xref: /openbmc/u-boot/drivers/mmc/tegra_mmc.c (revision 7ca6f363)
1 /*
2  * (C) Copyright 2009 SAMSUNG Electronics
3  * Minkyu Kang <mk7.kang@samsung.com>
4  * Jaehoon Chung <jh80.chung@samsung.com>
5  * Portions Copyright 2011-2013 NVIDIA Corporation
6  *
7  * SPDX-License-Identifier:	GPL-2.0+
8  */
9 
10 #include <bouncebuf.h>
11 #include <common.h>
12 #include <asm/gpio.h>
13 #include <asm/io.h>
14 #include <asm/arch/clock.h>
15 #include <asm/arch-tegra/clk_rst.h>
16 #include <asm/arch-tegra/tegra_mmc.h>
17 #include <mmc.h>
18 
19 DECLARE_GLOBAL_DATA_PTR;
20 
21 struct mmc mmc_dev[MAX_HOSTS];
22 struct mmc_host mmc_host[MAX_HOSTS];
23 
24 #ifndef CONFIG_OF_CONTROL
25 #error "Please enable device tree support to use this driver"
26 #endif
27 
28 static void mmc_set_power(struct mmc_host *host, unsigned short power)
29 {
30 	u8 pwr = 0;
31 	debug("%s: power = %x\n", __func__, power);
32 
33 	if (power != (unsigned short)-1) {
34 		switch (1 << power) {
35 		case MMC_VDD_165_195:
36 			pwr = TEGRA_MMC_PWRCTL_SD_BUS_VOLTAGE_V1_8;
37 			break;
38 		case MMC_VDD_29_30:
39 		case MMC_VDD_30_31:
40 			pwr = TEGRA_MMC_PWRCTL_SD_BUS_VOLTAGE_V3_0;
41 			break;
42 		case MMC_VDD_32_33:
43 		case MMC_VDD_33_34:
44 			pwr = TEGRA_MMC_PWRCTL_SD_BUS_VOLTAGE_V3_3;
45 			break;
46 		}
47 	}
48 	debug("%s: pwr = %X\n", __func__, pwr);
49 
50 	/* Set the bus voltage first (if any) */
51 	writeb(pwr, &host->reg->pwrcon);
52 	if (pwr == 0)
53 		return;
54 
55 	/* Now enable bus power */
56 	pwr |= TEGRA_MMC_PWRCTL_SD_BUS_POWER;
57 	writeb(pwr, &host->reg->pwrcon);
58 }
59 
60 static void mmc_prepare_data(struct mmc_host *host, struct mmc_data *data,
61 				struct bounce_buffer *bbstate)
62 {
63 	unsigned char ctrl;
64 
65 
66 	debug("buf: %p (%p), data->blocks: %u, data->blocksize: %u\n",
67 		bbstate->bounce_buffer, bbstate->user_buffer, data->blocks,
68 		data->blocksize);
69 
70 	writel((u32)bbstate->bounce_buffer, &host->reg->sysad);
71 	/*
72 	 * DMASEL[4:3]
73 	 * 00 = Selects SDMA
74 	 * 01 = Reserved
75 	 * 10 = Selects 32-bit Address ADMA2
76 	 * 11 = Selects 64-bit Address ADMA2
77 	 */
78 	ctrl = readb(&host->reg->hostctl);
79 	ctrl &= ~TEGRA_MMC_HOSTCTL_DMASEL_MASK;
80 	ctrl |= TEGRA_MMC_HOSTCTL_DMASEL_SDMA;
81 	writeb(ctrl, &host->reg->hostctl);
82 
83 	/* We do not handle DMA boundaries, so set it to max (512 KiB) */
84 	writew((7 << 12) | (data->blocksize & 0xFFF), &host->reg->blksize);
85 	writew(data->blocks, &host->reg->blkcnt);
86 }
87 
88 static void mmc_set_transfer_mode(struct mmc_host *host, struct mmc_data *data)
89 {
90 	unsigned short mode;
91 	debug(" mmc_set_transfer_mode called\n");
92 	/*
93 	 * TRNMOD
94 	 * MUL1SIN0[5]	: Multi/Single Block Select
95 	 * RD1WT0[4]	: Data Transfer Direction Select
96 	 *	1 = read
97 	 *	0 = write
98 	 * ENACMD12[2]	: Auto CMD12 Enable
99 	 * ENBLKCNT[1]	: Block Count Enable
100 	 * ENDMA[0]	: DMA Enable
101 	 */
102 	mode = (TEGRA_MMC_TRNMOD_DMA_ENABLE |
103 		TEGRA_MMC_TRNMOD_BLOCK_COUNT_ENABLE);
104 
105 	if (data->blocks > 1)
106 		mode |= TEGRA_MMC_TRNMOD_MULTI_BLOCK_SELECT;
107 
108 	if (data->flags & MMC_DATA_READ)
109 		mode |= TEGRA_MMC_TRNMOD_DATA_XFER_DIR_SEL_READ;
110 
111 	writew(mode, &host->reg->trnmod);
112 }
113 
114 static int mmc_wait_inhibit(struct mmc_host *host,
115 			    struct mmc_cmd *cmd,
116 			    struct mmc_data *data,
117 			    unsigned int timeout)
118 {
119 	/*
120 	 * PRNSTS
121 	 * CMDINHDAT[1] : Command Inhibit (DAT)
122 	 * CMDINHCMD[0] : Command Inhibit (CMD)
123 	 */
124 	unsigned int mask = TEGRA_MMC_PRNSTS_CMD_INHIBIT_CMD;
125 
126 	/*
127 	 * We shouldn't wait for data inhibit for stop commands, even
128 	 * though they might use busy signaling
129 	 */
130 	if ((data == NULL) && (cmd->resp_type & MMC_RSP_BUSY))
131 		mask |= TEGRA_MMC_PRNSTS_CMD_INHIBIT_DAT;
132 
133 	while (readl(&host->reg->prnsts) & mask) {
134 		if (timeout == 0) {
135 			printf("%s: timeout error\n", __func__);
136 			return -1;
137 		}
138 		timeout--;
139 		udelay(1000);
140 	}
141 
142 	return 0;
143 }
144 
145 static int mmc_send_cmd_bounced(struct mmc *mmc, struct mmc_cmd *cmd,
146 			struct mmc_data *data, struct bounce_buffer *bbstate)
147 {
148 	struct mmc_host *host = (struct mmc_host *)mmc->priv;
149 	int flags, i;
150 	int result;
151 	unsigned int mask = 0;
152 	unsigned int retry = 0x100000;
153 	debug(" mmc_send_cmd called\n");
154 
155 	result = mmc_wait_inhibit(host, cmd, data, 10 /* ms */);
156 
157 	if (result < 0)
158 		return result;
159 
160 	if (data)
161 		mmc_prepare_data(host, data, bbstate);
162 
163 	debug("cmd->arg: %08x\n", cmd->cmdarg);
164 	writel(cmd->cmdarg, &host->reg->argument);
165 
166 	if (data)
167 		mmc_set_transfer_mode(host, data);
168 
169 	if ((cmd->resp_type & MMC_RSP_136) && (cmd->resp_type & MMC_RSP_BUSY))
170 		return -1;
171 
172 	/*
173 	 * CMDREG
174 	 * CMDIDX[13:8]	: Command index
175 	 * DATAPRNT[5]	: Data Present Select
176 	 * ENCMDIDX[4]	: Command Index Check Enable
177 	 * ENCMDCRC[3]	: Command CRC Check Enable
178 	 * RSPTYP[1:0]
179 	 *	00 = No Response
180 	 *	01 = Length 136
181 	 *	10 = Length 48
182 	 *	11 = Length 48 Check busy after response
183 	 */
184 	if (!(cmd->resp_type & MMC_RSP_PRESENT))
185 		flags = TEGRA_MMC_CMDREG_RESP_TYPE_SELECT_NO_RESPONSE;
186 	else if (cmd->resp_type & MMC_RSP_136)
187 		flags = TEGRA_MMC_CMDREG_RESP_TYPE_SELECT_LENGTH_136;
188 	else if (cmd->resp_type & MMC_RSP_BUSY)
189 		flags = TEGRA_MMC_CMDREG_RESP_TYPE_SELECT_LENGTH_48_BUSY;
190 	else
191 		flags = TEGRA_MMC_CMDREG_RESP_TYPE_SELECT_LENGTH_48;
192 
193 	if (cmd->resp_type & MMC_RSP_CRC)
194 		flags |= TEGRA_MMC_TRNMOD_CMD_CRC_CHECK;
195 	if (cmd->resp_type & MMC_RSP_OPCODE)
196 		flags |= TEGRA_MMC_TRNMOD_CMD_INDEX_CHECK;
197 	if (data)
198 		flags |= TEGRA_MMC_TRNMOD_DATA_PRESENT_SELECT_DATA_TRANSFER;
199 
200 	debug("cmd: %d\n", cmd->cmdidx);
201 
202 	writew((cmd->cmdidx << 8) | flags, &host->reg->cmdreg);
203 
204 	for (i = 0; i < retry; i++) {
205 		mask = readl(&host->reg->norintsts);
206 		/* Command Complete */
207 		if (mask & TEGRA_MMC_NORINTSTS_CMD_COMPLETE) {
208 			if (!data)
209 				writel(mask, &host->reg->norintsts);
210 			break;
211 		}
212 	}
213 
214 	if (i == retry) {
215 		printf("%s: waiting for status update\n", __func__);
216 		writel(mask, &host->reg->norintsts);
217 		return TIMEOUT;
218 	}
219 
220 	if (mask & TEGRA_MMC_NORINTSTS_CMD_TIMEOUT) {
221 		/* Timeout Error */
222 		debug("timeout: %08x cmd %d\n", mask, cmd->cmdidx);
223 		writel(mask, &host->reg->norintsts);
224 		return TIMEOUT;
225 	} else if (mask & TEGRA_MMC_NORINTSTS_ERR_INTERRUPT) {
226 		/* Error Interrupt */
227 		debug("error: %08x cmd %d\n", mask, cmd->cmdidx);
228 		writel(mask, &host->reg->norintsts);
229 		return -1;
230 	}
231 
232 	if (cmd->resp_type & MMC_RSP_PRESENT) {
233 		if (cmd->resp_type & MMC_RSP_136) {
234 			/* CRC is stripped so we need to do some shifting. */
235 			for (i = 0; i < 4; i++) {
236 				unsigned int offset =
237 					(unsigned int)(&host->reg->rspreg3 - i);
238 				cmd->response[i] = readl(offset) << 8;
239 
240 				if (i != 3) {
241 					cmd->response[i] |=
242 						readb(offset - 1);
243 				}
244 				debug("cmd->resp[%d]: %08x\n",
245 						i, cmd->response[i]);
246 			}
247 		} else if (cmd->resp_type & MMC_RSP_BUSY) {
248 			for (i = 0; i < retry; i++) {
249 				/* PRNTDATA[23:20] : DAT[3:0] Line Signal */
250 				if (readl(&host->reg->prnsts)
251 					& (1 << 20))	/* DAT[0] */
252 					break;
253 			}
254 
255 			if (i == retry) {
256 				printf("%s: card is still busy\n", __func__);
257 				writel(mask, &host->reg->norintsts);
258 				return TIMEOUT;
259 			}
260 
261 			cmd->response[0] = readl(&host->reg->rspreg0);
262 			debug("cmd->resp[0]: %08x\n", cmd->response[0]);
263 		} else {
264 			cmd->response[0] = readl(&host->reg->rspreg0);
265 			debug("cmd->resp[0]: %08x\n", cmd->response[0]);
266 		}
267 	}
268 
269 	if (data) {
270 		unsigned long	start = get_timer(0);
271 
272 		while (1) {
273 			mask = readl(&host->reg->norintsts);
274 
275 			if (mask & TEGRA_MMC_NORINTSTS_ERR_INTERRUPT) {
276 				/* Error Interrupt */
277 				writel(mask, &host->reg->norintsts);
278 				printf("%s: error during transfer: 0x%08x\n",
279 						__func__, mask);
280 				return -1;
281 			} else if (mask & TEGRA_MMC_NORINTSTS_DMA_INTERRUPT) {
282 				/*
283 				 * DMA Interrupt, restart the transfer where
284 				 * it was interrupted.
285 				 */
286 				unsigned int address = readl(&host->reg->sysad);
287 
288 				debug("DMA end\n");
289 				writel(TEGRA_MMC_NORINTSTS_DMA_INTERRUPT,
290 				       &host->reg->norintsts);
291 				writel(address, &host->reg->sysad);
292 			} else if (mask & TEGRA_MMC_NORINTSTS_XFER_COMPLETE) {
293 				/* Transfer Complete */
294 				debug("r/w is done\n");
295 				break;
296 			} else if (get_timer(start) > 2000UL) {
297 				writel(mask, &host->reg->norintsts);
298 				printf("%s: MMC Timeout\n"
299 				       "    Interrupt status        0x%08x\n"
300 				       "    Interrupt status enable 0x%08x\n"
301 				       "    Interrupt signal enable 0x%08x\n"
302 				       "    Present status          0x%08x\n",
303 				       __func__, mask,
304 				       readl(&host->reg->norintstsen),
305 				       readl(&host->reg->norintsigen),
306 				       readl(&host->reg->prnsts));
307 				return -1;
308 			}
309 		}
310 		writel(mask, &host->reg->norintsts);
311 	}
312 
313 	udelay(1000);
314 	return 0;
315 }
316 
317 static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
318 			struct mmc_data *data)
319 {
320 	void *buf;
321 	unsigned int bbflags;
322 	size_t len;
323 	struct bounce_buffer bbstate;
324 	int ret;
325 
326 	if (data) {
327 		if (data->flags & MMC_DATA_READ) {
328 			buf = data->dest;
329 			bbflags = GEN_BB_WRITE;
330 		} else {
331 			buf = (void *)data->src;
332 			bbflags = GEN_BB_READ;
333 		}
334 		len = data->blocks * data->blocksize;
335 
336 		bounce_buffer_start(&bbstate, buf, len, bbflags);
337 	}
338 
339 	ret = mmc_send_cmd_bounced(mmc, cmd, data, &bbstate);
340 
341 	if (data)
342 		bounce_buffer_stop(&bbstate);
343 
344 	return ret;
345 }
346 
347 static void mmc_change_clock(struct mmc_host *host, uint clock)
348 {
349 	int div;
350 	unsigned short clk;
351 	unsigned long timeout;
352 
353 	debug(" mmc_change_clock called\n");
354 
355 	/*
356 	 * Change Tegra SDMMCx clock divisor here. Source is PLLP_OUT0
357 	 */
358 	if (clock == 0)
359 		goto out;
360 	clock_adjust_periph_pll_div(host->mmc_id, CLOCK_ID_PERIPH, clock,
361 				    &div);
362 	debug("div = %d\n", div);
363 
364 	writew(0, &host->reg->clkcon);
365 
366 	/*
367 	 * CLKCON
368 	 * SELFREQ[15:8]	: base clock divided by value
369 	 * ENSDCLK[2]		: SD Clock Enable
370 	 * STBLINTCLK[1]	: Internal Clock Stable
371 	 * ENINTCLK[0]		: Internal Clock Enable
372 	 */
373 	div >>= 1;
374 	clk = ((div << TEGRA_MMC_CLKCON_SDCLK_FREQ_SEL_SHIFT) |
375 	       TEGRA_MMC_CLKCON_INTERNAL_CLOCK_ENABLE);
376 	writew(clk, &host->reg->clkcon);
377 
378 	/* Wait max 10 ms */
379 	timeout = 10;
380 	while (!(readw(&host->reg->clkcon) &
381 		 TEGRA_MMC_CLKCON_INTERNAL_CLOCK_STABLE)) {
382 		if (timeout == 0) {
383 			printf("%s: timeout error\n", __func__);
384 			return;
385 		}
386 		timeout--;
387 		udelay(1000);
388 	}
389 
390 	clk |= TEGRA_MMC_CLKCON_SD_CLOCK_ENABLE;
391 	writew(clk, &host->reg->clkcon);
392 
393 	debug("mmc_change_clock: clkcon = %08X\n", clk);
394 
395 out:
396 	host->clock = clock;
397 }
398 
399 static void mmc_set_ios(struct mmc *mmc)
400 {
401 	struct mmc_host *host = mmc->priv;
402 	unsigned char ctrl;
403 	debug(" mmc_set_ios called\n");
404 
405 	debug("bus_width: %x, clock: %d\n", mmc->bus_width, mmc->clock);
406 
407 	/* Change clock first */
408 	mmc_change_clock(host, mmc->clock);
409 
410 	ctrl = readb(&host->reg->hostctl);
411 
412 	/*
413 	 * WIDE8[5]
414 	 * 0 = Depend on WIDE4
415 	 * 1 = 8-bit mode
416 	 * WIDE4[1]
417 	 * 1 = 4-bit mode
418 	 * 0 = 1-bit mode
419 	 */
420 	if (mmc->bus_width == 8)
421 		ctrl |= (1 << 5);
422 	else if (mmc->bus_width == 4)
423 		ctrl |= (1 << 1);
424 	else
425 		ctrl &= ~(1 << 1);
426 
427 	writeb(ctrl, &host->reg->hostctl);
428 	debug("mmc_set_ios: hostctl = %08X\n", ctrl);
429 }
430 
431 static void mmc_reset(struct mmc_host *host, struct mmc *mmc)
432 {
433 	unsigned int timeout;
434 	debug(" mmc_reset called\n");
435 
436 	/*
437 	 * RSTALL[0] : Software reset for all
438 	 * 1 = reset
439 	 * 0 = work
440 	 */
441 	writeb(TEGRA_MMC_SWRST_SW_RESET_FOR_ALL, &host->reg->swrst);
442 
443 	host->clock = 0;
444 
445 	/* Wait max 100 ms */
446 	timeout = 100;
447 
448 	/* hw clears the bit when it's done */
449 	while (readb(&host->reg->swrst) & TEGRA_MMC_SWRST_SW_RESET_FOR_ALL) {
450 		if (timeout == 0) {
451 			printf("%s: timeout error\n", __func__);
452 			return;
453 		}
454 		timeout--;
455 		udelay(1000);
456 	}
457 
458 	/* Set SD bus voltage & enable bus power */
459 	mmc_set_power(host, fls(mmc->voltages) - 1);
460 	debug("%s: power control = %02X, host control = %02X\n", __func__,
461 		readb(&host->reg->pwrcon), readb(&host->reg->hostctl));
462 
463 	/* Make sure SDIO pads are set up */
464 	pad_init_mmc(host);
465 }
466 
467 static int mmc_core_init(struct mmc *mmc)
468 {
469 	struct mmc_host *host = (struct mmc_host *)mmc->priv;
470 	unsigned int mask;
471 	debug(" mmc_core_init called\n");
472 
473 	mmc_reset(host, mmc);
474 
475 	host->version = readw(&host->reg->hcver);
476 	debug("host version = %x\n", host->version);
477 
478 	/* mask all */
479 	writel(0xffffffff, &host->reg->norintstsen);
480 	writel(0xffffffff, &host->reg->norintsigen);
481 
482 	writeb(0xe, &host->reg->timeoutcon);	/* TMCLK * 2^27 */
483 	/*
484 	 * NORMAL Interrupt Status Enable Register init
485 	 * [5] ENSTABUFRDRDY : Buffer Read Ready Status Enable
486 	 * [4] ENSTABUFWTRDY : Buffer write Ready Status Enable
487 	 * [3] ENSTADMAINT   : DMA boundary interrupt
488 	 * [1] ENSTASTANSCMPLT : Transfre Complete Status Enable
489 	 * [0] ENSTACMDCMPLT : Command Complete Status Enable
490 	*/
491 	mask = readl(&host->reg->norintstsen);
492 	mask &= ~(0xffff);
493 	mask |= (TEGRA_MMC_NORINTSTSEN_CMD_COMPLETE |
494 		 TEGRA_MMC_NORINTSTSEN_XFER_COMPLETE |
495 		 TEGRA_MMC_NORINTSTSEN_DMA_INTERRUPT |
496 		 TEGRA_MMC_NORINTSTSEN_BUFFER_WRITE_READY |
497 		 TEGRA_MMC_NORINTSTSEN_BUFFER_READ_READY);
498 	writel(mask, &host->reg->norintstsen);
499 
500 	/*
501 	 * NORMAL Interrupt Signal Enable Register init
502 	 * [1] ENSTACMDCMPLT : Transfer Complete Signal Enable
503 	 */
504 	mask = readl(&host->reg->norintsigen);
505 	mask &= ~(0xffff);
506 	mask |= TEGRA_MMC_NORINTSIGEN_XFER_COMPLETE;
507 	writel(mask, &host->reg->norintsigen);
508 
509 	return 0;
510 }
511 
512 int tegra_mmc_getcd(struct mmc *mmc)
513 {
514 	struct mmc_host *host = (struct mmc_host *)mmc->priv;
515 
516 	debug("tegra_mmc_getcd called\n");
517 
518 	if (fdt_gpio_isvalid(&host->cd_gpio))
519 		return fdtdec_get_gpio(&host->cd_gpio);
520 
521 	return 1;
522 }
523 
524 static int do_mmc_init(int dev_index)
525 {
526 	struct mmc_host *host;
527 	char gpusage[12]; /* "SD/MMCn PWR" or "SD/MMCn CD" */
528 	struct mmc *mmc;
529 
530 	/* DT should have been read & host config filled in */
531 	host = &mmc_host[dev_index];
532 	if (!host->enabled)
533 		return -1;
534 
535 	debug(" do_mmc_init: index %d, bus width %d "
536 		"pwr_gpio %d cd_gpio %d\n",
537 		dev_index, host->width,
538 		host->pwr_gpio.gpio, host->cd_gpio.gpio);
539 
540 	host->clock = 0;
541 	clock_start_periph_pll(host->mmc_id, CLOCK_ID_PERIPH, 20000000);
542 
543 	if (fdt_gpio_isvalid(&host->pwr_gpio)) {
544 		sprintf(gpusage, "SD/MMC%d PWR", dev_index);
545 		gpio_request(host->pwr_gpio.gpio, gpusage);
546 		gpio_direction_output(host->pwr_gpio.gpio, 1);
547 		debug(" Power GPIO name = %s\n", host->pwr_gpio.name);
548 	}
549 
550 	if (fdt_gpio_isvalid(&host->cd_gpio)) {
551 		sprintf(gpusage, "SD/MMC%d CD", dev_index);
552 		gpio_request(host->cd_gpio.gpio, gpusage);
553 		gpio_direction_input(host->cd_gpio.gpio);
554 		debug(" CD GPIO name = %s\n", host->cd_gpio.name);
555 	}
556 
557 	mmc = &mmc_dev[dev_index];
558 
559 	sprintf(mmc->name, "Tegra SD/MMC");
560 	mmc->priv = host;
561 	mmc->send_cmd = mmc_send_cmd;
562 	mmc->set_ios = mmc_set_ios;
563 	mmc->init = mmc_core_init;
564 	mmc->getcd = tegra_mmc_getcd;
565 	mmc->getwp = NULL;
566 
567 	mmc->voltages = MMC_VDD_32_33 | MMC_VDD_33_34 | MMC_VDD_165_195;
568 	mmc->host_caps = 0;
569 	if (host->width == 8)
570 		mmc->host_caps |= MMC_MODE_8BIT;
571 	if (host->width >= 4)
572 		mmc->host_caps |= MMC_MODE_4BIT;
573 	mmc->host_caps |= MMC_MODE_HS_52MHz | MMC_MODE_HS | MMC_MODE_HC;
574 
575 	/*
576 	 * min freq is for card identification, and is the highest
577 	 *  low-speed SDIO card frequency (actually 400KHz)
578 	 * max freq is highest HS eMMC clock as per the SD/MMC spec
579 	 *  (actually 52MHz)
580 	 */
581 	mmc->f_min = 375000;
582 	mmc->f_max = 48000000;
583 
584 	mmc_register(mmc);
585 
586 	return 0;
587 }
588 
589 /**
590  * Get the host address and peripheral ID for a node.
591  *
592  * @param blob		fdt blob
593  * @param node		Device index (0-3)
594  * @param host		Structure to fill in (reg, width, mmc_id)
595  */
596 static int mmc_get_config(const void *blob, int node, struct mmc_host *host)
597 {
598 	debug("%s: node = %d\n", __func__, node);
599 
600 	host->enabled = fdtdec_get_is_enabled(blob, node);
601 
602 	host->reg = (struct tegra_mmc *)fdtdec_get_addr(blob, node, "reg");
603 	if ((fdt_addr_t)host->reg == FDT_ADDR_T_NONE) {
604 		debug("%s: no sdmmc base reg info found\n", __func__);
605 		return -FDT_ERR_NOTFOUND;
606 	}
607 
608 	host->mmc_id = clock_decode_periph_id(blob, node);
609 	if (host->mmc_id == PERIPH_ID_NONE) {
610 		debug("%s: could not decode periph id\n", __func__);
611 		return -FDT_ERR_NOTFOUND;
612 	}
613 
614 	/*
615 	 * NOTE: mmc->bus_width is determined by mmc.c dynamically.
616 	 * TBD: Override it with this value?
617 	 */
618 	host->width = fdtdec_get_int(blob, node, "bus-width", 0);
619 	if (!host->width)
620 		debug("%s: no sdmmc width found\n", __func__);
621 
622 	/* These GPIOs are optional */
623 	fdtdec_decode_gpio(blob, node, "cd-gpios", &host->cd_gpio);
624 	fdtdec_decode_gpio(blob, node, "wp-gpios", &host->wp_gpio);
625 	fdtdec_decode_gpio(blob, node, "power-gpios", &host->pwr_gpio);
626 
627 	debug("%s: found controller at %p, width = %d, periph_id = %d\n",
628 		__func__, host->reg, host->width, host->mmc_id);
629 	return 0;
630 }
631 
632 /*
633  * Process a list of nodes, adding them to our list of SDMMC ports.
634  *
635  * @param blob          fdt blob
636  * @param node_list     list of nodes to process (any <=0 are ignored)
637  * @param count         number of nodes to process
638  * @return 0 if ok, -1 on error
639  */
640 static int process_nodes(const void *blob, int node_list[], int count)
641 {
642 	struct mmc_host *host;
643 	int i, node;
644 
645 	debug("%s: count = %d\n", __func__, count);
646 
647 	/* build mmc_host[] for each controller */
648 	for (i = 0; i < count; i++) {
649 		node = node_list[i];
650 		if (node <= 0)
651 			continue;
652 
653 		host = &mmc_host[i];
654 		host->id = i;
655 
656 		if (mmc_get_config(blob, node, host)) {
657 			printf("%s: failed to decode dev %d\n",	__func__, i);
658 			return -1;
659 		}
660 		do_mmc_init(i);
661 	}
662 	return 0;
663 }
664 
665 void tegra_mmc_init(void)
666 {
667 	int node_list[MAX_HOSTS], count;
668 	const void *blob = gd->fdt_blob;
669 	debug("%s entry\n", __func__);
670 
671 	/* See if any Tegra124 MMC controllers are present */
672 	count = fdtdec_find_aliases_for_id(blob, "sdhci",
673 		COMPAT_NVIDIA_TEGRA124_SDMMC, node_list, MAX_HOSTS);
674 	debug("%s: count of Tegra124 sdhci nodes is %d\n", __func__, count);
675 	if (process_nodes(blob, node_list, count)) {
676 		printf("%s: Error processing T30 mmc node(s)!\n", __func__);
677 		return;
678 	}
679 
680 	/* See if any Tegra30 MMC controllers are present */
681 	count = fdtdec_find_aliases_for_id(blob, "sdhci",
682 		COMPAT_NVIDIA_TEGRA30_SDMMC, node_list, MAX_HOSTS);
683 	debug("%s: count of T30 sdhci nodes is %d\n", __func__, count);
684 	if (process_nodes(blob, node_list, count)) {
685 		printf("%s: Error processing T30 mmc node(s)!\n", __func__);
686 		return;
687 	}
688 
689 	/* Now look for any Tegra20 MMC controllers */
690 	count = fdtdec_find_aliases_for_id(blob, "sdhci",
691 		COMPAT_NVIDIA_TEGRA20_SDMMC, node_list, MAX_HOSTS);
692 	debug("%s: count of T20 sdhci nodes is %d\n", __func__, count);
693 	if (process_nodes(blob, node_list, count)) {
694 		printf("%s: Error processing T20 mmc node(s)!\n", __func__);
695 		return;
696 	}
697 }
698