) & ~XSPI_CR_MODE_MASK;
202 if (spi->mode & SPI_CPHA)
203 cr |= XSPI_CR_CPHA;
204 if (spi->mode & SPI_CPOL)
205 cr |= XSPI_CR_CPOL;
206 if (spi->mode & SPI_LSB_FIRST)
207 cr |= XSPI_CR_LSB_FIRST;
208 if (spi->mode & SPI_LOOP)
209 cr |= XSPI_CR_LOOP;
210 xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
211
212 /* We do not check spi->max_speed_hz here as the SPI clock
213 * frequency is not software programmable (the IP block design
214 * parameter)
215 */
216
217 cs = xspi->cs_inactive;
218 cs ^= BIT(spi->chip_select);
219
220 /* Activate the chip select */
221 xspi->write_fn(cs, xspi->regs + XSPI_SSR_OFFSET);
222 }
223
224 /* spi_bitbang requires custom setup_transfer() to be defined if there is a
225 * custom txrx_bufs().
226 */
227 static int xilinx_spi_setup_transfer(struct spi_device *spi,
228 struct spi_transfer *t)
229 {
230 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
231
232 if (spi->mode & SPI_CS_HIGH)
233 xspi->cs_inactive &= ~BIT(spi->chip_select);
234 else
235 xspi->cs_inactive |= BIT(spi->chip_select);
236
237 return 0;
238 }
239
240 static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
241 {
242 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
243 int remaining_words; /* the number of words left to transfer */
244 bool use_irq = false;
245 u16 cr = 0;
246
247 /* We get here with transmitter inhibited */
248
249 xspi->tx_ptr = t->tx_buf;
250 xspi->rx_ptr = t->rx_buf;
251 remaining_words = t->len / xspi->bytes_per_word;
252
253 if (xspi->irq >= 0 && remaining_words > xspi->buffer_size) {
254 u32 isr;
255 use_irq = true;
256 /* Inhibit irq to avoid spurious irqs on tx_empty*/
257 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
258 xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
259 xspi->regs + XSPI_CR_OFFSET);
260 /* ACK old irqs (if any) */
261 isr = xspi->read_fn(xspi->regs + XIPIF_V123B_IISR_OFFSET);
262 if (isr)
263 xspi->write_fn(isr,
264 xspi->regs + XIPIF_V123B_IISR_OFFSET);
265 /* Enable the global IPIF interrupt */
266 xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
267 xspi->regs + XIPIF_V123B_DGIER_OFFSET);
268 reinit_completion(&xspi->done);
269 }
270
271 while (remaining_words) {
272 int n_words, tx_words, rx_words;
273 u32 sr;
274 int stalled;
275
276 n_words = min(remaining_words, xspi->buffer_size);
277
278 tx_words = n_words;
279 while (tx_words--)
280 xilinx_spi_tx(xspi);
281
282 /* Start the transfer by not inhibiting the transmitter any
283 * longer
284 */
285
286 if (use_irq) {
287 xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
288 wait_for_completion(&xspi->done);
289 /* A transmit has just completed. Process received data
290 * and check for more data to transmit. Always inhibit
291 * the transmitter while the Isr refills the transmit
292 * register/FIFO, or make sure it is stopped if we're
293 * done.
294 */
295 xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
296 xspi->regs + XSPI_CR_OFFSET);
297 sr = XSPI_SR_TX_EMPTY_MASK;
298 } else
299 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
300
301 /* Read out all the data from the Rx FIFO */
302 rx_words = n_words;
303 stalled = 10;
304 while (rx_words) {
305 if (rx_words == n_words && !(stalled--) &&
306 !(sr & XSPI_SR_TX_EMPTY_MASK) &&
307 (sr & XSPI_SR_RX_EMPTY_MASK)) {
308 dev_err(&spi->dev,
309 "Detected stall. Check C_SPI_MODE and C_SPI_MEMORY\n");
310 xspi_init_hw(xspi);
311 return -EIO;
312 }
313
314 if ((sr & XSPI_SR_TX_EMPTY_MASK) && (rx_words > 1)) {
315 xilinx_spi_rx(xspi);
316 rx_words--;
317 continue;
318 }
319
320 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
321 if (!(sr & XSPI_SR_RX_EMPTY_MASK)) {
322 xilinx_spi_rx(xspi);
323 rx_words--;
324 }
325 }
326
327 remaining_words -= n_words;
328 }
329
330 if (use_irq) {
331 xspi->write_fn(0, xspi->regs + XIPIF_V123B_DGIER_OFFSET);
332 xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
333 }
334
335 return t->len;
336 }
337
338
339 /* This driver supports single master mode only. Hence Tx FIFO Empty
340 * is the only interrupt we care about.
341 * Receive FIFO Overrun, Transmit FIFO Underrun, Mode Fault, and Slave Mode
342 * Fault are not to happen.
343 */
344 static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
345 {
346 struct xilinx_spi *xspi = dev_id;
347 u32 ipif_isr;
348
349 /* Get the IPIF interrupts, and clear them immediately */
350 ipif_isr = xspi->read_fn(xspi->regs + XIPIF_V123B_IISR_OFFSET);
351 xspi->write_fn(ipif_isr, xspi->regs + XIPIF_V123B_IISR_OFFSET);
352
353 if (ipif_isr & XSPI_INTR_TX_EMPTY) { /* Transmission completed */
354 complete(&xspi->done);
355 return IRQ_HANDLED;
356 }
357
358 return IRQ_NONE;
359 }
360
361 static int xilinx_spi_find_buffer_size(struct xilinx_spi *xspi)
362 {
363 u8 sr;
364 int n_words = 0;
365
366 /*
367 * Before the buffer_size detection we reset the core
368 * to make sure we start with a clean state.
369 */
370 xspi->write_fn(XIPIF_V123B_RESET_MASK,
371 xspi->regs + XIPIF_V123B_RESETR_OFFSET);
372
373 /* Fill the Tx FIFO with as many words as possible */
374 do {
375 xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
376 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
377 n_words++;
378 } while (!(sr & XSPI_SR_TX_FULL_MASK));
379
380 return n_words;
381 }
382
383 static const struct of_device_id xilinx_spi_of_match[] = {
384 { .compatible = "xlnx,axi-quad-spi-1.00.a", },
385 { .compatible = "xlnx,xps-spi-2.00.a", },
386 { .compatible = "xlnx,xps-spi-2.00.b", },
387 {}
388 };
389 MODULE_DEVICE_TABLE(of, xilinx_spi_of_match);
390
391 static int xilinx_spi_probe(struct platform_device *pdev)
392 {
393 struct xilinx_spi *xspi;
394 struct xspi_platform_data *pdata;
395 struct resource *res;
396 int ret, num_cs = 0, bits_per_word = 8;
397 struct spi_master *master;
398 u32 tmp;
399 u8 i;
400
401 pdata = dev_get_platdata(&pdev->dev);
402 if (pdata) {
403 num_cs = pdata->num_chipselect;
404 bits_per_word = pdata->bits_per_word;
405 } else {
406 of_property_read_u32(pdev->dev.of_node, "xlnx,num-ss-bits",
407 &num_cs);
408 }
409
410 if (!num_cs) {
411 dev_err(&pdev->dev,
412 "Missing slave select configuration data\n");
413 return -EINVAL;
414 }
415
416 if (num_cs > XILINX_SPI_MAX_CS) {
417 dev_err(&pdev->dev, "Invalid number of spi slaves\n");
418 return -EINVAL;
419 }
420
421 master = spi_alloc_master(&pdev->dev, sizeof(struct xilinx_spi));
422 if (!master)
423 return -ENODEV;
424
425 /* the spi->mode bits understood by this driver: */
426 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_LOOP |
427 SPI_CS_HIGH;
428
429 xspi = spi_master_get_devdata(master);
430 xspi->cs_inactive = 0xffffffff;
431 xspi->bitbang.master = master;
432 xspi->bitbang.chipselect = xilinx_spi_chipselect;
433 xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer;
434 xspi->bitbang.txrx_bufs = xilinx_spi_txrx_bufs;
435 init_completion(&xspi->done);
436
437 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
438 xspi->regs = devm_ioremap_resource(&pdev->dev, res);
439 if (IS_ERR(xspi->regs)) {
440 ret = PTR_ERR(xspi->regs);
441 goto put_master;
442 }
443
444 master->bus_num = pdev->id;
445 master->num_chipselect = num_cs;
446 master->dev.of_node = pdev->dev.of_node;
447
448 /*
449 * Detect endianess on the IP via loop bit in CR. Detection
450 * must be done before reset is sent because incorrect reset
451 * value generates error interrupt.
452 * Setup little endian helper functions first and try to use them
453 * and check if bit was correctly setup or not.
454 */
455 xspi->read_fn = xspi_read32;
456 xspi->write_fn = xspi_write32;
457
458 xspi->write_fn(XSPI_CR_LOOP, xspi->regs + XSPI_CR_OFFSET);
459 tmp = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
460 tmp &= XSPI_CR_LOOP;
461 if (tmp != XSPI_CR_LOOP) {
462 xspi->read_fn = xspi_read32_be;
463 xspi->write_fn = xspi_write32_be;
464 }
465
466 master->bits_per_word_mask = SPI_BPW_MASK(bits_per_word);
467 xspi->bytes_per_word = bits_per_word / 8;
468 xspi->buffer_size = xilinx_spi_find_buffer_size(xspi);
469
470 xspi->irq = platform_get_irq(pdev, 0);
471 if (xspi->irq < 0 && xspi->irq != -ENXIO) {
472 ret = xspi->irq;
473 goto put_master;
474 } else if (xspi->irq >= 0) {
475 /* Register for SPI Interrupt */
476 ret = devm_request_irq(&pdev->dev, xspi->irq, xilinx_spi_irq, 0,
477 dev_name(&pdev->dev), xspi);
478 if (ret)
479 goto put_master;
480 }
481
482 /* SPI controller initializations */
483 xspi_init_hw(xspi);
484
485 ret = spi_bitbang_start(&xspi->bitbang);
486 if (ret) {
487 dev_err(&pdev->dev, "spi_bitbang_start FAILED\n");
488 goto put_master;
489 }
490
491 dev_info(&pdev->dev, "at 0x%08llX mapped to 0x%p, irq=%d\n",
492 (unsigned long long)res->start, xspi->regs, xspi->irq);
493
494 if (pdata) {
495 for (i = 0; i < pdata->num_devices; i++)
496 spi_new_device(master, pdata->devices + i);
497 }
498
499 platform_set_drvdata(pdev, master);
500 return 0;
501
502 put_master:
503 spi_master_put(master);
504
505 return ret;
506 }
507
508 static int xilinx_spi_remove(struct platform_device *pdev)
509 {
510 struct spi_master *master = platform_get_drvdata(pdev);
511 struct xilinx_spi *xspi = spi_master_get_devdata(master);
512 void __iomem *regs_base = xspi->regs;
513
514 spi_bitbang_stop(&xspi->bitbang);
515
516 /* Disable all the interrupts just in case */
517 xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET);
518 /* Disable the global IPIF interrupt */
519 xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET);
520
521 spi_master_put(xspi->bitbang.master);
522
523 return 0;
524 }
525
526 /* work with hotplug and coldplug */
527 MODULE_ALIAS("platform:" XILINX_SPI_NAME);
528
529 static struct platform_driver xilinx_spi_driver = {
530 .probe = xilinx_spi_probe,
531 .remove = xilinx_spi_remove,
532 .driver = {
533 .name = XILINX_SPI_NAME,
534 .of_match_table = xilinx_spi_of_match,
535 },
536 };
537 module_platform_driver(xilinx_spi_driver);
538
539 MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
540 MODULE_DESCRIPTION("Xilinx SPI driver");
541 MODULE_LICENSE("GPL");
Linux with added FPC-III support