1 // SPDX-License-Identifier: GPL-2.0+
2 //
3 // Driver for Amlogic Meson SPI flash controller (SPIFC)
4 //
5 // Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
6 //
7 
8 #include <linux/clk.h>
9 #include <linux/delay.h>
10 #include <linux/device.h>
11 #include <linux/io.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/platform_device.h>
16 #include <linux/pm_runtime.h>
17 #include <linux/regmap.h>
18 #include <linux/spi/spi.h>
19 #include <linux/types.h>
20 
21 /* register map */
22 #define REG_CMD			0x00
23 #define REG_ADDR		0x04
24 #define REG_CTRL		0x08
25 #define REG_CTRL1		0x0c
26 #define REG_STATUS		0x10
27 #define REG_CTRL2		0x14
28 #define REG_CLOCK		0x18
29 #define REG_USER		0x1c
30 #define REG_USER1		0x20
31 #define REG_USER2		0x24
32 #define REG_USER3		0x28
33 #define REG_USER4		0x2c
34 #define REG_SLAVE		0x30
35 #define REG_SLAVE1		0x34
36 #define REG_SLAVE2		0x38
37 #define REG_SLAVE3		0x3c
38 #define REG_C0			0x40
39 #define REG_B8			0x60
40 #define REG_MAX			0x7c
41 
42 /* register fields */
43 #define CMD_USER		BIT(18)
44 #define CTRL_ENABLE_AHB		BIT(17)
45 #define CLOCK_SOURCE		BIT(31)
46 #define CLOCK_DIV_SHIFT		12
47 #define CLOCK_DIV_MASK		(0x3f << CLOCK_DIV_SHIFT)
48 #define CLOCK_CNT_HIGH_SHIFT	6
49 #define CLOCK_CNT_HIGH_MASK	(0x3f << CLOCK_CNT_HIGH_SHIFT)
50 #define CLOCK_CNT_LOW_SHIFT	0
51 #define CLOCK_CNT_LOW_MASK	(0x3f << CLOCK_CNT_LOW_SHIFT)
52 #define USER_DIN_EN_MS		BIT(0)
53 #define USER_CMP_MODE		BIT(2)
54 #define USER_UC_DOUT_SEL	BIT(27)
55 #define USER_UC_DIN_SEL		BIT(28)
56 #define USER_UC_MASK		((BIT(5) - 1) << 27)
57 #define USER1_BN_UC_DOUT_SHIFT	17
58 #define USER1_BN_UC_DOUT_MASK	(0xff << 16)
59 #define USER1_BN_UC_DIN_SHIFT	8
60 #define USER1_BN_UC_DIN_MASK	(0xff << 8)
61 #define USER4_CS_ACT		BIT(30)
62 #define SLAVE_TRST_DONE		BIT(4)
63 #define SLAVE_OP_MODE		BIT(30)
64 #define SLAVE_SW_RST		BIT(31)
65 
66 #define SPIFC_BUFFER_SIZE	64
67 
68 /**
69  * struct meson_spifc
70  * @master:	the SPI master
71  * @regmap:	regmap for device registers
72  * @clk:	input clock of the built-in baud rate generator
73  * @device:	the device structure
74  */
75 struct meson_spifc {
76 	struct spi_master *master;
77 	struct regmap *regmap;
78 	struct clk *clk;
79 	struct device *dev;
80 };
81 
82 static const struct regmap_config spifc_regmap_config = {
83 	.reg_bits = 32,
84 	.val_bits = 32,
85 	.reg_stride = 4,
86 	.max_register = REG_MAX,
87 };
88 
89 /**
90  * meson_spifc_wait_ready() - wait for the current operation to terminate
91  * @spifc:	the Meson SPI device
92  * Return:	0 on success, a negative value on error
93  */
meson_spifc_wait_ready(struct meson_spifc * spifc)94 static int meson_spifc_wait_ready(struct meson_spifc *spifc)
95 {
96 	unsigned long deadline = jiffies + msecs_to_jiffies(5);
97 	u32 data;
98 
99 	do {
100 		regmap_read(spifc->regmap, REG_SLAVE, &data);
101 		if (data & SLAVE_TRST_DONE)
102 			return 0;
103 		cond_resched();
104 	} while (!time_after(jiffies, deadline));
105 
106 	return -ETIMEDOUT;
107 }
108 
109 /**
110  * meson_spifc_drain_buffer() - copy data from device buffer to memory
111  * @spifc:	the Meson SPI device
112  * @buf:	the destination buffer
113  * @len:	number of bytes to copy
114  */
meson_spifc_drain_buffer(struct meson_spifc * spifc,u8 * buf,int len)115 static void meson_spifc_drain_buffer(struct meson_spifc *spifc, u8 *buf,
116 				     int len)
117 {
118 	u32 data;
119 	int i = 0;
120 
121 	while (i < len) {
122 		regmap_read(spifc->regmap, REG_C0 + i, &data);
123 
124 		if (len - i >= 4) {
125 			*((u32 *)buf) = data;
126 			buf += 4;
127 		} else {
128 			memcpy(buf, &data, len - i);
129 			break;
130 		}
131 		i += 4;
132 	}
133 }
134 
135 /**
136  * meson_spifc_fill_buffer() - copy data from memory to device buffer
137  * @spifc:	the Meson SPI device
138  * @buf:	the source buffer
139  * @len:	number of bytes to copy
140  */
meson_spifc_fill_buffer(struct meson_spifc * spifc,const u8 * buf,int len)141 static void meson_spifc_fill_buffer(struct meson_spifc *spifc, const u8 *buf,
142 				    int len)
143 {
144 	u32 data;
145 	int i = 0;
146 
147 	while (i < len) {
148 		if (len - i >= 4)
149 			data = *(u32 *)buf;
150 		else
151 			memcpy(&data, buf, len - i);
152 
153 		regmap_write(spifc->regmap, REG_C0 + i, data);
154 
155 		buf += 4;
156 		i += 4;
157 	}
158 }
159 
160 /**
161  * meson_spifc_setup_speed() - program the clock divider
162  * @spifc:	the Meson SPI device
163  * @speed:	desired speed in Hz
164  */
meson_spifc_setup_speed(struct meson_spifc * spifc,u32 speed)165 static void meson_spifc_setup_speed(struct meson_spifc *spifc, u32 speed)
166 {
167 	unsigned long parent, value;
168 	int n;
169 
170 	parent = clk_get_rate(spifc->clk);
171 	n = max_t(int, parent / speed - 1, 1);
172 
173 	dev_dbg(spifc->dev, "parent %lu, speed %u, n %d\n", parent,
174 		speed, n);
175 
176 	value = (n << CLOCK_DIV_SHIFT) & CLOCK_DIV_MASK;
177 	value |= (n << CLOCK_CNT_LOW_SHIFT) & CLOCK_CNT_LOW_MASK;
178 	value |= (((n + 1) / 2 - 1) << CLOCK_CNT_HIGH_SHIFT) &
179 		CLOCK_CNT_HIGH_MASK;
180 
181 	regmap_write(spifc->regmap, REG_CLOCK, value);
182 }
183 
184 /**
185  * meson_spifc_txrx() - transfer a chunk of data
186  * @spifc:	the Meson SPI device
187  * @xfer:	the current SPI transfer
188  * @offset:	offset of the data to transfer
189  * @len:	length of the data to transfer
190  * @last_xfer:	whether this is the last transfer of the message
191  * @last_chunk:	whether this is the last chunk of the transfer
192  * Return:	0 on success, a negative value on error
193  */
meson_spifc_txrx(struct meson_spifc * spifc,struct spi_transfer * xfer,int offset,int len,bool last_xfer,bool last_chunk)194 static int meson_spifc_txrx(struct meson_spifc *spifc,
195 			    struct spi_transfer *xfer,
196 			    int offset, int len, bool last_xfer,
197 			    bool last_chunk)
198 {
199 	bool keep_cs = true;
200 	int ret;
201 
202 	if (xfer->tx_buf)
203 		meson_spifc_fill_buffer(spifc, xfer->tx_buf + offset, len);
204 
205 	/* enable DOUT stage */
206 	regmap_update_bits(spifc->regmap, REG_USER, USER_UC_MASK,
207 			   USER_UC_DOUT_SEL);
208 	regmap_write(spifc->regmap, REG_USER1,
209 		     (8 * len - 1) << USER1_BN_UC_DOUT_SHIFT);
210 
211 	/* enable data input during DOUT */
212 	regmap_update_bits(spifc->regmap, REG_USER, USER_DIN_EN_MS,
213 			   USER_DIN_EN_MS);
214 
215 	if (last_chunk) {
216 		if (last_xfer)
217 			keep_cs = xfer->cs_change;
218 		else
219 			keep_cs = !xfer->cs_change;
220 	}
221 
222 	regmap_update_bits(spifc->regmap, REG_USER4, USER4_CS_ACT,
223 			   keep_cs ? USER4_CS_ACT : 0);
224 
225 	/* clear transition done bit */
226 	regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_TRST_DONE, 0);
227 	/* start transfer */
228 	regmap_update_bits(spifc->regmap, REG_CMD, CMD_USER, CMD_USER);
229 
230 	ret = meson_spifc_wait_ready(spifc);
231 
232 	if (!ret && xfer->rx_buf)
233 		meson_spifc_drain_buffer(spifc, xfer->rx_buf + offset, len);
234 
235 	return ret;
236 }
237 
238 /**
239  * meson_spifc_transfer_one() - perform a single transfer
240  * @master:	the SPI master
241  * @spi:	the SPI device
242  * @xfer:	the current SPI transfer
243  * Return:	0 on success, a negative value on error
244  */
meson_spifc_transfer_one(struct spi_master * master,struct spi_device * spi,struct spi_transfer * xfer)245 static int meson_spifc_transfer_one(struct spi_master *master,
246 				    struct spi_device *spi,
247 				    struct spi_transfer *xfer)
248 {
249 	struct meson_spifc *spifc = spi_master_get_devdata(master);
250 	int len, done = 0, ret = 0;
251 
252 	meson_spifc_setup_speed(spifc, xfer->speed_hz);
253 
254 	regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB, 0);
255 
256 	while (done < xfer->len && !ret) {
257 		len = min_t(int, xfer->len - done, SPIFC_BUFFER_SIZE);
258 		ret = meson_spifc_txrx(spifc, xfer, done, len,
259 				       spi_transfer_is_last(master, xfer),
260 				       done + len >= xfer->len);
261 		done += len;
262 	}
263 
264 	regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB,
265 			   CTRL_ENABLE_AHB);
266 
267 	return ret;
268 }
269 
270 /**
271  * meson_spifc_hw_init() - reset and initialize the SPI controller
272  * @spifc:	the Meson SPI device
273  */
meson_spifc_hw_init(struct meson_spifc * spifc)274 static void meson_spifc_hw_init(struct meson_spifc *spifc)
275 {
276 	/* reset device */
277 	regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_SW_RST,
278 			   SLAVE_SW_RST);
279 	/* disable compatible mode */
280 	regmap_update_bits(spifc->regmap, REG_USER, USER_CMP_MODE, 0);
281 	/* set master mode */
282 	regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_OP_MODE, 0);
283 }
284 
meson_spifc_probe(struct platform_device * pdev)285 static int meson_spifc_probe(struct platform_device *pdev)
286 {
287 	struct spi_master *master;
288 	struct meson_spifc *spifc;
289 	void __iomem *base;
290 	unsigned int rate;
291 	int ret = 0;
292 
293 	master = spi_alloc_master(&pdev->dev, sizeof(struct meson_spifc));
294 	if (!master)
295 		return -ENOMEM;
296 
297 	platform_set_drvdata(pdev, master);
298 
299 	spifc = spi_master_get_devdata(master);
300 	spifc->dev = &pdev->dev;
301 
302 	base = devm_platform_ioremap_resource(pdev, 0);
303 	if (IS_ERR(base)) {
304 		ret = PTR_ERR(base);
305 		goto out_err;
306 	}
307 
308 	spifc->regmap = devm_regmap_init_mmio(spifc->dev, base,
309 					      &spifc_regmap_config);
310 	if (IS_ERR(spifc->regmap)) {
311 		ret = PTR_ERR(spifc->regmap);
312 		goto out_err;
313 	}
314 
315 	spifc->clk = devm_clk_get(spifc->dev, NULL);
316 	if (IS_ERR(spifc->clk)) {
317 		dev_err(spifc->dev, "missing clock\n");
318 		ret = PTR_ERR(spifc->clk);
319 		goto out_err;
320 	}
321 
322 	ret = clk_prepare_enable(spifc->clk);
323 	if (ret) {
324 		dev_err(spifc->dev, "can't prepare clock\n");
325 		goto out_err;
326 	}
327 
328 	rate = clk_get_rate(spifc->clk);
329 
330 	master->num_chipselect = 1;
331 	master->dev.of_node = pdev->dev.of_node;
332 	master->bits_per_word_mask = SPI_BPW_MASK(8);
333 	master->auto_runtime_pm = true;
334 	master->transfer_one = meson_spifc_transfer_one;
335 	master->min_speed_hz = rate >> 6;
336 	master->max_speed_hz = rate >> 1;
337 
338 	meson_spifc_hw_init(spifc);
339 
340 	pm_runtime_set_active(spifc->dev);
341 	pm_runtime_enable(spifc->dev);
342 
343 	ret = devm_spi_register_master(spifc->dev, master);
344 	if (ret) {
345 		dev_err(spifc->dev, "failed to register spi master\n");
346 		goto out_clk;
347 	}
348 
349 	return 0;
350 out_clk:
351 	clk_disable_unprepare(spifc->clk);
352 out_err:
353 	spi_master_put(master);
354 	return ret;
355 }
356 
meson_spifc_remove(struct platform_device * pdev)357 static int meson_spifc_remove(struct platform_device *pdev)
358 {
359 	struct spi_master *master = platform_get_drvdata(pdev);
360 	struct meson_spifc *spifc = spi_master_get_devdata(master);
361 
362 	pm_runtime_get_sync(&pdev->dev);
363 	clk_disable_unprepare(spifc->clk);
364 	pm_runtime_disable(&pdev->dev);
365 
366 	return 0;
367 }
368 
369 #ifdef CONFIG_PM_SLEEP
meson_spifc_suspend(struct device * dev)370 static int meson_spifc_suspend(struct device *dev)
371 {
372 	struct spi_master *master = dev_get_drvdata(dev);
373 	struct meson_spifc *spifc = spi_master_get_devdata(master);
374 	int ret;
375 
376 	ret = spi_master_suspend(master);
377 	if (ret)
378 		return ret;
379 
380 	if (!pm_runtime_suspended(dev))
381 		clk_disable_unprepare(spifc->clk);
382 
383 	return 0;
384 }
385 
meson_spifc_resume(struct device * dev)386 static int meson_spifc_resume(struct device *dev)
387 {
388 	struct spi_master *master = dev_get_drvdata(dev);
389 	struct meson_spifc *spifc = spi_master_get_devdata(master);
390 	int ret;
391 
392 	if (!pm_runtime_suspended(dev)) {
393 		ret = clk_prepare_enable(spifc->clk);
394 		if (ret)
395 			return ret;
396 	}
397 
398 	meson_spifc_hw_init(spifc);
399 
400 	ret = spi_master_resume(master);
401 	if (ret)
402 		clk_disable_unprepare(spifc->clk);
403 
404 	return ret;
405 }
406 #endif /* CONFIG_PM_SLEEP */
407 
408 #ifdef CONFIG_PM
meson_spifc_runtime_suspend(struct device * dev)409 static int meson_spifc_runtime_suspend(struct device *dev)
410 {
411 	struct spi_master *master = dev_get_drvdata(dev);
412 	struct meson_spifc *spifc = spi_master_get_devdata(master);
413 
414 	clk_disable_unprepare(spifc->clk);
415 
416 	return 0;
417 }
418 
meson_spifc_runtime_resume(struct device * dev)419 static int meson_spifc_runtime_resume(struct device *dev)
420 {
421 	struct spi_master *master = dev_get_drvdata(dev);
422 	struct meson_spifc *spifc = spi_master_get_devdata(master);
423 
424 	return clk_prepare_enable(spifc->clk);
425 }
426 #endif /* CONFIG_PM */
427 
428 static const struct dev_pm_ops meson_spifc_pm_ops = {
429 	SET_SYSTEM_SLEEP_PM_OPS(meson_spifc_suspend, meson_spifc_resume)
430 	SET_RUNTIME_PM_OPS(meson_spifc_runtime_suspend,
431 			   meson_spifc_runtime_resume,
432 			   NULL)
433 };
434 
435 static const struct of_device_id meson_spifc_dt_match[] = {
436 	{ .compatible = "amlogic,meson6-spifc", },
437 	{ .compatible = "amlogic,meson-gxbb-spifc", },
438 	{ },
439 };
440 MODULE_DEVICE_TABLE(of, meson_spifc_dt_match);
441 
442 static struct platform_driver meson_spifc_driver = {
443 	.probe	= meson_spifc_probe,
444 	.remove	= meson_spifc_remove,
445 	.driver	= {
446 		.name		= "meson-spifc",
447 		.of_match_table	= of_match_ptr(meson_spifc_dt_match),
448 		.pm		= &meson_spifc_pm_ops,
449 	},
450 };
451 
452 module_platform_driver(meson_spifc_driver);
453 
454 MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
455 MODULE_DESCRIPTION("Amlogic Meson SPIFC driver");
456 MODULE_LICENSE("GPL v2");
457