xref: /linux/drivers/mmc/host/mmci_stm32_sdmmc.c (revision 0526b56cbc3c489642bd6a5fe4b718dea7ef0ee8)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) STMicroelectronics 2018 - All Rights Reserved
4  * Author: Ludovic.barre@st.com for STMicroelectronics.
5  */
6 #include <linux/bitfield.h>
7 #include <linux/delay.h>
8 #include <linux/dma-mapping.h>
9 #include <linux/iopoll.h>
10 #include <linux/mmc/host.h>
11 #include <linux/mmc/card.h>
12 #include <linux/of_address.h>
13 #include <linux/reset.h>
14 #include <linux/scatterlist.h>
15 #include "mmci.h"
16 
17 #define SDMMC_LLI_BUF_LEN	PAGE_SIZE
18 #define SDMMC_IDMA_BURST	BIT(MMCI_STM32_IDMABNDT_SHIFT)
19 
20 #define DLYB_CR			0x0
21 #define DLYB_CR_DEN		BIT(0)
22 #define DLYB_CR_SEN		BIT(1)
23 
24 #define DLYB_CFGR		0x4
25 #define DLYB_CFGR_SEL_MASK	GENMASK(3, 0)
26 #define DLYB_CFGR_UNIT_MASK	GENMASK(14, 8)
27 #define DLYB_CFGR_LNG_MASK	GENMASK(27, 16)
28 #define DLYB_CFGR_LNGF		BIT(31)
29 
30 #define DLYB_NB_DELAY		11
31 #define DLYB_CFGR_SEL_MAX	(DLYB_NB_DELAY + 1)
32 #define DLYB_CFGR_UNIT_MAX	127
33 
34 #define DLYB_LNG_TIMEOUT_US	1000
35 #define SDMMC_VSWEND_TIMEOUT_US 10000
36 
37 struct sdmmc_lli_desc {
38 	u32 idmalar;
39 	u32 idmabase;
40 	u32 idmasize;
41 };
42 
43 struct sdmmc_idma {
44 	dma_addr_t sg_dma;
45 	void *sg_cpu;
46 	dma_addr_t bounce_dma_addr;
47 	void *bounce_buf;
48 	bool use_bounce_buffer;
49 };
50 
51 struct sdmmc_dlyb {
52 	void __iomem *base;
53 	u32 unit;
54 	u32 max;
55 };
56 
57 static int sdmmc_idma_validate_data(struct mmci_host *host,
58 				    struct mmc_data *data)
59 {
60 	struct sdmmc_idma *idma = host->dma_priv;
61 	struct device *dev = mmc_dev(host->mmc);
62 	struct scatterlist *sg;
63 	int i;
64 
65 	/*
66 	 * idma has constraints on idmabase & idmasize for each element
67 	 * excepted the last element which has no constraint on idmasize
68 	 */
69 	idma->use_bounce_buffer = false;
70 	for_each_sg(data->sg, sg, data->sg_len - 1, i) {
71 		if (!IS_ALIGNED(sg->offset, sizeof(u32)) ||
72 		    !IS_ALIGNED(sg->length, SDMMC_IDMA_BURST)) {
73 			dev_dbg(mmc_dev(host->mmc),
74 				"unaligned scatterlist: ofst:%x length:%d\n",
75 				data->sg->offset, data->sg->length);
76 			goto use_bounce_buffer;
77 		}
78 	}
79 
80 	if (!IS_ALIGNED(sg->offset, sizeof(u32))) {
81 		dev_dbg(mmc_dev(host->mmc),
82 			"unaligned last scatterlist: ofst:%x length:%d\n",
83 			data->sg->offset, data->sg->length);
84 		goto use_bounce_buffer;
85 	}
86 
87 	return 0;
88 
89 use_bounce_buffer:
90 	if (!idma->bounce_buf) {
91 		idma->bounce_buf = dmam_alloc_coherent(dev,
92 						       host->mmc->max_req_size,
93 						       &idma->bounce_dma_addr,
94 						       GFP_KERNEL);
95 		if (!idma->bounce_buf) {
96 			dev_err(dev, "Unable to map allocate DMA bounce buffer.\n");
97 			return -ENOMEM;
98 		}
99 	}
100 
101 	idma->use_bounce_buffer = true;
102 
103 	return 0;
104 }
105 
106 static int _sdmmc_idma_prep_data(struct mmci_host *host,
107 				 struct mmc_data *data)
108 {
109 	struct sdmmc_idma *idma = host->dma_priv;
110 
111 	if (idma->use_bounce_buffer) {
112 		if (data->flags & MMC_DATA_WRITE) {
113 			unsigned int xfer_bytes = data->blksz * data->blocks;
114 
115 			sg_copy_to_buffer(data->sg, data->sg_len,
116 					  idma->bounce_buf, xfer_bytes);
117 			dma_wmb();
118 		}
119 	} else {
120 		int n_elem;
121 
122 		n_elem = dma_map_sg(mmc_dev(host->mmc),
123 				    data->sg,
124 				    data->sg_len,
125 				    mmc_get_dma_dir(data));
126 
127 		if (!n_elem) {
128 			dev_err(mmc_dev(host->mmc), "dma_map_sg failed\n");
129 			return -EINVAL;
130 		}
131 	}
132 	return 0;
133 }
134 
135 static int sdmmc_idma_prep_data(struct mmci_host *host,
136 				struct mmc_data *data, bool next)
137 {
138 	/* Check if job is already prepared. */
139 	if (!next && data->host_cookie == host->next_cookie)
140 		return 0;
141 
142 	return _sdmmc_idma_prep_data(host, data);
143 }
144 
145 static void sdmmc_idma_unprep_data(struct mmci_host *host,
146 				   struct mmc_data *data, int err)
147 {
148 	struct sdmmc_idma *idma = host->dma_priv;
149 
150 	if (idma->use_bounce_buffer) {
151 		if (data->flags & MMC_DATA_READ) {
152 			unsigned int xfer_bytes = data->blksz * data->blocks;
153 
154 			sg_copy_from_buffer(data->sg, data->sg_len,
155 					    idma->bounce_buf, xfer_bytes);
156 		}
157 	} else {
158 		dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
159 			     mmc_get_dma_dir(data));
160 	}
161 }
162 
163 static int sdmmc_idma_setup(struct mmci_host *host)
164 {
165 	struct sdmmc_idma *idma;
166 	struct device *dev = mmc_dev(host->mmc);
167 
168 	idma = devm_kzalloc(dev, sizeof(*idma), GFP_KERNEL);
169 	if (!idma)
170 		return -ENOMEM;
171 
172 	host->dma_priv = idma;
173 
174 	if (host->variant->dma_lli) {
175 		idma->sg_cpu = dmam_alloc_coherent(dev, SDMMC_LLI_BUF_LEN,
176 						   &idma->sg_dma, GFP_KERNEL);
177 		if (!idma->sg_cpu) {
178 			dev_err(dev, "Failed to alloc IDMA descriptor\n");
179 			return -ENOMEM;
180 		}
181 		host->mmc->max_segs = SDMMC_LLI_BUF_LEN /
182 			sizeof(struct sdmmc_lli_desc);
183 		host->mmc->max_seg_size = host->variant->stm32_idmabsize_mask;
184 
185 		host->mmc->max_req_size = SZ_1M;
186 	} else {
187 		host->mmc->max_segs = 1;
188 		host->mmc->max_seg_size = host->mmc->max_req_size;
189 	}
190 
191 	return dma_set_max_seg_size(dev, host->mmc->max_seg_size);
192 }
193 
194 static int sdmmc_idma_start(struct mmci_host *host, unsigned int *datactrl)
195 
196 {
197 	struct sdmmc_idma *idma = host->dma_priv;
198 	struct sdmmc_lli_desc *desc = (struct sdmmc_lli_desc *)idma->sg_cpu;
199 	struct mmc_data *data = host->data;
200 	struct scatterlist *sg;
201 	int i;
202 
203 	if (!host->variant->dma_lli || data->sg_len == 1 ||
204 	    idma->use_bounce_buffer) {
205 		u32 dma_addr;
206 
207 		if (idma->use_bounce_buffer)
208 			dma_addr = idma->bounce_dma_addr;
209 		else
210 			dma_addr = sg_dma_address(data->sg);
211 
212 		writel_relaxed(dma_addr,
213 			       host->base + MMCI_STM32_IDMABASE0R);
214 		writel_relaxed(MMCI_STM32_IDMAEN,
215 			       host->base + MMCI_STM32_IDMACTRLR);
216 		return 0;
217 	}
218 
219 	for_each_sg(data->sg, sg, data->sg_len, i) {
220 		desc[i].idmalar = (i + 1) * sizeof(struct sdmmc_lli_desc);
221 		desc[i].idmalar |= MMCI_STM32_ULA | MMCI_STM32_ULS
222 			| MMCI_STM32_ABR;
223 		desc[i].idmabase = sg_dma_address(sg);
224 		desc[i].idmasize = sg_dma_len(sg);
225 	}
226 
227 	/* notice the end of link list */
228 	desc[data->sg_len - 1].idmalar &= ~MMCI_STM32_ULA;
229 
230 	dma_wmb();
231 	writel_relaxed(idma->sg_dma, host->base + MMCI_STM32_IDMABAR);
232 	writel_relaxed(desc[0].idmalar, host->base + MMCI_STM32_IDMALAR);
233 	writel_relaxed(desc[0].idmabase, host->base + MMCI_STM32_IDMABASE0R);
234 	writel_relaxed(desc[0].idmasize, host->base + MMCI_STM32_IDMABSIZER);
235 	writel_relaxed(MMCI_STM32_IDMAEN | MMCI_STM32_IDMALLIEN,
236 		       host->base + MMCI_STM32_IDMACTRLR);
237 
238 	return 0;
239 }
240 
241 static void sdmmc_idma_finalize(struct mmci_host *host, struct mmc_data *data)
242 {
243 	writel_relaxed(0, host->base + MMCI_STM32_IDMACTRLR);
244 
245 	if (!data->host_cookie)
246 		sdmmc_idma_unprep_data(host, data, 0);
247 }
248 
249 static void mmci_sdmmc_set_clkreg(struct mmci_host *host, unsigned int desired)
250 {
251 	unsigned int clk = 0, ddr = 0;
252 
253 	if (host->mmc->ios.timing == MMC_TIMING_MMC_DDR52 ||
254 	    host->mmc->ios.timing == MMC_TIMING_UHS_DDR50)
255 		ddr = MCI_STM32_CLK_DDR;
256 
257 	/*
258 	 * cclk = mclk / (2 * clkdiv)
259 	 * clkdiv 0 => bypass
260 	 * in ddr mode bypass is not possible
261 	 */
262 	if (desired) {
263 		if (desired >= host->mclk && !ddr) {
264 			host->cclk = host->mclk;
265 		} else {
266 			clk = DIV_ROUND_UP(host->mclk, 2 * desired);
267 			if (clk > MCI_STM32_CLK_CLKDIV_MSK)
268 				clk = MCI_STM32_CLK_CLKDIV_MSK;
269 			host->cclk = host->mclk / (2 * clk);
270 		}
271 	} else {
272 		/*
273 		 * while power-on phase the clock can't be define to 0,
274 		 * Only power-off and power-cyc deactivate the clock.
275 		 * if desired clock is 0, set max divider
276 		 */
277 		clk = MCI_STM32_CLK_CLKDIV_MSK;
278 		host->cclk = host->mclk / (2 * clk);
279 	}
280 
281 	/* Set actual clock for debug */
282 	if (host->mmc->ios.power_mode == MMC_POWER_ON)
283 		host->mmc->actual_clock = host->cclk;
284 	else
285 		host->mmc->actual_clock = 0;
286 
287 	if (host->mmc->ios.bus_width == MMC_BUS_WIDTH_4)
288 		clk |= MCI_STM32_CLK_WIDEBUS_4;
289 	if (host->mmc->ios.bus_width == MMC_BUS_WIDTH_8)
290 		clk |= MCI_STM32_CLK_WIDEBUS_8;
291 
292 	clk |= MCI_STM32_CLK_HWFCEN;
293 	clk |= host->clk_reg_add;
294 	clk |= ddr;
295 
296 	/*
297 	 * SDMMC_FBCK is selected when an external Delay Block is needed
298 	 * with SDR104 or HS200.
299 	 */
300 	if (host->mmc->ios.timing >= MMC_TIMING_UHS_SDR50) {
301 		clk |= MCI_STM32_CLK_BUSSPEED;
302 		if (host->mmc->ios.timing == MMC_TIMING_UHS_SDR104 ||
303 		    host->mmc->ios.timing == MMC_TIMING_MMC_HS200) {
304 			clk &= ~MCI_STM32_CLK_SEL_MSK;
305 			clk |= MCI_STM32_CLK_SELFBCK;
306 		}
307 	}
308 
309 	mmci_write_clkreg(host, clk);
310 }
311 
312 static void sdmmc_dlyb_input_ck(struct sdmmc_dlyb *dlyb)
313 {
314 	if (!dlyb || !dlyb->base)
315 		return;
316 
317 	/* Output clock = Input clock */
318 	writel_relaxed(0, dlyb->base + DLYB_CR);
319 }
320 
321 static void mmci_sdmmc_set_pwrreg(struct mmci_host *host, unsigned int pwr)
322 {
323 	struct mmc_ios ios = host->mmc->ios;
324 	struct sdmmc_dlyb *dlyb = host->variant_priv;
325 
326 	/* adds OF options */
327 	pwr = host->pwr_reg_add;
328 
329 	sdmmc_dlyb_input_ck(dlyb);
330 
331 	if (ios.power_mode == MMC_POWER_OFF) {
332 		/* Only a reset could power-off sdmmc */
333 		reset_control_assert(host->rst);
334 		udelay(2);
335 		reset_control_deassert(host->rst);
336 
337 		/*
338 		 * Set the SDMMC in Power-cycle state.
339 		 * This will make that the SDMMC_D[7:0], SDMMC_CMD and SDMMC_CK
340 		 * are driven low, to prevent the Card from being supplied
341 		 * through the signal lines.
342 		 */
343 		mmci_write_pwrreg(host, MCI_STM32_PWR_CYC | pwr);
344 	} else if (ios.power_mode == MMC_POWER_ON) {
345 		/*
346 		 * After power-off (reset): the irq mask defined in probe
347 		 * functionis lost
348 		 * ault irq mask (probe) must be activated
349 		 */
350 		writel(MCI_IRQENABLE | host->variant->start_err,
351 		       host->base + MMCIMASK0);
352 
353 		/* preserves voltage switch bits */
354 		pwr |= host->pwr_reg & (MCI_STM32_VSWITCHEN |
355 					MCI_STM32_VSWITCH);
356 
357 		/*
358 		 * After a power-cycle state, we must set the SDMMC in
359 		 * Power-off. The SDMMC_D[7:0], SDMMC_CMD and SDMMC_CK are
360 		 * driven high. Then we can set the SDMMC to Power-on state
361 		 */
362 		mmci_write_pwrreg(host, MCI_PWR_OFF | pwr);
363 		mdelay(1);
364 		mmci_write_pwrreg(host, MCI_PWR_ON | pwr);
365 	}
366 }
367 
368 static u32 sdmmc_get_dctrl_cfg(struct mmci_host *host)
369 {
370 	u32 datactrl;
371 
372 	datactrl = mmci_dctrl_blksz(host);
373 
374 	if (host->mmc->card && mmc_card_sdio(host->mmc->card) &&
375 	    host->data->blocks == 1)
376 		datactrl |= MCI_DPSM_STM32_MODE_SDIO;
377 	else if (host->data->stop && !host->mrq->sbc)
378 		datactrl |= MCI_DPSM_STM32_MODE_BLOCK_STOP;
379 	else
380 		datactrl |= MCI_DPSM_STM32_MODE_BLOCK;
381 
382 	return datactrl;
383 }
384 
385 static bool sdmmc_busy_complete(struct mmci_host *host, u32 status, u32 err_msk)
386 {
387 	void __iomem *base = host->base;
388 	u32 busy_d0, busy_d0end, mask, sdmmc_status;
389 
390 	mask = readl_relaxed(base + MMCIMASK0);
391 	sdmmc_status = readl_relaxed(base + MMCISTATUS);
392 	busy_d0end = sdmmc_status & MCI_STM32_BUSYD0END;
393 	busy_d0 = sdmmc_status & MCI_STM32_BUSYD0;
394 
395 	/* complete if there is an error or busy_d0end */
396 	if ((status & err_msk) || busy_d0end)
397 		goto complete;
398 
399 	/*
400 	 * On response the busy signaling is reflected in the BUSYD0 flag.
401 	 * if busy_d0 is in-progress we must activate busyd0end interrupt
402 	 * to wait this completion. Else this request has no busy step.
403 	 */
404 	if (busy_d0) {
405 		if (!host->busy_status) {
406 			writel_relaxed(mask | host->variant->busy_detect_mask,
407 				       base + MMCIMASK0);
408 			host->busy_status = status &
409 				(MCI_CMDSENT | MCI_CMDRESPEND);
410 		}
411 		return false;
412 	}
413 
414 complete:
415 	if (host->busy_status) {
416 		writel_relaxed(mask & ~host->variant->busy_detect_mask,
417 			       base + MMCIMASK0);
418 		host->busy_status = 0;
419 	}
420 
421 	writel_relaxed(host->variant->busy_detect_mask, base + MMCICLEAR);
422 
423 	return true;
424 }
425 
426 static void sdmmc_dlyb_set_cfgr(struct sdmmc_dlyb *dlyb,
427 				int unit, int phase, bool sampler)
428 {
429 	u32 cfgr;
430 
431 	writel_relaxed(DLYB_CR_SEN | DLYB_CR_DEN, dlyb->base + DLYB_CR);
432 
433 	cfgr = FIELD_PREP(DLYB_CFGR_UNIT_MASK, unit) |
434 	       FIELD_PREP(DLYB_CFGR_SEL_MASK, phase);
435 	writel_relaxed(cfgr, dlyb->base + DLYB_CFGR);
436 
437 	if (!sampler)
438 		writel_relaxed(DLYB_CR_DEN, dlyb->base + DLYB_CR);
439 }
440 
441 static int sdmmc_dlyb_lng_tuning(struct mmci_host *host)
442 {
443 	struct sdmmc_dlyb *dlyb = host->variant_priv;
444 	u32 cfgr;
445 	int i, lng, ret;
446 
447 	for (i = 0; i <= DLYB_CFGR_UNIT_MAX; i++) {
448 		sdmmc_dlyb_set_cfgr(dlyb, i, DLYB_CFGR_SEL_MAX, true);
449 
450 		ret = readl_relaxed_poll_timeout(dlyb->base + DLYB_CFGR, cfgr,
451 						 (cfgr & DLYB_CFGR_LNGF),
452 						 1, DLYB_LNG_TIMEOUT_US);
453 		if (ret) {
454 			dev_warn(mmc_dev(host->mmc),
455 				 "delay line cfg timeout unit:%d cfgr:%d\n",
456 				 i, cfgr);
457 			continue;
458 		}
459 
460 		lng = FIELD_GET(DLYB_CFGR_LNG_MASK, cfgr);
461 		if (lng < BIT(DLYB_NB_DELAY) && lng > 0)
462 			break;
463 	}
464 
465 	if (i > DLYB_CFGR_UNIT_MAX)
466 		return -EINVAL;
467 
468 	dlyb->unit = i;
469 	dlyb->max = __fls(lng);
470 
471 	return 0;
472 }
473 
474 static int sdmmc_dlyb_phase_tuning(struct mmci_host *host, u32 opcode)
475 {
476 	struct sdmmc_dlyb *dlyb = host->variant_priv;
477 	int cur_len = 0, max_len = 0, end_of_len = 0;
478 	int phase;
479 
480 	for (phase = 0; phase <= dlyb->max; phase++) {
481 		sdmmc_dlyb_set_cfgr(dlyb, dlyb->unit, phase, false);
482 
483 		if (mmc_send_tuning(host->mmc, opcode, NULL)) {
484 			cur_len = 0;
485 		} else {
486 			cur_len++;
487 			if (cur_len > max_len) {
488 				max_len = cur_len;
489 				end_of_len = phase;
490 			}
491 		}
492 	}
493 
494 	if (!max_len) {
495 		dev_err(mmc_dev(host->mmc), "no tuning point found\n");
496 		return -EINVAL;
497 	}
498 
499 	writel_relaxed(0, dlyb->base + DLYB_CR);
500 
501 	phase = end_of_len - max_len / 2;
502 	sdmmc_dlyb_set_cfgr(dlyb, dlyb->unit, phase, false);
503 
504 	dev_dbg(mmc_dev(host->mmc), "unit:%d max_dly:%d phase:%d\n",
505 		dlyb->unit, dlyb->max, phase);
506 
507 	return 0;
508 }
509 
510 static int sdmmc_execute_tuning(struct mmc_host *mmc, u32 opcode)
511 {
512 	struct mmci_host *host = mmc_priv(mmc);
513 	struct sdmmc_dlyb *dlyb = host->variant_priv;
514 
515 	if (!dlyb || !dlyb->base)
516 		return -EINVAL;
517 
518 	if (sdmmc_dlyb_lng_tuning(host))
519 		return -EINVAL;
520 
521 	return sdmmc_dlyb_phase_tuning(host, opcode);
522 }
523 
524 static void sdmmc_pre_sig_volt_vswitch(struct mmci_host *host)
525 {
526 	/* clear the voltage switch completion flag */
527 	writel_relaxed(MCI_STM32_VSWENDC, host->base + MMCICLEAR);
528 	/* enable Voltage switch procedure */
529 	mmci_write_pwrreg(host, host->pwr_reg | MCI_STM32_VSWITCHEN);
530 }
531 
532 static int sdmmc_post_sig_volt_switch(struct mmci_host *host,
533 				      struct mmc_ios *ios)
534 {
535 	unsigned long flags;
536 	u32 status;
537 	int ret = 0;
538 
539 	spin_lock_irqsave(&host->lock, flags);
540 	if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180 &&
541 	    host->pwr_reg & MCI_STM32_VSWITCHEN) {
542 		mmci_write_pwrreg(host, host->pwr_reg | MCI_STM32_VSWITCH);
543 		spin_unlock_irqrestore(&host->lock, flags);
544 
545 		/* wait voltage switch completion while 10ms */
546 		ret = readl_relaxed_poll_timeout(host->base + MMCISTATUS,
547 						 status,
548 						 (status & MCI_STM32_VSWEND),
549 						 10, SDMMC_VSWEND_TIMEOUT_US);
550 
551 		writel_relaxed(MCI_STM32_VSWENDC | MCI_STM32_CKSTOPC,
552 			       host->base + MMCICLEAR);
553 		spin_lock_irqsave(&host->lock, flags);
554 		mmci_write_pwrreg(host, host->pwr_reg &
555 				  ~(MCI_STM32_VSWITCHEN | MCI_STM32_VSWITCH));
556 	}
557 	spin_unlock_irqrestore(&host->lock, flags);
558 
559 	return ret;
560 }
561 
562 static struct mmci_host_ops sdmmc_variant_ops = {
563 	.validate_data = sdmmc_idma_validate_data,
564 	.prep_data = sdmmc_idma_prep_data,
565 	.unprep_data = sdmmc_idma_unprep_data,
566 	.get_datactrl_cfg = sdmmc_get_dctrl_cfg,
567 	.dma_setup = sdmmc_idma_setup,
568 	.dma_start = sdmmc_idma_start,
569 	.dma_finalize = sdmmc_idma_finalize,
570 	.set_clkreg = mmci_sdmmc_set_clkreg,
571 	.set_pwrreg = mmci_sdmmc_set_pwrreg,
572 	.busy_complete = sdmmc_busy_complete,
573 	.pre_sig_volt_switch = sdmmc_pre_sig_volt_vswitch,
574 	.post_sig_volt_switch = sdmmc_post_sig_volt_switch,
575 };
576 
577 void sdmmc_variant_init(struct mmci_host *host)
578 {
579 	struct device_node *np = host->mmc->parent->of_node;
580 	void __iomem *base_dlyb;
581 	struct sdmmc_dlyb *dlyb;
582 
583 	host->ops = &sdmmc_variant_ops;
584 	host->pwr_reg = readl_relaxed(host->base + MMCIPOWER);
585 
586 	base_dlyb = devm_of_iomap(mmc_dev(host->mmc), np, 1, NULL);
587 	if (IS_ERR(base_dlyb))
588 		return;
589 
590 	dlyb = devm_kzalloc(mmc_dev(host->mmc), sizeof(*dlyb), GFP_KERNEL);
591 	if (!dlyb)
592 		return;
593 
594 	dlyb->base = base_dlyb;
595 	host->variant_priv = dlyb;
596 	host->mmc_ops->execute_tuning = sdmmc_execute_tuning;
597 }
598