1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Freescale/Motorola Coldfire Queued SPI driver
4  *
5  * Copyright 2010 Steven King <sfking@fdwdc.com>
6 */
7 
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/interrupt.h>
11 #include <linux/errno.h>
12 #include <linux/platform_device.h>
13 #include <linux/sched.h>
14 #include <linux/delay.h>
15 #include <linux/io.h>
16 #include <linux/clk.h>
17 #include <linux/err.h>
18 #include <linux/spi/spi.h>
19 #include <linux/pm_runtime.h>
20 
21 #include <asm/coldfire.h>
22 #include <asm/mcfsim.h>
23 #include <asm/mcfqspi.h>
24 
25 #define	DRIVER_NAME "mcfqspi"
26 
27 #define	MCFQSPI_BUSCLK			(MCF_BUSCLK / 2)
28 
29 #define	MCFQSPI_QMR			0x00
30 #define		MCFQSPI_QMR_MSTR	0x8000
31 #define		MCFQSPI_QMR_CPOL	0x0200
32 #define		MCFQSPI_QMR_CPHA	0x0100
33 #define	MCFQSPI_QDLYR			0x04
34 #define		MCFQSPI_QDLYR_SPE	0x8000
35 #define	MCFQSPI_QWR			0x08
36 #define		MCFQSPI_QWR_HALT	0x8000
37 #define		MCFQSPI_QWR_WREN	0x4000
38 #define		MCFQSPI_QWR_CSIV	0x1000
39 #define	MCFQSPI_QIR			0x0C
40 #define		MCFQSPI_QIR_WCEFB	0x8000
41 #define		MCFQSPI_QIR_ABRTB	0x4000
42 #define		MCFQSPI_QIR_ABRTL	0x1000
43 #define		MCFQSPI_QIR_WCEFE	0x0800
44 #define		MCFQSPI_QIR_ABRTE	0x0400
45 #define		MCFQSPI_QIR_SPIFE	0x0100
46 #define		MCFQSPI_QIR_WCEF	0x0008
47 #define		MCFQSPI_QIR_ABRT	0x0004
48 #define		MCFQSPI_QIR_SPIF	0x0001
49 #define	MCFQSPI_QAR			0x010
50 #define		MCFQSPI_QAR_TXBUF	0x00
51 #define		MCFQSPI_QAR_RXBUF	0x10
52 #define		MCFQSPI_QAR_CMDBUF	0x20
53 #define	MCFQSPI_QDR			0x014
54 #define	MCFQSPI_QCR			0x014
55 #define		MCFQSPI_QCR_CONT	0x8000
56 #define		MCFQSPI_QCR_BITSE	0x4000
57 #define		MCFQSPI_QCR_DT		0x2000
58 
59 struct mcfqspi {
60 	void __iomem *iobase;
61 	int irq;
62 	struct clk *clk;
63 	struct mcfqspi_cs_control *cs_control;
64 
65 	wait_queue_head_t waitq;
66 };
67 
68 static void mcfqspi_wr_qmr(struct mcfqspi *mcfqspi, u16 val)
69 {
70 	writew(val, mcfqspi->iobase + MCFQSPI_QMR);
71 }
72 
73 static void mcfqspi_wr_qdlyr(struct mcfqspi *mcfqspi, u16 val)
74 {
75 	writew(val, mcfqspi->iobase + MCFQSPI_QDLYR);
76 }
77 
78 static u16 mcfqspi_rd_qdlyr(struct mcfqspi *mcfqspi)
79 {
80 	return readw(mcfqspi->iobase + MCFQSPI_QDLYR);
81 }
82 
83 static void mcfqspi_wr_qwr(struct mcfqspi *mcfqspi, u16 val)
84 {
85 	writew(val, mcfqspi->iobase + MCFQSPI_QWR);
86 }
87 
88 static void mcfqspi_wr_qir(struct mcfqspi *mcfqspi, u16 val)
89 {
90 	writew(val, mcfqspi->iobase + MCFQSPI_QIR);
91 }
92 
93 static void mcfqspi_wr_qar(struct mcfqspi *mcfqspi, u16 val)
94 {
95 	writew(val, mcfqspi->iobase + MCFQSPI_QAR);
96 }
97 
98 static void mcfqspi_wr_qdr(struct mcfqspi *mcfqspi, u16 val)
99 {
100 	writew(val, mcfqspi->iobase + MCFQSPI_QDR);
101 }
102 
103 static u16 mcfqspi_rd_qdr(struct mcfqspi *mcfqspi)
104 {
105 	return readw(mcfqspi->iobase + MCFQSPI_QDR);
106 }
107 
108 static void mcfqspi_cs_select(struct mcfqspi *mcfqspi, u8 chip_select,
109 			    bool cs_high)
110 {
111 	mcfqspi->cs_control->select(mcfqspi->cs_control, chip_select, cs_high);
112 }
113 
114 static void mcfqspi_cs_deselect(struct mcfqspi *mcfqspi, u8 chip_select,
115 				bool cs_high)
116 {
117 	mcfqspi->cs_control->deselect(mcfqspi->cs_control, chip_select, cs_high);
118 }
119 
120 static int mcfqspi_cs_setup(struct mcfqspi *mcfqspi)
121 {
122 	return (mcfqspi->cs_control->setup) ?
123 		mcfqspi->cs_control->setup(mcfqspi->cs_control) : 0;
124 }
125 
126 static void mcfqspi_cs_teardown(struct mcfqspi *mcfqspi)
127 {
128 	if (mcfqspi->cs_control->teardown)
129 		mcfqspi->cs_control->teardown(mcfqspi->cs_control);
130 }
131 
132 static u8 mcfqspi_qmr_baud(u32 speed_hz)
133 {
134 	return clamp((MCFQSPI_BUSCLK + speed_hz - 1) / speed_hz, 2u, 255u);
135 }
136 
137 static bool mcfqspi_qdlyr_spe(struct mcfqspi *mcfqspi)
138 {
139 	return mcfqspi_rd_qdlyr(mcfqspi) & MCFQSPI_QDLYR_SPE;
140 }
141 
142 static irqreturn_t mcfqspi_irq_handler(int this_irq, void *dev_id)
143 {
144 	struct mcfqspi *mcfqspi = dev_id;
145 
146 	/* clear interrupt */
147 	mcfqspi_wr_qir(mcfqspi, MCFQSPI_QIR_SPIFE | MCFQSPI_QIR_SPIF);
148 	wake_up(&mcfqspi->waitq);
149 
150 	return IRQ_HANDLED;
151 }
152 
153 static void mcfqspi_transfer_msg8(struct mcfqspi *mcfqspi, unsigned count,
154 				  const u8 *txbuf, u8 *rxbuf)
155 {
156 	unsigned i, n, offset = 0;
157 
158 	n = min(count, 16u);
159 
160 	mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_CMDBUF);
161 	for (i = 0; i < n; ++i)
162 		mcfqspi_wr_qdr(mcfqspi, MCFQSPI_QCR_BITSE);
163 
164 	mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_TXBUF);
165 	if (txbuf)
166 		for (i = 0; i < n; ++i)
167 			mcfqspi_wr_qdr(mcfqspi, *txbuf++);
168 	else
169 		for (i = 0; i < count; ++i)
170 			mcfqspi_wr_qdr(mcfqspi, 0);
171 
172 	count -= n;
173 	if (count) {
174 		u16 qwr = 0xf08;
175 		mcfqspi_wr_qwr(mcfqspi, 0x700);
176 		mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
177 
178 		do {
179 			wait_event(mcfqspi->waitq, !mcfqspi_qdlyr_spe(mcfqspi));
180 			mcfqspi_wr_qwr(mcfqspi, qwr);
181 			mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
182 			if (rxbuf) {
183 				mcfqspi_wr_qar(mcfqspi,
184 					       MCFQSPI_QAR_RXBUF + offset);
185 				for (i = 0; i < 8; ++i)
186 					*rxbuf++ = mcfqspi_rd_qdr(mcfqspi);
187 			}
188 			n = min(count, 8u);
189 			if (txbuf) {
190 				mcfqspi_wr_qar(mcfqspi,
191 					       MCFQSPI_QAR_TXBUF + offset);
192 				for (i = 0; i < n; ++i)
193 					mcfqspi_wr_qdr(mcfqspi, *txbuf++);
194 			}
195 			qwr = (offset ? 0x808 : 0) + ((n - 1) << 8);
196 			offset ^= 8;
197 			count -= n;
198 		} while (count);
199 		wait_event(mcfqspi->waitq, !mcfqspi_qdlyr_spe(mcfqspi));
200 		mcfqspi_wr_qwr(mcfqspi, qwr);
201 		mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
202 		if (rxbuf) {
203 			mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_RXBUF + offset);
204 			for (i = 0; i < 8; ++i)
205 				*rxbuf++ = mcfqspi_rd_qdr(mcfqspi);
206 			offset ^= 8;
207 		}
208 	} else {
209 		mcfqspi_wr_qwr(mcfqspi, (n - 1) << 8);
210 		mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
211 	}
212 	wait_event(mcfqspi->waitq, !mcfqspi_qdlyr_spe(mcfqspi));
213 	if (rxbuf) {
214 		mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_RXBUF + offset);
215 		for (i = 0; i < n; ++i)
216 			*rxbuf++ = mcfqspi_rd_qdr(mcfqspi);
217 	}
218 }
219 
220 static void mcfqspi_transfer_msg16(struct mcfqspi *mcfqspi, unsigned count,
221 				   const u16 *txbuf, u16 *rxbuf)
222 {
223 	unsigned i, n, offset = 0;
224 
225 	n = min(count, 16u);
226 
227 	mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_CMDBUF);
228 	for (i = 0; i < n; ++i)
229 		mcfqspi_wr_qdr(mcfqspi, MCFQSPI_QCR_BITSE);
230 
231 	mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_TXBUF);
232 	if (txbuf)
233 		for (i = 0; i < n; ++i)
234 			mcfqspi_wr_qdr(mcfqspi, *txbuf++);
235 	else
236 		for (i = 0; i < count; ++i)
237 			mcfqspi_wr_qdr(mcfqspi, 0);
238 
239 	count -= n;
240 	if (count) {
241 		u16 qwr = 0xf08;
242 		mcfqspi_wr_qwr(mcfqspi, 0x700);
243 		mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
244 
245 		do {
246 			wait_event(mcfqspi->waitq, !mcfqspi_qdlyr_spe(mcfqspi));
247 			mcfqspi_wr_qwr(mcfqspi, qwr);
248 			mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
249 			if (rxbuf) {
250 				mcfqspi_wr_qar(mcfqspi,
251 					       MCFQSPI_QAR_RXBUF + offset);
252 				for (i = 0; i < 8; ++i)
253 					*rxbuf++ = mcfqspi_rd_qdr(mcfqspi);
254 			}
255 			n = min(count, 8u);
256 			if (txbuf) {
257 				mcfqspi_wr_qar(mcfqspi,
258 					       MCFQSPI_QAR_TXBUF + offset);
259 				for (i = 0; i < n; ++i)
260 					mcfqspi_wr_qdr(mcfqspi, *txbuf++);
261 			}
262 			qwr = (offset ? 0x808 : 0x000) + ((n - 1) << 8);
263 			offset ^= 8;
264 			count -= n;
265 		} while (count);
266 		wait_event(mcfqspi->waitq, !mcfqspi_qdlyr_spe(mcfqspi));
267 		mcfqspi_wr_qwr(mcfqspi, qwr);
268 		mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
269 		if (rxbuf) {
270 			mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_RXBUF + offset);
271 			for (i = 0; i < 8; ++i)
272 				*rxbuf++ = mcfqspi_rd_qdr(mcfqspi);
273 			offset ^= 8;
274 		}
275 	} else {
276 		mcfqspi_wr_qwr(mcfqspi, (n - 1) << 8);
277 		mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
278 	}
279 	wait_event(mcfqspi->waitq, !mcfqspi_qdlyr_spe(mcfqspi));
280 	if (rxbuf) {
281 		mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_RXBUF + offset);
282 		for (i = 0; i < n; ++i)
283 			*rxbuf++ = mcfqspi_rd_qdr(mcfqspi);
284 	}
285 }
286 
287 static void mcfqspi_set_cs(struct spi_device *spi, bool enable)
288 {
289 	struct mcfqspi *mcfqspi = spi_master_get_devdata(spi->master);
290 	bool cs_high = spi->mode & SPI_CS_HIGH;
291 
292 	if (enable)
293 		mcfqspi_cs_select(mcfqspi, spi_get_chipselect(spi, 0), cs_high);
294 	else
295 		mcfqspi_cs_deselect(mcfqspi, spi_get_chipselect(spi, 0), cs_high);
296 }
297 
298 static int mcfqspi_transfer_one(struct spi_master *master,
299 				struct spi_device *spi,
300 				struct spi_transfer *t)
301 {
302 	struct mcfqspi *mcfqspi = spi_master_get_devdata(master);
303 	u16 qmr = MCFQSPI_QMR_MSTR;
304 
305 	qmr |= t->bits_per_word << 10;
306 	if (spi->mode & SPI_CPHA)
307 		qmr |= MCFQSPI_QMR_CPHA;
308 	if (spi->mode & SPI_CPOL)
309 		qmr |= MCFQSPI_QMR_CPOL;
310 	qmr |= mcfqspi_qmr_baud(t->speed_hz);
311 	mcfqspi_wr_qmr(mcfqspi, qmr);
312 
313 	mcfqspi_wr_qir(mcfqspi, MCFQSPI_QIR_SPIFE);
314 	if (t->bits_per_word == 8)
315 		mcfqspi_transfer_msg8(mcfqspi, t->len, t->tx_buf, t->rx_buf);
316 	else
317 		mcfqspi_transfer_msg16(mcfqspi, t->len / 2, t->tx_buf,
318 				       t->rx_buf);
319 	mcfqspi_wr_qir(mcfqspi, 0);
320 
321 	return 0;
322 }
323 
324 static int mcfqspi_setup(struct spi_device *spi)
325 {
326 	mcfqspi_cs_deselect(spi_master_get_devdata(spi->master),
327 			    spi_get_chipselect(spi, 0), spi->mode & SPI_CS_HIGH);
328 
329 	dev_dbg(&spi->dev,
330 			"bits per word %d, chip select %d, speed %d KHz\n",
331 			spi->bits_per_word, spi_get_chipselect(spi, 0),
332 			(MCFQSPI_BUSCLK / mcfqspi_qmr_baud(spi->max_speed_hz))
333 			/ 1000);
334 
335 	return 0;
336 }
337 
338 static int mcfqspi_probe(struct platform_device *pdev)
339 {
340 	struct spi_master *master;
341 	struct mcfqspi *mcfqspi;
342 	struct mcfqspi_platform_data *pdata;
343 	int status;
344 
345 	pdata = dev_get_platdata(&pdev->dev);
346 	if (!pdata) {
347 		dev_dbg(&pdev->dev, "platform data is missing\n");
348 		return -ENOENT;
349 	}
350 
351 	if (!pdata->cs_control) {
352 		dev_dbg(&pdev->dev, "pdata->cs_control is NULL\n");
353 		return -EINVAL;
354 	}
355 
356 	master = spi_alloc_master(&pdev->dev, sizeof(*mcfqspi));
357 	if (master == NULL) {
358 		dev_dbg(&pdev->dev, "spi_alloc_master failed\n");
359 		return -ENOMEM;
360 	}
361 
362 	mcfqspi = spi_master_get_devdata(master);
363 
364 	mcfqspi->iobase = devm_platform_ioremap_resource(pdev, 0);
365 	if (IS_ERR(mcfqspi->iobase)) {
366 		status = PTR_ERR(mcfqspi->iobase);
367 		goto fail0;
368 	}
369 
370 	mcfqspi->irq = platform_get_irq(pdev, 0);
371 	if (mcfqspi->irq < 0) {
372 		dev_dbg(&pdev->dev, "platform_get_irq failed\n");
373 		status = -ENXIO;
374 		goto fail0;
375 	}
376 
377 	status = devm_request_irq(&pdev->dev, mcfqspi->irq, mcfqspi_irq_handler,
378 				0, pdev->name, mcfqspi);
379 	if (status) {
380 		dev_dbg(&pdev->dev, "request_irq failed\n");
381 		goto fail0;
382 	}
383 
384 	mcfqspi->clk = devm_clk_get(&pdev->dev, "qspi_clk");
385 	if (IS_ERR(mcfqspi->clk)) {
386 		dev_dbg(&pdev->dev, "clk_get failed\n");
387 		status = PTR_ERR(mcfqspi->clk);
388 		goto fail0;
389 	}
390 	clk_prepare_enable(mcfqspi->clk);
391 
392 	master->bus_num = pdata->bus_num;
393 	master->num_chipselect = pdata->num_chipselect;
394 
395 	mcfqspi->cs_control = pdata->cs_control;
396 	status = mcfqspi_cs_setup(mcfqspi);
397 	if (status) {
398 		dev_dbg(&pdev->dev, "error initializing cs_control\n");
399 		goto fail1;
400 	}
401 
402 	init_waitqueue_head(&mcfqspi->waitq);
403 
404 	master->mode_bits = SPI_CS_HIGH | SPI_CPOL | SPI_CPHA;
405 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
406 	master->setup = mcfqspi_setup;
407 	master->set_cs = mcfqspi_set_cs;
408 	master->transfer_one = mcfqspi_transfer_one;
409 	master->auto_runtime_pm = true;
410 
411 	platform_set_drvdata(pdev, master);
412 	pm_runtime_enable(&pdev->dev);
413 
414 	status = devm_spi_register_master(&pdev->dev, master);
415 	if (status) {
416 		dev_dbg(&pdev->dev, "spi_register_master failed\n");
417 		goto fail2;
418 	}
419 
420 	dev_info(&pdev->dev, "Coldfire QSPI bus driver\n");
421 
422 	return 0;
423 
424 fail2:
425 	pm_runtime_disable(&pdev->dev);
426 	mcfqspi_cs_teardown(mcfqspi);
427 fail1:
428 	clk_disable_unprepare(mcfqspi->clk);
429 fail0:
430 	spi_master_put(master);
431 
432 	dev_dbg(&pdev->dev, "Coldfire QSPI probe failed\n");
433 
434 	return status;
435 }
436 
437 static void mcfqspi_remove(struct platform_device *pdev)
438 {
439 	struct spi_master *master = platform_get_drvdata(pdev);
440 	struct mcfqspi *mcfqspi = spi_master_get_devdata(master);
441 
442 	pm_runtime_disable(&pdev->dev);
443 	/* disable the hardware (set the baud rate to 0) */
444 	mcfqspi_wr_qmr(mcfqspi, MCFQSPI_QMR_MSTR);
445 
446 	mcfqspi_cs_teardown(mcfqspi);
447 	clk_disable_unprepare(mcfqspi->clk);
448 }
449 
450 #ifdef CONFIG_PM_SLEEP
451 static int mcfqspi_suspend(struct device *dev)
452 {
453 	struct spi_master *master = dev_get_drvdata(dev);
454 	struct mcfqspi *mcfqspi = spi_master_get_devdata(master);
455 	int ret;
456 
457 	ret = spi_master_suspend(master);
458 	if (ret)
459 		return ret;
460 
461 	clk_disable(mcfqspi->clk);
462 
463 	return 0;
464 }
465 
466 static int mcfqspi_resume(struct device *dev)
467 {
468 	struct spi_master *master = dev_get_drvdata(dev);
469 	struct mcfqspi *mcfqspi = spi_master_get_devdata(master);
470 
471 	clk_enable(mcfqspi->clk);
472 
473 	return spi_master_resume(master);
474 }
475 #endif
476 
477 #ifdef CONFIG_PM
478 static int mcfqspi_runtime_suspend(struct device *dev)
479 {
480 	struct spi_master *master = dev_get_drvdata(dev);
481 	struct mcfqspi *mcfqspi = spi_master_get_devdata(master);
482 
483 	clk_disable(mcfqspi->clk);
484 
485 	return 0;
486 }
487 
488 static int mcfqspi_runtime_resume(struct device *dev)
489 {
490 	struct spi_master *master = dev_get_drvdata(dev);
491 	struct mcfqspi *mcfqspi = spi_master_get_devdata(master);
492 
493 	clk_enable(mcfqspi->clk);
494 
495 	return 0;
496 }
497 #endif
498 
499 static const struct dev_pm_ops mcfqspi_pm = {
500 	SET_SYSTEM_SLEEP_PM_OPS(mcfqspi_suspend, mcfqspi_resume)
501 	SET_RUNTIME_PM_OPS(mcfqspi_runtime_suspend, mcfqspi_runtime_resume,
502 			NULL)
503 };
504 
505 static struct platform_driver mcfqspi_driver = {
506 	.driver.name	= DRIVER_NAME,
507 	.driver.owner	= THIS_MODULE,
508 	.driver.pm	= &mcfqspi_pm,
509 	.probe		= mcfqspi_probe,
510 	.remove_new	= mcfqspi_remove,
511 };
512 module_platform_driver(mcfqspi_driver);
513 
514 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
515 MODULE_DESCRIPTION("Coldfire QSPI Controller Driver");
516 MODULE_LICENSE("GPL");
517 MODULE_ALIAS("platform:" DRIVER_NAME);
518