xref: /openbmc/linux/drivers/mmc/host/meson-gx-mmc.c (revision 2169e6da)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Amlogic SD/eMMC driver for the GX/S905 family SoCs
4  *
5  * Copyright (c) 2016 BayLibre, SAS.
6  * Author: Kevin Hilman <khilman@baylibre.com>
7  */
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/delay.h>
12 #include <linux/device.h>
13 #include <linux/iopoll.h>
14 #include <linux/of_device.h>
15 #include <linux/platform_device.h>
16 #include <linux/ioport.h>
17 #include <linux/dma-mapping.h>
18 #include <linux/mmc/host.h>
19 #include <linux/mmc/mmc.h>
20 #include <linux/mmc/sdio.h>
21 #include <linux/mmc/slot-gpio.h>
22 #include <linux/io.h>
23 #include <linux/clk.h>
24 #include <linux/clk-provider.h>
25 #include <linux/regulator/consumer.h>
26 #include <linux/reset.h>
27 #include <linux/interrupt.h>
28 #include <linux/bitfield.h>
29 #include <linux/pinctrl/consumer.h>
30 
31 #define DRIVER_NAME "meson-gx-mmc"
32 
33 #define SD_EMMC_CLOCK 0x0
34 #define   CLK_DIV_MASK GENMASK(5, 0)
35 #define   CLK_SRC_MASK GENMASK(7, 6)
36 #define   CLK_CORE_PHASE_MASK GENMASK(9, 8)
37 #define   CLK_TX_PHASE_MASK GENMASK(11, 10)
38 #define   CLK_RX_PHASE_MASK GENMASK(13, 12)
39 #define   CLK_PHASE_0 0
40 #define   CLK_PHASE_180 2
41 #define   CLK_V2_TX_DELAY_MASK GENMASK(19, 16)
42 #define   CLK_V2_RX_DELAY_MASK GENMASK(23, 20)
43 #define   CLK_V2_ALWAYS_ON BIT(24)
44 
45 #define   CLK_V3_TX_DELAY_MASK GENMASK(21, 16)
46 #define   CLK_V3_RX_DELAY_MASK GENMASK(27, 22)
47 #define   CLK_V3_ALWAYS_ON BIT(28)
48 
49 #define   CLK_TX_DELAY_MASK(h)		(h->data->tx_delay_mask)
50 #define   CLK_RX_DELAY_MASK(h)		(h->data->rx_delay_mask)
51 #define   CLK_ALWAYS_ON(h)		(h->data->always_on)
52 
53 #define SD_EMMC_DELAY 0x4
54 #define SD_EMMC_ADJUST 0x8
55 #define   ADJUST_ADJ_DELAY_MASK GENMASK(21, 16)
56 #define   ADJUST_DS_EN BIT(15)
57 #define   ADJUST_ADJ_EN BIT(13)
58 
59 #define SD_EMMC_DELAY1 0x4
60 #define SD_EMMC_DELAY2 0x8
61 #define SD_EMMC_V3_ADJUST 0xc
62 
63 #define SD_EMMC_CALOUT 0x10
64 #define SD_EMMC_START 0x40
65 #define   START_DESC_INIT BIT(0)
66 #define   START_DESC_BUSY BIT(1)
67 #define   START_DESC_ADDR_MASK GENMASK(31, 2)
68 
69 #define SD_EMMC_CFG 0x44
70 #define   CFG_BUS_WIDTH_MASK GENMASK(1, 0)
71 #define   CFG_BUS_WIDTH_1 0x0
72 #define   CFG_BUS_WIDTH_4 0x1
73 #define   CFG_BUS_WIDTH_8 0x2
74 #define   CFG_DDR BIT(2)
75 #define   CFG_BLK_LEN_MASK GENMASK(7, 4)
76 #define   CFG_RESP_TIMEOUT_MASK GENMASK(11, 8)
77 #define   CFG_RC_CC_MASK GENMASK(15, 12)
78 #define   CFG_STOP_CLOCK BIT(22)
79 #define   CFG_CLK_ALWAYS_ON BIT(18)
80 #define   CFG_CHK_DS BIT(20)
81 #define   CFG_AUTO_CLK BIT(23)
82 #define   CFG_ERR_ABORT BIT(27)
83 
84 #define SD_EMMC_STATUS 0x48
85 #define   STATUS_BUSY BIT(31)
86 #define   STATUS_DESC_BUSY BIT(30)
87 #define   STATUS_DATI GENMASK(23, 16)
88 
89 #define SD_EMMC_IRQ_EN 0x4c
90 #define   IRQ_RXD_ERR_MASK GENMASK(7, 0)
91 #define   IRQ_TXD_ERR BIT(8)
92 #define   IRQ_DESC_ERR BIT(9)
93 #define   IRQ_RESP_ERR BIT(10)
94 #define   IRQ_CRC_ERR \
95 	(IRQ_RXD_ERR_MASK | IRQ_TXD_ERR | IRQ_DESC_ERR | IRQ_RESP_ERR)
96 #define   IRQ_RESP_TIMEOUT BIT(11)
97 #define   IRQ_DESC_TIMEOUT BIT(12)
98 #define   IRQ_TIMEOUTS \
99 	(IRQ_RESP_TIMEOUT | IRQ_DESC_TIMEOUT)
100 #define   IRQ_END_OF_CHAIN BIT(13)
101 #define   IRQ_RESP_STATUS BIT(14)
102 #define   IRQ_SDIO BIT(15)
103 #define   IRQ_EN_MASK \
104 	(IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN | IRQ_RESP_STATUS |\
105 	 IRQ_SDIO)
106 
107 #define SD_EMMC_CMD_CFG 0x50
108 #define SD_EMMC_CMD_ARG 0x54
109 #define SD_EMMC_CMD_DAT 0x58
110 #define SD_EMMC_CMD_RSP 0x5c
111 #define SD_EMMC_CMD_RSP1 0x60
112 #define SD_EMMC_CMD_RSP2 0x64
113 #define SD_EMMC_CMD_RSP3 0x68
114 
115 #define SD_EMMC_RXD 0x94
116 #define SD_EMMC_TXD 0x94
117 #define SD_EMMC_LAST_REG SD_EMMC_TXD
118 
119 #define SD_EMMC_SRAM_DATA_BUF_LEN 1536
120 #define SD_EMMC_SRAM_DATA_BUF_OFF 0x200
121 
122 #define SD_EMMC_CFG_BLK_SIZE 512 /* internal buffer max: 512 bytes */
123 #define SD_EMMC_CFG_RESP_TIMEOUT 256 /* in clock cycles */
124 #define SD_EMMC_CMD_TIMEOUT 1024 /* in ms */
125 #define SD_EMMC_CMD_TIMEOUT_DATA 4096 /* in ms */
126 #define SD_EMMC_CFG_CMD_GAP 16 /* in clock cycles */
127 #define SD_EMMC_DESC_BUF_LEN PAGE_SIZE
128 
129 #define SD_EMMC_PRE_REQ_DONE BIT(0)
130 #define SD_EMMC_DESC_CHAIN_MODE BIT(1)
131 
132 #define MUX_CLK_NUM_PARENTS 2
133 
134 struct meson_mmc_data {
135 	unsigned int tx_delay_mask;
136 	unsigned int rx_delay_mask;
137 	unsigned int always_on;
138 	unsigned int adjust;
139 };
140 
141 struct sd_emmc_desc {
142 	u32 cmd_cfg;
143 	u32 cmd_arg;
144 	u32 cmd_data;
145 	u32 cmd_resp;
146 };
147 
148 struct meson_host {
149 	struct	device		*dev;
150 	struct	meson_mmc_data *data;
151 	struct	mmc_host	*mmc;
152 	struct	mmc_command	*cmd;
153 
154 	void __iomem *regs;
155 	struct clk *core_clk;
156 	struct clk *mux_clk;
157 	struct clk *mmc_clk;
158 	unsigned long req_rate;
159 	bool ddr;
160 
161 	bool dram_access_quirk;
162 
163 	struct pinctrl *pinctrl;
164 	struct pinctrl_state *pins_default;
165 	struct pinctrl_state *pins_clk_gate;
166 
167 	unsigned int bounce_buf_size;
168 	void *bounce_buf;
169 	dma_addr_t bounce_dma_addr;
170 	struct sd_emmc_desc *descs;
171 	dma_addr_t descs_dma_addr;
172 
173 	int irq;
174 
175 	bool vqmmc_enabled;
176 };
177 
178 #define CMD_CFG_LENGTH_MASK GENMASK(8, 0)
179 #define CMD_CFG_BLOCK_MODE BIT(9)
180 #define CMD_CFG_R1B BIT(10)
181 #define CMD_CFG_END_OF_CHAIN BIT(11)
182 #define CMD_CFG_TIMEOUT_MASK GENMASK(15, 12)
183 #define CMD_CFG_NO_RESP BIT(16)
184 #define CMD_CFG_NO_CMD BIT(17)
185 #define CMD_CFG_DATA_IO BIT(18)
186 #define CMD_CFG_DATA_WR BIT(19)
187 #define CMD_CFG_RESP_NOCRC BIT(20)
188 #define CMD_CFG_RESP_128 BIT(21)
189 #define CMD_CFG_RESP_NUM BIT(22)
190 #define CMD_CFG_DATA_NUM BIT(23)
191 #define CMD_CFG_CMD_INDEX_MASK GENMASK(29, 24)
192 #define CMD_CFG_ERROR BIT(30)
193 #define CMD_CFG_OWNER BIT(31)
194 
195 #define CMD_DATA_MASK GENMASK(31, 2)
196 #define CMD_DATA_BIG_ENDIAN BIT(1)
197 #define CMD_DATA_SRAM BIT(0)
198 #define CMD_RESP_MASK GENMASK(31, 1)
199 #define CMD_RESP_SRAM BIT(0)
200 
201 static unsigned int meson_mmc_get_timeout_msecs(struct mmc_data *data)
202 {
203 	unsigned int timeout = data->timeout_ns / NSEC_PER_MSEC;
204 
205 	if (!timeout)
206 		return SD_EMMC_CMD_TIMEOUT_DATA;
207 
208 	timeout = roundup_pow_of_two(timeout);
209 
210 	return min(timeout, 32768U); /* max. 2^15 ms */
211 }
212 
213 static struct mmc_command *meson_mmc_get_next_command(struct mmc_command *cmd)
214 {
215 	if (cmd->opcode == MMC_SET_BLOCK_COUNT && !cmd->error)
216 		return cmd->mrq->cmd;
217 	else if (mmc_op_multi(cmd->opcode) &&
218 		 (!cmd->mrq->sbc || cmd->error || cmd->data->error))
219 		return cmd->mrq->stop;
220 	else
221 		return NULL;
222 }
223 
224 static void meson_mmc_get_transfer_mode(struct mmc_host *mmc,
225 					struct mmc_request *mrq)
226 {
227 	struct meson_host *host = mmc_priv(mmc);
228 	struct mmc_data *data = mrq->data;
229 	struct scatterlist *sg;
230 	int i;
231 	bool use_desc_chain_mode = true;
232 
233 	/*
234 	 * When Controller DMA cannot directly access DDR memory, disable
235 	 * support for Chain Mode to directly use the internal SRAM using
236 	 * the bounce buffer mode.
237 	 */
238 	if (host->dram_access_quirk)
239 		return;
240 
241 	/*
242 	 * Broken SDIO with AP6255-based WiFi on Khadas VIM Pro has been
243 	 * reported. For some strange reason this occurs in descriptor
244 	 * chain mode only. So let's fall back to bounce buffer mode
245 	 * for command SD_IO_RW_EXTENDED.
246 	 */
247 	if (mrq->cmd->opcode == SD_IO_RW_EXTENDED)
248 		return;
249 
250 	for_each_sg(data->sg, sg, data->sg_len, i)
251 		/* check for 8 byte alignment */
252 		if (sg->offset & 7) {
253 			WARN_ONCE(1, "unaligned scatterlist buffer\n");
254 			use_desc_chain_mode = false;
255 			break;
256 		}
257 
258 	if (use_desc_chain_mode)
259 		data->host_cookie |= SD_EMMC_DESC_CHAIN_MODE;
260 }
261 
262 static inline bool meson_mmc_desc_chain_mode(const struct mmc_data *data)
263 {
264 	return data->host_cookie & SD_EMMC_DESC_CHAIN_MODE;
265 }
266 
267 static inline bool meson_mmc_bounce_buf_read(const struct mmc_data *data)
268 {
269 	return data && data->flags & MMC_DATA_READ &&
270 	       !meson_mmc_desc_chain_mode(data);
271 }
272 
273 static void meson_mmc_pre_req(struct mmc_host *mmc, struct mmc_request *mrq)
274 {
275 	struct mmc_data *data = mrq->data;
276 
277 	if (!data)
278 		return;
279 
280 	meson_mmc_get_transfer_mode(mmc, mrq);
281 	data->host_cookie |= SD_EMMC_PRE_REQ_DONE;
282 
283 	if (!meson_mmc_desc_chain_mode(data))
284 		return;
285 
286 	data->sg_count = dma_map_sg(mmc_dev(mmc), data->sg, data->sg_len,
287                                    mmc_get_dma_dir(data));
288 	if (!data->sg_count)
289 		dev_err(mmc_dev(mmc), "dma_map_sg failed");
290 }
291 
292 static void meson_mmc_post_req(struct mmc_host *mmc, struct mmc_request *mrq,
293 			       int err)
294 {
295 	struct mmc_data *data = mrq->data;
296 
297 	if (data && meson_mmc_desc_chain_mode(data) && data->sg_count)
298 		dma_unmap_sg(mmc_dev(mmc), data->sg, data->sg_len,
299 			     mmc_get_dma_dir(data));
300 }
301 
302 /*
303  * Gating the clock on this controller is tricky.  It seems the mmc clock
304  * is also used by the controller.  It may crash during some operation if the
305  * clock is stopped.  The safest thing to do, whenever possible, is to keep
306  * clock running at stop it at the pad using the pinmux.
307  */
308 static void meson_mmc_clk_gate(struct meson_host *host)
309 {
310 	u32 cfg;
311 
312 	if (host->pins_clk_gate) {
313 		pinctrl_select_state(host->pinctrl, host->pins_clk_gate);
314 	} else {
315 		/*
316 		 * If the pinmux is not provided - default to the classic and
317 		 * unsafe method
318 		 */
319 		cfg = readl(host->regs + SD_EMMC_CFG);
320 		cfg |= CFG_STOP_CLOCK;
321 		writel(cfg, host->regs + SD_EMMC_CFG);
322 	}
323 }
324 
325 static void meson_mmc_clk_ungate(struct meson_host *host)
326 {
327 	u32 cfg;
328 
329 	if (host->pins_clk_gate)
330 		pinctrl_select_state(host->pinctrl, host->pins_default);
331 
332 	/* Make sure the clock is not stopped in the controller */
333 	cfg = readl(host->regs + SD_EMMC_CFG);
334 	cfg &= ~CFG_STOP_CLOCK;
335 	writel(cfg, host->regs + SD_EMMC_CFG);
336 }
337 
338 static int meson_mmc_clk_set(struct meson_host *host, unsigned long rate,
339 			     bool ddr)
340 {
341 	struct mmc_host *mmc = host->mmc;
342 	int ret;
343 	u32 cfg;
344 
345 	/* Same request - bail-out */
346 	if (host->ddr == ddr && host->req_rate == rate)
347 		return 0;
348 
349 	/* stop clock */
350 	meson_mmc_clk_gate(host);
351 	host->req_rate = 0;
352 	mmc->actual_clock = 0;
353 
354 	/* return with clock being stopped */
355 	if (!rate)
356 		return 0;
357 
358 	/* Stop the clock during rate change to avoid glitches */
359 	cfg = readl(host->regs + SD_EMMC_CFG);
360 	cfg |= CFG_STOP_CLOCK;
361 	writel(cfg, host->regs + SD_EMMC_CFG);
362 
363 	if (ddr) {
364 		/* DDR modes require higher module clock */
365 		rate <<= 1;
366 		cfg |= CFG_DDR;
367 	} else {
368 		cfg &= ~CFG_DDR;
369 	}
370 	writel(cfg, host->regs + SD_EMMC_CFG);
371 	host->ddr = ddr;
372 
373 	ret = clk_set_rate(host->mmc_clk, rate);
374 	if (ret) {
375 		dev_err(host->dev, "Unable to set cfg_div_clk to %lu. ret=%d\n",
376 			rate, ret);
377 		return ret;
378 	}
379 
380 	host->req_rate = rate;
381 	mmc->actual_clock = clk_get_rate(host->mmc_clk);
382 
383 	/* We should report the real output frequency of the controller */
384 	if (ddr) {
385 		host->req_rate >>= 1;
386 		mmc->actual_clock >>= 1;
387 	}
388 
389 	dev_dbg(host->dev, "clk rate: %u Hz\n", mmc->actual_clock);
390 	if (rate != mmc->actual_clock)
391 		dev_dbg(host->dev, "requested rate was %lu\n", rate);
392 
393 	/* (re)start clock */
394 	meson_mmc_clk_ungate(host);
395 
396 	return 0;
397 }
398 
399 /*
400  * The SD/eMMC IP block has an internal mux and divider used for
401  * generating the MMC clock.  Use the clock framework to create and
402  * manage these clocks.
403  */
404 static int meson_mmc_clk_init(struct meson_host *host)
405 {
406 	struct clk_init_data init;
407 	struct clk_mux *mux;
408 	struct clk_divider *div;
409 	char clk_name[32];
410 	int i, ret = 0;
411 	const char *mux_parent_names[MUX_CLK_NUM_PARENTS];
412 	const char *clk_parent[1];
413 	u32 clk_reg;
414 
415 	/* init SD_EMMC_CLOCK to sane defaults w/min clock rate */
416 	clk_reg = CLK_ALWAYS_ON(host);
417 	clk_reg |= CLK_DIV_MASK;
418 	clk_reg |= FIELD_PREP(CLK_CORE_PHASE_MASK, CLK_PHASE_180);
419 	clk_reg |= FIELD_PREP(CLK_TX_PHASE_MASK, CLK_PHASE_0);
420 	clk_reg |= FIELD_PREP(CLK_RX_PHASE_MASK, CLK_PHASE_0);
421 	writel(clk_reg, host->regs + SD_EMMC_CLOCK);
422 
423 	/* get the mux parents */
424 	for (i = 0; i < MUX_CLK_NUM_PARENTS; i++) {
425 		struct clk *clk;
426 		char name[16];
427 
428 		snprintf(name, sizeof(name), "clkin%d", i);
429 		clk = devm_clk_get(host->dev, name);
430 		if (IS_ERR(clk)) {
431 			if (clk != ERR_PTR(-EPROBE_DEFER))
432 				dev_err(host->dev, "Missing clock %s\n", name);
433 			return PTR_ERR(clk);
434 		}
435 
436 		mux_parent_names[i] = __clk_get_name(clk);
437 	}
438 
439 	/* create the mux */
440 	mux = devm_kzalloc(host->dev, sizeof(*mux), GFP_KERNEL);
441 	if (!mux)
442 		return -ENOMEM;
443 
444 	snprintf(clk_name, sizeof(clk_name), "%s#mux", dev_name(host->dev));
445 	init.name = clk_name;
446 	init.ops = &clk_mux_ops;
447 	init.flags = 0;
448 	init.parent_names = mux_parent_names;
449 	init.num_parents = MUX_CLK_NUM_PARENTS;
450 
451 	mux->reg = host->regs + SD_EMMC_CLOCK;
452 	mux->shift = __ffs(CLK_SRC_MASK);
453 	mux->mask = CLK_SRC_MASK >> mux->shift;
454 	mux->hw.init = &init;
455 
456 	host->mux_clk = devm_clk_register(host->dev, &mux->hw);
457 	if (WARN_ON(IS_ERR(host->mux_clk)))
458 		return PTR_ERR(host->mux_clk);
459 
460 	/* create the divider */
461 	div = devm_kzalloc(host->dev, sizeof(*div), GFP_KERNEL);
462 	if (!div)
463 		return -ENOMEM;
464 
465 	snprintf(clk_name, sizeof(clk_name), "%s#div", dev_name(host->dev));
466 	init.name = clk_name;
467 	init.ops = &clk_divider_ops;
468 	init.flags = CLK_SET_RATE_PARENT;
469 	clk_parent[0] = __clk_get_name(host->mux_clk);
470 	init.parent_names = clk_parent;
471 	init.num_parents = 1;
472 
473 	div->reg = host->regs + SD_EMMC_CLOCK;
474 	div->shift = __ffs(CLK_DIV_MASK);
475 	div->width = __builtin_popcountl(CLK_DIV_MASK);
476 	div->hw.init = &init;
477 	div->flags = CLK_DIVIDER_ONE_BASED;
478 
479 	host->mmc_clk = devm_clk_register(host->dev, &div->hw);
480 	if (WARN_ON(IS_ERR(host->mmc_clk)))
481 		return PTR_ERR(host->mmc_clk);
482 
483 	/* init SD_EMMC_CLOCK to sane defaults w/min clock rate */
484 	host->mmc->f_min = clk_round_rate(host->mmc_clk, 400000);
485 	ret = clk_set_rate(host->mmc_clk, host->mmc->f_min);
486 	if (ret)
487 		return ret;
488 
489 	return clk_prepare_enable(host->mmc_clk);
490 }
491 
492 static void meson_mmc_disable_resampling(struct meson_host *host)
493 {
494 	unsigned int val = readl(host->regs + host->data->adjust);
495 
496 	val &= ~ADJUST_ADJ_EN;
497 	writel(val, host->regs + host->data->adjust);
498 }
499 
500 static void meson_mmc_reset_resampling(struct meson_host *host)
501 {
502 	unsigned int val;
503 
504 	meson_mmc_disable_resampling(host);
505 
506 	val = readl(host->regs + host->data->adjust);
507 	val &= ~ADJUST_ADJ_DELAY_MASK;
508 	writel(val, host->regs + host->data->adjust);
509 }
510 
511 static int meson_mmc_resampling_tuning(struct mmc_host *mmc, u32 opcode)
512 {
513 	struct meson_host *host = mmc_priv(mmc);
514 	unsigned int val, dly, max_dly, i;
515 	int ret;
516 
517 	/* Resampling is done using the source clock */
518 	max_dly = DIV_ROUND_UP(clk_get_rate(host->mux_clk),
519 			       clk_get_rate(host->mmc_clk));
520 
521 	val = readl(host->regs + host->data->adjust);
522 	val |= ADJUST_ADJ_EN;
523 	writel(val, host->regs + host->data->adjust);
524 
525 	if (mmc->doing_retune)
526 		dly = FIELD_GET(ADJUST_ADJ_DELAY_MASK, val) + 1;
527 	else
528 		dly = 0;
529 
530 	for (i = 0; i < max_dly; i++) {
531 		val &= ~ADJUST_ADJ_DELAY_MASK;
532 		val |= FIELD_PREP(ADJUST_ADJ_DELAY_MASK, (dly + i) % max_dly);
533 		writel(val, host->regs + host->data->adjust);
534 
535 		ret = mmc_send_tuning(mmc, opcode, NULL);
536 		if (!ret) {
537 			dev_dbg(mmc_dev(mmc), "resampling delay: %u\n",
538 				(dly + i) % max_dly);
539 			return 0;
540 		}
541 	}
542 
543 	meson_mmc_reset_resampling(host);
544 	return -EIO;
545 }
546 
547 static int meson_mmc_prepare_ios_clock(struct meson_host *host,
548 				       struct mmc_ios *ios)
549 {
550 	bool ddr;
551 
552 	switch (ios->timing) {
553 	case MMC_TIMING_MMC_DDR52:
554 	case MMC_TIMING_UHS_DDR50:
555 		ddr = true;
556 		break;
557 
558 	default:
559 		ddr = false;
560 		break;
561 	}
562 
563 	return meson_mmc_clk_set(host, ios->clock, ddr);
564 }
565 
566 static void meson_mmc_check_resampling(struct meson_host *host,
567 				       struct mmc_ios *ios)
568 {
569 	switch (ios->timing) {
570 	case MMC_TIMING_LEGACY:
571 	case MMC_TIMING_MMC_HS:
572 	case MMC_TIMING_SD_HS:
573 	case MMC_TIMING_MMC_DDR52:
574 		meson_mmc_disable_resampling(host);
575 		break;
576 	}
577 }
578 
579 static void meson_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
580 {
581 	struct meson_host *host = mmc_priv(mmc);
582 	u32 bus_width, val;
583 	int err;
584 
585 	/*
586 	 * GPIO regulator, only controls switching between 1v8 and
587 	 * 3v3, doesn't support MMC_POWER_OFF, MMC_POWER_ON.
588 	 */
589 	switch (ios->power_mode) {
590 	case MMC_POWER_OFF:
591 		if (!IS_ERR(mmc->supply.vmmc))
592 			mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);
593 
594 		if (!IS_ERR(mmc->supply.vqmmc) && host->vqmmc_enabled) {
595 			regulator_disable(mmc->supply.vqmmc);
596 			host->vqmmc_enabled = false;
597 		}
598 
599 		break;
600 
601 	case MMC_POWER_UP:
602 		if (!IS_ERR(mmc->supply.vmmc))
603 			mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, ios->vdd);
604 
605 		break;
606 
607 	case MMC_POWER_ON:
608 		if (!IS_ERR(mmc->supply.vqmmc) && !host->vqmmc_enabled) {
609 			int ret = regulator_enable(mmc->supply.vqmmc);
610 
611 			if (ret < 0)
612 				dev_err(host->dev,
613 					"failed to enable vqmmc regulator\n");
614 			else
615 				host->vqmmc_enabled = true;
616 		}
617 
618 		break;
619 	}
620 
621 	/* Bus width */
622 	switch (ios->bus_width) {
623 	case MMC_BUS_WIDTH_1:
624 		bus_width = CFG_BUS_WIDTH_1;
625 		break;
626 	case MMC_BUS_WIDTH_4:
627 		bus_width = CFG_BUS_WIDTH_4;
628 		break;
629 	case MMC_BUS_WIDTH_8:
630 		bus_width = CFG_BUS_WIDTH_8;
631 		break;
632 	default:
633 		dev_err(host->dev, "Invalid ios->bus_width: %u.  Setting to 4.\n",
634 			ios->bus_width);
635 		bus_width = CFG_BUS_WIDTH_4;
636 	}
637 
638 	val = readl(host->regs + SD_EMMC_CFG);
639 	val &= ~CFG_BUS_WIDTH_MASK;
640 	val |= FIELD_PREP(CFG_BUS_WIDTH_MASK, bus_width);
641 	writel(val, host->regs + SD_EMMC_CFG);
642 
643 	meson_mmc_check_resampling(host, ios);
644 	err = meson_mmc_prepare_ios_clock(host, ios);
645 	if (err)
646 		dev_err(host->dev, "Failed to set clock: %d\n,", err);
647 
648 	dev_dbg(host->dev, "SD_EMMC_CFG:  0x%08x\n", val);
649 }
650 
651 static void meson_mmc_request_done(struct mmc_host *mmc,
652 				   struct mmc_request *mrq)
653 {
654 	struct meson_host *host = mmc_priv(mmc);
655 
656 	host->cmd = NULL;
657 	mmc_request_done(host->mmc, mrq);
658 }
659 
660 static void meson_mmc_set_blksz(struct mmc_host *mmc, unsigned int blksz)
661 {
662 	struct meson_host *host = mmc_priv(mmc);
663 	u32 cfg, blksz_old;
664 
665 	cfg = readl(host->regs + SD_EMMC_CFG);
666 	blksz_old = FIELD_GET(CFG_BLK_LEN_MASK, cfg);
667 
668 	if (!is_power_of_2(blksz))
669 		dev_err(host->dev, "blksz %u is not a power of 2\n", blksz);
670 
671 	blksz = ilog2(blksz);
672 
673 	/* check if block-size matches, if not update */
674 	if (blksz == blksz_old)
675 		return;
676 
677 	dev_dbg(host->dev, "%s: update blk_len %d -> %d\n", __func__,
678 		blksz_old, blksz);
679 
680 	cfg &= ~CFG_BLK_LEN_MASK;
681 	cfg |= FIELD_PREP(CFG_BLK_LEN_MASK, blksz);
682 	writel(cfg, host->regs + SD_EMMC_CFG);
683 }
684 
685 static void meson_mmc_set_response_bits(struct mmc_command *cmd, u32 *cmd_cfg)
686 {
687 	if (cmd->flags & MMC_RSP_PRESENT) {
688 		if (cmd->flags & MMC_RSP_136)
689 			*cmd_cfg |= CMD_CFG_RESP_128;
690 		*cmd_cfg |= CMD_CFG_RESP_NUM;
691 
692 		if (!(cmd->flags & MMC_RSP_CRC))
693 			*cmd_cfg |= CMD_CFG_RESP_NOCRC;
694 
695 		if (cmd->flags & MMC_RSP_BUSY)
696 			*cmd_cfg |= CMD_CFG_R1B;
697 	} else {
698 		*cmd_cfg |= CMD_CFG_NO_RESP;
699 	}
700 }
701 
702 static void meson_mmc_desc_chain_transfer(struct mmc_host *mmc, u32 cmd_cfg)
703 {
704 	struct meson_host *host = mmc_priv(mmc);
705 	struct sd_emmc_desc *desc = host->descs;
706 	struct mmc_data *data = host->cmd->data;
707 	struct scatterlist *sg;
708 	u32 start;
709 	int i;
710 
711 	if (data->flags & MMC_DATA_WRITE)
712 		cmd_cfg |= CMD_CFG_DATA_WR;
713 
714 	if (data->blocks > 1) {
715 		cmd_cfg |= CMD_CFG_BLOCK_MODE;
716 		meson_mmc_set_blksz(mmc, data->blksz);
717 	}
718 
719 	for_each_sg(data->sg, sg, data->sg_count, i) {
720 		unsigned int len = sg_dma_len(sg);
721 
722 		if (data->blocks > 1)
723 			len /= data->blksz;
724 
725 		desc[i].cmd_cfg = cmd_cfg;
726 		desc[i].cmd_cfg |= FIELD_PREP(CMD_CFG_LENGTH_MASK, len);
727 		if (i > 0)
728 			desc[i].cmd_cfg |= CMD_CFG_NO_CMD;
729 		desc[i].cmd_arg = host->cmd->arg;
730 		desc[i].cmd_resp = 0;
731 		desc[i].cmd_data = sg_dma_address(sg);
732 	}
733 	desc[data->sg_count - 1].cmd_cfg |= CMD_CFG_END_OF_CHAIN;
734 
735 	dma_wmb(); /* ensure descriptor is written before kicked */
736 	start = host->descs_dma_addr | START_DESC_BUSY;
737 	writel(start, host->regs + SD_EMMC_START);
738 }
739 
740 static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
741 {
742 	struct meson_host *host = mmc_priv(mmc);
743 	struct mmc_data *data = cmd->data;
744 	u32 cmd_cfg = 0, cmd_data = 0;
745 	unsigned int xfer_bytes = 0;
746 
747 	/* Setup descriptors */
748 	dma_rmb();
749 
750 	host->cmd = cmd;
751 
752 	cmd_cfg |= FIELD_PREP(CMD_CFG_CMD_INDEX_MASK, cmd->opcode);
753 	cmd_cfg |= CMD_CFG_OWNER;  /* owned by CPU */
754 	cmd_cfg |= CMD_CFG_ERROR; /* stop in case of error */
755 
756 	meson_mmc_set_response_bits(cmd, &cmd_cfg);
757 
758 	/* data? */
759 	if (data) {
760 		data->bytes_xfered = 0;
761 		cmd_cfg |= CMD_CFG_DATA_IO;
762 		cmd_cfg |= FIELD_PREP(CMD_CFG_TIMEOUT_MASK,
763 				      ilog2(meson_mmc_get_timeout_msecs(data)));
764 
765 		if (meson_mmc_desc_chain_mode(data)) {
766 			meson_mmc_desc_chain_transfer(mmc, cmd_cfg);
767 			return;
768 		}
769 
770 		if (data->blocks > 1) {
771 			cmd_cfg |= CMD_CFG_BLOCK_MODE;
772 			cmd_cfg |= FIELD_PREP(CMD_CFG_LENGTH_MASK,
773 					      data->blocks);
774 			meson_mmc_set_blksz(mmc, data->blksz);
775 		} else {
776 			cmd_cfg |= FIELD_PREP(CMD_CFG_LENGTH_MASK, data->blksz);
777 		}
778 
779 		xfer_bytes = data->blksz * data->blocks;
780 		if (data->flags & MMC_DATA_WRITE) {
781 			cmd_cfg |= CMD_CFG_DATA_WR;
782 			WARN_ON(xfer_bytes > host->bounce_buf_size);
783 			sg_copy_to_buffer(data->sg, data->sg_len,
784 					  host->bounce_buf, xfer_bytes);
785 			dma_wmb();
786 		}
787 
788 		cmd_data = host->bounce_dma_addr & CMD_DATA_MASK;
789 	} else {
790 		cmd_cfg |= FIELD_PREP(CMD_CFG_TIMEOUT_MASK,
791 				      ilog2(SD_EMMC_CMD_TIMEOUT));
792 	}
793 
794 	/* Last descriptor */
795 	cmd_cfg |= CMD_CFG_END_OF_CHAIN;
796 	writel(cmd_cfg, host->regs + SD_EMMC_CMD_CFG);
797 	writel(cmd_data, host->regs + SD_EMMC_CMD_DAT);
798 	writel(0, host->regs + SD_EMMC_CMD_RSP);
799 	wmb(); /* ensure descriptor is written before kicked */
800 	writel(cmd->arg, host->regs + SD_EMMC_CMD_ARG);
801 }
802 
803 static void meson_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
804 {
805 	struct meson_host *host = mmc_priv(mmc);
806 	bool needs_pre_post_req = mrq->data &&
807 			!(mrq->data->host_cookie & SD_EMMC_PRE_REQ_DONE);
808 
809 	if (needs_pre_post_req) {
810 		meson_mmc_get_transfer_mode(mmc, mrq);
811 		if (!meson_mmc_desc_chain_mode(mrq->data))
812 			needs_pre_post_req = false;
813 	}
814 
815 	if (needs_pre_post_req)
816 		meson_mmc_pre_req(mmc, mrq);
817 
818 	/* Stop execution */
819 	writel(0, host->regs + SD_EMMC_START);
820 
821 	meson_mmc_start_cmd(mmc, mrq->sbc ?: mrq->cmd);
822 
823 	if (needs_pre_post_req)
824 		meson_mmc_post_req(mmc, mrq, 0);
825 }
826 
827 static void meson_mmc_read_resp(struct mmc_host *mmc, struct mmc_command *cmd)
828 {
829 	struct meson_host *host = mmc_priv(mmc);
830 
831 	if (cmd->flags & MMC_RSP_136) {
832 		cmd->resp[0] = readl(host->regs + SD_EMMC_CMD_RSP3);
833 		cmd->resp[1] = readl(host->regs + SD_EMMC_CMD_RSP2);
834 		cmd->resp[2] = readl(host->regs + SD_EMMC_CMD_RSP1);
835 		cmd->resp[3] = readl(host->regs + SD_EMMC_CMD_RSP);
836 	} else if (cmd->flags & MMC_RSP_PRESENT) {
837 		cmd->resp[0] = readl(host->regs + SD_EMMC_CMD_RSP);
838 	}
839 }
840 
841 static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
842 {
843 	struct meson_host *host = dev_id;
844 	struct mmc_command *cmd;
845 	struct mmc_data *data;
846 	u32 irq_en, status, raw_status;
847 	irqreturn_t ret = IRQ_NONE;
848 
849 	irq_en = readl(host->regs + SD_EMMC_IRQ_EN);
850 	raw_status = readl(host->regs + SD_EMMC_STATUS);
851 	status = raw_status & irq_en;
852 
853 	if (!status) {
854 		dev_dbg(host->dev,
855 			"Unexpected IRQ! irq_en 0x%08x - status 0x%08x\n",
856 			 irq_en, raw_status);
857 		return IRQ_NONE;
858 	}
859 
860 	if (WARN_ON(!host) || WARN_ON(!host->cmd))
861 		return IRQ_NONE;
862 
863 	/* ack all raised interrupts */
864 	writel(status, host->regs + SD_EMMC_STATUS);
865 
866 	cmd = host->cmd;
867 	data = cmd->data;
868 	cmd->error = 0;
869 	if (status & IRQ_CRC_ERR) {
870 		dev_dbg(host->dev, "CRC Error - status 0x%08x\n", status);
871 		cmd->error = -EILSEQ;
872 		ret = IRQ_WAKE_THREAD;
873 		goto out;
874 	}
875 
876 	if (status & IRQ_TIMEOUTS) {
877 		dev_dbg(host->dev, "Timeout - status 0x%08x\n", status);
878 		cmd->error = -ETIMEDOUT;
879 		ret = IRQ_WAKE_THREAD;
880 		goto out;
881 	}
882 
883 	meson_mmc_read_resp(host->mmc, cmd);
884 
885 	if (status & IRQ_SDIO) {
886 		dev_dbg(host->dev, "IRQ: SDIO TODO.\n");
887 		ret = IRQ_HANDLED;
888 	}
889 
890 	if (status & (IRQ_END_OF_CHAIN | IRQ_RESP_STATUS)) {
891 		if (data && !cmd->error)
892 			data->bytes_xfered = data->blksz * data->blocks;
893 		if (meson_mmc_bounce_buf_read(data) ||
894 		    meson_mmc_get_next_command(cmd))
895 			ret = IRQ_WAKE_THREAD;
896 		else
897 			ret = IRQ_HANDLED;
898 	}
899 
900 out:
901 	if (cmd->error) {
902 		/* Stop desc in case of errors */
903 		u32 start = readl(host->regs + SD_EMMC_START);
904 
905 		start &= ~START_DESC_BUSY;
906 		writel(start, host->regs + SD_EMMC_START);
907 	}
908 
909 	if (ret == IRQ_HANDLED)
910 		meson_mmc_request_done(host->mmc, cmd->mrq);
911 
912 	return ret;
913 }
914 
915 static int meson_mmc_wait_desc_stop(struct meson_host *host)
916 {
917 	u32 status;
918 
919 	/*
920 	 * It may sometimes take a while for it to actually halt. Here, we
921 	 * are giving it 5ms to comply
922 	 *
923 	 * If we don't confirm the descriptor is stopped, it might raise new
924 	 * IRQs after we have called mmc_request_done() which is bad.
925 	 */
926 
927 	return readl_poll_timeout(host->regs + SD_EMMC_STATUS, status,
928 				  !(status & (STATUS_BUSY | STATUS_DESC_BUSY)),
929 				  100, 5000);
930 }
931 
932 static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id)
933 {
934 	struct meson_host *host = dev_id;
935 	struct mmc_command *next_cmd, *cmd = host->cmd;
936 	struct mmc_data *data;
937 	unsigned int xfer_bytes;
938 
939 	if (WARN_ON(!cmd))
940 		return IRQ_NONE;
941 
942 	if (cmd->error) {
943 		meson_mmc_wait_desc_stop(host);
944 		meson_mmc_request_done(host->mmc, cmd->mrq);
945 
946 		return IRQ_HANDLED;
947 	}
948 
949 	data = cmd->data;
950 	if (meson_mmc_bounce_buf_read(data)) {
951 		xfer_bytes = data->blksz * data->blocks;
952 		WARN_ON(xfer_bytes > host->bounce_buf_size);
953 		sg_copy_from_buffer(data->sg, data->sg_len,
954 				    host->bounce_buf, xfer_bytes);
955 	}
956 
957 	next_cmd = meson_mmc_get_next_command(cmd);
958 	if (next_cmd)
959 		meson_mmc_start_cmd(host->mmc, next_cmd);
960 	else
961 		meson_mmc_request_done(host->mmc, cmd->mrq);
962 
963 	return IRQ_HANDLED;
964 }
965 
966 /*
967  * NOTE: we only need this until the GPIO/pinctrl driver can handle
968  * interrupts.  For now, the MMC core will use this for polling.
969  */
970 static int meson_mmc_get_cd(struct mmc_host *mmc)
971 {
972 	int status = mmc_gpio_get_cd(mmc);
973 
974 	if (status == -ENOSYS)
975 		return 1; /* assume present */
976 
977 	return status;
978 }
979 
980 static void meson_mmc_cfg_init(struct meson_host *host)
981 {
982 	u32 cfg = 0;
983 
984 	cfg |= FIELD_PREP(CFG_RESP_TIMEOUT_MASK,
985 			  ilog2(SD_EMMC_CFG_RESP_TIMEOUT));
986 	cfg |= FIELD_PREP(CFG_RC_CC_MASK, ilog2(SD_EMMC_CFG_CMD_GAP));
987 	cfg |= FIELD_PREP(CFG_BLK_LEN_MASK, ilog2(SD_EMMC_CFG_BLK_SIZE));
988 
989 	/* abort chain on R/W errors */
990 	cfg |= CFG_ERR_ABORT;
991 
992 	writel(cfg, host->regs + SD_EMMC_CFG);
993 }
994 
995 static int meson_mmc_card_busy(struct mmc_host *mmc)
996 {
997 	struct meson_host *host = mmc_priv(mmc);
998 	u32 regval;
999 
1000 	regval = readl(host->regs + SD_EMMC_STATUS);
1001 
1002 	/* We are only interrested in lines 0 to 3, so mask the other ones */
1003 	return !(FIELD_GET(STATUS_DATI, regval) & 0xf);
1004 }
1005 
1006 static int meson_mmc_voltage_switch(struct mmc_host *mmc, struct mmc_ios *ios)
1007 {
1008 	/* vqmmc regulator is available */
1009 	if (!IS_ERR(mmc->supply.vqmmc)) {
1010 		/*
1011 		 * The usual amlogic setup uses a GPIO to switch from one
1012 		 * regulator to the other. While the voltage ramp up is
1013 		 * pretty fast, care must be taken when switching from 3.3v
1014 		 * to 1.8v. Please make sure the regulator framework is aware
1015 		 * of your own regulator constraints
1016 		 */
1017 		return mmc_regulator_set_vqmmc(mmc, ios);
1018 	}
1019 
1020 	/* no vqmmc regulator, assume fixed regulator at 3/3.3V */
1021 	if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330)
1022 		return 0;
1023 
1024 	return -EINVAL;
1025 }
1026 
1027 static const struct mmc_host_ops meson_mmc_ops = {
1028 	.request	= meson_mmc_request,
1029 	.set_ios	= meson_mmc_set_ios,
1030 	.get_cd         = meson_mmc_get_cd,
1031 	.pre_req	= meson_mmc_pre_req,
1032 	.post_req	= meson_mmc_post_req,
1033 	.execute_tuning = meson_mmc_resampling_tuning,
1034 	.card_busy	= meson_mmc_card_busy,
1035 	.start_signal_voltage_switch = meson_mmc_voltage_switch,
1036 };
1037 
1038 static int meson_mmc_probe(struct platform_device *pdev)
1039 {
1040 	struct resource *res;
1041 	struct meson_host *host;
1042 	struct mmc_host *mmc;
1043 	int ret;
1044 
1045 	mmc = mmc_alloc_host(sizeof(struct meson_host), &pdev->dev);
1046 	if (!mmc)
1047 		return -ENOMEM;
1048 	host = mmc_priv(mmc);
1049 	host->mmc = mmc;
1050 	host->dev = &pdev->dev;
1051 	dev_set_drvdata(&pdev->dev, host);
1052 
1053 	/* The G12A SDIO Controller needs an SRAM bounce buffer */
1054 	host->dram_access_quirk = device_property_read_bool(&pdev->dev,
1055 					"amlogic,dram-access-quirk");
1056 
1057 	/* Get regulators and the supported OCR mask */
1058 	host->vqmmc_enabled = false;
1059 	ret = mmc_regulator_get_supply(mmc);
1060 	if (ret)
1061 		goto free_host;
1062 
1063 	ret = mmc_of_parse(mmc);
1064 	if (ret) {
1065 		if (ret != -EPROBE_DEFER)
1066 			dev_warn(&pdev->dev, "error parsing DT: %d\n", ret);
1067 		goto free_host;
1068 	}
1069 
1070 	host->data = (struct meson_mmc_data *)
1071 		of_device_get_match_data(&pdev->dev);
1072 	if (!host->data) {
1073 		ret = -EINVAL;
1074 		goto free_host;
1075 	}
1076 
1077 	ret = device_reset_optional(&pdev->dev);
1078 	if (ret) {
1079 		if (ret != -EPROBE_DEFER)
1080 			dev_err(&pdev->dev, "device reset failed: %d\n", ret);
1081 
1082 		return ret;
1083 	}
1084 
1085 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1086 	host->regs = devm_ioremap_resource(&pdev->dev, res);
1087 	if (IS_ERR(host->regs)) {
1088 		ret = PTR_ERR(host->regs);
1089 		goto free_host;
1090 	}
1091 
1092 	host->irq = platform_get_irq(pdev, 0);
1093 	if (host->irq <= 0) {
1094 		dev_err(&pdev->dev, "failed to get interrupt resource.\n");
1095 		ret = -EINVAL;
1096 		goto free_host;
1097 	}
1098 
1099 	host->pinctrl = devm_pinctrl_get(&pdev->dev);
1100 	if (IS_ERR(host->pinctrl)) {
1101 		ret = PTR_ERR(host->pinctrl);
1102 		goto free_host;
1103 	}
1104 
1105 	host->pins_default = pinctrl_lookup_state(host->pinctrl,
1106 						  PINCTRL_STATE_DEFAULT);
1107 	if (IS_ERR(host->pins_default)) {
1108 		ret = PTR_ERR(host->pins_default);
1109 		goto free_host;
1110 	}
1111 
1112 	host->pins_clk_gate = pinctrl_lookup_state(host->pinctrl,
1113 						   "clk-gate");
1114 	if (IS_ERR(host->pins_clk_gate)) {
1115 		dev_warn(&pdev->dev,
1116 			 "can't get clk-gate pinctrl, using clk_stop bit\n");
1117 		host->pins_clk_gate = NULL;
1118 	}
1119 
1120 	host->core_clk = devm_clk_get(&pdev->dev, "core");
1121 	if (IS_ERR(host->core_clk)) {
1122 		ret = PTR_ERR(host->core_clk);
1123 		goto free_host;
1124 	}
1125 
1126 	ret = clk_prepare_enable(host->core_clk);
1127 	if (ret)
1128 		goto free_host;
1129 
1130 	ret = meson_mmc_clk_init(host);
1131 	if (ret)
1132 		goto err_core_clk;
1133 
1134 	/* set config to sane default */
1135 	meson_mmc_cfg_init(host);
1136 
1137 	/* Stop execution */
1138 	writel(0, host->regs + SD_EMMC_START);
1139 
1140 	/* clear, ack and enable interrupts */
1141 	writel(0, host->regs + SD_EMMC_IRQ_EN);
1142 	writel(IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN,
1143 	       host->regs + SD_EMMC_STATUS);
1144 	writel(IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN,
1145 	       host->regs + SD_EMMC_IRQ_EN);
1146 
1147 	ret = request_threaded_irq(host->irq, meson_mmc_irq,
1148 				   meson_mmc_irq_thread, IRQF_ONESHOT,
1149 				   dev_name(&pdev->dev), host);
1150 	if (ret)
1151 		goto err_init_clk;
1152 
1153 	mmc->caps |= MMC_CAP_CMD23;
1154 	if (host->dram_access_quirk) {
1155 		/* Limit to the available sram memory */
1156 		mmc->max_segs = SD_EMMC_SRAM_DATA_BUF_LEN / mmc->max_blk_size;
1157 		mmc->max_blk_count = mmc->max_segs;
1158 	} else {
1159 		mmc->max_blk_count = CMD_CFG_LENGTH_MASK;
1160 		mmc->max_segs = SD_EMMC_DESC_BUF_LEN /
1161 				sizeof(struct sd_emmc_desc);
1162 	}
1163 	mmc->max_req_size = mmc->max_blk_count * mmc->max_blk_size;
1164 	mmc->max_seg_size = mmc->max_req_size;
1165 
1166 	/*
1167 	 * At the moment, we don't know how to reliably enable HS400.
1168 	 * From the different datasheets, it is not even clear if this mode
1169 	 * is officially supported by any of the SoCs
1170 	 */
1171 	mmc->caps2 &= ~MMC_CAP2_HS400;
1172 
1173 	if (host->dram_access_quirk) {
1174 		/*
1175 		 * The MMC Controller embeds 1,5KiB of internal SRAM
1176 		 * that can be used to be used as bounce buffer.
1177 		 * In the case of the G12A SDIO controller, use these
1178 		 * instead of the DDR memory
1179 		 */
1180 		host->bounce_buf_size = SD_EMMC_SRAM_DATA_BUF_LEN;
1181 		host->bounce_buf = host->regs + SD_EMMC_SRAM_DATA_BUF_OFF;
1182 		host->bounce_dma_addr = res->start + SD_EMMC_SRAM_DATA_BUF_OFF;
1183 	} else {
1184 		/* data bounce buffer */
1185 		host->bounce_buf_size = mmc->max_req_size;
1186 		host->bounce_buf =
1187 			dma_alloc_coherent(host->dev, host->bounce_buf_size,
1188 					   &host->bounce_dma_addr, GFP_KERNEL);
1189 		if (host->bounce_buf == NULL) {
1190 			dev_err(host->dev, "Unable to map allocate DMA bounce buffer.\n");
1191 			ret = -ENOMEM;
1192 			goto err_free_irq;
1193 		}
1194 	}
1195 
1196 	host->descs = dma_alloc_coherent(host->dev, SD_EMMC_DESC_BUF_LEN,
1197 		      &host->descs_dma_addr, GFP_KERNEL);
1198 	if (!host->descs) {
1199 		dev_err(host->dev, "Allocating descriptor DMA buffer failed\n");
1200 		ret = -ENOMEM;
1201 		goto err_bounce_buf;
1202 	}
1203 
1204 	mmc->ops = &meson_mmc_ops;
1205 	mmc_add_host(mmc);
1206 
1207 	return 0;
1208 
1209 err_bounce_buf:
1210 	if (!host->dram_access_quirk)
1211 		dma_free_coherent(host->dev, host->bounce_buf_size,
1212 				  host->bounce_buf, host->bounce_dma_addr);
1213 err_free_irq:
1214 	free_irq(host->irq, host);
1215 err_init_clk:
1216 	clk_disable_unprepare(host->mmc_clk);
1217 err_core_clk:
1218 	clk_disable_unprepare(host->core_clk);
1219 free_host:
1220 	mmc_free_host(mmc);
1221 	return ret;
1222 }
1223 
1224 static int meson_mmc_remove(struct platform_device *pdev)
1225 {
1226 	struct meson_host *host = dev_get_drvdata(&pdev->dev);
1227 
1228 	mmc_remove_host(host->mmc);
1229 
1230 	/* disable interrupts */
1231 	writel(0, host->regs + SD_EMMC_IRQ_EN);
1232 	free_irq(host->irq, host);
1233 
1234 	dma_free_coherent(host->dev, SD_EMMC_DESC_BUF_LEN,
1235 			  host->descs, host->descs_dma_addr);
1236 
1237 	if (!host->dram_access_quirk)
1238 		dma_free_coherent(host->dev, host->bounce_buf_size,
1239 				  host->bounce_buf, host->bounce_dma_addr);
1240 
1241 	clk_disable_unprepare(host->mmc_clk);
1242 	clk_disable_unprepare(host->core_clk);
1243 
1244 	mmc_free_host(host->mmc);
1245 	return 0;
1246 }
1247 
1248 static const struct meson_mmc_data meson_gx_data = {
1249 	.tx_delay_mask	= CLK_V2_TX_DELAY_MASK,
1250 	.rx_delay_mask	= CLK_V2_RX_DELAY_MASK,
1251 	.always_on	= CLK_V2_ALWAYS_ON,
1252 	.adjust		= SD_EMMC_ADJUST,
1253 };
1254 
1255 static const struct meson_mmc_data meson_axg_data = {
1256 	.tx_delay_mask	= CLK_V3_TX_DELAY_MASK,
1257 	.rx_delay_mask	= CLK_V3_RX_DELAY_MASK,
1258 	.always_on	= CLK_V3_ALWAYS_ON,
1259 	.adjust		= SD_EMMC_V3_ADJUST,
1260 };
1261 
1262 static const struct of_device_id meson_mmc_of_match[] = {
1263 	{ .compatible = "amlogic,meson-gx-mmc",		.data = &meson_gx_data },
1264 	{ .compatible = "amlogic,meson-gxbb-mmc", 	.data = &meson_gx_data },
1265 	{ .compatible = "amlogic,meson-gxl-mmc",	.data = &meson_gx_data },
1266 	{ .compatible = "amlogic,meson-gxm-mmc",	.data = &meson_gx_data },
1267 	{ .compatible = "amlogic,meson-axg-mmc",	.data = &meson_axg_data },
1268 	{}
1269 };
1270 MODULE_DEVICE_TABLE(of, meson_mmc_of_match);
1271 
1272 static struct platform_driver meson_mmc_driver = {
1273 	.probe		= meson_mmc_probe,
1274 	.remove		= meson_mmc_remove,
1275 	.driver		= {
1276 		.name = DRIVER_NAME,
1277 		.of_match_table = of_match_ptr(meson_mmc_of_match),
1278 	},
1279 };
1280 
1281 module_platform_driver(meson_mmc_driver);
1282 
1283 MODULE_DESCRIPTION("Amlogic S905*/GX*/AXG SD/eMMC driver");
1284 MODULE_AUTHOR("Kevin Hilman <khilman@baylibre.com>");
1285 MODULE_LICENSE("GPL v2");
1286