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 * @dev: 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 pm_runtime_disable(spifc->dev);
353 out_err:
354 spi_master_put(master);
355 return ret;
356 }
357
meson_spifc_remove(struct platform_device * pdev)358 static void meson_spifc_remove(struct platform_device *pdev)
359 {
360 struct spi_master *master = platform_get_drvdata(pdev);
361 struct meson_spifc *spifc = spi_master_get_devdata(master);
362
363 pm_runtime_get_sync(&pdev->dev);
364 clk_disable_unprepare(spifc->clk);
365 pm_runtime_disable(&pdev->dev);
366 }
367
368 #ifdef CONFIG_PM_SLEEP
meson_spifc_suspend(struct device * dev)369 static int meson_spifc_suspend(struct device *dev)
370 {
371 struct spi_master *master = dev_get_drvdata(dev);
372 struct meson_spifc *spifc = spi_master_get_devdata(master);
373 int ret;
374
375 ret = spi_master_suspend(master);
376 if (ret)
377 return ret;
378
379 if (!pm_runtime_suspended(dev))
380 clk_disable_unprepare(spifc->clk);
381
382 return 0;
383 }
384
meson_spifc_resume(struct device * dev)385 static int meson_spifc_resume(struct device *dev)
386 {
387 struct spi_master *master = dev_get_drvdata(dev);
388 struct meson_spifc *spifc = spi_master_get_devdata(master);
389 int ret;
390
391 if (!pm_runtime_suspended(dev)) {
392 ret = clk_prepare_enable(spifc->clk);
393 if (ret)
394 return ret;
395 }
396
397 meson_spifc_hw_init(spifc);
398
399 ret = spi_master_resume(master);
400 if (ret)
401 clk_disable_unprepare(spifc->clk);
402
403 return ret;
404 }
405 #endif /* CONFIG_PM_SLEEP */
406
407 #ifdef CONFIG_PM
meson_spifc_runtime_suspend(struct device * dev)408 static int meson_spifc_runtime_suspend(struct device *dev)
409 {
410 struct spi_master *master = dev_get_drvdata(dev);
411 struct meson_spifc *spifc = spi_master_get_devdata(master);
412
413 clk_disable_unprepare(spifc->clk);
414
415 return 0;
416 }
417
meson_spifc_runtime_resume(struct device * dev)418 static int meson_spifc_runtime_resume(struct device *dev)
419 {
420 struct spi_master *master = dev_get_drvdata(dev);
421 struct meson_spifc *spifc = spi_master_get_devdata(master);
422
423 return clk_prepare_enable(spifc->clk);
424 }
425 #endif /* CONFIG_PM */
426
427 static const struct dev_pm_ops meson_spifc_pm_ops = {
428 SET_SYSTEM_SLEEP_PM_OPS(meson_spifc_suspend, meson_spifc_resume)
429 SET_RUNTIME_PM_OPS(meson_spifc_runtime_suspend,
430 meson_spifc_runtime_resume,
431 NULL)
432 };
433
434 static const struct of_device_id meson_spifc_dt_match[] = {
435 { .compatible = "amlogic,meson6-spifc", },
436 { .compatible = "amlogic,meson-gxbb-spifc", },
437 { },
438 };
439 MODULE_DEVICE_TABLE(of, meson_spifc_dt_match);
440
441 static struct platform_driver meson_spifc_driver = {
442 .probe = meson_spifc_probe,
443 .remove_new = meson_spifc_remove,
444 .driver = {
445 .name = "meson-spifc",
446 .of_match_table = of_match_ptr(meson_spifc_dt_match),
447 .pm = &meson_spifc_pm_ops,
448 },
449 };
450
451 module_platform_driver(meson_spifc_driver);
452
453 MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
454 MODULE_DESCRIPTION("Amlogic Meson SPIFC driver");
455 MODULE_LICENSE("GPL v2");
456