xref: /openbmc/linux/drivers/mmc/host/owl-mmc.c (revision 6c33a6f4)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Actions Semi Owl SoCs SD/MMC driver
4  *
5  * Copyright (c) 2014 Actions Semi Inc.
6  * Copyright (c) 2019 Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
7  *
8  * TODO: SDIO support
9  */
10 
11 #include <linux/clk.h>
12 #include <linux/delay.h>
13 #include <linux/dmaengine.h>
14 #include <linux/dma-direction.h>
15 #include <linux/dma-mapping.h>
16 #include <linux/interrupt.h>
17 #include <linux/mmc/host.h>
18 #include <linux/mmc/slot-gpio.h>
19 #include <linux/module.h>
20 #include <linux/of_platform.h>
21 #include <linux/reset.h>
22 #include <linux/spinlock.h>
23 
24 /*
25  * SDC registers
26  */
27 #define OWL_REG_SD_EN			0x0000
28 #define OWL_REG_SD_CTL			0x0004
29 #define OWL_REG_SD_STATE		0x0008
30 #define OWL_REG_SD_CMD			0x000c
31 #define OWL_REG_SD_ARG			0x0010
32 #define OWL_REG_SD_RSPBUF0		0x0014
33 #define OWL_REG_SD_RSPBUF1		0x0018
34 #define OWL_REG_SD_RSPBUF2		0x001c
35 #define OWL_REG_SD_RSPBUF3		0x0020
36 #define OWL_REG_SD_RSPBUF4		0x0024
37 #define OWL_REG_SD_DAT			0x0028
38 #define OWL_REG_SD_BLK_SIZE		0x002c
39 #define OWL_REG_SD_BLK_NUM		0x0030
40 #define OWL_REG_SD_BUF_SIZE		0x0034
41 
42 /* SD_EN Bits */
43 #define OWL_SD_EN_RANE			BIT(31)
44 #define OWL_SD_EN_RAN_SEED(x)		(((x) & 0x3f) << 24)
45 #define OWL_SD_EN_S18EN			BIT(12)
46 #define OWL_SD_EN_RESE			BIT(10)
47 #define OWL_SD_EN_DAT1_S		BIT(9)
48 #define OWL_SD_EN_CLK_S			BIT(8)
49 #define OWL_SD_ENABLE			BIT(7)
50 #define OWL_SD_EN_BSEL			BIT(6)
51 #define OWL_SD_EN_SDIOEN		BIT(3)
52 #define OWL_SD_EN_DDREN			BIT(2)
53 #define OWL_SD_EN_DATAWID(x)		(((x) & 0x3) << 0)
54 
55 /* SD_CTL Bits */
56 #define OWL_SD_CTL_TOUTEN		BIT(31)
57 #define OWL_SD_CTL_TOUTCNT(x)		(((x) & 0x7f) << 24)
58 #define OWL_SD_CTL_DELAY_MSK		GENMASK(23, 16)
59 #define OWL_SD_CTL_RDELAY(x)		(((x) & 0xf) << 20)
60 #define OWL_SD_CTL_WDELAY(x)		(((x) & 0xf) << 16)
61 #define OWL_SD_CTL_CMDLEN		BIT(13)
62 #define OWL_SD_CTL_SCC			BIT(12)
63 #define OWL_SD_CTL_TCN(x)		(((x) & 0xf) << 8)
64 #define OWL_SD_CTL_TS			BIT(7)
65 #define OWL_SD_CTL_LBE			BIT(6)
66 #define OWL_SD_CTL_C7EN			BIT(5)
67 #define OWL_SD_CTL_TM(x)		(((x) & 0xf) << 0)
68 
69 #define OWL_SD_DELAY_LOW_CLK		0x0f
70 #define OWL_SD_DELAY_MID_CLK		0x0a
71 #define OWL_SD_DELAY_HIGH_CLK		0x09
72 #define OWL_SD_RDELAY_DDR50		0x0a
73 #define OWL_SD_WDELAY_DDR50		0x08
74 
75 /* SD_STATE Bits */
76 #define OWL_SD_STATE_DAT1BS		BIT(18)
77 #define OWL_SD_STATE_SDIOB_P		BIT(17)
78 #define OWL_SD_STATE_SDIOB_EN		BIT(16)
79 #define OWL_SD_STATE_TOUTE		BIT(15)
80 #define OWL_SD_STATE_BAEP		BIT(14)
81 #define OWL_SD_STATE_MEMRDY		BIT(12)
82 #define OWL_SD_STATE_CMDS		BIT(11)
83 #define OWL_SD_STATE_DAT1AS		BIT(10)
84 #define OWL_SD_STATE_SDIOA_P		BIT(9)
85 #define OWL_SD_STATE_SDIOA_EN		BIT(8)
86 #define OWL_SD_STATE_DAT0S		BIT(7)
87 #define OWL_SD_STATE_TEIE		BIT(6)
88 #define OWL_SD_STATE_TEI		BIT(5)
89 #define OWL_SD_STATE_CLNR		BIT(4)
90 #define OWL_SD_STATE_CLC		BIT(3)
91 #define OWL_SD_STATE_WC16ER		BIT(2)
92 #define OWL_SD_STATE_RC16ER		BIT(1)
93 #define OWL_SD_STATE_CRC7ER		BIT(0)
94 
95 struct owl_mmc_host {
96 	struct device *dev;
97 	struct reset_control *reset;
98 	void __iomem *base;
99 	struct clk *clk;
100 	struct completion sdc_complete;
101 	spinlock_t lock;
102 	int irq;
103 	u32 clock;
104 	bool ddr_50;
105 
106 	enum dma_data_direction dma_dir;
107 	struct dma_chan *dma;
108 	struct dma_async_tx_descriptor *desc;
109 	struct dma_slave_config dma_cfg;
110 	struct completion dma_complete;
111 
112 	struct mmc_host	*mmc;
113 	struct mmc_request *mrq;
114 	struct mmc_command *cmd;
115 	struct mmc_data	*data;
116 };
117 
118 static void owl_mmc_update_reg(void __iomem *reg, unsigned int val, bool state)
119 {
120 	unsigned int regval;
121 
122 	regval = readl(reg);
123 
124 	if (state)
125 		regval |= val;
126 	else
127 		regval &= ~val;
128 
129 	writel(regval, reg);
130 }
131 
132 static irqreturn_t owl_irq_handler(int irq, void *devid)
133 {
134 	struct owl_mmc_host *owl_host = devid;
135 	unsigned long flags;
136 	u32 state;
137 
138 	spin_lock_irqsave(&owl_host->lock, flags);
139 
140 	state = readl(owl_host->base + OWL_REG_SD_STATE);
141 	if (state & OWL_SD_STATE_TEI) {
142 		state = readl(owl_host->base + OWL_REG_SD_STATE);
143 		state |= OWL_SD_STATE_TEI;
144 		writel(state, owl_host->base + OWL_REG_SD_STATE);
145 		complete(&owl_host->sdc_complete);
146 	}
147 
148 	spin_unlock_irqrestore(&owl_host->lock, flags);
149 
150 	return IRQ_HANDLED;
151 }
152 
153 static void owl_mmc_finish_request(struct owl_mmc_host *owl_host)
154 {
155 	struct mmc_request *mrq = owl_host->mrq;
156 	struct mmc_data *data = mrq->data;
157 
158 	/* Should never be NULL */
159 	WARN_ON(!mrq);
160 
161 	owl_host->mrq = NULL;
162 
163 	if (data)
164 		dma_unmap_sg(owl_host->dma->device->dev, data->sg, data->sg_len,
165 			     owl_host->dma_dir);
166 
167 	/* Finally finish request */
168 	mmc_request_done(owl_host->mmc, mrq);
169 }
170 
171 static void owl_mmc_send_cmd(struct owl_mmc_host *owl_host,
172 			     struct mmc_command *cmd,
173 			     struct mmc_data *data)
174 {
175 	u32 mode, state, resp[2];
176 	u32 cmd_rsp_mask = 0;
177 
178 	init_completion(&owl_host->sdc_complete);
179 
180 	switch (mmc_resp_type(cmd)) {
181 	case MMC_RSP_NONE:
182 		mode = OWL_SD_CTL_TM(0);
183 		break;
184 
185 	case MMC_RSP_R1:
186 		if (data) {
187 			if (data->flags & MMC_DATA_READ)
188 				mode = OWL_SD_CTL_TM(4);
189 			else
190 				mode = OWL_SD_CTL_TM(5);
191 		} else {
192 			mode = OWL_SD_CTL_TM(1);
193 		}
194 		cmd_rsp_mask = OWL_SD_STATE_CLNR | OWL_SD_STATE_CRC7ER;
195 
196 		break;
197 
198 	case MMC_RSP_R1B:
199 		mode = OWL_SD_CTL_TM(3);
200 		cmd_rsp_mask = OWL_SD_STATE_CLNR | OWL_SD_STATE_CRC7ER;
201 		break;
202 
203 	case MMC_RSP_R2:
204 		mode = OWL_SD_CTL_TM(2);
205 		cmd_rsp_mask = OWL_SD_STATE_CLNR | OWL_SD_STATE_CRC7ER;
206 		break;
207 
208 	case MMC_RSP_R3:
209 		mode = OWL_SD_CTL_TM(1);
210 		cmd_rsp_mask = OWL_SD_STATE_CLNR;
211 		break;
212 
213 	default:
214 		dev_warn(owl_host->dev, "Unknown MMC command\n");
215 		cmd->error = -EINVAL;
216 		return;
217 	}
218 
219 	/* Keep current WDELAY and RDELAY */
220 	mode |= (readl(owl_host->base + OWL_REG_SD_CTL) & (0xff << 16));
221 
222 	/* Start to send corresponding command type */
223 	writel(cmd->arg, owl_host->base + OWL_REG_SD_ARG);
224 	writel(cmd->opcode, owl_host->base + OWL_REG_SD_CMD);
225 
226 	/* Set LBE to send clk at the end of last read block */
227 	if (data) {
228 		mode |= (OWL_SD_CTL_TS | OWL_SD_CTL_LBE | 0x64000000);
229 	} else {
230 		mode &= ~(OWL_SD_CTL_TOUTEN | OWL_SD_CTL_LBE);
231 		mode |= OWL_SD_CTL_TS;
232 	}
233 
234 	owl_host->cmd = cmd;
235 
236 	/* Start transfer */
237 	writel(mode, owl_host->base + OWL_REG_SD_CTL);
238 
239 	if (data)
240 		return;
241 
242 	if (!wait_for_completion_timeout(&owl_host->sdc_complete, 30 * HZ)) {
243 		dev_err(owl_host->dev, "CMD interrupt timeout\n");
244 		cmd->error = -ETIMEDOUT;
245 		return;
246 	}
247 
248 	state = readl(owl_host->base + OWL_REG_SD_STATE);
249 	if (mmc_resp_type(cmd) & MMC_RSP_PRESENT) {
250 		if (cmd_rsp_mask & state) {
251 			if (state & OWL_SD_STATE_CLNR) {
252 				dev_err(owl_host->dev, "Error CMD_NO_RSP\n");
253 				cmd->error = -EILSEQ;
254 				return;
255 			}
256 
257 			if (state & OWL_SD_STATE_CRC7ER) {
258 				dev_err(owl_host->dev, "Error CMD_RSP_CRC\n");
259 				cmd->error = -EILSEQ;
260 				return;
261 			}
262 		}
263 
264 		if (mmc_resp_type(cmd) & MMC_RSP_136) {
265 			cmd->resp[3] = readl(owl_host->base + OWL_REG_SD_RSPBUF0);
266 			cmd->resp[2] = readl(owl_host->base + OWL_REG_SD_RSPBUF1);
267 			cmd->resp[1] = readl(owl_host->base + OWL_REG_SD_RSPBUF2);
268 			cmd->resp[0] = readl(owl_host->base + OWL_REG_SD_RSPBUF3);
269 		} else {
270 			resp[0] = readl(owl_host->base + OWL_REG_SD_RSPBUF0);
271 			resp[1] = readl(owl_host->base + OWL_REG_SD_RSPBUF1);
272 			cmd->resp[0] = resp[1] << 24 | resp[0] >> 8;
273 			cmd->resp[1] = resp[1] >> 8;
274 		}
275 	}
276 }
277 
278 static void owl_mmc_dma_complete(void *param)
279 {
280 	struct owl_mmc_host *owl_host = param;
281 	struct mmc_data *data = owl_host->data;
282 
283 	if (data)
284 		complete(&owl_host->dma_complete);
285 }
286 
287 static int owl_mmc_prepare_data(struct owl_mmc_host *owl_host,
288 				struct mmc_data *data)
289 {
290 	u32 total;
291 
292 	owl_mmc_update_reg(owl_host->base + OWL_REG_SD_EN, OWL_SD_EN_BSEL,
293 			   true);
294 	writel(data->blocks, owl_host->base + OWL_REG_SD_BLK_NUM);
295 	writel(data->blksz, owl_host->base + OWL_REG_SD_BLK_SIZE);
296 	total = data->blksz * data->blocks;
297 
298 	if (total < 512)
299 		writel(total, owl_host->base + OWL_REG_SD_BUF_SIZE);
300 	else
301 		writel(512, owl_host->base + OWL_REG_SD_BUF_SIZE);
302 
303 	if (data->flags & MMC_DATA_WRITE) {
304 		owl_host->dma_dir = DMA_TO_DEVICE;
305 		owl_host->dma_cfg.direction = DMA_MEM_TO_DEV;
306 	} else {
307 		owl_host->dma_dir = DMA_FROM_DEVICE;
308 		owl_host->dma_cfg.direction = DMA_DEV_TO_MEM;
309 	}
310 
311 	dma_map_sg(owl_host->dma->device->dev, data->sg,
312 		   data->sg_len, owl_host->dma_dir);
313 
314 	dmaengine_slave_config(owl_host->dma, &owl_host->dma_cfg);
315 	owl_host->desc = dmaengine_prep_slave_sg(owl_host->dma, data->sg,
316 						 data->sg_len,
317 						 owl_host->dma_cfg.direction,
318 						 DMA_PREP_INTERRUPT |
319 						 DMA_CTRL_ACK);
320 	if (!owl_host->desc) {
321 		dev_err(owl_host->dev, "Can't prepare slave sg\n");
322 		return -EBUSY;
323 	}
324 
325 	owl_host->data = data;
326 
327 	owl_host->desc->callback = owl_mmc_dma_complete;
328 	owl_host->desc->callback_param = (void *)owl_host;
329 	data->error = 0;
330 
331 	return 0;
332 }
333 
334 static void owl_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
335 {
336 	struct owl_mmc_host *owl_host = mmc_priv(mmc);
337 	struct mmc_data *data = mrq->data;
338 	int ret;
339 
340 	owl_host->mrq = mrq;
341 	if (mrq->data) {
342 		ret = owl_mmc_prepare_data(owl_host, data);
343 		if (ret < 0) {
344 			data->error = ret;
345 			goto err_out;
346 		}
347 
348 		init_completion(&owl_host->dma_complete);
349 		dmaengine_submit(owl_host->desc);
350 		dma_async_issue_pending(owl_host->dma);
351 	}
352 
353 	owl_mmc_send_cmd(owl_host, mrq->cmd, data);
354 
355 	if (data) {
356 		if (!wait_for_completion_timeout(&owl_host->sdc_complete,
357 						 10 * HZ)) {
358 			dev_err(owl_host->dev, "CMD interrupt timeout\n");
359 			mrq->cmd->error = -ETIMEDOUT;
360 			dmaengine_terminate_all(owl_host->dma);
361 			goto err_out;
362 		}
363 
364 		if (!wait_for_completion_timeout(&owl_host->dma_complete,
365 						 5 * HZ)) {
366 			dev_err(owl_host->dev, "DMA interrupt timeout\n");
367 			mrq->cmd->error = -ETIMEDOUT;
368 			dmaengine_terminate_all(owl_host->dma);
369 			goto err_out;
370 		}
371 
372 		if (data->stop)
373 			owl_mmc_send_cmd(owl_host, data->stop, NULL);
374 
375 		data->bytes_xfered = data->blocks * data->blksz;
376 	}
377 
378 err_out:
379 	owl_mmc_finish_request(owl_host);
380 }
381 
382 static int owl_mmc_set_clk_rate(struct owl_mmc_host *owl_host,
383 				unsigned int rate)
384 {
385 	unsigned long clk_rate;
386 	int ret;
387 	u32 reg;
388 
389 	reg = readl(owl_host->base + OWL_REG_SD_CTL);
390 	reg &= ~OWL_SD_CTL_DELAY_MSK;
391 
392 	/* Set RDELAY and WDELAY based on the clock */
393 	if (rate <= 1000000) {
394 		writel(reg | OWL_SD_CTL_RDELAY(OWL_SD_DELAY_LOW_CLK) |
395 		       OWL_SD_CTL_WDELAY(OWL_SD_DELAY_LOW_CLK),
396 		       owl_host->base + OWL_REG_SD_CTL);
397 	} else if ((rate > 1000000) && (rate <= 26000000)) {
398 		writel(reg | OWL_SD_CTL_RDELAY(OWL_SD_DELAY_MID_CLK) |
399 		       OWL_SD_CTL_WDELAY(OWL_SD_DELAY_MID_CLK),
400 		       owl_host->base + OWL_REG_SD_CTL);
401 	} else if ((rate > 26000000) && (rate <= 52000000) && !owl_host->ddr_50) {
402 		writel(reg | OWL_SD_CTL_RDELAY(OWL_SD_DELAY_HIGH_CLK) |
403 		       OWL_SD_CTL_WDELAY(OWL_SD_DELAY_HIGH_CLK),
404 		       owl_host->base + OWL_REG_SD_CTL);
405 	/* DDR50 mode has special delay chain */
406 	} else if ((rate > 26000000) && (rate <= 52000000) && owl_host->ddr_50) {
407 		writel(reg | OWL_SD_CTL_RDELAY(OWL_SD_RDELAY_DDR50) |
408 		       OWL_SD_CTL_WDELAY(OWL_SD_WDELAY_DDR50),
409 		       owl_host->base + OWL_REG_SD_CTL);
410 	} else {
411 		dev_err(owl_host->dev, "SD clock rate not supported\n");
412 		return -EINVAL;
413 	}
414 
415 	clk_rate = clk_round_rate(owl_host->clk, rate << 1);
416 	ret = clk_set_rate(owl_host->clk, clk_rate);
417 
418 	return ret;
419 }
420 
421 static void owl_mmc_set_clk(struct owl_mmc_host *owl_host, struct mmc_ios *ios)
422 {
423 	if (!ios->clock)
424 		return;
425 
426 	owl_host->clock = ios->clock;
427 	owl_mmc_set_clk_rate(owl_host, ios->clock);
428 }
429 
430 static void owl_mmc_set_bus_width(struct owl_mmc_host *owl_host,
431 				  struct mmc_ios *ios)
432 {
433 	u32 reg;
434 
435 	reg = readl(owl_host->base + OWL_REG_SD_EN);
436 	reg &= ~0x03;
437 	switch (ios->bus_width) {
438 	case MMC_BUS_WIDTH_1:
439 		break;
440 	case MMC_BUS_WIDTH_4:
441 		reg |= OWL_SD_EN_DATAWID(1);
442 		break;
443 	case MMC_BUS_WIDTH_8:
444 		reg |= OWL_SD_EN_DATAWID(2);
445 		break;
446 	}
447 
448 	writel(reg, owl_host->base + OWL_REG_SD_EN);
449 }
450 
451 static void owl_mmc_ctr_reset(struct owl_mmc_host *owl_host)
452 {
453 	reset_control_assert(owl_host->reset);
454 	udelay(20);
455 	reset_control_deassert(owl_host->reset);
456 }
457 
458 static void owl_mmc_power_on(struct owl_mmc_host *owl_host)
459 {
460 	u32 mode;
461 
462 	init_completion(&owl_host->sdc_complete);
463 
464 	/* Enable transfer end IRQ */
465 	owl_mmc_update_reg(owl_host->base + OWL_REG_SD_STATE,
466 		       OWL_SD_STATE_TEIE, true);
467 
468 	/* Send init clk */
469 	mode = (readl(owl_host->base + OWL_REG_SD_CTL) & (0xff << 16));
470 	mode |= OWL_SD_CTL_TS | OWL_SD_CTL_TCN(5) | OWL_SD_CTL_TM(8);
471 	writel(mode, owl_host->base + OWL_REG_SD_CTL);
472 
473 	if (!wait_for_completion_timeout(&owl_host->sdc_complete, HZ)) {
474 		dev_err(owl_host->dev, "CMD interrupt timeout\n");
475 		return;
476 	}
477 }
478 
479 static void owl_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
480 {
481 	struct owl_mmc_host *owl_host = mmc_priv(mmc);
482 
483 	switch (ios->power_mode) {
484 	case MMC_POWER_UP:
485 		dev_dbg(owl_host->dev, "Powering card up\n");
486 
487 		/* Reset the SDC controller to clear all previous states */
488 		owl_mmc_ctr_reset(owl_host);
489 		clk_prepare_enable(owl_host->clk);
490 		writel(OWL_SD_ENABLE | OWL_SD_EN_RESE,
491 		       owl_host->base + OWL_REG_SD_EN);
492 
493 		break;
494 
495 	case MMC_POWER_ON:
496 		dev_dbg(owl_host->dev, "Powering card on\n");
497 		owl_mmc_power_on(owl_host);
498 
499 		break;
500 
501 	case MMC_POWER_OFF:
502 		dev_dbg(owl_host->dev, "Powering card off\n");
503 		clk_disable_unprepare(owl_host->clk);
504 
505 		return;
506 
507 	default:
508 		dev_dbg(owl_host->dev, "Ignoring unknown card power state\n");
509 		break;
510 	}
511 
512 	if (ios->clock != owl_host->clock)
513 		owl_mmc_set_clk(owl_host, ios);
514 
515 	owl_mmc_set_bus_width(owl_host, ios);
516 
517 	/* Enable DDR mode if requested */
518 	if (ios->timing == MMC_TIMING_UHS_DDR50) {
519 		owl_host->ddr_50 = 1;
520 		owl_mmc_update_reg(owl_host->base + OWL_REG_SD_EN,
521 			       OWL_SD_EN_DDREN, true);
522 	} else {
523 		owl_host->ddr_50 = 0;
524 	}
525 }
526 
527 static int owl_mmc_start_signal_voltage_switch(struct mmc_host *mmc,
528 					       struct mmc_ios *ios)
529 {
530 	struct owl_mmc_host *owl_host = mmc_priv(mmc);
531 
532 	/* It is enough to change the pad ctrl bit for voltage switch */
533 	switch (ios->signal_voltage) {
534 	case MMC_SIGNAL_VOLTAGE_330:
535 		owl_mmc_update_reg(owl_host->base + OWL_REG_SD_EN,
536 			       OWL_SD_EN_S18EN, false);
537 		break;
538 	case MMC_SIGNAL_VOLTAGE_180:
539 		owl_mmc_update_reg(owl_host->base + OWL_REG_SD_EN,
540 			       OWL_SD_EN_S18EN, true);
541 		break;
542 	default:
543 		return -ENOTSUPP;
544 	}
545 
546 	return 0;
547 }
548 
549 static const struct mmc_host_ops owl_mmc_ops = {
550 	.request	= owl_mmc_request,
551 	.set_ios	= owl_mmc_set_ios,
552 	.get_ro		= mmc_gpio_get_ro,
553 	.get_cd		= mmc_gpio_get_cd,
554 	.start_signal_voltage_switch = owl_mmc_start_signal_voltage_switch,
555 };
556 
557 static int owl_mmc_probe(struct platform_device *pdev)
558 {
559 	struct owl_mmc_host *owl_host;
560 	struct mmc_host *mmc;
561 	struct resource *res;
562 	int ret;
563 
564 	mmc = mmc_alloc_host(sizeof(struct owl_mmc_host), &pdev->dev);
565 	if (!mmc) {
566 		dev_err(&pdev->dev, "mmc alloc host failed\n");
567 		return -ENOMEM;
568 	}
569 	platform_set_drvdata(pdev, mmc);
570 
571 	owl_host = mmc_priv(mmc);
572 	owl_host->dev = &pdev->dev;
573 	owl_host->mmc = mmc;
574 	spin_lock_init(&owl_host->lock);
575 
576 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
577 	owl_host->base = devm_ioremap_resource(&pdev->dev, res);
578 	if (IS_ERR(owl_host->base)) {
579 		dev_err(&pdev->dev, "Failed to remap registers\n");
580 		ret = PTR_ERR(owl_host->base);
581 		goto err_free_host;
582 	}
583 
584 	owl_host->clk = devm_clk_get(&pdev->dev, NULL);
585 	if (IS_ERR(owl_host->clk)) {
586 		dev_err(&pdev->dev, "No clock defined\n");
587 		ret = PTR_ERR(owl_host->clk);
588 		goto err_free_host;
589 	}
590 
591 	owl_host->reset = devm_reset_control_get_exclusive(&pdev->dev, NULL);
592 	if (IS_ERR(owl_host->reset)) {
593 		dev_err(&pdev->dev, "Could not get reset control\n");
594 		ret = PTR_ERR(owl_host->reset);
595 		goto err_free_host;
596 	}
597 
598 	mmc->ops		= &owl_mmc_ops;
599 	mmc->max_blk_count	= 512;
600 	mmc->max_blk_size	= 512;
601 	mmc->max_segs		= 256;
602 	mmc->max_seg_size	= 262144;
603 	mmc->max_req_size	= 262144;
604 	/* 100kHz ~ 52MHz */
605 	mmc->f_min		= 100000;
606 	mmc->f_max		= 52000000;
607 	mmc->caps	       |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED |
608 				  MMC_CAP_4_BIT_DATA;
609 	mmc->caps2		= (MMC_CAP2_BOOTPART_NOACC | MMC_CAP2_NO_SDIO);
610 	mmc->ocr_avail		= MMC_VDD_32_33 | MMC_VDD_33_34 |
611 				  MMC_VDD_165_195;
612 
613 	ret = mmc_of_parse(mmc);
614 	if (ret)
615 		goto err_free_host;
616 
617 	pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
618 	pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
619 	owl_host->dma = dma_request_chan(&pdev->dev, "mmc");
620 	if (IS_ERR(owl_host->dma)) {
621 		dev_err(owl_host->dev, "Failed to get external DMA channel.\n");
622 		ret = PTR_ERR(owl_host->dma);
623 		goto err_free_host;
624 	}
625 
626 	dev_info(&pdev->dev, "Using %s for DMA transfers\n",
627 		 dma_chan_name(owl_host->dma));
628 
629 	owl_host->dma_cfg.src_addr = res->start + OWL_REG_SD_DAT;
630 	owl_host->dma_cfg.dst_addr = res->start + OWL_REG_SD_DAT;
631 	owl_host->dma_cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
632 	owl_host->dma_cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
633 	owl_host->dma_cfg.device_fc = false;
634 
635 	owl_host->irq = platform_get_irq(pdev, 0);
636 	if (owl_host->irq < 0) {
637 		ret = -EINVAL;
638 		goto err_free_host;
639 	}
640 
641 	ret = devm_request_irq(&pdev->dev, owl_host->irq, owl_irq_handler,
642 			       0, dev_name(&pdev->dev), owl_host);
643 	if (ret) {
644 		dev_err(&pdev->dev, "Failed to request irq %d\n",
645 			owl_host->irq);
646 		goto err_free_host;
647 	}
648 
649 	ret = mmc_add_host(mmc);
650 	if (ret) {
651 		dev_err(&pdev->dev, "Failed to add host\n");
652 		goto err_free_host;
653 	}
654 
655 	dev_dbg(&pdev->dev, "Owl MMC Controller Initialized\n");
656 
657 	return 0;
658 
659 err_free_host:
660 	mmc_free_host(mmc);
661 
662 	return ret;
663 }
664 
665 static int owl_mmc_remove(struct platform_device *pdev)
666 {
667 	struct mmc_host	*mmc = platform_get_drvdata(pdev);
668 	struct owl_mmc_host *owl_host = mmc_priv(mmc);
669 
670 	mmc_remove_host(mmc);
671 	disable_irq(owl_host->irq);
672 	mmc_free_host(mmc);
673 
674 	return 0;
675 }
676 
677 static const struct of_device_id owl_mmc_of_match[] = {
678 	{.compatible = "actions,owl-mmc",},
679 	{ /* sentinel */ }
680 };
681 MODULE_DEVICE_TABLE(of, owl_mmc_of_match);
682 
683 static struct platform_driver owl_mmc_driver = {
684 	.driver = {
685 		.name	= "owl_mmc",
686 		.of_match_table = of_match_ptr(owl_mmc_of_match),
687 	},
688 	.probe		= owl_mmc_probe,
689 	.remove		= owl_mmc_remove,
690 };
691 module_platform_driver(owl_mmc_driver);
692 
693 MODULE_DESCRIPTION("Actions Semi Owl SoCs SD/MMC Driver");
694 MODULE_AUTHOR("Actions Semi");
695 MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
696 MODULE_LICENSE("GPL");
697