1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Amlogic Meson6/Meson8/Meson8b/Meson8m2 SDHC MMC host controller driver.
4  *
5  * Copyright (C) 2020 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
6  */
7 
8 #include <linux/clk.h>
9 #include <linux/device.h>
10 #include <linux/dma-mapping.h>
11 #include <linux/interrupt.h>
12 #include <linux/iopoll.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/platform_device.h>
16 #include <linux/property.h>
17 #include <linux/regmap.h>
18 #include <linux/regulator/consumer.h>
19 #include <linux/types.h>
20 
21 #include <linux/mmc/host.h>
22 #include <linux/mmc/mmc.h>
23 #include <linux/mmc/sdio.h>
24 #include <linux/mmc/slot-gpio.h>
25 
26 #include "meson-mx-sdhc.h"
27 
28 #define MESON_SDHC_NUM_BULK_CLKS				4
29 #define MESON_SDHC_MAX_BLK_SIZE					512
30 #define MESON_SDHC_NUM_TUNING_TRIES				10
31 
32 #define MESON_SDHC_WAIT_CMD_READY_SLEEP_US			1
33 #define MESON_SDHC_WAIT_CMD_READY_TIMEOUT_US			100000
34 #define MESON_SDHC_WAIT_BEFORE_SEND_SLEEP_US			1
35 #define MESON_SDHC_WAIT_BEFORE_SEND_TIMEOUT_US			200
36 
37 struct meson_mx_sdhc_data {
38 	void		(*init_hw)(struct mmc_host *mmc);
39 	void		(*set_pdma)(struct mmc_host *mmc);
40 	void		(*wait_before_send)(struct mmc_host *mmc);
41 	bool		hardware_flush_all_cmds;
42 };
43 
44 struct meson_mx_sdhc_host {
45 	struct mmc_host			*mmc;
46 
47 	struct mmc_request		*mrq;
48 	struct mmc_command		*cmd;
49 	int				error;
50 
51 	struct regmap			*regmap;
52 
53 	struct clk			*pclk;
54 	struct clk			*sd_clk;
55 	struct clk_bulk_data		bulk_clks[MESON_SDHC_NUM_BULK_CLKS];
56 	bool				bulk_clks_enabled;
57 
58 	const struct meson_mx_sdhc_data	*platform;
59 };
60 
61 static const struct regmap_config meson_mx_sdhc_regmap_config = {
62 	.reg_bits = 8,
63 	.val_bits = 32,
64 	.reg_stride = 4,
65 	.max_register = MESON_SDHC_CLK2,
66 };
67 
68 static void meson_mx_sdhc_hw_reset(struct mmc_host *mmc)
69 {
70 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
71 
72 	regmap_write(host->regmap, MESON_SDHC_SRST, MESON_SDHC_SRST_MAIN_CTRL |
73 		     MESON_SDHC_SRST_RXFIFO | MESON_SDHC_SRST_TXFIFO |
74 		     MESON_SDHC_SRST_DPHY_RX | MESON_SDHC_SRST_DPHY_TX |
75 		     MESON_SDHC_SRST_DMA_IF);
76 	usleep_range(10, 100);
77 
78 	regmap_write(host->regmap, MESON_SDHC_SRST, 0);
79 	usleep_range(10, 100);
80 }
81 
82 static void meson_mx_sdhc_clear_fifo(struct mmc_host *mmc)
83 {
84 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
85 	u32 stat;
86 
87 	regmap_read(host->regmap, MESON_SDHC_STAT, &stat);
88 	if (!FIELD_GET(MESON_SDHC_STAT_RXFIFO_CNT, stat) &&
89 	    !FIELD_GET(MESON_SDHC_STAT_TXFIFO_CNT, stat))
90 		return;
91 
92 	regmap_write(host->regmap, MESON_SDHC_SRST, MESON_SDHC_SRST_RXFIFO |
93 		     MESON_SDHC_SRST_TXFIFO | MESON_SDHC_SRST_MAIN_CTRL);
94 	udelay(5);
95 
96 	regmap_read(host->regmap, MESON_SDHC_STAT, &stat);
97 	if (FIELD_GET(MESON_SDHC_STAT_RXFIFO_CNT, stat) ||
98 	    FIELD_GET(MESON_SDHC_STAT_TXFIFO_CNT, stat))
99 		dev_warn(mmc_dev(host->mmc),
100 			 "Failed to clear FIFOs, RX: %lu, TX: %lu\n",
101 			 FIELD_GET(MESON_SDHC_STAT_RXFIFO_CNT, stat),
102 			 FIELD_GET(MESON_SDHC_STAT_TXFIFO_CNT, stat));
103 }
104 
105 static void meson_mx_sdhc_wait_cmd_ready(struct mmc_host *mmc)
106 {
107 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
108 	u32 stat, esta;
109 	int ret;
110 
111 	ret = regmap_read_poll_timeout(host->regmap, MESON_SDHC_STAT, stat,
112 				       !(stat & MESON_SDHC_STAT_CMD_BUSY),
113 				       MESON_SDHC_WAIT_CMD_READY_SLEEP_US,
114 				       MESON_SDHC_WAIT_CMD_READY_TIMEOUT_US);
115 	if (ret) {
116 		dev_warn(mmc_dev(mmc),
117 			 "Failed to poll for CMD_BUSY while processing CMD%d\n",
118 			 host->cmd->opcode);
119 		meson_mx_sdhc_hw_reset(mmc);
120 	}
121 
122 	ret = regmap_read_poll_timeout(host->regmap, MESON_SDHC_ESTA, esta,
123 				       !(esta & MESON_SDHC_ESTA_11_13),
124 				       MESON_SDHC_WAIT_CMD_READY_SLEEP_US,
125 				       MESON_SDHC_WAIT_CMD_READY_TIMEOUT_US);
126 	if (ret) {
127 		dev_warn(mmc_dev(mmc),
128 			 "Failed to poll for ESTA[13:11] while processing CMD%d\n",
129 			 host->cmd->opcode);
130 		meson_mx_sdhc_hw_reset(mmc);
131 	}
132 }
133 
134 static void meson_mx_sdhc_start_cmd(struct mmc_host *mmc,
135 				    struct mmc_command *cmd)
136 {
137 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
138 	u32 ictl, send;
139 	int pack_len;
140 
141 	host->cmd = cmd;
142 
143 	ictl = MESON_SDHC_ICTL_DATA_TIMEOUT | MESON_SDHC_ICTL_DATA_ERR_CRC |
144 	       MESON_SDHC_ICTL_RXFIFO_FULL | MESON_SDHC_ICTL_TXFIFO_EMPTY |
145 	       MESON_SDHC_ICTL_RESP_TIMEOUT | MESON_SDHC_ICTL_RESP_ERR_CRC;
146 
147 	send = FIELD_PREP(MESON_SDHC_SEND_CMD_INDEX, cmd->opcode);
148 
149 	if (cmd->data) {
150 		send |= MESON_SDHC_SEND_CMD_HAS_DATA;
151 		send |= FIELD_PREP(MESON_SDHC_SEND_TOTAL_PACK,
152 				   cmd->data->blocks - 1);
153 
154 		if (cmd->data->blksz < MESON_SDHC_MAX_BLK_SIZE)
155 			pack_len = cmd->data->blksz;
156 		else
157 			pack_len = 0;
158 
159 		if (cmd->data->flags & MMC_DATA_WRITE)
160 			send |= MESON_SDHC_SEND_DATA_DIR;
161 
162 		/*
163 		 * If command with no data, just wait response done
164 		 * interrupt(int[0]), and if command with data transfer, just
165 		 * wait dma done interrupt(int[11]), don't need care about
166 		 * dat0 busy or not.
167 		 */
168 		if (host->platform->hardware_flush_all_cmds ||
169 		    cmd->data->flags & MMC_DATA_WRITE)
170 			/* hardware flush: */
171 			ictl |= MESON_SDHC_ICTL_DMA_DONE;
172 		else
173 			/* software flush: */
174 			ictl |= MESON_SDHC_ICTL_DATA_XFER_OK;
175 	} else {
176 		pack_len = 0;
177 
178 		ictl |= MESON_SDHC_ICTL_RESP_OK;
179 	}
180 
181 	if (cmd->opcode == MMC_STOP_TRANSMISSION)
182 		send |= MESON_SDHC_SEND_DATA_STOP;
183 
184 	if (cmd->flags & MMC_RSP_PRESENT)
185 		send |= MESON_SDHC_SEND_CMD_HAS_RESP;
186 
187 	if (cmd->flags & MMC_RSP_136) {
188 		send |= MESON_SDHC_SEND_RESP_LEN;
189 		send |= MESON_SDHC_SEND_RESP_NO_CRC;
190 	}
191 
192 	if (!(cmd->flags & MMC_RSP_CRC))
193 		send |= MESON_SDHC_SEND_RESP_NO_CRC;
194 
195 	if (cmd->flags & MMC_RSP_BUSY)
196 		send |= MESON_SDHC_SEND_R1B;
197 
198 	/* enable the new IRQs and mask all pending ones */
199 	regmap_write(host->regmap, MESON_SDHC_ICTL, ictl);
200 	regmap_write(host->regmap, MESON_SDHC_ISTA, MESON_SDHC_ISTA_ALL_IRQS);
201 
202 	regmap_write(host->regmap, MESON_SDHC_ARGU, cmd->arg);
203 
204 	regmap_update_bits(host->regmap, MESON_SDHC_CTRL,
205 			   MESON_SDHC_CTRL_PACK_LEN,
206 			   FIELD_PREP(MESON_SDHC_CTRL_PACK_LEN, pack_len));
207 
208 	if (cmd->data)
209 		regmap_write(host->regmap, MESON_SDHC_ADDR,
210 			     sg_dma_address(cmd->data->sg));
211 
212 	meson_mx_sdhc_wait_cmd_ready(mmc);
213 
214 	if (cmd->data)
215 		host->platform->set_pdma(mmc);
216 
217 	if (host->platform->wait_before_send)
218 		host->platform->wait_before_send(mmc);
219 
220 	regmap_write(host->regmap, MESON_SDHC_SEND, send);
221 }
222 
223 static void meson_mx_sdhc_disable_clks(struct mmc_host *mmc)
224 {
225 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
226 
227 	if (!host->bulk_clks_enabled)
228 		return;
229 
230 	clk_bulk_disable_unprepare(MESON_SDHC_NUM_BULK_CLKS, host->bulk_clks);
231 
232 	host->bulk_clks_enabled = false;
233 }
234 
235 static int meson_mx_sdhc_enable_clks(struct mmc_host *mmc)
236 {
237 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
238 	int ret;
239 
240 	if (host->bulk_clks_enabled)
241 		return 0;
242 
243 	ret = clk_bulk_prepare_enable(MESON_SDHC_NUM_BULK_CLKS,
244 				      host->bulk_clks);
245 	if (ret)
246 		return ret;
247 
248 	host->bulk_clks_enabled = true;
249 
250 	return 0;
251 }
252 
253 static int meson_mx_sdhc_set_clk(struct mmc_host *mmc, struct mmc_ios *ios)
254 {
255 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
256 	u32 rx_clk_phase;
257 	int ret;
258 
259 	meson_mx_sdhc_disable_clks(mmc);
260 
261 	if (ios->clock) {
262 		ret = clk_set_rate(host->sd_clk, ios->clock);
263 		if (ret) {
264 			dev_warn(mmc_dev(mmc),
265 				 "Failed to set MMC clock to %uHz: %d\n",
266 				 ios->clock, host->error);
267 			return ret;
268 		}
269 
270 		ret = meson_mx_sdhc_enable_clks(mmc);
271 		if (ret)
272 			return ret;
273 
274 		mmc->actual_clock = clk_get_rate(host->sd_clk);
275 
276 		/*
277 		 * according to Amlogic the following latching points are
278 		 * selected with empirical values, there is no (known) formula
279 		 * to calculate these.
280 		 */
281 		if (mmc->actual_clock > 100000000) {
282 			rx_clk_phase = 1;
283 		} else if (mmc->actual_clock > 45000000) {
284 			if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330)
285 				rx_clk_phase = 15;
286 			else
287 				rx_clk_phase = 11;
288 		} else if (mmc->actual_clock >= 25000000) {
289 			rx_clk_phase = 15;
290 		} else if (mmc->actual_clock > 5000000) {
291 			rx_clk_phase = 23;
292 		} else if (mmc->actual_clock > 1000000) {
293 			rx_clk_phase = 55;
294 		} else {
295 			rx_clk_phase = 1061;
296 		}
297 
298 		regmap_update_bits(host->regmap, MESON_SDHC_CLK2,
299 				   MESON_SDHC_CLK2_RX_CLK_PHASE,
300 				   FIELD_PREP(MESON_SDHC_CLK2_RX_CLK_PHASE,
301 					      rx_clk_phase));
302 	} else {
303 		mmc->actual_clock = 0;
304 	}
305 
306 	return 0;
307 }
308 
309 static void meson_mx_sdhc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
310 {
311 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
312 	unsigned short vdd = ios->vdd;
313 
314 	switch (ios->power_mode) {
315 	case MMC_POWER_OFF:
316 		vdd = 0;
317 		fallthrough;
318 
319 	case MMC_POWER_UP:
320 		if (!IS_ERR(mmc->supply.vmmc)) {
321 			host->error = mmc_regulator_set_ocr(mmc,
322 							    mmc->supply.vmmc,
323 							    vdd);
324 			if (host->error)
325 				return;
326 		}
327 
328 		break;
329 
330 	case MMC_POWER_ON:
331 		break;
332 	}
333 
334 	host->error = meson_mx_sdhc_set_clk(mmc, ios);
335 	if (host->error)
336 		return;
337 
338 	switch (ios->bus_width) {
339 	case MMC_BUS_WIDTH_1:
340 		regmap_update_bits(host->regmap, MESON_SDHC_CTRL,
341 				   MESON_SDHC_CTRL_DAT_TYPE,
342 				   FIELD_PREP(MESON_SDHC_CTRL_DAT_TYPE, 0));
343 		break;
344 
345 	case MMC_BUS_WIDTH_4:
346 		regmap_update_bits(host->regmap, MESON_SDHC_CTRL,
347 				   MESON_SDHC_CTRL_DAT_TYPE,
348 				   FIELD_PREP(MESON_SDHC_CTRL_DAT_TYPE, 1));
349 		break;
350 
351 	case MMC_BUS_WIDTH_8:
352 		regmap_update_bits(host->regmap, MESON_SDHC_CTRL,
353 				   MESON_SDHC_CTRL_DAT_TYPE,
354 				   FIELD_PREP(MESON_SDHC_CTRL_DAT_TYPE, 2));
355 		break;
356 
357 	default:
358 		dev_err(mmc_dev(mmc), "unsupported bus width: %d\n",
359 			ios->bus_width);
360 		host->error = -EINVAL;
361 		return;
362 	}
363 }
364 
365 static int meson_mx_sdhc_map_dma(struct mmc_host *mmc, struct mmc_request *mrq)
366 {
367 	struct mmc_data *data = mrq->data;
368 	int dma_len;
369 
370 	if (!data)
371 		return 0;
372 
373 	dma_len = dma_map_sg(mmc_dev(mmc), data->sg, data->sg_len,
374 			     mmc_get_dma_dir(data));
375 	if (dma_len <= 0) {
376 		dev_err(mmc_dev(mmc), "dma_map_sg failed\n");
377 		return -ENOMEM;
378 	}
379 
380 	return 0;
381 }
382 
383 static void meson_mx_sdhc_request(struct mmc_host *mmc, struct mmc_request *mrq)
384 {
385 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
386 	struct mmc_command *cmd = mrq->cmd;
387 
388 	if (!host->error)
389 		host->error = meson_mx_sdhc_map_dma(mmc, mrq);
390 
391 	if (host->error) {
392 		cmd->error = host->error;
393 		mmc_request_done(mmc, mrq);
394 		return;
395 	}
396 
397 	host->mrq = mrq;
398 
399 	meson_mx_sdhc_start_cmd(mmc, mrq->cmd);
400 }
401 
402 static int meson_mx_sdhc_card_busy(struct mmc_host *mmc)
403 {
404 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
405 	u32 stat;
406 
407 	regmap_read(host->regmap, MESON_SDHC_STAT, &stat);
408 	return FIELD_GET(MESON_SDHC_STAT_DAT3_0, stat) == 0;
409 }
410 
411 static bool meson_mx_sdhc_tuning_point_matches(struct mmc_host *mmc,
412 					       u32 opcode)
413 {
414 	unsigned int i, num_matches = 0;
415 	int ret;
416 
417 	for (i = 0; i < MESON_SDHC_NUM_TUNING_TRIES; i++) {
418 		ret = mmc_send_tuning(mmc, opcode, NULL);
419 		if (!ret)
420 			num_matches++;
421 	}
422 
423 	return num_matches == MESON_SDHC_NUM_TUNING_TRIES;
424 }
425 
426 static int meson_mx_sdhc_execute_tuning(struct mmc_host *mmc, u32 opcode)
427 {
428 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
429 	int div, start, len, best_start, best_len;
430 	int curr_phase, old_phase, new_phase;
431 	u32 val;
432 
433 	len = 0;
434 	start = 0;
435 	best_len = 0;
436 
437 	regmap_read(host->regmap, MESON_SDHC_CLK2, &val);
438 	old_phase = FIELD_GET(MESON_SDHC_CLK2_RX_CLK_PHASE, val);
439 
440 	regmap_read(host->regmap, MESON_SDHC_CLKC, &val);
441 	div = FIELD_GET(MESON_SDHC_CLKC_CLK_DIV, val);
442 
443 	for (curr_phase = 0; curr_phase <= div; curr_phase++) {
444 		regmap_update_bits(host->regmap, MESON_SDHC_CLK2,
445 				   MESON_SDHC_CLK2_RX_CLK_PHASE,
446 				   FIELD_PREP(MESON_SDHC_CLK2_RX_CLK_PHASE,
447 					      curr_phase));
448 
449 		if (meson_mx_sdhc_tuning_point_matches(mmc, opcode)) {
450 			if (!len) {
451 				start = curr_phase;
452 
453 				dev_dbg(mmc_dev(mmc),
454 					"New RX phase window starts at %u\n",
455 					start);
456 			}
457 
458 			len++;
459 		} else {
460 			if (len > best_len) {
461 				best_start = start;
462 				best_len = len;
463 
464 				dev_dbg(mmc_dev(mmc),
465 					"New best RX phase window: %u - %u\n",
466 					best_start, best_start + best_len);
467 			}
468 
469 			/* reset the current window */
470 			len = 0;
471 		}
472 	}
473 
474 	if (len > best_len)
475 		/* the last window is the best (or possibly only) window */
476 		new_phase = start + (len / 2);
477 	else if (best_len)
478 		/* there was a better window than the last */
479 		new_phase = best_start + (best_len / 2);
480 	else
481 		/* no window was found at all, reset to the original phase */
482 		new_phase = old_phase;
483 
484 	regmap_update_bits(host->regmap, MESON_SDHC_CLK2,
485 			   MESON_SDHC_CLK2_RX_CLK_PHASE,
486 			   FIELD_PREP(MESON_SDHC_CLK2_RX_CLK_PHASE,
487 				      new_phase));
488 
489 	if (!len && !best_len)
490 		return -EIO;
491 
492 	dev_dbg(mmc_dev(mmc), "Tuned RX clock phase to %u\n", new_phase);
493 
494 	return 0;
495 }
496 
497 static const struct mmc_host_ops meson_mx_sdhc_ops = {
498 	.hw_reset			= meson_mx_sdhc_hw_reset,
499 	.request			= meson_mx_sdhc_request,
500 	.set_ios			= meson_mx_sdhc_set_ios,
501 	.card_busy			= meson_mx_sdhc_card_busy,
502 	.execute_tuning			= meson_mx_sdhc_execute_tuning,
503 	.get_cd				= mmc_gpio_get_cd,
504 	.get_ro				= mmc_gpio_get_ro,
505 };
506 
507 static void meson_mx_sdhc_request_done(struct meson_mx_sdhc_host *host)
508 {
509 	struct mmc_request *mrq = host->mrq;
510 	struct mmc_host *mmc = host->mmc;
511 
512 	/* disable interrupts and mask all pending ones */
513 	regmap_update_bits(host->regmap, MESON_SDHC_ICTL,
514 			   MESON_SDHC_ICTL_ALL_IRQS, 0);
515 	regmap_update_bits(host->regmap, MESON_SDHC_ISTA,
516 			   MESON_SDHC_ISTA_ALL_IRQS, MESON_SDHC_ISTA_ALL_IRQS);
517 
518 	host->mrq = NULL;
519 	host->cmd = NULL;
520 
521 	mmc_request_done(mmc, mrq);
522 }
523 
524 static u32 meson_mx_sdhc_read_response(struct meson_mx_sdhc_host *host, u8 idx)
525 {
526 	u32 val;
527 
528 	regmap_update_bits(host->regmap, MESON_SDHC_PDMA,
529 			   MESON_SDHC_PDMA_DMA_MODE, 0);
530 
531 	regmap_update_bits(host->regmap, MESON_SDHC_PDMA,
532 			   MESON_SDHC_PDMA_PIO_RDRESP,
533 			   FIELD_PREP(MESON_SDHC_PDMA_PIO_RDRESP, idx));
534 
535 	regmap_read(host->regmap, MESON_SDHC_ARGU, &val);
536 
537 	return val;
538 }
539 
540 static irqreturn_t meson_mx_sdhc_irq(int irq, void *data)
541 {
542 	struct meson_mx_sdhc_host *host = data;
543 	struct mmc_command *cmd = host->cmd;
544 	u32 ictl, ista;
545 
546 	regmap_read(host->regmap, MESON_SDHC_ICTL, &ictl);
547 	regmap_read(host->regmap, MESON_SDHC_ISTA, &ista);
548 
549 	if (!(ictl & ista))
550 		return IRQ_NONE;
551 
552 	if (ista & MESON_SDHC_ISTA_RXFIFO_FULL ||
553 	    ista & MESON_SDHC_ISTA_TXFIFO_EMPTY)
554 		cmd->error = -EIO;
555 	else if (ista & MESON_SDHC_ISTA_RESP_ERR_CRC)
556 		cmd->error = -EILSEQ;
557 	else if (ista & MESON_SDHC_ISTA_RESP_TIMEOUT)
558 		cmd->error = -ETIMEDOUT;
559 
560 	if (cmd->data) {
561 		if (ista & MESON_SDHC_ISTA_DATA_ERR_CRC)
562 			cmd->data->error = -EILSEQ;
563 		else if (ista & MESON_SDHC_ISTA_DATA_TIMEOUT)
564 			cmd->data->error = -ETIMEDOUT;
565 	}
566 
567 	if (cmd->error || (cmd->data && cmd->data->error))
568 		dev_dbg(mmc_dev(host->mmc), "CMD%d error, ISTA: 0x%08x\n",
569 			cmd->opcode, ista);
570 
571 	return IRQ_WAKE_THREAD;
572 }
573 
574 static irqreturn_t meson_mx_sdhc_irq_thread(int irq, void *irq_data)
575 {
576 	struct meson_mx_sdhc_host *host = irq_data;
577 	struct mmc_command *cmd;
578 	u32 val;
579 
580 	cmd = host->cmd;
581 	if (WARN_ON(!cmd))
582 		return IRQ_HANDLED;
583 
584 	if (cmd->data && !cmd->data->error) {
585 		if (!host->platform->hardware_flush_all_cmds &&
586 		    cmd->data->flags & MMC_DATA_READ) {
587 			meson_mx_sdhc_wait_cmd_ready(host->mmc);
588 
589 			/*
590 			 * If MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH was
591 			 * previously 0x1 then it has to be set to 0x3. If it
592 			 * was 0x0 before then it has to be set to 0x2. Without
593 			 * this reading SD cards sometimes transfers garbage,
594 			 * which results in cards not being detected due to:
595 			 *   unrecognised SCR structure version <random number>
596 			 */
597 			val = FIELD_PREP(MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH,
598 					 2);
599 			regmap_update_bits(host->regmap, MESON_SDHC_PDMA, val,
600 					   val);
601 		}
602 
603 		dma_unmap_sg(mmc_dev(host->mmc), cmd->data->sg,
604 			     cmd->data->sg_len, mmc_get_dma_dir(cmd->data));
605 
606 		cmd->data->bytes_xfered = cmd->data->blksz * cmd->data->blocks;
607 	}
608 
609 	meson_mx_sdhc_wait_cmd_ready(host->mmc);
610 
611 	if (cmd->flags & MMC_RSP_136) {
612 		cmd->resp[0] = meson_mx_sdhc_read_response(host, 4);
613 		cmd->resp[1] = meson_mx_sdhc_read_response(host, 3);
614 		cmd->resp[2] = meson_mx_sdhc_read_response(host, 2);
615 		cmd->resp[3] = meson_mx_sdhc_read_response(host, 1);
616 	} else {
617 		cmd->resp[0] = meson_mx_sdhc_read_response(host, 0);
618 	}
619 
620 	if (cmd->error == -EIO || cmd->error == -ETIMEDOUT)
621 		meson_mx_sdhc_hw_reset(host->mmc);
622 	else if (cmd->data)
623 		/*
624 		 * Clear the FIFOs after completing data transfers to prevent
625 		 * corrupting data on write access. It's not clear why this is
626 		 * needed (for reads and writes), but it mimics what the BSP
627 		 * kernel did.
628 		 */
629 		meson_mx_sdhc_clear_fifo(host->mmc);
630 
631 	meson_mx_sdhc_request_done(host);
632 
633 	return IRQ_HANDLED;
634 }
635 
636 static void meson_mx_sdhc_init_hw_meson8(struct mmc_host *mmc)
637 {
638 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
639 
640 	regmap_write(host->regmap, MESON_SDHC_MISC,
641 		     FIELD_PREP(MESON_SDHC_MISC_TXSTART_THRES, 7) |
642 		     FIELD_PREP(MESON_SDHC_MISC_WCRC_ERR_PATT, 5) |
643 		     FIELD_PREP(MESON_SDHC_MISC_WCRC_OK_PATT, 2));
644 
645 	regmap_write(host->regmap, MESON_SDHC_ENHC,
646 		     FIELD_PREP(MESON_SDHC_ENHC_RXFIFO_TH, 63) |
647 		     MESON_SDHC_ENHC_MESON6_DMA_WR_RESP |
648 		     FIELD_PREP(MESON_SDHC_ENHC_MESON6_RX_TIMEOUT, 255) |
649 		     FIELD_PREP(MESON_SDHC_ENHC_SDIO_IRQ_PERIOD, 12));
650 };
651 
652 static void meson_mx_sdhc_set_pdma_meson8(struct mmc_host *mmc)
653 {
654 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
655 
656 	if (host->cmd->data->flags & MMC_DATA_WRITE)
657 		regmap_update_bits(host->regmap, MESON_SDHC_PDMA,
658 				   MESON_SDHC_PDMA_DMA_MODE |
659 				   MESON_SDHC_PDMA_RD_BURST |
660 				   MESON_SDHC_PDMA_TXFIFO_FILL,
661 				   MESON_SDHC_PDMA_DMA_MODE |
662 				   FIELD_PREP(MESON_SDHC_PDMA_RD_BURST, 31) |
663 				   MESON_SDHC_PDMA_TXFIFO_FILL);
664 	else
665 		regmap_update_bits(host->regmap, MESON_SDHC_PDMA,
666 				   MESON_SDHC_PDMA_DMA_MODE |
667 				   MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH,
668 				   MESON_SDHC_PDMA_DMA_MODE |
669 				   FIELD_PREP(MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH,
670 					      1));
671 
672 	if (host->cmd->data->flags & MMC_DATA_WRITE)
673 		regmap_update_bits(host->regmap, MESON_SDHC_PDMA,
674 				   MESON_SDHC_PDMA_RD_BURST,
675 				   FIELD_PREP(MESON_SDHC_PDMA_RD_BURST, 15));
676 }
677 
678 static void meson_mx_sdhc_wait_before_send_meson8(struct mmc_host *mmc)
679 {
680 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
681 	u32 val;
682 	int ret;
683 
684 	ret = regmap_read_poll_timeout(host->regmap, MESON_SDHC_ESTA, val,
685 				       val == 0,
686 				       MESON_SDHC_WAIT_BEFORE_SEND_SLEEP_US,
687 				       MESON_SDHC_WAIT_BEFORE_SEND_TIMEOUT_US);
688 	if (ret)
689 		dev_warn(mmc_dev(mmc),
690 			 "Failed to wait for ESTA to clear: 0x%08x\n", val);
691 
692 	if (host->cmd->data && host->cmd->data->flags & MMC_DATA_WRITE) {
693 		ret = regmap_read_poll_timeout(host->regmap, MESON_SDHC_STAT,
694 					val, val & MESON_SDHC_STAT_TXFIFO_CNT,
695 					MESON_SDHC_WAIT_BEFORE_SEND_SLEEP_US,
696 					MESON_SDHC_WAIT_BEFORE_SEND_TIMEOUT_US);
697 		if (ret)
698 			dev_warn(mmc_dev(mmc),
699 				 "Failed to wait for TX FIFO to fill\n");
700 	}
701 }
702 
703 static void meson_mx_sdhc_init_hw_meson8m2(struct mmc_host *mmc)
704 {
705 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
706 
707 	regmap_write(host->regmap, MESON_SDHC_MISC,
708 		     FIELD_PREP(MESON_SDHC_MISC_TXSTART_THRES, 6) |
709 		     FIELD_PREP(MESON_SDHC_MISC_WCRC_ERR_PATT, 5) |
710 		     FIELD_PREP(MESON_SDHC_MISC_WCRC_OK_PATT, 2));
711 
712 	regmap_write(host->regmap, MESON_SDHC_ENHC,
713 		     FIELD_PREP(MESON_SDHC_ENHC_RXFIFO_TH, 64) |
714 		     FIELD_PREP(MESON_SDHC_ENHC_MESON8M2_DEBUG, 1) |
715 		     MESON_SDHC_ENHC_MESON8M2_WRRSP_MODE |
716 		     FIELD_PREP(MESON_SDHC_ENHC_SDIO_IRQ_PERIOD, 12));
717 }
718 
719 static void meson_mx_sdhc_set_pdma_meson8m2(struct mmc_host *mmc)
720 {
721 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
722 
723 	regmap_update_bits(host->regmap, MESON_SDHC_PDMA,
724 			   MESON_SDHC_PDMA_DMA_MODE, MESON_SDHC_PDMA_DMA_MODE);
725 }
726 
727 static void meson_mx_sdhc_init_hw(struct mmc_host *mmc)
728 {
729 	struct meson_mx_sdhc_host *host = mmc_priv(mmc);
730 
731 	meson_mx_sdhc_hw_reset(mmc);
732 
733 	regmap_write(host->regmap, MESON_SDHC_CTRL,
734 		     FIELD_PREP(MESON_SDHC_CTRL_RX_PERIOD, 0xf) |
735 		     FIELD_PREP(MESON_SDHC_CTRL_RX_TIMEOUT, 0x7f) |
736 		     FIELD_PREP(MESON_SDHC_CTRL_RX_ENDIAN, 0x7) |
737 		     FIELD_PREP(MESON_SDHC_CTRL_TX_ENDIAN, 0x7));
738 
739 	/*
740 	 * start with a valid divider and enable the memory (un-setting
741 	 * MESON_SDHC_CLKC_MEM_PWR_OFF).
742 	 */
743 	regmap_write(host->regmap, MESON_SDHC_CLKC, MESON_SDHC_CLKC_CLK_DIV);
744 
745 	regmap_write(host->regmap, MESON_SDHC_CLK2,
746 		     FIELD_PREP(MESON_SDHC_CLK2_SD_CLK_PHASE, 1));
747 
748 	regmap_write(host->regmap, MESON_SDHC_PDMA,
749 		     MESON_SDHC_PDMA_DMA_URGENT |
750 		     FIELD_PREP(MESON_SDHC_PDMA_WR_BURST, 7) |
751 		     FIELD_PREP(MESON_SDHC_PDMA_TXFIFO_TH, 49) |
752 		     FIELD_PREP(MESON_SDHC_PDMA_RD_BURST, 15) |
753 		     FIELD_PREP(MESON_SDHC_PDMA_RXFIFO_TH, 7));
754 
755 	/* some initialization bits depend on the SoC: */
756 	host->platform->init_hw(mmc);
757 
758 	/* disable and mask all interrupts: */
759 	regmap_write(host->regmap, MESON_SDHC_ICTL, 0);
760 	regmap_write(host->regmap, MESON_SDHC_ISTA, MESON_SDHC_ISTA_ALL_IRQS);
761 }
762 
763 static int meson_mx_sdhc_probe(struct platform_device *pdev)
764 {
765 	struct device *dev = &pdev->dev;
766 	struct meson_mx_sdhc_host *host;
767 	struct mmc_host *mmc;
768 	void __iomem *base;
769 	int ret, irq;
770 
771 	mmc = mmc_alloc_host(sizeof(*host), dev);
772 	if (!mmc)
773 		return -ENOMEM;
774 
775 	ret = devm_add_action_or_reset(dev, (void(*)(void *))mmc_free_host,
776 				       mmc);
777 	if (ret) {
778 		dev_err(dev, "Failed to register mmc_free_host action\n");
779 		return ret;
780 	}
781 
782 	host = mmc_priv(mmc);
783 	host->mmc = mmc;
784 
785 	platform_set_drvdata(pdev, host);
786 
787 	host->platform = device_get_match_data(dev);
788 	if (!host->platform)
789 		return -EINVAL;
790 
791 	base = devm_platform_ioremap_resource(pdev, 0);
792 	if (IS_ERR(base))
793 		return PTR_ERR(base);
794 
795 	host->regmap = devm_regmap_init_mmio(dev, base,
796 					     &meson_mx_sdhc_regmap_config);
797 	if (IS_ERR(host->regmap))
798 		return PTR_ERR(host->regmap);
799 
800 	host->pclk = devm_clk_get(dev, "pclk");
801 	if (IS_ERR(host->pclk))
802 		return PTR_ERR(host->pclk);
803 
804 	/* accessing any register requires the module clock to be enabled: */
805 	ret = clk_prepare_enable(host->pclk);
806 	if (ret) {
807 		dev_err(dev, "Failed to enable 'pclk' clock\n");
808 		return ret;
809 	}
810 
811 	meson_mx_sdhc_init_hw(mmc);
812 
813 	ret = meson_mx_sdhc_register_clkc(dev, base, host->bulk_clks);
814 	if (ret)
815 		goto err_disable_pclk;
816 
817 	host->sd_clk = host->bulk_clks[1].clk;
818 
819 	/* Get regulators and the supported OCR mask */
820 	ret = mmc_regulator_get_supply(mmc);
821 	if (ret)
822 		goto err_disable_pclk;
823 
824 	mmc->max_req_size = SZ_128K;
825 	mmc->max_seg_size = mmc->max_req_size;
826 	mmc->max_blk_count = FIELD_GET(MESON_SDHC_SEND_TOTAL_PACK, ~0);
827 	mmc->max_blk_size = MESON_SDHC_MAX_BLK_SIZE;
828 	mmc->max_busy_timeout = 30 * MSEC_PER_SEC;
829 	mmc->f_min = clk_round_rate(host->sd_clk, 1);
830 	mmc->f_max = clk_round_rate(host->sd_clk, ULONG_MAX);
831 	mmc->max_current_180 = 300;
832 	mmc->max_current_330 = 300;
833 	mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY | MMC_CAP_HW_RESET;
834 	mmc->ops = &meson_mx_sdhc_ops;
835 
836 	ret = mmc_of_parse(mmc);
837 	if (ret)
838 		goto err_disable_pclk;
839 
840 	irq = platform_get_irq(pdev, 0);
841 	ret = devm_request_threaded_irq(dev, irq, meson_mx_sdhc_irq,
842 					meson_mx_sdhc_irq_thread, IRQF_ONESHOT,
843 					NULL, host);
844 	if (ret)
845 		goto err_disable_pclk;
846 
847 	ret = mmc_add_host(mmc);
848 	if (ret)
849 		goto err_disable_pclk;
850 
851 	return 0;
852 
853 err_disable_pclk:
854 	clk_disable_unprepare(host->pclk);
855 	return ret;
856 }
857 
858 static int meson_mx_sdhc_remove(struct platform_device *pdev)
859 {
860 	struct meson_mx_sdhc_host *host = platform_get_drvdata(pdev);
861 
862 	mmc_remove_host(host->mmc);
863 
864 	meson_mx_sdhc_disable_clks(host->mmc);
865 
866 	clk_disable_unprepare(host->pclk);
867 
868 	return 0;
869 }
870 
871 static const struct meson_mx_sdhc_data meson_mx_sdhc_data_meson8 = {
872 	.init_hw			= meson_mx_sdhc_init_hw_meson8,
873 	.set_pdma			= meson_mx_sdhc_set_pdma_meson8,
874 	.wait_before_send		= meson_mx_sdhc_wait_before_send_meson8,
875 	.hardware_flush_all_cmds	= false,
876 };
877 
878 static const struct meson_mx_sdhc_data meson_mx_sdhc_data_meson8m2 = {
879 	.init_hw			= meson_mx_sdhc_init_hw_meson8m2,
880 	.set_pdma			= meson_mx_sdhc_set_pdma_meson8m2,
881 	.hardware_flush_all_cmds	= true,
882 };
883 
884 static const struct of_device_id meson_mx_sdhc_of_match[] = {
885 	{
886 		.compatible = "amlogic,meson8-sdhc",
887 		.data = &meson_mx_sdhc_data_meson8
888 	},
889 	{
890 		.compatible = "amlogic,meson8b-sdhc",
891 		.data = &meson_mx_sdhc_data_meson8
892 	},
893 	{
894 		.compatible = "amlogic,meson8m2-sdhc",
895 		.data = &meson_mx_sdhc_data_meson8m2
896 	},
897 	{ /* sentinel */ }
898 };
899 MODULE_DEVICE_TABLE(of, meson_mx_sdhc_of_match);
900 
901 static struct platform_driver meson_mx_sdhc_driver = {
902 	.probe   = meson_mx_sdhc_probe,
903 	.remove  = meson_mx_sdhc_remove,
904 	.driver  = {
905 		.name = "meson-mx-sdhc",
906 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
907 		.of_match_table = of_match_ptr(meson_mx_sdhc_of_match),
908 	},
909 };
910 
911 module_platform_driver(meson_mx_sdhc_driver);
912 
913 MODULE_DESCRIPTION("Meson6, Meson8, Meson8b and Meson8m2 SDHC Host Driver");
914 MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
915 MODULE_LICENSE("GPL v2");
916