xref: /linux/drivers/mmc/core/host.c (revision 6c7353836a91b1479e6b81791cdc163fb04b4834)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/drivers/mmc/core/host.c
4  *
5  *  Copyright (C) 2003 Russell King, All Rights Reserved.
6  *  Copyright (C) 2007-2008 Pierre Ossman
7  *  Copyright (C) 2010 Linus Walleij
8  *
9  *  MMC host class device management
10  */
11 
12 #include <linux/device.h>
13 #include <linux/err.h>
14 #include <linux/idr.h>
15 #include <linux/of.h>
16 #include <linux/of_gpio.h>
17 #include <linux/pagemap.h>
18 #include <linux/pm_wakeup.h>
19 #include <linux/export.h>
20 #include <linux/leds.h>
21 #include <linux/slab.h>
22 
23 #include <linux/mmc/host.h>
24 #include <linux/mmc/card.h>
25 #include <linux/mmc/slot-gpio.h>
26 
27 #include "core.h"
28 #include "crypto.h"
29 #include "host.h"
30 #include "slot-gpio.h"
31 #include "pwrseq.h"
32 #include "sdio_ops.h"
33 
34 #define cls_dev_to_mmc_host(d)	container_of(d, struct mmc_host, class_dev)
35 
36 static DEFINE_IDA(mmc_host_ida);
37 
38 #ifdef CONFIG_PM_SLEEP
39 static int mmc_host_class_prepare(struct device *dev)
40 {
41 	struct mmc_host *host = cls_dev_to_mmc_host(dev);
42 
43 	/*
44 	 * It's safe to access the bus_ops pointer, as both userspace and the
45 	 * workqueue for detecting cards are frozen at this point.
46 	 */
47 	if (!host->bus_ops)
48 		return 0;
49 
50 	/* Validate conditions for system suspend. */
51 	if (host->bus_ops->pre_suspend)
52 		return host->bus_ops->pre_suspend(host);
53 
54 	return 0;
55 }
56 
57 static void mmc_host_class_complete(struct device *dev)
58 {
59 	struct mmc_host *host = cls_dev_to_mmc_host(dev);
60 
61 	_mmc_detect_change(host, 0, false);
62 }
63 
64 static const struct dev_pm_ops mmc_host_class_dev_pm_ops = {
65 	.prepare = mmc_host_class_prepare,
66 	.complete = mmc_host_class_complete,
67 };
68 
69 #define MMC_HOST_CLASS_DEV_PM_OPS (&mmc_host_class_dev_pm_ops)
70 #else
71 #define MMC_HOST_CLASS_DEV_PM_OPS NULL
72 #endif
73 
74 static void mmc_host_classdev_release(struct device *dev)
75 {
76 	struct mmc_host *host = cls_dev_to_mmc_host(dev);
77 	wakeup_source_unregister(host->ws);
78 	if (of_alias_get_id(host->parent->of_node, "mmc") < 0)
79 		ida_simple_remove(&mmc_host_ida, host->index);
80 	kfree(host);
81 }
82 
83 static int mmc_host_classdev_shutdown(struct device *dev)
84 {
85 	struct mmc_host *host = cls_dev_to_mmc_host(dev);
86 
87 	__mmc_stop_host(host);
88 	return 0;
89 }
90 
91 static struct class mmc_host_class = {
92 	.name		= "mmc_host",
93 	.dev_release	= mmc_host_classdev_release,
94 	.shutdown_pre	= mmc_host_classdev_shutdown,
95 	.pm		= MMC_HOST_CLASS_DEV_PM_OPS,
96 };
97 
98 int mmc_register_host_class(void)
99 {
100 	return class_register(&mmc_host_class);
101 }
102 
103 void mmc_unregister_host_class(void)
104 {
105 	class_unregister(&mmc_host_class);
106 }
107 
108 /**
109  * mmc_retune_enable() - enter a transfer mode that requires retuning
110  * @host: host which should retune now
111  */
112 void mmc_retune_enable(struct mmc_host *host)
113 {
114 	host->can_retune = 1;
115 	if (host->retune_period)
116 		mod_timer(&host->retune_timer,
117 			  jiffies + host->retune_period * HZ);
118 }
119 
120 /*
121  * Pause re-tuning for a small set of operations.  The pause begins after the
122  * next command.
123  */
124 void mmc_retune_pause(struct mmc_host *host)
125 {
126 	if (!host->retune_paused) {
127 		host->retune_paused = 1;
128 		mmc_retune_hold(host);
129 	}
130 }
131 EXPORT_SYMBOL(mmc_retune_pause);
132 
133 void mmc_retune_unpause(struct mmc_host *host)
134 {
135 	if (host->retune_paused) {
136 		host->retune_paused = 0;
137 		mmc_retune_release(host);
138 	}
139 }
140 EXPORT_SYMBOL(mmc_retune_unpause);
141 
142 /**
143  * mmc_retune_disable() - exit a transfer mode that requires retuning
144  * @host: host which should not retune anymore
145  *
146  * It is not meant for temporarily preventing retuning!
147  */
148 void mmc_retune_disable(struct mmc_host *host)
149 {
150 	mmc_retune_unpause(host);
151 	host->can_retune = 0;
152 	del_timer_sync(&host->retune_timer);
153 	mmc_retune_clear(host);
154 }
155 
156 void mmc_retune_timer_stop(struct mmc_host *host)
157 {
158 	del_timer_sync(&host->retune_timer);
159 }
160 EXPORT_SYMBOL(mmc_retune_timer_stop);
161 
162 void mmc_retune_hold(struct mmc_host *host)
163 {
164 	if (!host->hold_retune)
165 		host->retune_now = 1;
166 	host->hold_retune += 1;
167 }
168 
169 void mmc_retune_release(struct mmc_host *host)
170 {
171 	if (host->hold_retune)
172 		host->hold_retune -= 1;
173 	else
174 		WARN_ON(1);
175 }
176 EXPORT_SYMBOL(mmc_retune_release);
177 
178 int mmc_retune(struct mmc_host *host)
179 {
180 	bool return_to_hs400 = false;
181 	int err;
182 
183 	if (host->retune_now)
184 		host->retune_now = 0;
185 	else
186 		return 0;
187 
188 	if (!host->need_retune || host->doing_retune || !host->card)
189 		return 0;
190 
191 	host->need_retune = 0;
192 
193 	host->doing_retune = 1;
194 
195 	if (host->ios.timing == MMC_TIMING_MMC_HS400) {
196 		err = mmc_hs400_to_hs200(host->card);
197 		if (err)
198 			goto out;
199 
200 		return_to_hs400 = true;
201 	}
202 
203 	err = mmc_execute_tuning(host->card);
204 	if (err)
205 		goto out;
206 
207 	if (return_to_hs400)
208 		err = mmc_hs200_to_hs400(host->card);
209 out:
210 	host->doing_retune = 0;
211 
212 	return err;
213 }
214 
215 static void mmc_retune_timer(struct timer_list *t)
216 {
217 	struct mmc_host *host = from_timer(host, t, retune_timer);
218 
219 	mmc_retune_needed(host);
220 }
221 
222 static void mmc_of_parse_timing_phase(struct device *dev, const char *prop,
223 				      struct mmc_clk_phase *phase)
224 {
225 	int degrees[2] = {0};
226 	int rc;
227 
228 	rc = device_property_read_u32_array(dev, prop, degrees, 2);
229 	phase->valid = !rc;
230 	if (phase->valid) {
231 		phase->in_deg = degrees[0];
232 		phase->out_deg = degrees[1];
233 	}
234 }
235 
236 void
237 mmc_of_parse_clk_phase(struct mmc_host *host, struct mmc_clk_phase_map *map)
238 {
239 	struct device *dev = host->parent;
240 
241 	mmc_of_parse_timing_phase(dev, "clk-phase-legacy",
242 				  &map->phase[MMC_TIMING_LEGACY]);
243 	mmc_of_parse_timing_phase(dev, "clk-phase-mmc-hs",
244 				  &map->phase[MMC_TIMING_MMC_HS]);
245 	mmc_of_parse_timing_phase(dev, "clk-phase-sd-hs",
246 				  &map->phase[MMC_TIMING_SD_HS]);
247 	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr12",
248 				  &map->phase[MMC_TIMING_UHS_SDR12]);
249 	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr25",
250 				  &map->phase[MMC_TIMING_UHS_SDR25]);
251 	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr50",
252 				  &map->phase[MMC_TIMING_UHS_SDR50]);
253 	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr104",
254 				  &map->phase[MMC_TIMING_UHS_SDR104]);
255 	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-ddr50",
256 				  &map->phase[MMC_TIMING_UHS_DDR50]);
257 	mmc_of_parse_timing_phase(dev, "clk-phase-mmc-ddr52",
258 				  &map->phase[MMC_TIMING_MMC_DDR52]);
259 	mmc_of_parse_timing_phase(dev, "clk-phase-mmc-hs200",
260 				  &map->phase[MMC_TIMING_MMC_HS200]);
261 	mmc_of_parse_timing_phase(dev, "clk-phase-mmc-hs400",
262 				  &map->phase[MMC_TIMING_MMC_HS400]);
263 }
264 EXPORT_SYMBOL(mmc_of_parse_clk_phase);
265 
266 /**
267  * mmc_of_parse() - parse host's device properties
268  * @host: host whose properties should be parsed.
269  *
270  * To keep the rest of the MMC subsystem unaware of whether DT has been
271  * used to instantiate and configure this host instance or not, we
272  * parse the properties and set respective generic mmc-host flags and
273  * parameters.
274  */
275 int mmc_of_parse(struct mmc_host *host)
276 {
277 	struct device *dev = host->parent;
278 	u32 bus_width, drv_type, cd_debounce_delay_ms;
279 	int ret;
280 
281 	if (!dev || !dev_fwnode(dev))
282 		return 0;
283 
284 	/* "bus-width" is translated to MMC_CAP_*_BIT_DATA flags */
285 	if (device_property_read_u32(dev, "bus-width", &bus_width) < 0) {
286 		dev_dbg(host->parent,
287 			"\"bus-width\" property is missing, assuming 1 bit.\n");
288 		bus_width = 1;
289 	}
290 
291 	switch (bus_width) {
292 	case 8:
293 		host->caps |= MMC_CAP_8_BIT_DATA;
294 		fallthrough;	/* Hosts capable of 8-bit can also do 4 bits */
295 	case 4:
296 		host->caps |= MMC_CAP_4_BIT_DATA;
297 		break;
298 	case 1:
299 		break;
300 	default:
301 		dev_err(host->parent,
302 			"Invalid \"bus-width\" value %u!\n", bus_width);
303 		return -EINVAL;
304 	}
305 
306 	/* f_max is obtained from the optional "max-frequency" property */
307 	device_property_read_u32(dev, "max-frequency", &host->f_max);
308 
309 	/*
310 	 * Configure CD and WP pins. They are both by default active low to
311 	 * match the SDHCI spec. If GPIOs are provided for CD and / or WP, the
312 	 * mmc-gpio helpers are used to attach, configure and use them. If
313 	 * polarity inversion is specified in DT, one of MMC_CAP2_CD_ACTIVE_HIGH
314 	 * and MMC_CAP2_RO_ACTIVE_HIGH capability-2 flags is set. If the
315 	 * "broken-cd" property is provided, the MMC_CAP_NEEDS_POLL capability
316 	 * is set. If the "non-removable" property is found, the
317 	 * MMC_CAP_NONREMOVABLE capability is set and no card-detection
318 	 * configuration is performed.
319 	 */
320 
321 	/* Parse Card Detection */
322 
323 	if (device_property_read_bool(dev, "non-removable")) {
324 		host->caps |= MMC_CAP_NONREMOVABLE;
325 	} else {
326 		if (device_property_read_bool(dev, "cd-inverted"))
327 			host->caps2 |= MMC_CAP2_CD_ACTIVE_HIGH;
328 
329 		if (device_property_read_u32(dev, "cd-debounce-delay-ms",
330 					     &cd_debounce_delay_ms))
331 			cd_debounce_delay_ms = 200;
332 
333 		if (device_property_read_bool(dev, "broken-cd"))
334 			host->caps |= MMC_CAP_NEEDS_POLL;
335 
336 		ret = mmc_gpiod_request_cd(host, "cd", 0, false,
337 					   cd_debounce_delay_ms * 1000);
338 		if (!ret)
339 			dev_info(host->parent, "Got CD GPIO\n");
340 		else if (ret != -ENOENT && ret != -ENOSYS)
341 			return ret;
342 	}
343 
344 	/* Parse Write Protection */
345 
346 	if (device_property_read_bool(dev, "wp-inverted"))
347 		host->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH;
348 
349 	ret = mmc_gpiod_request_ro(host, "wp", 0, 0);
350 	if (!ret)
351 		dev_info(host->parent, "Got WP GPIO\n");
352 	else if (ret != -ENOENT && ret != -ENOSYS)
353 		return ret;
354 
355 	if (device_property_read_bool(dev, "disable-wp"))
356 		host->caps2 |= MMC_CAP2_NO_WRITE_PROTECT;
357 
358 	if (device_property_read_bool(dev, "cap-sd-highspeed"))
359 		host->caps |= MMC_CAP_SD_HIGHSPEED;
360 	if (device_property_read_bool(dev, "cap-mmc-highspeed"))
361 		host->caps |= MMC_CAP_MMC_HIGHSPEED;
362 	if (device_property_read_bool(dev, "sd-uhs-sdr12"))
363 		host->caps |= MMC_CAP_UHS_SDR12;
364 	if (device_property_read_bool(dev, "sd-uhs-sdr25"))
365 		host->caps |= MMC_CAP_UHS_SDR25;
366 	if (device_property_read_bool(dev, "sd-uhs-sdr50"))
367 		host->caps |= MMC_CAP_UHS_SDR50;
368 	if (device_property_read_bool(dev, "sd-uhs-sdr104"))
369 		host->caps |= MMC_CAP_UHS_SDR104;
370 	if (device_property_read_bool(dev, "sd-uhs-ddr50"))
371 		host->caps |= MMC_CAP_UHS_DDR50;
372 	if (device_property_read_bool(dev, "cap-power-off-card"))
373 		host->caps |= MMC_CAP_POWER_OFF_CARD;
374 	if (device_property_read_bool(dev, "cap-mmc-hw-reset"))
375 		host->caps |= MMC_CAP_HW_RESET;
376 	if (device_property_read_bool(dev, "cap-sdio-irq"))
377 		host->caps |= MMC_CAP_SDIO_IRQ;
378 	if (device_property_read_bool(dev, "full-pwr-cycle"))
379 		host->caps2 |= MMC_CAP2_FULL_PWR_CYCLE;
380 	if (device_property_read_bool(dev, "full-pwr-cycle-in-suspend"))
381 		host->caps2 |= MMC_CAP2_FULL_PWR_CYCLE_IN_SUSPEND;
382 	if (device_property_read_bool(dev, "keep-power-in-suspend"))
383 		host->pm_caps |= MMC_PM_KEEP_POWER;
384 	if (device_property_read_bool(dev, "wakeup-source") ||
385 	    device_property_read_bool(dev, "enable-sdio-wakeup")) /* legacy */
386 		host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
387 	if (device_property_read_bool(dev, "mmc-ddr-3_3v"))
388 		host->caps |= MMC_CAP_3_3V_DDR;
389 	if (device_property_read_bool(dev, "mmc-ddr-1_8v"))
390 		host->caps |= MMC_CAP_1_8V_DDR;
391 	if (device_property_read_bool(dev, "mmc-ddr-1_2v"))
392 		host->caps |= MMC_CAP_1_2V_DDR;
393 	if (device_property_read_bool(dev, "mmc-hs200-1_8v"))
394 		host->caps2 |= MMC_CAP2_HS200_1_8V_SDR;
395 	if (device_property_read_bool(dev, "mmc-hs200-1_2v"))
396 		host->caps2 |= MMC_CAP2_HS200_1_2V_SDR;
397 	if (device_property_read_bool(dev, "mmc-hs400-1_8v"))
398 		host->caps2 |= MMC_CAP2_HS400_1_8V | MMC_CAP2_HS200_1_8V_SDR;
399 	if (device_property_read_bool(dev, "mmc-hs400-1_2v"))
400 		host->caps2 |= MMC_CAP2_HS400_1_2V | MMC_CAP2_HS200_1_2V_SDR;
401 	if (device_property_read_bool(dev, "mmc-hs400-enhanced-strobe"))
402 		host->caps2 |= MMC_CAP2_HS400_ES;
403 	if (device_property_read_bool(dev, "no-sdio"))
404 		host->caps2 |= MMC_CAP2_NO_SDIO;
405 	if (device_property_read_bool(dev, "no-sd"))
406 		host->caps2 |= MMC_CAP2_NO_SD;
407 	if (device_property_read_bool(dev, "no-mmc"))
408 		host->caps2 |= MMC_CAP2_NO_MMC;
409 	if (device_property_read_bool(dev, "no-mmc-hs400"))
410 		host->caps2 &= ~(MMC_CAP2_HS400_1_8V | MMC_CAP2_HS400_1_2V |
411 				 MMC_CAP2_HS400_ES);
412 
413 	/* Must be after "non-removable" check */
414 	if (device_property_read_u32(dev, "fixed-emmc-driver-type", &drv_type) == 0) {
415 		if (host->caps & MMC_CAP_NONREMOVABLE)
416 			host->fixed_drv_type = drv_type;
417 		else
418 			dev_err(host->parent,
419 				"can't use fixed driver type, media is removable\n");
420 	}
421 
422 	host->dsr_req = !device_property_read_u32(dev, "dsr", &host->dsr);
423 	if (host->dsr_req && (host->dsr & ~0xffff)) {
424 		dev_err(host->parent,
425 			"device tree specified broken value for DSR: 0x%x, ignoring\n",
426 			host->dsr);
427 		host->dsr_req = 0;
428 	}
429 
430 	device_property_read_u32(dev, "post-power-on-delay-ms",
431 				 &host->ios.power_delay_ms);
432 
433 	return mmc_pwrseq_alloc(host);
434 }
435 
436 EXPORT_SYMBOL(mmc_of_parse);
437 
438 /**
439  * mmc_of_parse_voltage - return mask of supported voltages
440  * @host: host whose properties should be parsed.
441  * @mask: mask of voltages available for MMC/SD/SDIO
442  *
443  * Parse the "voltage-ranges" property, returning zero if it is not
444  * found, negative errno if the voltage-range specification is invalid,
445  * or one if the voltage-range is specified and successfully parsed.
446  */
447 int mmc_of_parse_voltage(struct mmc_host *host, u32 *mask)
448 {
449 	const char *prop = "voltage-ranges";
450 	struct device *dev = host->parent;
451 	u32 *voltage_ranges;
452 	int num_ranges, i;
453 	int ret;
454 
455 	if (!device_property_present(dev, prop)) {
456 		dev_dbg(dev, "%s unspecified\n", prop);
457 		return 0;
458 	}
459 
460 	ret = device_property_count_u32(dev, prop);
461 	if (ret < 0)
462 		return ret;
463 
464 	num_ranges = ret / 2;
465 	if (!num_ranges) {
466 		dev_err(dev, "%s empty\n", prop);
467 		return -EINVAL;
468 	}
469 
470 	voltage_ranges = kcalloc(2 * num_ranges, sizeof(*voltage_ranges), GFP_KERNEL);
471 	if (!voltage_ranges)
472 		return -ENOMEM;
473 
474 	ret = device_property_read_u32_array(dev, prop, voltage_ranges, 2 * num_ranges);
475 	if (ret) {
476 		kfree(voltage_ranges);
477 		return ret;
478 	}
479 
480 	for (i = 0; i < num_ranges; i++) {
481 		const int j = i * 2;
482 		u32 ocr_mask;
483 
484 		ocr_mask = mmc_vddrange_to_ocrmask(voltage_ranges[j + 0],
485 						   voltage_ranges[j + 1]);
486 		if (!ocr_mask) {
487 			dev_err(dev, "range #%d in %s is invalid\n", i, prop);
488 			kfree(voltage_ranges);
489 			return -EINVAL;
490 		}
491 		*mask |= ocr_mask;
492 	}
493 
494 	kfree(voltage_ranges);
495 
496 	return 1;
497 }
498 EXPORT_SYMBOL(mmc_of_parse_voltage);
499 
500 /**
501  * mmc_first_nonreserved_index() - get the first index that is not reserved
502  */
503 static int mmc_first_nonreserved_index(void)
504 {
505 	int max;
506 
507 	max = of_alias_get_highest_id("mmc");
508 	if (max < 0)
509 		return 0;
510 
511 	return max + 1;
512 }
513 
514 /**
515  *	mmc_alloc_host - initialise the per-host structure.
516  *	@extra: sizeof private data structure
517  *	@dev: pointer to host device model structure
518  *
519  *	Initialise the per-host structure.
520  */
521 struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
522 {
523 	int index;
524 	struct mmc_host *host;
525 	int alias_id, min_idx, max_idx;
526 
527 	host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
528 	if (!host)
529 		return NULL;
530 
531 	/* scanning will be enabled when we're ready */
532 	host->rescan_disable = 1;
533 
534 	alias_id = of_alias_get_id(dev->of_node, "mmc");
535 	if (alias_id >= 0) {
536 		index = alias_id;
537 	} else {
538 		min_idx = mmc_first_nonreserved_index();
539 		max_idx = 0;
540 
541 		index = ida_simple_get(&mmc_host_ida, min_idx, max_idx, GFP_KERNEL);
542 		if (index < 0) {
543 			kfree(host);
544 			return NULL;
545 		}
546 	}
547 
548 	host->index = index;
549 
550 	dev_set_name(&host->class_dev, "mmc%d", host->index);
551 	host->ws = wakeup_source_register(NULL, dev_name(&host->class_dev));
552 
553 	host->parent = dev;
554 	host->class_dev.parent = dev;
555 	host->class_dev.class = &mmc_host_class;
556 	device_initialize(&host->class_dev);
557 	device_enable_async_suspend(&host->class_dev);
558 
559 	if (mmc_gpio_alloc(host)) {
560 		put_device(&host->class_dev);
561 		return NULL;
562 	}
563 
564 	spin_lock_init(&host->lock);
565 	init_waitqueue_head(&host->wq);
566 	INIT_DELAYED_WORK(&host->detect, mmc_rescan);
567 	INIT_WORK(&host->sdio_irq_work, sdio_irq_work);
568 	timer_setup(&host->retune_timer, mmc_retune_timer, 0);
569 
570 	/*
571 	 * By default, hosts do not support SGIO or large requests.
572 	 * They have to set these according to their abilities.
573 	 */
574 	host->max_segs = 1;
575 	host->max_seg_size = PAGE_SIZE;
576 
577 	host->max_req_size = PAGE_SIZE;
578 	host->max_blk_size = 512;
579 	host->max_blk_count = PAGE_SIZE / 512;
580 
581 	host->fixed_drv_type = -EINVAL;
582 	host->ios.power_delay_ms = 10;
583 	host->ios.power_mode = MMC_POWER_UNDEFINED;
584 
585 	return host;
586 }
587 
588 EXPORT_SYMBOL(mmc_alloc_host);
589 
590 static void devm_mmc_host_release(struct device *dev, void *res)
591 {
592 	mmc_free_host(*(struct mmc_host **)res);
593 }
594 
595 struct mmc_host *devm_mmc_alloc_host(struct device *dev, int extra)
596 {
597 	struct mmc_host **dr, *host;
598 
599 	dr = devres_alloc(devm_mmc_host_release, sizeof(*dr), GFP_KERNEL);
600 	if (!dr)
601 		return NULL;
602 
603 	host = mmc_alloc_host(extra, dev);
604 	if (!host) {
605 		devres_free(dr);
606 		return NULL;
607 	}
608 
609 	*dr = host;
610 	devres_add(dev, dr);
611 
612 	return host;
613 }
614 EXPORT_SYMBOL(devm_mmc_alloc_host);
615 
616 static int mmc_validate_host_caps(struct mmc_host *host)
617 {
618 	struct device *dev = host->parent;
619 	u32 caps = host->caps, caps2 = host->caps2;
620 
621 	if (caps & MMC_CAP_SDIO_IRQ && !host->ops->enable_sdio_irq) {
622 		dev_warn(dev, "missing ->enable_sdio_irq() ops\n");
623 		return -EINVAL;
624 	}
625 
626 	if (caps2 & (MMC_CAP2_HS400_ES | MMC_CAP2_HS400) &&
627 	    !(caps & MMC_CAP_8_BIT_DATA) && !(caps2 & MMC_CAP2_NO_MMC)) {
628 		dev_warn(dev, "drop HS400 support since no 8-bit bus\n");
629 		host->caps2 = caps2 & ~MMC_CAP2_HS400_ES & ~MMC_CAP2_HS400;
630 	}
631 
632 	return 0;
633 }
634 
635 /**
636  *	mmc_add_host - initialise host hardware
637  *	@host: mmc host
638  *
639  *	Register the host with the driver model. The host must be
640  *	prepared to start servicing requests before this function
641  *	completes.
642  */
643 int mmc_add_host(struct mmc_host *host)
644 {
645 	int err;
646 
647 	err = mmc_validate_host_caps(host);
648 	if (err)
649 		return err;
650 
651 	err = device_add(&host->class_dev);
652 	if (err)
653 		return err;
654 
655 	led_trigger_register_simple(dev_name(&host->class_dev), &host->led);
656 
657 	mmc_add_host_debugfs(host);
658 
659 	mmc_start_host(host);
660 	return 0;
661 }
662 
663 EXPORT_SYMBOL(mmc_add_host);
664 
665 /**
666  *	mmc_remove_host - remove host hardware
667  *	@host: mmc host
668  *
669  *	Unregister and remove all cards associated with this host,
670  *	and power down the MMC bus. No new requests will be issued
671  *	after this function has returned.
672  */
673 void mmc_remove_host(struct mmc_host *host)
674 {
675 	mmc_stop_host(host);
676 
677 	mmc_remove_host_debugfs(host);
678 
679 	device_del(&host->class_dev);
680 
681 	led_trigger_unregister_simple(host->led);
682 }
683 
684 EXPORT_SYMBOL(mmc_remove_host);
685 
686 /**
687  *	mmc_free_host - free the host structure
688  *	@host: mmc host
689  *
690  *	Free the host once all references to it have been dropped.
691  */
692 void mmc_free_host(struct mmc_host *host)
693 {
694 	cancel_delayed_work_sync(&host->detect);
695 	mmc_pwrseq_free(host);
696 	put_device(&host->class_dev);
697 }
698 
699 EXPORT_SYMBOL(mmc_free_host);
700