xref: /openbmc/linux/drivers/mmc/core/host.c (revision 2a598d0b)
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 and after first doing re-tuning.
123  */
124 void mmc_retune_pause(struct mmc_host *host)
125 {
126 	if (!host->retune_paused) {
127 		host->retune_paused = 1;
128 		mmc_retune_needed(host);
129 		mmc_retune_hold(host);
130 	}
131 }
132 EXPORT_SYMBOL(mmc_retune_pause);
133 
134 void mmc_retune_unpause(struct mmc_host *host)
135 {
136 	if (host->retune_paused) {
137 		host->retune_paused = 0;
138 		mmc_retune_release(host);
139 	}
140 }
141 EXPORT_SYMBOL(mmc_retune_unpause);
142 
143 /**
144  * mmc_retune_disable() - exit a transfer mode that requires retuning
145  * @host: host which should not retune anymore
146  *
147  * It is not meant for temporarily preventing retuning!
148  */
149 void mmc_retune_disable(struct mmc_host *host)
150 {
151 	mmc_retune_unpause(host);
152 	host->can_retune = 0;
153 	del_timer_sync(&host->retune_timer);
154 	mmc_retune_clear(host);
155 }
156 
157 void mmc_retune_timer_stop(struct mmc_host *host)
158 {
159 	del_timer_sync(&host->retune_timer);
160 }
161 EXPORT_SYMBOL(mmc_retune_timer_stop);
162 
163 void mmc_retune_hold(struct mmc_host *host)
164 {
165 	if (!host->hold_retune)
166 		host->retune_now = 1;
167 	host->hold_retune += 1;
168 }
169 
170 void mmc_retune_release(struct mmc_host *host)
171 {
172 	if (host->hold_retune)
173 		host->hold_retune -= 1;
174 	else
175 		WARN_ON(1);
176 }
177 EXPORT_SYMBOL(mmc_retune_release);
178 
179 int mmc_retune(struct mmc_host *host)
180 {
181 	bool return_to_hs400 = false;
182 	int err;
183 
184 	if (host->retune_now)
185 		host->retune_now = 0;
186 	else
187 		return 0;
188 
189 	if (!host->need_retune || host->doing_retune || !host->card)
190 		return 0;
191 
192 	host->need_retune = 0;
193 
194 	host->doing_retune = 1;
195 
196 	if (host->ios.timing == MMC_TIMING_MMC_HS400) {
197 		err = mmc_hs400_to_hs200(host->card);
198 		if (err)
199 			goto out;
200 
201 		return_to_hs400 = true;
202 	}
203 
204 	err = mmc_execute_tuning(host->card);
205 	if (err)
206 		goto out;
207 
208 	if (return_to_hs400)
209 		err = mmc_hs200_to_hs400(host->card);
210 out:
211 	host->doing_retune = 0;
212 
213 	return err;
214 }
215 
216 static void mmc_retune_timer(struct timer_list *t)
217 {
218 	struct mmc_host *host = from_timer(host, t, retune_timer);
219 
220 	mmc_retune_needed(host);
221 }
222 
223 static void mmc_of_parse_timing_phase(struct device *dev, const char *prop,
224 				      struct mmc_clk_phase *phase)
225 {
226 	int degrees[2] = {0};
227 	int rc;
228 
229 	rc = device_property_read_u32_array(dev, prop, degrees, 2);
230 	phase->valid = !rc;
231 	if (phase->valid) {
232 		phase->in_deg = degrees[0];
233 		phase->out_deg = degrees[1];
234 	}
235 }
236 
237 void
238 mmc_of_parse_clk_phase(struct mmc_host *host, struct mmc_clk_phase_map *map)
239 {
240 	struct device *dev = host->parent;
241 
242 	mmc_of_parse_timing_phase(dev, "clk-phase-legacy",
243 				  &map->phase[MMC_TIMING_LEGACY]);
244 	mmc_of_parse_timing_phase(dev, "clk-phase-mmc-hs",
245 				  &map->phase[MMC_TIMING_MMC_HS]);
246 	mmc_of_parse_timing_phase(dev, "clk-phase-sd-hs",
247 				  &map->phase[MMC_TIMING_SD_HS]);
248 	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr12",
249 				  &map->phase[MMC_TIMING_UHS_SDR12]);
250 	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr25",
251 				  &map->phase[MMC_TIMING_UHS_SDR25]);
252 	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr50",
253 				  &map->phase[MMC_TIMING_UHS_SDR50]);
254 	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr104",
255 				  &map->phase[MMC_TIMING_UHS_SDR104]);
256 	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-ddr50",
257 				  &map->phase[MMC_TIMING_UHS_DDR50]);
258 	mmc_of_parse_timing_phase(dev, "clk-phase-mmc-ddr52",
259 				  &map->phase[MMC_TIMING_MMC_DDR52]);
260 	mmc_of_parse_timing_phase(dev, "clk-phase-mmc-hs200",
261 				  &map->phase[MMC_TIMING_MMC_HS200]);
262 	mmc_of_parse_timing_phase(dev, "clk-phase-mmc-hs400",
263 				  &map->phase[MMC_TIMING_MMC_HS400]);
264 }
265 EXPORT_SYMBOL(mmc_of_parse_clk_phase);
266 
267 /**
268  * mmc_of_parse() - parse host's device properties
269  * @host: host whose properties should be parsed.
270  *
271  * To keep the rest of the MMC subsystem unaware of whether DT has been
272  * used to instantiate and configure this host instance or not, we
273  * parse the properties and set respective generic mmc-host flags and
274  * parameters.
275  */
276 int mmc_of_parse(struct mmc_host *host)
277 {
278 	struct device *dev = host->parent;
279 	u32 bus_width, drv_type, cd_debounce_delay_ms;
280 	int ret;
281 
282 	if (!dev || !dev_fwnode(dev))
283 		return 0;
284 
285 	/* "bus-width" is translated to MMC_CAP_*_BIT_DATA flags */
286 	if (device_property_read_u32(dev, "bus-width", &bus_width) < 0) {
287 		dev_dbg(host->parent,
288 			"\"bus-width\" property is missing, assuming 1 bit.\n");
289 		bus_width = 1;
290 	}
291 
292 	switch (bus_width) {
293 	case 8:
294 		host->caps |= MMC_CAP_8_BIT_DATA;
295 		fallthrough;	/* Hosts capable of 8-bit can also do 4 bits */
296 	case 4:
297 		host->caps |= MMC_CAP_4_BIT_DATA;
298 		break;
299 	case 1:
300 		break;
301 	default:
302 		dev_err(host->parent,
303 			"Invalid \"bus-width\" value %u!\n", bus_width);
304 		return -EINVAL;
305 	}
306 
307 	/* f_max is obtained from the optional "max-frequency" property */
308 	device_property_read_u32(dev, "max-frequency", &host->f_max);
309 
310 	/*
311 	 * Configure CD and WP pins. They are both by default active low to
312 	 * match the SDHCI spec. If GPIOs are provided for CD and / or WP, the
313 	 * mmc-gpio helpers are used to attach, configure and use them. If
314 	 * polarity inversion is specified in DT, one of MMC_CAP2_CD_ACTIVE_HIGH
315 	 * and MMC_CAP2_RO_ACTIVE_HIGH capability-2 flags is set. If the
316 	 * "broken-cd" property is provided, the MMC_CAP_NEEDS_POLL capability
317 	 * is set. If the "non-removable" property is found, the
318 	 * MMC_CAP_NONREMOVABLE capability is set and no card-detection
319 	 * configuration is performed.
320 	 */
321 
322 	/* Parse Card Detection */
323 
324 	if (device_property_read_bool(dev, "non-removable")) {
325 		host->caps |= MMC_CAP_NONREMOVABLE;
326 	} else {
327 		if (device_property_read_bool(dev, "cd-inverted"))
328 			host->caps2 |= MMC_CAP2_CD_ACTIVE_HIGH;
329 
330 		if (device_property_read_u32(dev, "cd-debounce-delay-ms",
331 					     &cd_debounce_delay_ms))
332 			cd_debounce_delay_ms = 200;
333 
334 		if (device_property_read_bool(dev, "broken-cd"))
335 			host->caps |= MMC_CAP_NEEDS_POLL;
336 
337 		ret = mmc_gpiod_request_cd(host, "cd", 0, false,
338 					   cd_debounce_delay_ms * 1000);
339 		if (!ret)
340 			dev_info(host->parent, "Got CD GPIO\n");
341 		else if (ret != -ENOENT && ret != -ENOSYS)
342 			return ret;
343 	}
344 
345 	/* Parse Write Protection */
346 
347 	if (device_property_read_bool(dev, "wp-inverted"))
348 		host->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH;
349 
350 	ret = mmc_gpiod_request_ro(host, "wp", 0, 0);
351 	if (!ret)
352 		dev_info(host->parent, "Got WP GPIO\n");
353 	else if (ret != -ENOENT && ret != -ENOSYS)
354 		return ret;
355 
356 	if (device_property_read_bool(dev, "disable-wp"))
357 		host->caps2 |= MMC_CAP2_NO_WRITE_PROTECT;
358 
359 	if (device_property_read_bool(dev, "cap-sd-highspeed"))
360 		host->caps |= MMC_CAP_SD_HIGHSPEED;
361 	if (device_property_read_bool(dev, "cap-mmc-highspeed"))
362 		host->caps |= MMC_CAP_MMC_HIGHSPEED;
363 	if (device_property_read_bool(dev, "sd-uhs-sdr12"))
364 		host->caps |= MMC_CAP_UHS_SDR12;
365 	if (device_property_read_bool(dev, "sd-uhs-sdr25"))
366 		host->caps |= MMC_CAP_UHS_SDR25;
367 	if (device_property_read_bool(dev, "sd-uhs-sdr50"))
368 		host->caps |= MMC_CAP_UHS_SDR50;
369 	if (device_property_read_bool(dev, "sd-uhs-sdr104"))
370 		host->caps |= MMC_CAP_UHS_SDR104;
371 	if (device_property_read_bool(dev, "sd-uhs-ddr50"))
372 		host->caps |= MMC_CAP_UHS_DDR50;
373 	if (device_property_read_bool(dev, "cap-power-off-card"))
374 		host->caps |= MMC_CAP_POWER_OFF_CARD;
375 	if (device_property_read_bool(dev, "cap-mmc-hw-reset"))
376 		host->caps |= MMC_CAP_HW_RESET;
377 	if (device_property_read_bool(dev, "cap-sdio-irq"))
378 		host->caps |= MMC_CAP_SDIO_IRQ;
379 	if (device_property_read_bool(dev, "full-pwr-cycle"))
380 		host->caps2 |= MMC_CAP2_FULL_PWR_CYCLE;
381 	if (device_property_read_bool(dev, "full-pwr-cycle-in-suspend"))
382 		host->caps2 |= MMC_CAP2_FULL_PWR_CYCLE_IN_SUSPEND;
383 	if (device_property_read_bool(dev, "keep-power-in-suspend"))
384 		host->pm_caps |= MMC_PM_KEEP_POWER;
385 	if (device_property_read_bool(dev, "wakeup-source") ||
386 	    device_property_read_bool(dev, "enable-sdio-wakeup")) /* legacy */
387 		host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
388 	if (device_property_read_bool(dev, "mmc-ddr-3_3v"))
389 		host->caps |= MMC_CAP_3_3V_DDR;
390 	if (device_property_read_bool(dev, "mmc-ddr-1_8v"))
391 		host->caps |= MMC_CAP_1_8V_DDR;
392 	if (device_property_read_bool(dev, "mmc-ddr-1_2v"))
393 		host->caps |= MMC_CAP_1_2V_DDR;
394 	if (device_property_read_bool(dev, "mmc-hs200-1_8v"))
395 		host->caps2 |= MMC_CAP2_HS200_1_8V_SDR;
396 	if (device_property_read_bool(dev, "mmc-hs200-1_2v"))
397 		host->caps2 |= MMC_CAP2_HS200_1_2V_SDR;
398 	if (device_property_read_bool(dev, "mmc-hs400-1_8v"))
399 		host->caps2 |= MMC_CAP2_HS400_1_8V | MMC_CAP2_HS200_1_8V_SDR;
400 	if (device_property_read_bool(dev, "mmc-hs400-1_2v"))
401 		host->caps2 |= MMC_CAP2_HS400_1_2V | MMC_CAP2_HS200_1_2V_SDR;
402 	if (device_property_read_bool(dev, "mmc-hs400-enhanced-strobe"))
403 		host->caps2 |= MMC_CAP2_HS400_ES;
404 	if (device_property_read_bool(dev, "no-sdio"))
405 		host->caps2 |= MMC_CAP2_NO_SDIO;
406 	if (device_property_read_bool(dev, "no-sd"))
407 		host->caps2 |= MMC_CAP2_NO_SD;
408 	if (device_property_read_bool(dev, "no-mmc"))
409 		host->caps2 |= MMC_CAP2_NO_MMC;
410 	if (device_property_read_bool(dev, "no-mmc-hs400"))
411 		host->caps2 &= ~(MMC_CAP2_HS400_1_8V | MMC_CAP2_HS400_1_2V |
412 				 MMC_CAP2_HS400_ES);
413 
414 	/* Must be after "non-removable" check */
415 	if (device_property_read_u32(dev, "fixed-emmc-driver-type", &drv_type) == 0) {
416 		if (host->caps & MMC_CAP_NONREMOVABLE)
417 			host->fixed_drv_type = drv_type;
418 		else
419 			dev_err(host->parent,
420 				"can't use fixed driver type, media is removable\n");
421 	}
422 
423 	host->dsr_req = !device_property_read_u32(dev, "dsr", &host->dsr);
424 	if (host->dsr_req && (host->dsr & ~0xffff)) {
425 		dev_err(host->parent,
426 			"device tree specified broken value for DSR: 0x%x, ignoring\n",
427 			host->dsr);
428 		host->dsr_req = 0;
429 	}
430 
431 	device_property_read_u32(dev, "post-power-on-delay-ms",
432 				 &host->ios.power_delay_ms);
433 
434 	return mmc_pwrseq_alloc(host);
435 }
436 
437 EXPORT_SYMBOL(mmc_of_parse);
438 
439 /**
440  * mmc_of_parse_voltage - return mask of supported voltages
441  * @host: host whose properties should be parsed.
442  * @mask: mask of voltages available for MMC/SD/SDIO
443  *
444  * Parse the "voltage-ranges" property, returning zero if it is not
445  * found, negative errno if the voltage-range specification is invalid,
446  * or one if the voltage-range is specified and successfully parsed.
447  */
448 int mmc_of_parse_voltage(struct mmc_host *host, u32 *mask)
449 {
450 	const char *prop = "voltage-ranges";
451 	struct device *dev = host->parent;
452 	u32 *voltage_ranges;
453 	int num_ranges, i;
454 	int ret;
455 
456 	if (!device_property_present(dev, prop)) {
457 		dev_dbg(dev, "%s unspecified\n", prop);
458 		return 0;
459 	}
460 
461 	ret = device_property_count_u32(dev, prop);
462 	if (ret < 0)
463 		return ret;
464 
465 	num_ranges = ret / 2;
466 	if (!num_ranges) {
467 		dev_err(dev, "%s empty\n", prop);
468 		return -EINVAL;
469 	}
470 
471 	voltage_ranges = kcalloc(2 * num_ranges, sizeof(*voltage_ranges), GFP_KERNEL);
472 	if (!voltage_ranges)
473 		return -ENOMEM;
474 
475 	ret = device_property_read_u32_array(dev, prop, voltage_ranges, 2 * num_ranges);
476 	if (ret) {
477 		kfree(voltage_ranges);
478 		return ret;
479 	}
480 
481 	for (i = 0; i < num_ranges; i++) {
482 		const int j = i * 2;
483 		u32 ocr_mask;
484 
485 		ocr_mask = mmc_vddrange_to_ocrmask(voltage_ranges[j + 0],
486 						   voltage_ranges[j + 1]);
487 		if (!ocr_mask) {
488 			dev_err(dev, "range #%d in %s is invalid\n", i, prop);
489 			kfree(voltage_ranges);
490 			return -EINVAL;
491 		}
492 		*mask |= ocr_mask;
493 	}
494 
495 	kfree(voltage_ranges);
496 
497 	return 1;
498 }
499 EXPORT_SYMBOL(mmc_of_parse_voltage);
500 
501 /**
502  * mmc_first_nonreserved_index() - get the first index that is not reserved
503  */
504 static int mmc_first_nonreserved_index(void)
505 {
506 	int max;
507 
508 	max = of_alias_get_highest_id("mmc");
509 	if (max < 0)
510 		return 0;
511 
512 	return max + 1;
513 }
514 
515 /**
516  *	mmc_alloc_host - initialise the per-host structure.
517  *	@extra: sizeof private data structure
518  *	@dev: pointer to host device model structure
519  *
520  *	Initialise the per-host structure.
521  */
522 struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
523 {
524 	int index;
525 	struct mmc_host *host;
526 	int alias_id, min_idx, max_idx;
527 
528 	host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
529 	if (!host)
530 		return NULL;
531 
532 	/* scanning will be enabled when we're ready */
533 	host->rescan_disable = 1;
534 
535 	alias_id = of_alias_get_id(dev->of_node, "mmc");
536 	if (alias_id >= 0) {
537 		index = alias_id;
538 	} else {
539 		min_idx = mmc_first_nonreserved_index();
540 		max_idx = 0;
541 
542 		index = ida_simple_get(&mmc_host_ida, min_idx, max_idx, GFP_KERNEL);
543 		if (index < 0) {
544 			kfree(host);
545 			return NULL;
546 		}
547 	}
548 
549 	host->index = index;
550 
551 	dev_set_name(&host->class_dev, "mmc%d", host->index);
552 	host->ws = wakeup_source_register(NULL, dev_name(&host->class_dev));
553 
554 	host->parent = dev;
555 	host->class_dev.parent = dev;
556 	host->class_dev.class = &mmc_host_class;
557 	device_initialize(&host->class_dev);
558 	device_enable_async_suspend(&host->class_dev);
559 
560 	if (mmc_gpio_alloc(host)) {
561 		put_device(&host->class_dev);
562 		return NULL;
563 	}
564 
565 	spin_lock_init(&host->lock);
566 	init_waitqueue_head(&host->wq);
567 	INIT_DELAYED_WORK(&host->detect, mmc_rescan);
568 	INIT_WORK(&host->sdio_irq_work, sdio_irq_work);
569 	timer_setup(&host->retune_timer, mmc_retune_timer, 0);
570 
571 	/*
572 	 * By default, hosts do not support SGIO or large requests.
573 	 * They have to set these according to their abilities.
574 	 */
575 	host->max_segs = 1;
576 	host->max_seg_size = PAGE_SIZE;
577 
578 	host->max_req_size = PAGE_SIZE;
579 	host->max_blk_size = 512;
580 	host->max_blk_count = PAGE_SIZE / 512;
581 
582 	host->fixed_drv_type = -EINVAL;
583 	host->ios.power_delay_ms = 10;
584 	host->ios.power_mode = MMC_POWER_UNDEFINED;
585 
586 	return host;
587 }
588 
589 EXPORT_SYMBOL(mmc_alloc_host);
590 
591 static void devm_mmc_host_release(struct device *dev, void *res)
592 {
593 	mmc_free_host(*(struct mmc_host **)res);
594 }
595 
596 struct mmc_host *devm_mmc_alloc_host(struct device *dev, int extra)
597 {
598 	struct mmc_host **dr, *host;
599 
600 	dr = devres_alloc(devm_mmc_host_release, sizeof(*dr), GFP_KERNEL);
601 	if (!dr)
602 		return NULL;
603 
604 	host = mmc_alloc_host(extra, dev);
605 	if (!host) {
606 		devres_free(dr);
607 		return NULL;
608 	}
609 
610 	*dr = host;
611 	devres_add(dev, dr);
612 
613 	return host;
614 }
615 EXPORT_SYMBOL(devm_mmc_alloc_host);
616 
617 static int mmc_validate_host_caps(struct mmc_host *host)
618 {
619 	struct device *dev = host->parent;
620 	u32 caps = host->caps, caps2 = host->caps2;
621 
622 	if (caps & MMC_CAP_SDIO_IRQ && !host->ops->enable_sdio_irq) {
623 		dev_warn(dev, "missing ->enable_sdio_irq() ops\n");
624 		return -EINVAL;
625 	}
626 
627 	if (caps2 & (MMC_CAP2_HS400_ES | MMC_CAP2_HS400) &&
628 	    !(caps & MMC_CAP_8_BIT_DATA) && !(caps2 & MMC_CAP2_NO_MMC)) {
629 		dev_warn(dev, "drop HS400 support since no 8-bit bus\n");
630 		host->caps2 = caps2 & ~MMC_CAP2_HS400_ES & ~MMC_CAP2_HS400;
631 	}
632 
633 	return 0;
634 }
635 
636 /**
637  *	mmc_add_host - initialise host hardware
638  *	@host: mmc host
639  *
640  *	Register the host with the driver model. The host must be
641  *	prepared to start servicing requests before this function
642  *	completes.
643  */
644 int mmc_add_host(struct mmc_host *host)
645 {
646 	int err;
647 
648 	err = mmc_validate_host_caps(host);
649 	if (err)
650 		return err;
651 
652 	err = device_add(&host->class_dev);
653 	if (err)
654 		return err;
655 
656 	led_trigger_register_simple(dev_name(&host->class_dev), &host->led);
657 
658 	mmc_add_host_debugfs(host);
659 
660 	mmc_start_host(host);
661 	return 0;
662 }
663 
664 EXPORT_SYMBOL(mmc_add_host);
665 
666 /**
667  *	mmc_remove_host - remove host hardware
668  *	@host: mmc host
669  *
670  *	Unregister and remove all cards associated with this host,
671  *	and power down the MMC bus. No new requests will be issued
672  *	after this function has returned.
673  */
674 void mmc_remove_host(struct mmc_host *host)
675 {
676 	mmc_stop_host(host);
677 
678 	mmc_remove_host_debugfs(host);
679 
680 	device_del(&host->class_dev);
681 
682 	led_trigger_unregister_simple(host->led);
683 }
684 
685 EXPORT_SYMBOL(mmc_remove_host);
686 
687 /**
688  *	mmc_free_host - free the host structure
689  *	@host: mmc host
690  *
691  *	Free the host once all references to it have been dropped.
692  */
693 void mmc_free_host(struct mmc_host *host)
694 {
695 	mmc_pwrseq_free(host);
696 	put_device(&host->class_dev);
697 }
698 
699 EXPORT_SYMBOL(mmc_free_host);
700