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PM / sleep: Asynchronous threads for suspend_noirq
[linux/fpc-iii.git] / drivers / spi / spi-xilinx.c
blob6d4ce4615163ddb8efbdfc798cec36341b6baa1b
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/init.h>
18 #include <linux/interrupt.h>
19 #include <linux/of.h>
20 #include <linux/platform_device.h>
21 #include <linux/spi/spi.h>
22 #include <linux/spi/spi_bitbang.h>
23 #include <linux/spi/xilinx_spi.h>
24 #include <linux/io.h>
25
26 #define XILINX_SPI_NAME "xilinx_spi"
27
28 /* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
29 * Product Specification", DS464
30 */
31 #define XSPI_CR_OFFSET 0x60 /* Control Register */
32
33 #define XSPI_CR_LOOP 0x01
34 #define XSPI_CR_ENABLE 0x02
35 #define XSPI_CR_MASTER_MODE 0x04
36 #define XSPI_CR_CPOL 0x08
37 #define XSPI_CR_CPHA 0x10
38 #define XSPI_CR_MODE_MASK (XSPI_CR_CPHA | XSPI_CR_CPOL)
39 #define XSPI_CR_TXFIFO_RESET 0x20
40 #define XSPI_CR_RXFIFO_RESET 0x40
41 #define XSPI_CR_MANUAL_SSELECT 0x80
42 #define XSPI_CR_TRANS_INHIBIT 0x100
43 #define XSPI_CR_LSB_FIRST 0x200
44
45 #define XSPI_SR_OFFSET 0x64 /* Status Register */
46
47 #define XSPI_SR_RX_EMPTY_MASK 0x01 /* Receive FIFO is empty */
48 #define XSPI_SR_RX_FULL_MASK 0x02 /* Receive FIFO is full */
49 #define XSPI_SR_TX_EMPTY_MASK 0x04 /* Transmit FIFO is empty */
50 #define XSPI_SR_TX_FULL_MASK 0x08 /* Transmit FIFO is full */
51 #define XSPI_SR_MODE_FAULT_MASK 0x10 /* Mode fault error */
52
53 #define XSPI_TXD_OFFSET 0x68 /* Data Transmit Register */
54 #define XSPI_RXD_OFFSET 0x6c /* Data Receive Register */
55
56 #define XSPI_SSR_OFFSET 0x70 /* 32-bit Slave Select Register */
57
58 /* Register definitions as per "OPB IPIF (v3.01c) Product Specification", DS414
59 * IPIF registers are 32 bit
60 */
61 #define XIPIF_V123B_DGIER_OFFSET 0x1c /* IPIF global int enable reg */
62 #define XIPIF_V123B_GINTR_ENABLE 0x80000000
63
64 #define XIPIF_V123B_IISR_OFFSET 0x20 /* IPIF interrupt status reg */
65 #define XIPIF_V123B_IIER_OFFSET 0x28 /* IPIF interrupt enable reg */
66
67 #define XSPI_INTR_MODE_FAULT 0x01 /* Mode fault error */
68 #define XSPI_INTR_SLAVE_MODE_FAULT 0x02 /* Selected as slave while
69 * disabled */
70 #define XSPI_INTR_TX_EMPTY 0x04 /* TxFIFO is empty */
71 #define XSPI_INTR_TX_UNDERRUN 0x08 /* TxFIFO was underrun */
72 #define XSPI_INTR_RX_FULL 0x10 /* RxFIFO is full */
73 #define XSPI_INTR_RX_OVERRUN 0x20 /* RxFIFO was overrun */
74 #define XSPI_INTR_TX_HALF_EMPTY 0x40 /* TxFIFO is half empty */
75
76 #define XIPIF_V123B_RESETR_OFFSET 0x40 /* IPIF reset register */
77 #define XIPIF_V123B_RESET_MASK 0x0a /* the value to write */
78
79 struct xilinx_spi {
80 /* bitbang has to be first */
81 struct spi_bitbang bitbang;
82 struct completion done;
83 void __iomem *regs; /* virt. address of the control registers */
84
85 int irq;
86
87 u8 *rx_ptr; /* pointer in the Tx buffer */
88 const u8 *tx_ptr; /* pointer in the Rx buffer */
89 int remaining_bytes; /* the number of bytes left to transfer */
90 u8 bits_per_word;
91 unsigned int (*read_fn) (void __iomem *);
92 void (*write_fn) (u32, void __iomem *);
93 void (*tx_fn) (struct xilinx_spi *);
94 void (*rx_fn) (struct xilinx_spi *);
95 };
96
97 static void xspi_write32(u32 val, void __iomem *addr)
98 {
99 iowrite32(val, addr);
100 }
101
102 static unsigned int xspi_read32(void __iomem *addr)
103 {
104 return ioread32(addr);
105 }
106
107 static void xspi_write32_be(u32 val, void __iomem *addr)
108 {
109 iowrite32be(val, addr);
110 }
111
112 static unsigned int xspi_read32_be(void __iomem *addr)
113 {
114 return ioread32be(addr);
115 }
116
117 static void xspi_tx8(struct xilinx_spi *xspi)
118 {
119 xspi->write_fn(*xspi->tx_ptr, xspi->regs + XSPI_TXD_OFFSET);
120 xspi->tx_ptr++;
121 }
122
123 static void xspi_tx16(struct xilinx_spi *xspi)
124 {
125 xspi->write_fn(*(u16 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
126 xspi->tx_ptr += 2;
127 }
128
129 static void xspi_tx32(struct xilinx_spi *xspi)
130 {
131 xspi->write_fn(*(u32 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
132 xspi->tx_ptr += 4;
133 }
134
135 static void xspi_rx8(struct xilinx_spi *xspi)
136 {
137 u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
138 if (xspi->rx_ptr) {
139 *xspi->rx_ptr = data & 0xff;
140 xspi->rx_ptr++;
141 }
142 }
143
144 static void xspi_rx16(struct xilinx_spi *xspi)
145 {
146 u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
147 if (xspi->rx_ptr) {
148 *(u16 *)(xspi->rx_ptr) = data & 0xffff;
149 xspi->rx_ptr += 2;
150 }
151 }
152
153 static void xspi_rx32(struct xilinx_spi *xspi)
154 {
155 u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
156 if (xspi->rx_ptr) {
157 *(u32 *)(xspi->rx_ptr) = data;
158 xspi->rx_ptr += 4;
159 }
160 }
161
162 static void xspi_init_hw(struct xilinx_spi *xspi)
163 {
164 void __iomem *regs_base = xspi->regs;
165
166 /* Reset the SPI device */
167 xspi->write_fn(XIPIF_V123B_RESET_MASK,
168 regs_base + XIPIF_V123B_RESETR_OFFSET);
169 /* Disable all the interrupts just in case */
170 xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET);
171 /* Enable the global IPIF interrupt */
172 xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
173 regs_base + XIPIF_V123B_DGIER_OFFSET);
174 /* Deselect the slave on the SPI bus */
175 xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET);
176 /* Disable the transmitter, enable Manual Slave Select Assertion,
177 * put SPI controller into master mode, and enable it */
178 xspi->write_fn(XSPI_CR_TRANS_INHIBIT | XSPI_CR_MANUAL_SSELECT |
179 XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET |
180 XSPI_CR_RXFIFO_RESET, regs_base + XSPI_CR_OFFSET);
181 }
182
183 static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
184 {
185 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
186
187 if (is_on == BITBANG_CS_INACTIVE) {
188 /* Deselect the slave on the SPI bus */
189 xspi->write_fn(0xffff, xspi->regs + XSPI_SSR_OFFSET);
190 } else if (is_on == BITBANG_CS_ACTIVE) {
191 /* Set the SPI clock phase and polarity */
192 u16 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET)
193 & ~XSPI_CR_MODE_MASK;
194 if (spi->mode & SPI_CPHA)
195 cr |= XSPI_CR_CPHA;
196 if (spi->mode & SPI_CPOL)
197 cr |= XSPI_CR_CPOL;
198 xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
199
200 /* We do not check spi->max_speed_hz here as the SPI clock
201 * frequency is not software programmable (the IP block design
202 * parameter)
203 */
204
205 /* Activate the chip select */
206 xspi->write_fn(~(0x0001 << spi->chip_select),
207 xspi->regs + XSPI_SSR_OFFSET);
208 }
209 }
210
211 /* spi_bitbang requires custom setup_transfer() to be defined if there is a
212 * custom txrx_bufs(). We have nothing to setup here as the SPI IP block
213 * supports 8 or 16 bits per word which cannot be changed in software.
214 * SPI clock can't be changed in software either.
215 * Check for correct bits per word. Chip select delay calculations could be
216 * added here as soon as bitbang_work() can be made aware of the delay value.
217 */
218 static int xilinx_spi_setup_transfer(struct spi_device *spi,
219 struct spi_transfer *t)
220 {
221 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
222 u8 bits_per_word;
223
224 bits_per_word = (t && t->bits_per_word)
225 ? t->bits_per_word : spi->bits_per_word;
226 if (bits_per_word != xspi->bits_per_word) {
227 dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
228 __func__, bits_per_word);
229 return -EINVAL;
230 }
231
232 return 0;
233 }
234
235 static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi)
236 {
237 u8 sr;
238
239 /* Fill the Tx FIFO with as many bytes as possible */
240 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
241 while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) {
242 if (xspi->tx_ptr)
243 xspi->tx_fn(xspi);
244 else
245 xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
246 xspi->remaining_bytes -= xspi->bits_per_word / 8;
247 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
248 }
249 }
250
251 static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
252 {
253 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
254 u32 ipif_ier;
255
256 /* We get here with transmitter inhibited */
257
258 xspi->tx_ptr = t->tx_buf;
259 xspi->rx_ptr = t->rx_buf;
260 xspi->remaining_bytes = t->len;
261 reinit_completion(&xspi->done);
262
263
264 /* Enable the transmit empty interrupt, which we use to determine
265 * progress on the transmission.
266 */
267 ipif_ier = xspi->read_fn(xspi->regs + XIPIF_V123B_IIER_OFFSET);
268 xspi->write_fn(ipif_ier | XSPI_INTR_TX_EMPTY,
269 xspi->regs + XIPIF_V123B_IIER_OFFSET);
270
271 for (;;) {
272 u16 cr;
273 u8 sr;
274
275 xilinx_spi_fill_tx_fifo(xspi);
276
277 /* Start the transfer by not inhibiting the transmitter any
278 * longer
279 */
280 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) &
281 ~XSPI_CR_TRANS_INHIBIT;
282 xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
283
284 wait_for_completion(&xspi->done);
285
286 /* A transmit has just completed. Process received data and
287 * check for more data to transmit. Always inhibit the
288 * transmitter while the Isr refills the transmit register/FIFO,
289 * or make sure it is stopped if we're done.
290 */
291 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
292 xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
293 xspi->regs + XSPI_CR_OFFSET);
294
295 /* Read out all the data from the Rx FIFO */
296 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
297 while ((sr & XSPI_SR_RX_EMPTY_MASK) == 0) {
298 xspi->rx_fn(xspi);
299 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
300 }
301
302 /* See if there is more data to send */
303 if (xspi->remaining_bytes <= 0)
304 break;
305 }
306
307 /* Disable the transmit empty interrupt */
308 xspi->write_fn(ipif_ier, xspi->regs + XIPIF_V123B_IIER_OFFSET);
309
310 return t->len - xspi->remaining_bytes;
311 }
312
313
314 /* This driver supports single master mode only. Hence Tx FIFO Empty
315 * is the only interrupt we care about.
316 * Receive FIFO Overrun, Transmit FIFO Underrun, Mode Fault, and Slave Mode
317 * Fault are not to happen.
318 */
319 static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
320 {
321 struct xilinx_spi *xspi = dev_id;
322 u32 ipif_isr;
323
324 /* Get the IPIF interrupts, and clear them immediately */
325 ipif_isr = xspi->read_fn(xspi->regs + XIPIF_V123B_IISR_OFFSET);
326 xspi->write_fn(ipif_isr, xspi->regs + XIPIF_V123B_IISR_OFFSET);
327
328 if (ipif_isr & XSPI_INTR_TX_EMPTY) { /* Transmission completed */
329 complete(&xspi->done);
330 }
331
332 return IRQ_HANDLED;
333 }
334
335 static const struct of_device_id xilinx_spi_of_match[] = {
336 { .compatible = "xlnx,xps-spi-2.00.a", },
337 { .compatible = "xlnx,xps-spi-2.00.b", },
338 {}
339 };
340 MODULE_DEVICE_TABLE(of, xilinx_spi_of_match);
341
342 static int xilinx_spi_probe(struct platform_device *pdev)
343 {
344 struct xilinx_spi *xspi;
345 struct xspi_platform_data *pdata;
346 struct resource *res;
347 int ret, num_cs = 0, bits_per_word = 8;
348 struct spi_master *master;
349 u32 tmp;
350 u8 i;
351
352 pdata = dev_get_platdata(&pdev->dev);
353 if (pdata) {
354 num_cs = pdata->num_chipselect;
355 bits_per_word = pdata->bits_per_word;
356 } else {
357 of_property_read_u32(pdev->dev.of_node, "xlnx,num-ss-bits",
358 &num_cs);
359 }
360
361 if (!num_cs) {
362 dev_err(&pdev->dev,
363 "Missing slave select configuration data\n");
364 return -EINVAL;
365 }
366
367 master = spi_alloc_master(&pdev->dev, sizeof(struct xilinx_spi));
368 if (!master)
369 return -ENODEV;
370
371 /* the spi->mode bits understood by this driver: */
372 master->mode_bits = SPI_CPOL | SPI_CPHA;
373
374 xspi = spi_master_get_devdata(master);
375 xspi->bitbang.master = master;
376 xspi->bitbang.chipselect = xilinx_spi_chipselect;
377 xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer;
378 xspi->bitbang.txrx_bufs = xilinx_spi_txrx_bufs;
379 init_completion(&xspi->done);
380
381 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
382 xspi->regs = devm_ioremap_resource(&pdev->dev, res);
383 if (IS_ERR(xspi->regs)) {
384 ret = PTR_ERR(xspi->regs);
385 goto put_master;
386 }
387
388 master->bus_num = pdev->dev.id;
389 master->num_chipselect = num_cs;
390 master->dev.of_node = pdev->dev.of_node;
391
392 /*
393 * Detect endianess on the IP via loop bit in CR. Detection
394 * must be done before reset is sent because incorrect reset
395 * value generates error interrupt.
396 * Setup little endian helper functions first and try to use them
397 * and check if bit was correctly setup or not.
398 */
399 xspi->read_fn = xspi_read32;
400 xspi->write_fn = xspi_write32;
401
402 xspi->write_fn(XSPI_CR_LOOP, xspi->regs + XSPI_CR_OFFSET);
403 tmp = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
404 tmp &= XSPI_CR_LOOP;
405 if (tmp != XSPI_CR_LOOP) {
406 xspi->read_fn = xspi_read32_be;
407 xspi->write_fn = xspi_write32_be;
408 }
409
410 xspi->bits_per_word = bits_per_word;
411 if (xspi->bits_per_word == 8) {
412 xspi->tx_fn = xspi_tx8;
413 xspi->rx_fn = xspi_rx8;
414 } else if (xspi->bits_per_word == 16) {
415 xspi->tx_fn = xspi_tx16;
416 xspi->rx_fn = xspi_rx16;
417 } else if (xspi->bits_per_word == 32) {
418 xspi->tx_fn = xspi_tx32;
419 xspi->rx_fn = xspi_rx32;
420 } else {
421 ret = -EINVAL;
422 goto put_master;
423 }
424
425 /* SPI controller initializations */
426 xspi_init_hw(xspi);
427
428 xspi->irq = platform_get_irq(pdev, 0);
429 if (xspi->irq < 0) {
430 ret = xspi->irq;
431 goto put_master;
432 }
433
434 /* Register for SPI Interrupt */
435 ret = devm_request_irq(&pdev->dev, xspi->irq, xilinx_spi_irq, 0,
436 dev_name(&pdev->dev), xspi);
437 if (ret)
438 goto put_master;
439
440 ret = spi_bitbang_start(&xspi->bitbang);
441 if (ret) {
442 dev_err(&pdev->dev, "spi_bitbang_start FAILED\n");
443 goto put_master;
444 }
445
446 dev_info(&pdev->dev, "at 0x%08llX mapped to 0x%p, irq=%d\n",
447 (unsigned long long)res->start, xspi->regs, xspi->irq);
448
449 if (pdata) {
450 for (i = 0; i < pdata->num_devices; i++)
451 spi_new_device(master, pdata->devices + i);
452 }
453
454 platform_set_drvdata(pdev, master);
455 return 0;
456
457 put_master:
458 spi_master_put(master);
459
460 return ret;
461 }
462
463 static int xilinx_spi_remove(struct platform_device *pdev)
464 {
465 struct spi_master *master = platform_get_drvdata(pdev);
466 struct xilinx_spi *xspi = spi_master_get_devdata(master);
467 void __iomem *regs_base = xspi->regs;
468
469 spi_bitbang_stop(&xspi->bitbang);
470
471 /* Disable all the interrupts just in case */
472 xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET);
473 /* Disable the global IPIF interrupt */
474 xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET);
475
476 spi_master_put(xspi->bitbang.master);
477
478 return 0;
479 }
480
481 /* work with hotplug and coldplug */
482 MODULE_ALIAS("platform:" XILINX_SPI_NAME);
483
484 static struct platform_driver xilinx_spi_driver = {
485 .probe = xilinx_spi_probe,
486 .remove = xilinx_spi_remove,
487 .driver = {
488 .name = XILINX_SPI_NAME,
489 .owner = THIS_MODULE,
490 .of_match_table = xilinx_spi_of_match,
491 },
492 };
493 module_platform_driver(xilinx_spi_driver);
494
495 MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
496 MODULE_DESCRIPTION("Xilinx SPI driver");
497 MODULE_LICENSE("GPL");
Linux with added FPC-III support