xref: /linux/drivers/mmc/host/owl-mmc.c (revision 7f71507851fc7764b36a3221839607d3a45c2025)
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/mod_devicetable.h>
20 #include <linux/module.h>
21 #include <linux/platform_device.h>
22 #include <linux/reset.h>
23 #include <linux/spinlock.h>
24 
25 /*
26  * SDC registers
27  */
28 #define OWL_REG_SD_EN			0x0000
29 #define OWL_REG_SD_CTL			0x0004
30 #define OWL_REG_SD_STATE		0x0008
31 #define OWL_REG_SD_CMD			0x000c
32 #define OWL_REG_SD_ARG			0x0010
33 #define OWL_REG_SD_RSPBUF0		0x0014
34 #define OWL_REG_SD_RSPBUF1		0x0018
35 #define OWL_REG_SD_RSPBUF2		0x001c
36 #define OWL_REG_SD_RSPBUF3		0x0020
37 #define OWL_REG_SD_RSPBUF4		0x0024
38 #define OWL_REG_SD_DAT			0x0028
39 #define OWL_REG_SD_BLK_SIZE		0x002c
40 #define OWL_REG_SD_BLK_NUM		0x0030
41 #define OWL_REG_SD_BUF_SIZE		0x0034
42 
43 /* SD_EN Bits */
44 #define OWL_SD_EN_RANE			BIT(31)
45 #define OWL_SD_EN_RAN_SEED(x)		(((x) & 0x3f) << 24)
46 #define OWL_SD_EN_S18EN			BIT(12)
47 #define OWL_SD_EN_RESE			BIT(10)
48 #define OWL_SD_EN_DAT1_S		BIT(9)
49 #define OWL_SD_EN_CLK_S			BIT(8)
50 #define OWL_SD_ENABLE			BIT(7)
51 #define OWL_SD_EN_BSEL			BIT(6)
52 #define OWL_SD_EN_SDIOEN		BIT(3)
53 #define OWL_SD_EN_DDREN			BIT(2)
54 #define OWL_SD_EN_DATAWID(x)		(((x) & 0x3) << 0)
55 
56 /* SD_CTL Bits */
57 #define OWL_SD_CTL_TOUTEN		BIT(31)
58 #define OWL_SD_CTL_TOUTCNT(x)		(((x) & 0x7f) << 24)
59 #define OWL_SD_CTL_DELAY_MSK		GENMASK(23, 16)
60 #define OWL_SD_CTL_RDELAY(x)		(((x) & 0xf) << 20)
61 #define OWL_SD_CTL_WDELAY(x)		(((x) & 0xf) << 16)
62 #define OWL_SD_CTL_CMDLEN		BIT(13)
63 #define OWL_SD_CTL_SCC			BIT(12)
64 #define OWL_SD_CTL_TCN(x)		(((x) & 0xf) << 8)
65 #define OWL_SD_CTL_TS			BIT(7)
66 #define OWL_SD_CTL_LBE			BIT(6)
67 #define OWL_SD_CTL_C7EN			BIT(5)
68 #define OWL_SD_CTL_TM(x)		(((x) & 0xf) << 0)
69 
70 #define OWL_SD_DELAY_LOW_CLK		0x0f
71 #define OWL_SD_DELAY_MID_CLK		0x0a
72 #define OWL_SD_DELAY_HIGH_CLK		0x09
73 #define OWL_SD_RDELAY_DDR50		0x0a
74 #define OWL_SD_WDELAY_DDR50		0x08
75 
76 /* SD_STATE Bits */
77 #define OWL_SD_STATE_DAT1BS		BIT(18)
78 #define OWL_SD_STATE_SDIOB_P		BIT(17)
79 #define OWL_SD_STATE_SDIOB_EN		BIT(16)
80 #define OWL_SD_STATE_TOUTE		BIT(15)
81 #define OWL_SD_STATE_BAEP		BIT(14)
82 #define OWL_SD_STATE_MEMRDY		BIT(12)
83 #define OWL_SD_STATE_CMDS		BIT(11)
84 #define OWL_SD_STATE_DAT1AS		BIT(10)
85 #define OWL_SD_STATE_SDIOA_P		BIT(9)
86 #define OWL_SD_STATE_SDIOA_EN		BIT(8)
87 #define OWL_SD_STATE_DAT0S		BIT(7)
88 #define OWL_SD_STATE_TEIE		BIT(6)
89 #define OWL_SD_STATE_TEI		BIT(5)
90 #define OWL_SD_STATE_CLNR		BIT(4)
91 #define OWL_SD_STATE_CLC		BIT(3)
92 #define OWL_SD_STATE_WC16ER		BIT(2)
93 #define OWL_SD_STATE_RC16ER		BIT(1)
94 #define OWL_SD_STATE_CRC7ER		BIT(0)
95 
96 #define OWL_CMD_TIMEOUT_MS		30000
97 
98 struct owl_mmc_host {
99 	struct device *dev;
100 	struct reset_control *reset;
101 	void __iomem *base;
102 	struct clk *clk;
103 	struct completion sdc_complete;
104 	spinlock_t lock;
105 	int irq;
106 	u32 clock;
107 	bool ddr_50;
108 
109 	enum dma_data_direction dma_dir;
110 	struct dma_chan *dma;
111 	struct dma_async_tx_descriptor *desc;
112 	struct dma_slave_config dma_cfg;
113 	struct completion dma_complete;
114 
115 	struct mmc_host	*mmc;
116 	struct mmc_request *mrq;
117 	struct mmc_command *cmd;
118 	struct mmc_data	*data;
119 };
120 
121 static void owl_mmc_update_reg(void __iomem *reg, unsigned int val, bool state)
122 {
123 	unsigned int regval;
124 
125 	regval = readl(reg);
126 
127 	if (state)
128 		regval |= val;
129 	else
130 		regval &= ~val;
131 
132 	writel(regval, reg);
133 }
134 
135 static irqreturn_t owl_irq_handler(int irq, void *devid)
136 {
137 	struct owl_mmc_host *owl_host = devid;
138 	u32 state;
139 
140 	spin_lock(&owl_host->lock);
141 
142 	state = readl(owl_host->base + OWL_REG_SD_STATE);
143 	if (state & OWL_SD_STATE_TEI) {
144 		state = readl(owl_host->base + OWL_REG_SD_STATE);
145 		state |= OWL_SD_STATE_TEI;
146 		writel(state, owl_host->base + OWL_REG_SD_STATE);
147 		complete(&owl_host->sdc_complete);
148 	}
149 
150 	spin_unlock(&owl_host->lock);
151 
152 	return IRQ_HANDLED;
153 }
154 
155 static void owl_mmc_finish_request(struct owl_mmc_host *owl_host)
156 {
157 	struct mmc_request *mrq = owl_host->mrq;
158 	struct mmc_data *data = mrq->data;
159 
160 	/* Should never be NULL */
161 	WARN_ON(!mrq);
162 
163 	owl_host->mrq = NULL;
164 
165 	if (data)
166 		dma_unmap_sg(owl_host->dma->device->dev, data->sg, data->sg_len,
167 			     owl_host->dma_dir);
168 
169 	/* Finally finish request */
170 	mmc_request_done(owl_host->mmc, mrq);
171 }
172 
173 static void owl_mmc_send_cmd(struct owl_mmc_host *owl_host,
174 			     struct mmc_command *cmd,
175 			     struct mmc_data *data)
176 {
177 	unsigned long timeout;
178 	u32 mode, state, resp[2];
179 	u32 cmd_rsp_mask = 0;
180 
181 	init_completion(&owl_host->sdc_complete);
182 
183 	switch (mmc_resp_type(cmd)) {
184 	case MMC_RSP_NONE:
185 		mode = OWL_SD_CTL_TM(0);
186 		break;
187 
188 	case MMC_RSP_R1:
189 		if (data) {
190 			if (data->flags & MMC_DATA_READ)
191 				mode = OWL_SD_CTL_TM(4);
192 			else
193 				mode = OWL_SD_CTL_TM(5);
194 		} else {
195 			mode = OWL_SD_CTL_TM(1);
196 		}
197 		cmd_rsp_mask = OWL_SD_STATE_CLNR | OWL_SD_STATE_CRC7ER;
198 
199 		break;
200 
201 	case MMC_RSP_R1B:
202 		mode = OWL_SD_CTL_TM(3);
203 		cmd_rsp_mask = OWL_SD_STATE_CLNR | OWL_SD_STATE_CRC7ER;
204 		break;
205 
206 	case MMC_RSP_R2:
207 		mode = OWL_SD_CTL_TM(2);
208 		cmd_rsp_mask = OWL_SD_STATE_CLNR | OWL_SD_STATE_CRC7ER;
209 		break;
210 
211 	case MMC_RSP_R3:
212 		mode = OWL_SD_CTL_TM(1);
213 		cmd_rsp_mask = OWL_SD_STATE_CLNR;
214 		break;
215 
216 	default:
217 		dev_warn(owl_host->dev, "Unknown MMC command\n");
218 		cmd->error = -EINVAL;
219 		return;
220 	}
221 
222 	/* Keep current WDELAY and RDELAY */
223 	mode |= (readl(owl_host->base + OWL_REG_SD_CTL) & (0xff << 16));
224 
225 	/* Start to send corresponding command type */
226 	writel(cmd->arg, owl_host->base + OWL_REG_SD_ARG);
227 	writel(cmd->opcode, owl_host->base + OWL_REG_SD_CMD);
228 
229 	/* Set LBE to send clk at the end of last read block */
230 	if (data) {
231 		mode |= (OWL_SD_CTL_TS | OWL_SD_CTL_LBE | 0x64000000);
232 	} else {
233 		mode &= ~(OWL_SD_CTL_TOUTEN | OWL_SD_CTL_LBE);
234 		mode |= OWL_SD_CTL_TS;
235 	}
236 
237 	owl_host->cmd = cmd;
238 
239 	/* Start transfer */
240 	writel(mode, owl_host->base + OWL_REG_SD_CTL);
241 
242 	if (data)
243 		return;
244 
245 	timeout = msecs_to_jiffies(cmd->busy_timeout ? cmd->busy_timeout :
246 		OWL_CMD_TIMEOUT_MS);
247 
248 	if (!wait_for_completion_timeout(&owl_host->sdc_complete, timeout)) {
249 		dev_err(owl_host->dev, "CMD interrupt timeout\n");
250 		cmd->error = -ETIMEDOUT;
251 		return;
252 	}
253 
254 	state = readl(owl_host->base + OWL_REG_SD_STATE);
255 	if (mmc_resp_type(cmd) & MMC_RSP_PRESENT) {
256 		if (cmd_rsp_mask & state) {
257 			if (state & OWL_SD_STATE_CLNR) {
258 				dev_err(owl_host->dev, "Error CMD_NO_RSP\n");
259 				cmd->error = -EILSEQ;
260 				return;
261 			}
262 
263 			if (state & OWL_SD_STATE_CRC7ER) {
264 				dev_err(owl_host->dev, "Error CMD_RSP_CRC\n");
265 				cmd->error = -EILSEQ;
266 				return;
267 			}
268 		}
269 
270 		if (mmc_resp_type(cmd) & MMC_RSP_136) {
271 			cmd->resp[3] = readl(owl_host->base + OWL_REG_SD_RSPBUF0);
272 			cmd->resp[2] = readl(owl_host->base + OWL_REG_SD_RSPBUF1);
273 			cmd->resp[1] = readl(owl_host->base + OWL_REG_SD_RSPBUF2);
274 			cmd->resp[0] = readl(owl_host->base + OWL_REG_SD_RSPBUF3);
275 		} else {
276 			resp[0] = readl(owl_host->base + OWL_REG_SD_RSPBUF0);
277 			resp[1] = readl(owl_host->base + OWL_REG_SD_RSPBUF1);
278 			cmd->resp[0] = resp[1] << 24 | resp[0] >> 8;
279 			cmd->resp[1] = resp[1] >> 8;
280 		}
281 	}
282 }
283 
284 static void owl_mmc_dma_complete(void *param)
285 {
286 	struct owl_mmc_host *owl_host = param;
287 	struct mmc_data *data = owl_host->data;
288 
289 	if (data)
290 		complete(&owl_host->dma_complete);
291 }
292 
293 static int owl_mmc_prepare_data(struct owl_mmc_host *owl_host,
294 				struct mmc_data *data)
295 {
296 	u32 total;
297 
298 	owl_mmc_update_reg(owl_host->base + OWL_REG_SD_EN, OWL_SD_EN_BSEL,
299 			   true);
300 	writel(data->blocks, owl_host->base + OWL_REG_SD_BLK_NUM);
301 	writel(data->blksz, owl_host->base + OWL_REG_SD_BLK_SIZE);
302 	total = data->blksz * data->blocks;
303 
304 	if (total < 512)
305 		writel(total, owl_host->base + OWL_REG_SD_BUF_SIZE);
306 	else
307 		writel(512, owl_host->base + OWL_REG_SD_BUF_SIZE);
308 
309 	if (data->flags & MMC_DATA_WRITE) {
310 		owl_host->dma_dir = DMA_TO_DEVICE;
311 		owl_host->dma_cfg.direction = DMA_MEM_TO_DEV;
312 	} else {
313 		owl_host->dma_dir = DMA_FROM_DEVICE;
314 		owl_host->dma_cfg.direction = DMA_DEV_TO_MEM;
315 	}
316 
317 	dma_map_sg(owl_host->dma->device->dev, data->sg,
318 		   data->sg_len, owl_host->dma_dir);
319 
320 	dmaengine_slave_config(owl_host->dma, &owl_host->dma_cfg);
321 	owl_host->desc = dmaengine_prep_slave_sg(owl_host->dma, data->sg,
322 						 data->sg_len,
323 						 owl_host->dma_cfg.direction,
324 						 DMA_PREP_INTERRUPT |
325 						 DMA_CTRL_ACK);
326 	if (!owl_host->desc) {
327 		dev_err(owl_host->dev, "Can't prepare slave sg\n");
328 		return -EBUSY;
329 	}
330 
331 	owl_host->data = data;
332 
333 	owl_host->desc->callback = owl_mmc_dma_complete;
334 	owl_host->desc->callback_param = (void *)owl_host;
335 	data->error = 0;
336 
337 	return 0;
338 }
339 
340 static void owl_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
341 {
342 	struct owl_mmc_host *owl_host = mmc_priv(mmc);
343 	struct mmc_data *data = mrq->data;
344 	int ret;
345 
346 	owl_host->mrq = mrq;
347 	if (mrq->data) {
348 		ret = owl_mmc_prepare_data(owl_host, data);
349 		if (ret < 0) {
350 			data->error = ret;
351 			goto err_out;
352 		}
353 
354 		init_completion(&owl_host->dma_complete);
355 		dmaengine_submit(owl_host->desc);
356 		dma_async_issue_pending(owl_host->dma);
357 	}
358 
359 	owl_mmc_send_cmd(owl_host, mrq->cmd, data);
360 
361 	if (data) {
362 		if (!wait_for_completion_timeout(&owl_host->sdc_complete,
363 						 10 * HZ)) {
364 			dev_err(owl_host->dev, "CMD interrupt timeout\n");
365 			mrq->cmd->error = -ETIMEDOUT;
366 			dmaengine_terminate_all(owl_host->dma);
367 			goto err_out;
368 		}
369 
370 		if (!wait_for_completion_timeout(&owl_host->dma_complete,
371 						 5 * HZ)) {
372 			dev_err(owl_host->dev, "DMA interrupt timeout\n");
373 			mrq->cmd->error = -ETIMEDOUT;
374 			dmaengine_terminate_all(owl_host->dma);
375 			goto err_out;
376 		}
377 
378 		if (data->stop)
379 			owl_mmc_send_cmd(owl_host, data->stop, NULL);
380 
381 		data->bytes_xfered = data->blocks * data->blksz;
382 	}
383 
384 err_out:
385 	owl_mmc_finish_request(owl_host);
386 }
387 
388 static int owl_mmc_set_clk_rate(struct owl_mmc_host *owl_host,
389 				unsigned int rate)
390 {
391 	unsigned long clk_rate;
392 	int ret;
393 	u32 reg;
394 
395 	reg = readl(owl_host->base + OWL_REG_SD_CTL);
396 	reg &= ~OWL_SD_CTL_DELAY_MSK;
397 
398 	/* Set RDELAY and WDELAY based on the clock */
399 	if (rate <= 1000000) {
400 		writel(reg | OWL_SD_CTL_RDELAY(OWL_SD_DELAY_LOW_CLK) |
401 		       OWL_SD_CTL_WDELAY(OWL_SD_DELAY_LOW_CLK),
402 		       owl_host->base + OWL_REG_SD_CTL);
403 	} else if ((rate > 1000000) && (rate <= 26000000)) {
404 		writel(reg | OWL_SD_CTL_RDELAY(OWL_SD_DELAY_MID_CLK) |
405 		       OWL_SD_CTL_WDELAY(OWL_SD_DELAY_MID_CLK),
406 		       owl_host->base + OWL_REG_SD_CTL);
407 	} else if ((rate > 26000000) && (rate <= 52000000) && !owl_host->ddr_50) {
408 		writel(reg | OWL_SD_CTL_RDELAY(OWL_SD_DELAY_HIGH_CLK) |
409 		       OWL_SD_CTL_WDELAY(OWL_SD_DELAY_HIGH_CLK),
410 		       owl_host->base + OWL_REG_SD_CTL);
411 	/* DDR50 mode has special delay chain */
412 	} else if ((rate > 26000000) && (rate <= 52000000) && owl_host->ddr_50) {
413 		writel(reg | OWL_SD_CTL_RDELAY(OWL_SD_RDELAY_DDR50) |
414 		       OWL_SD_CTL_WDELAY(OWL_SD_WDELAY_DDR50),
415 		       owl_host->base + OWL_REG_SD_CTL);
416 	} else {
417 		dev_err(owl_host->dev, "SD clock rate not supported\n");
418 		return -EINVAL;
419 	}
420 
421 	clk_rate = clk_round_rate(owl_host->clk, rate << 1);
422 	ret = clk_set_rate(owl_host->clk, clk_rate);
423 
424 	return ret;
425 }
426 
427 static void owl_mmc_set_clk(struct owl_mmc_host *owl_host, struct mmc_ios *ios)
428 {
429 	if (!ios->clock)
430 		return;
431 
432 	owl_host->clock = ios->clock;
433 	owl_mmc_set_clk_rate(owl_host, ios->clock);
434 }
435 
436 static void owl_mmc_set_bus_width(struct owl_mmc_host *owl_host,
437 				  struct mmc_ios *ios)
438 {
439 	u32 reg;
440 
441 	reg = readl(owl_host->base + OWL_REG_SD_EN);
442 	reg &= ~0x03;
443 	switch (ios->bus_width) {
444 	case MMC_BUS_WIDTH_1:
445 		break;
446 	case MMC_BUS_WIDTH_4:
447 		reg |= OWL_SD_EN_DATAWID(1);
448 		break;
449 	case MMC_BUS_WIDTH_8:
450 		reg |= OWL_SD_EN_DATAWID(2);
451 		break;
452 	}
453 
454 	writel(reg, owl_host->base + OWL_REG_SD_EN);
455 }
456 
457 static void owl_mmc_ctr_reset(struct owl_mmc_host *owl_host)
458 {
459 	reset_control_assert(owl_host->reset);
460 	udelay(20);
461 	reset_control_deassert(owl_host->reset);
462 }
463 
464 static void owl_mmc_power_on(struct owl_mmc_host *owl_host)
465 {
466 	u32 mode;
467 
468 	init_completion(&owl_host->sdc_complete);
469 
470 	/* Enable transfer end IRQ */
471 	owl_mmc_update_reg(owl_host->base + OWL_REG_SD_STATE,
472 		       OWL_SD_STATE_TEIE, true);
473 
474 	/* Send init clk */
475 	mode = (readl(owl_host->base + OWL_REG_SD_CTL) & (0xff << 16));
476 	mode |= OWL_SD_CTL_TS | OWL_SD_CTL_TCN(5) | OWL_SD_CTL_TM(8);
477 	writel(mode, owl_host->base + OWL_REG_SD_CTL);
478 
479 	if (!wait_for_completion_timeout(&owl_host->sdc_complete, HZ)) {
480 		dev_err(owl_host->dev, "CMD interrupt timeout\n");
481 		return;
482 	}
483 }
484 
485 static void owl_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
486 {
487 	struct owl_mmc_host *owl_host = mmc_priv(mmc);
488 
489 	switch (ios->power_mode) {
490 	case MMC_POWER_UP:
491 		dev_dbg(owl_host->dev, "Powering card up\n");
492 
493 		/* Reset the SDC controller to clear all previous states */
494 		owl_mmc_ctr_reset(owl_host);
495 		clk_prepare_enable(owl_host->clk);
496 		writel(OWL_SD_ENABLE | OWL_SD_EN_RESE,
497 		       owl_host->base + OWL_REG_SD_EN);
498 
499 		break;
500 
501 	case MMC_POWER_ON:
502 		dev_dbg(owl_host->dev, "Powering card on\n");
503 		owl_mmc_power_on(owl_host);
504 
505 		break;
506 
507 	case MMC_POWER_OFF:
508 		dev_dbg(owl_host->dev, "Powering card off\n");
509 		clk_disable_unprepare(owl_host->clk);
510 
511 		return;
512 
513 	default:
514 		dev_dbg(owl_host->dev, "Ignoring unknown card power state\n");
515 		break;
516 	}
517 
518 	if (ios->clock != owl_host->clock)
519 		owl_mmc_set_clk(owl_host, ios);
520 
521 	owl_mmc_set_bus_width(owl_host, ios);
522 
523 	/* Enable DDR mode if requested */
524 	if (ios->timing == MMC_TIMING_UHS_DDR50) {
525 		owl_host->ddr_50 = true;
526 		owl_mmc_update_reg(owl_host->base + OWL_REG_SD_EN,
527 			       OWL_SD_EN_DDREN, true);
528 	} else {
529 		owl_host->ddr_50 = false;
530 	}
531 }
532 
533 static int owl_mmc_start_signal_voltage_switch(struct mmc_host *mmc,
534 					       struct mmc_ios *ios)
535 {
536 	struct owl_mmc_host *owl_host = mmc_priv(mmc);
537 
538 	/* It is enough to change the pad ctrl bit for voltage switch */
539 	switch (ios->signal_voltage) {
540 	case MMC_SIGNAL_VOLTAGE_330:
541 		owl_mmc_update_reg(owl_host->base + OWL_REG_SD_EN,
542 			       OWL_SD_EN_S18EN, false);
543 		break;
544 	case MMC_SIGNAL_VOLTAGE_180:
545 		owl_mmc_update_reg(owl_host->base + OWL_REG_SD_EN,
546 			       OWL_SD_EN_S18EN, true);
547 		break;
548 	default:
549 		return -ENOTSUPP;
550 	}
551 
552 	return 0;
553 }
554 
555 static const struct mmc_host_ops owl_mmc_ops = {
556 	.request	= owl_mmc_request,
557 	.set_ios	= owl_mmc_set_ios,
558 	.get_ro		= mmc_gpio_get_ro,
559 	.get_cd		= mmc_gpio_get_cd,
560 	.start_signal_voltage_switch = owl_mmc_start_signal_voltage_switch,
561 };
562 
563 static int owl_mmc_probe(struct platform_device *pdev)
564 {
565 	struct owl_mmc_host *owl_host;
566 	struct mmc_host *mmc;
567 	struct resource *res;
568 	int ret;
569 
570 	mmc = mmc_alloc_host(sizeof(struct owl_mmc_host), &pdev->dev);
571 	if (!mmc) {
572 		dev_err(&pdev->dev, "mmc alloc host failed\n");
573 		return -ENOMEM;
574 	}
575 	platform_set_drvdata(pdev, mmc);
576 
577 	owl_host = mmc_priv(mmc);
578 	owl_host->dev = &pdev->dev;
579 	owl_host->mmc = mmc;
580 	spin_lock_init(&owl_host->lock);
581 
582 	owl_host->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
583 	if (IS_ERR(owl_host->base)) {
584 		ret = PTR_ERR(owl_host->base);
585 		goto err_free_host;
586 	}
587 
588 	owl_host->clk = devm_clk_get(&pdev->dev, NULL);
589 	if (IS_ERR(owl_host->clk)) {
590 		dev_err(&pdev->dev, "No clock defined\n");
591 		ret = PTR_ERR(owl_host->clk);
592 		goto err_free_host;
593 	}
594 
595 	owl_host->reset = devm_reset_control_get_exclusive(&pdev->dev, NULL);
596 	if (IS_ERR(owl_host->reset)) {
597 		dev_err(&pdev->dev, "Could not get reset control\n");
598 		ret = PTR_ERR(owl_host->reset);
599 		goto err_free_host;
600 	}
601 
602 	mmc->ops		= &owl_mmc_ops;
603 	mmc->max_blk_count	= 512;
604 	mmc->max_blk_size	= 512;
605 	mmc->max_segs		= 256;
606 	mmc->max_seg_size	= 262144;
607 	mmc->max_req_size	= 262144;
608 	/* 100kHz ~ 52MHz */
609 	mmc->f_min		= 100000;
610 	mmc->f_max		= 52000000;
611 	mmc->caps	       |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED |
612 				  MMC_CAP_4_BIT_DATA;
613 	mmc->caps2		= (MMC_CAP2_BOOTPART_NOACC | MMC_CAP2_NO_SDIO);
614 	mmc->ocr_avail		= MMC_VDD_32_33 | MMC_VDD_33_34 |
615 				  MMC_VDD_165_195;
616 
617 	ret = mmc_of_parse(mmc);
618 	if (ret)
619 		goto err_free_host;
620 
621 	pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
622 	pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
623 	owl_host->dma = dma_request_chan(&pdev->dev, "mmc");
624 	if (IS_ERR(owl_host->dma)) {
625 		dev_err(owl_host->dev, "Failed to get external DMA channel.\n");
626 		ret = PTR_ERR(owl_host->dma);
627 		goto err_free_host;
628 	}
629 
630 	dev_info(&pdev->dev, "Using %s for DMA transfers\n",
631 		 dma_chan_name(owl_host->dma));
632 
633 	owl_host->dma_cfg.src_addr = res->start + OWL_REG_SD_DAT;
634 	owl_host->dma_cfg.dst_addr = res->start + OWL_REG_SD_DAT;
635 	owl_host->dma_cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
636 	owl_host->dma_cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
637 	owl_host->dma_cfg.device_fc = false;
638 
639 	owl_host->irq = platform_get_irq(pdev, 0);
640 	if (owl_host->irq < 0) {
641 		ret = owl_host->irq;
642 		goto err_release_channel;
643 	}
644 
645 	ret = devm_request_irq(&pdev->dev, owl_host->irq, owl_irq_handler,
646 			       0, dev_name(&pdev->dev), owl_host);
647 	if (ret) {
648 		dev_err(&pdev->dev, "Failed to request irq %d\n",
649 			owl_host->irq);
650 		goto err_release_channel;
651 	}
652 
653 	ret = mmc_add_host(mmc);
654 	if (ret) {
655 		dev_err(&pdev->dev, "Failed to add host\n");
656 		goto err_release_channel;
657 	}
658 
659 	dev_dbg(&pdev->dev, "Owl MMC Controller Initialized\n");
660 
661 	return 0;
662 
663 err_release_channel:
664 	dma_release_channel(owl_host->dma);
665 err_free_host:
666 	mmc_free_host(mmc);
667 
668 	return ret;
669 }
670 
671 static void owl_mmc_remove(struct platform_device *pdev)
672 {
673 	struct mmc_host	*mmc = platform_get_drvdata(pdev);
674 	struct owl_mmc_host *owl_host = mmc_priv(mmc);
675 
676 	mmc_remove_host(mmc);
677 	disable_irq(owl_host->irq);
678 	dma_release_channel(owl_host->dma);
679 	mmc_free_host(mmc);
680 }
681 
682 static const struct of_device_id owl_mmc_of_match[] = {
683 	{.compatible = "actions,owl-mmc",},
684 	{ /* sentinel */ }
685 };
686 MODULE_DEVICE_TABLE(of, owl_mmc_of_match);
687 
688 static struct platform_driver owl_mmc_driver = {
689 	.driver = {
690 		.name	= "owl_mmc",
691 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
692 		.of_match_table = owl_mmc_of_match,
693 	},
694 	.probe		= owl_mmc_probe,
695 	.remove		= owl_mmc_remove,
696 };
697 module_platform_driver(owl_mmc_driver);
698 
699 MODULE_DESCRIPTION("Actions Semi Owl SoCs SD/MMC Driver");
700 MODULE_AUTHOR("Actions Semi");
701 MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
702 MODULE_LICENSE("GPL");
703