drivers/mmc/core/sd.c - kernel/msm-4.9 - Gitiles

 /*
  *  linux/drivers/mmc/core/sd.c
  *
  *  Copyright (C) 2003-2004 Russell King, All Rights Reserved.
  *  SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
  *  Copyright (C) 2005-2007 Pierre Ossman, All Rights Reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <linux/err.h>
 #include <linux/slab.h>

 #include <linux/mmc/host.h>
 #include <linux/mmc/card.h>
 #include <linux/mmc/mmc.h>
 #include <linux/mmc/sd.h>

 #include "core.h"
 #include "bus.h"
 #include "mmc_ops.h"
 #include "sd_ops.h"

 static const unsigned int tran_exp[] = {
 	10000,		100000,		1000000,	10000000,
 	0,		0,		0,		0
 };

 static const unsigned char tran_mant[] = {
 	0,	10,	12,	13,	15,	20,	25,	30,
 	35,	40,	45,	50,	55,	60,	70,	80,
 };

 static const unsigned int tacc_exp[] = {
 	1,	10,	100,	1000,	10000,	100000,	1000000, 10000000,
 };

 static const unsigned int tacc_mant[] = {
 	0,	10,	12,	13,	15,	20,	25,	30,
 	35,	40,	45,	50,	55,	60,	70,	80,
 };

 #define UNSTUFF_BITS(resp,start,size)					\
 	({								\
 		const int __size = size;				\
 		const u32 __mask = (__size < 32 ? 1 << __size : 0) - 1;	\
 		const int __off = 3 - ((start) / 32);			\
 		const int __shft = (start) & 31;			\
 		u32 __res;						\
 									\
 		__res = resp[__off] >> __shft;				\
 		if (__size + __shft > 32)				\
 			__res |= resp[__off-1] << ((32 - __shft) % 32);	\
 		__res & __mask;						\
 	})

 /*
  * Given the decoded CSD structure, decode the raw CID to our CID structure.
  */
 void mmc_decode_cid(struct mmc_card *card)
 {
 	u32 *resp = card->raw_cid;

 	memset(&card->cid, 0, sizeof(struct mmc_cid));

 	/*
 	 * SD doesn't currently have a version field so we will
 	 * have to assume we can parse this.
 	 */
 	card->cid.manfid		= UNSTUFF_BITS(resp, 120, 8);
 	card->cid.oemid			= UNSTUFF_BITS(resp, 104, 16);
 	card->cid.prod_name[0]		= UNSTUFF_BITS(resp, 96, 8);
 	card->cid.prod_name[1]		= UNSTUFF_BITS(resp, 88, 8);
 	card->cid.prod_name[2]		= UNSTUFF_BITS(resp, 80, 8);
 	card->cid.prod_name[3]		= UNSTUFF_BITS(resp, 72, 8);
 	card->cid.prod_name[4]		= UNSTUFF_BITS(resp, 64, 8);
 	card->cid.hwrev			= UNSTUFF_BITS(resp, 60, 4);
 	card->cid.fwrev			= UNSTUFF_BITS(resp, 56, 4);
 	card->cid.serial		= UNSTUFF_BITS(resp, 24, 32);
 	card->cid.year			= UNSTUFF_BITS(resp, 12, 8);
 	card->cid.month			= UNSTUFF_BITS(resp, 8, 4);

 	card->cid.year += 2000; /* SD cards year offset */
 }

 /*
  * Given a 128-bit response, decode to our card CSD structure.
  */
 static int mmc_decode_csd(struct mmc_card *card)
 {
 	struct mmc_csd *csd = &card->csd;
 	unsigned int e, m, csd_struct;
 	u32 *resp = card->raw_csd;

 	csd_struct = UNSTUFF_BITS(resp, 126, 2);

 	switch (csd_struct) {
 	case 0:
 		m = UNSTUFF_BITS(resp, 115, 4);
 		e = UNSTUFF_BITS(resp, 112, 3);
 		csd->tacc_ns	 = (tacc_exp[e] * tacc_mant[m] + 9) / 10;
 		csd->tacc_clks	 = UNSTUFF_BITS(resp, 104, 8) * 100;

 		m = UNSTUFF_BITS(resp, 99, 4);
 		e = UNSTUFF_BITS(resp, 96, 3);
 		csd->max_dtr	  = tran_exp[e] * tran_mant[m];
 		csd->cmdclass	  = UNSTUFF_BITS(resp, 84, 12);

 		e = UNSTUFF_BITS(resp, 47, 3);
 		m = UNSTUFF_BITS(resp, 62, 12);
 		csd->capacity	  = (1 + m) << (e + 2);

 		csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
 		csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
 		csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
 		csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
 		csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3);
 		csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
 		csd->write_partial = UNSTUFF_BITS(resp, 21, 1);

 		if (UNSTUFF_BITS(resp, 46, 1)) {
 			csd->erase_size = 1;
 		} else if (csd->write_blkbits >= 9) {
 			csd->erase_size = UNSTUFF_BITS(resp, 39, 7) + 1;
 			csd->erase_size <<= csd->write_blkbits - 9;
 		}
 		break;
 	case 1:
 		/*
 		 * This is a block-addressed SDHC card. Most
 		 * interesting fields are unused and have fixed
 		 * values. To avoid getting tripped by buggy cards,
 		 * we assume those fixed values ourselves.
 		 */
 		mmc_card_set_blockaddr(card);

 		csd->tacc_ns	 = 0; /* Unused */
 		csd->tacc_clks	 = 0; /* Unused */

 		m = UNSTUFF_BITS(resp, 99, 4);
 		e = UNSTUFF_BITS(resp, 96, 3);
 		csd->max_dtr	  = tran_exp[e] * tran_mant[m];
 		csd->cmdclass	  = UNSTUFF_BITS(resp, 84, 12);

 		m = UNSTUFF_BITS(resp, 48, 22);
 		csd->capacity     = (1 + m) << 10;

 		csd->read_blkbits = 9;
 		csd->read_partial = 0;
 		csd->write_misalign = 0;
 		csd->read_misalign = 0;
 		csd->r2w_factor = 4; /* Unused */
 		csd->write_blkbits = 9;
 		csd->write_partial = 0;
 		csd->erase_size = 1;
 		break;
 	default:
 		printk(KERN_ERR "%s: unrecognised CSD structure version %d\n",
 			mmc_hostname(card->host), csd_struct);
 		return -EINVAL;
 	}

 	card->erase_size = csd->erase_size;

 	return 0;
 }

 /*
  * Given a 64-bit response, decode to our card SCR structure.
  */
 static int mmc_decode_scr(struct mmc_card *card)
 {
 	struct sd_scr *scr = &card->scr;
 	unsigned int scr_struct;
 	u32 resp[4];

 	resp[3] = card->raw_scr[1];
 	resp[2] = card->raw_scr[0];

 	scr_struct = UNSTUFF_BITS(resp, 60, 4);
 	if (scr_struct != 0) {
 		printk(KERN_ERR "%s: unrecognised SCR structure version %d\n",
 			mmc_hostname(card->host), scr_struct);
 		return -EINVAL;
 	}

 	scr->sda_vsn = UNSTUFF_BITS(resp, 56, 4);
 	scr->bus_widths = UNSTUFF_BITS(resp, 48, 4);

 	if (UNSTUFF_BITS(resp, 55, 1))
 		card->erased_byte = 0xFF;
 	else
 		card->erased_byte = 0x0;

 	return 0;
 }

 /*
  * Fetch and process SD Status register.
  */
 static int mmc_read_ssr(struct mmc_card *card)
 {
 	unsigned int au, es, et, eo;
 	int err, i;
 	u32 *ssr;

 	if (!(card->csd.cmdclass & CCC_APP_SPEC)) {
 		printk(KERN_WARNING "%s: card lacks mandatory SD Status "
 			"function.\n", mmc_hostname(card->host));
 		return 0;
 	}

 	ssr = kmalloc(64, GFP_KERNEL);
 	if (!ssr)
 		return -ENOMEM;

 	err = mmc_app_sd_status(card, ssr);
 	if (err) {
 		printk(KERN_WARNING "%s: problem reading SD Status "
 			"register.\n", mmc_hostname(card->host));
 		err = 0;
 		goto out;
 	}

 	for (i = 0; i < 16; i++)
 		ssr[i] = be32_to_cpu(ssr[i]);

 	/*
 	 * UNSTUFF_BITS only works with four u32s so we have to offset the
 	 * bitfield positions accordingly.
 	 */
 	au = UNSTUFF_BITS(ssr, 428 - 384, 4);
 	if (au > 0 || au <= 9) {
 		card->ssr.au = 1 << (au + 4);
 		es = UNSTUFF_BITS(ssr, 408 - 384, 16);
 		et = UNSTUFF_BITS(ssr, 402 - 384, 6);
 		eo = UNSTUFF_BITS(ssr, 400 - 384, 2);
 		if (es && et) {
 			card->ssr.erase_timeout = (et * 1000) / es;
 			card->ssr.erase_offset = eo * 1000;
 		}
 	} else {
 		printk(KERN_WARNING "%s: SD Status: Invalid Allocation Unit "
 			"size.\n", mmc_hostname(card->host));
 	}
 out:
 	kfree(ssr);
 	return err;
 }

 /*
  * Fetches and decodes switch information
  */
 static int mmc_read_switch(struct mmc_card *card)
 {
 	int err;
 	u8 *status;

 	if (card->scr.sda_vsn < SCR_SPEC_VER_1)
 		return 0;

 	if (!(card->csd.cmdclass & CCC_SWITCH)) {
 		printk(KERN_WARNING "%s: card lacks mandatory switch "
 			"function, performance might suffer.\n",
 			mmc_hostname(card->host));
 		return 0;
 	}

 	err = -EIO;

 	status = kmalloc(64, GFP_KERNEL);
 	if (!status) {
 		printk(KERN_ERR "%s: could not allocate a buffer for "
 			"switch capabilities.\n", mmc_hostname(card->host));
 		return -ENOMEM;
 	}

 	err = mmc_sd_switch(card, 0, 0, 1, status);
 	if (err) {
 		/* If the host or the card can't do the switch,
 		 * fail more gracefully. */
 		if ((err != -EINVAL)
 		 && (err != -ENOSYS)
 		 && (err != -EFAULT))
 			goto out;

 		printk(KERN_WARNING "%s: problem reading switch "
 			"capabilities, performance might suffer.\n",
 			mmc_hostname(card->host));
 		err = 0;

 		goto out;
 	}

 	if (status[13] & 0x02)
 		card->sw_caps.hs_max_dtr = 50000000;

 out:
 	kfree(status);

 	return err;
 }

 /*
  * Test if the card supports high-speed mode and, if so, switch to it.
  */
 int mmc_sd_switch_hs(struct mmc_card *card)
 {
 	int err;
 	u8 *status;

 	if (card->scr.sda_vsn < SCR_SPEC_VER_1)
 		return 0;

 	if (!(card->csd.cmdclass & CCC_SWITCH))
 		return 0;

 	if (!(card->host->caps & MMC_CAP_SD_HIGHSPEED))
 		return 0;

 	if (card->sw_caps.hs_max_dtr == 0)
 		return 0;

 	err = -EIO;

 	status = kmalloc(64, GFP_KERNEL);
 	if (!status) {
 		printk(KERN_ERR "%s: could not allocate a buffer for "
 			"switch capabilities.\n", mmc_hostname(card->host));
 		return -ENOMEM;
 	}

 	err = mmc_sd_switch(card, 1, 0, 1, status);
 	if (err)
 		goto out;

 	if ((status[16] & 0xF) != 1) {
 		printk(KERN_WARNING "%s: Problem switching card "
 			"into high-speed mode!\n",
 			mmc_hostname(card->host));
 		err = 0;
 	} else {
 		err = 1;
 	}

 out:
 	kfree(status);

 	return err;
 }

 MMC_DEV_ATTR(cid, "%08x%08x%08x%08x\n", card->raw_cid[0], card->raw_cid[1],
 	card->raw_cid[2], card->raw_cid[3]);
 MMC_DEV_ATTR(csd, "%08x%08x%08x%08x\n", card->raw_csd[0], card->raw_csd[1],
 	card->raw_csd[2], card->raw_csd[3]);
 MMC_DEV_ATTR(scr, "%08x%08x\n", card->raw_scr[0], card->raw_scr[1]);
 MMC_DEV_ATTR(date, "%02d/%04d\n", card->cid.month, card->cid.year);
 MMC_DEV_ATTR(erase_size, "%u\n", card->erase_size << 9);
 MMC_DEV_ATTR(preferred_erase_size, "%u\n", card->pref_erase << 9);
 MMC_DEV_ATTR(fwrev, "0x%x\n", card->cid.fwrev);
 MMC_DEV_ATTR(hwrev, "0x%x\n", card->cid.hwrev);
 MMC_DEV_ATTR(manfid, "0x%06x\n", card->cid.manfid);
 MMC_DEV_ATTR(name, "%s\n", card->cid.prod_name);
 MMC_DEV_ATTR(oemid, "0x%04x\n", card->cid.oemid);
 MMC_DEV_ATTR(serial, "0x%08x\n", card->cid.serial);


 static struct attribute *sd_std_attrs[] = {
 	&dev_attr_cid.attr,
 	&dev_attr_csd.attr,
 	&dev_attr_scr.attr,
 	&dev_attr_date.attr,
 	&dev_attr_erase_size.attr,
 	&dev_attr_preferred_erase_size.attr,
 	&dev_attr_fwrev.attr,
 	&dev_attr_hwrev.attr,
 	&dev_attr_manfid.attr,
 	&dev_attr_name.attr,
 	&dev_attr_oemid.attr,
 	&dev_attr_serial.attr,
 	NULL,
 };

 static struct attribute_group sd_std_attr_group = {
 	.attrs = sd_std_attrs,
 };

 static const struct attribute_group *sd_attr_groups[] = {
 	&sd_std_attr_group,
 	NULL,
 };

 struct device_type sd_type = {
 	.groups = sd_attr_groups,
 };

 /*
  * Fetch CID from card.
  */
 int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid)
 {
 	int err;

 	/*
 	 * Since we're changing the OCR value, we seem to
 	 * need to tell some cards to go back to the idle
 	 * state.  We wait 1ms to give cards time to
 	 * respond.
 	 */
 	mmc_go_idle(host);

 	/*
 	 * If SD_SEND_IF_COND indicates an SD 2.0
 	 * compliant card and we should set bit 30
 	 * of the ocr to indicate that we can handle
 	 * block-addressed SDHC cards.
 	 */
 	err = mmc_send_if_cond(host, ocr);
 	if (!err)
 		ocr |= 1 << 30;

 	err = mmc_send_app_op_cond(host, ocr, NULL);
 	if (err)
 		return err;

 	if (mmc_host_is_spi(host))
 		err = mmc_send_cid(host, cid);
 	else
 		err = mmc_all_send_cid(host, cid);

 	return err;
 }

 int mmc_sd_get_csd(struct mmc_host *host, struct mmc_card *card)
 {
 	int err;

 	/*
 	 * Fetch CSD from card.
 	 */
 	err = mmc_send_csd(card, card->raw_csd);
 	if (err)
 		return err;

 	err = mmc_decode_csd(card);
 	if (err)
 		return err;

 	return 0;
 }

 int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card,
 	bool reinit)
 {
 	int err;

 	if (!reinit) {
 		/*
 		 * Fetch SCR from card.
 		 */
 		err = mmc_app_send_scr(card, card->raw_scr);
 		if (err)
 			return err;

 		err = mmc_decode_scr(card);
 		if (err)
 			return err;

 		/*
 		 * Fetch and process SD Status register.
 		 */
 		err = mmc_read_ssr(card);
 		if (err)
 			return err;

 		/* Erase init depends on CSD and SSR */
 		mmc_init_erase(card);

 		/*
 		 * Fetch switch information from card.
 		 */
 		err = mmc_read_switch(card);
 		if (err)
 			return err;
 	}

 	/*
 	 * For SPI, enable CRC as appropriate.
 	 * This CRC enable is located AFTER the reading of the
 	 * card registers because some SDHC cards are not able
 	 * to provide valid CRCs for non-512-byte blocks.
 	 */
 	if (mmc_host_is_spi(host)) {
 		err = mmc_spi_set_crc(host, use_spi_crc);
 		if (err)
 			return err;
 	}

 	/*
 	 * Check if read-only switch is active.
 	 */
 	if (!reinit) {
 		int ro = -1;

 		if (host->ops->get_ro)
 			ro = host->ops->get_ro(host);

 		if (ro < 0) {
 			printk(KERN_WARNING "%s: host does not "
 				"support reading read-only "
 				"switch. assuming write-enable.\n",
 				mmc_hostname(host));
 		} else if (ro > 0) {
 			mmc_card_set_readonly(card);
 		}
 	}

 	return 0;
 }

 unsigned mmc_sd_get_max_clock(struct mmc_card *card)
 {
 	unsigned max_dtr = (unsigned int)-1;

 	if (mmc_card_highspeed(card)) {
 		if (max_dtr > card->sw_caps.hs_max_dtr)
 			max_dtr = card->sw_caps.hs_max_dtr;
 	} else if (max_dtr > card->csd.max_dtr) {
 		max_dtr = card->csd.max_dtr;
 	}

 	return max_dtr;
 }

 void mmc_sd_go_highspeed(struct mmc_card *card)
 {
 	mmc_card_set_highspeed(card);
 	mmc_set_timing(card->host, MMC_TIMING_SD_HS);
 }

 /*
  * Handle the detection and initialisation of a card.
  *
  * In the case of a resume, "oldcard" will contain the card
  * we're trying to reinitialise.
  */
 static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
 	struct mmc_card *oldcard)
 {
 	struct mmc_card *card;
 	int err;
 	u32 cid[4];

 	BUG_ON(!host);
 	WARN_ON(!host->claimed);

 	err = mmc_sd_get_cid(host, ocr, cid);
 	if (err)
 		return err;

 	if (oldcard) {
 		if (memcmp(cid, oldcard->raw_cid, sizeof(cid)) != 0)
 			return -ENOENT;

 		card = oldcard;
 	} else {
 		/*
 		 * Allocate card structure.
 		 */
 		card = mmc_alloc_card(host, &sd_type);
 		if (IS_ERR(card))
 			return PTR_ERR(card);

 		card->type = MMC_TYPE_SD;
 		memcpy(card->raw_cid, cid, sizeof(card->raw_cid));
 	}

 	/*
 	 * For native busses:  get card RCA and quit open drain mode.
 	 */
 	if (!mmc_host_is_spi(host)) {
 		err = mmc_send_relative_addr(host, &card->rca);
 		if (err)
 			return err;

 		mmc_set_bus_mode(host, MMC_BUSMODE_PUSHPULL);
 	}

 	if (!oldcard) {
 		err = mmc_sd_get_csd(host, card);
 		if (err)
 			return err;

 		mmc_decode_cid(card);
 	}

 	/*
 	 * Select card, as all following commands rely on that.
 	 */
 	if (!mmc_host_is_spi(host)) {
 		err = mmc_select_card(card);
 		if (err)
 			return err;
 	}

 	err = mmc_sd_setup_card(host, card, oldcard != NULL);
 	if (err)
 		goto free_card;

 	/*
 	 * Attempt to change to high-speed (if supported)
 	 */
 	err = mmc_sd_switch_hs(card);
 	if (err > 0)
 		mmc_sd_go_highspeed(card);
 	else if (err)
 		goto free_card;

 	/*
 	 * Set bus speed.
 	 */
 	mmc_set_clock(host, mmc_sd_get_max_clock(card));

 	/*
 	 * Switch to wider bus (if supported).
 	 */
 	if ((host->caps & MMC_CAP_4_BIT_DATA) &&
 		(card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
 		err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
 		if (err)
 			goto free_card;

 		mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
 	}

 	host->card = card;
 	return 0;

 free_card:
 	if (!oldcard)
 		mmc_remove_card(card);

 	return err;
 }

 /*
  * Host is being removed. Free up the current card.
  */
 static void mmc_sd_remove(struct mmc_host *host)
 {
 	BUG_ON(!host);
 	BUG_ON(!host->card);

 	mmc_remove_card(host->card);
 	host->card = NULL;
 }

 /*
  * Card detection callback from host.
  */
 static void mmc_sd_detect(struct mmc_host *host)
 {
 	int err;

 	BUG_ON(!host);
 	BUG_ON(!host->card);

 	mmc_claim_host(host);

 	/*
 	 * Just check if our card has been removed.
 	 */
 	err = mmc_send_status(host->card, NULL);

 	mmc_release_host(host);

 	if (err) {
 		mmc_sd_remove(host);

 		mmc_claim_host(host);
 		mmc_detach_bus(host);
 		mmc_release_host(host);
 	}
 }

 /*
  * Suspend callback from host.
  */
 static int mmc_sd_suspend(struct mmc_host *host)
 {
 	BUG_ON(!host);
 	BUG_ON(!host->card);

 	mmc_claim_host(host);
 	if (!mmc_host_is_spi(host))
 		mmc_deselect_cards(host);
 	host->card->state &= ~MMC_STATE_HIGHSPEED;
 	mmc_release_host(host);

 	return 0;
 }

 /*
  * Resume callback from host.
  *
  * This function tries to determine if the same card is still present
  * and, if so, restore all state to it.
  */
 static int mmc_sd_resume(struct mmc_host *host)
 {
 	int err;

 	BUG_ON(!host);
 	BUG_ON(!host->card);

 	mmc_claim_host(host);
 	err = mmc_sd_init_card(host, host->ocr, host->card);
 	mmc_release_host(host);

 	return err;
 }

 static void mmc_sd_power_restore(struct mmc_host *host)
 {
 	host->card->state &= ~MMC_STATE_HIGHSPEED;
 	mmc_claim_host(host);
 	mmc_sd_init_card(host, host->ocr, host->card);
 	mmc_release_host(host);
 }

 static const struct mmc_bus_ops mmc_sd_ops = {
 	.remove = mmc_sd_remove,
 	.detect = mmc_sd_detect,
 	.suspend = NULL,
 	.resume = NULL,
 	.power_restore = mmc_sd_power_restore,
 };

 static const struct mmc_bus_ops mmc_sd_ops_unsafe = {
 	.remove = mmc_sd_remove,
 	.detect = mmc_sd_detect,
 	.suspend = mmc_sd_suspend,
 	.resume = mmc_sd_resume,
 	.power_restore = mmc_sd_power_restore,
 };

 static void mmc_sd_attach_bus_ops(struct mmc_host *host)
 {
 	const struct mmc_bus_ops *bus_ops;

 	if (host->caps & MMC_CAP_NONREMOVABLE || !mmc_assume_removable)
 		bus_ops = &mmc_sd_ops_unsafe;
 	else
 		bus_ops = &mmc_sd_ops;
 	mmc_attach_bus(host, bus_ops);
 }

 /*
  * Starting point for SD card init.
  */
 int mmc_attach_sd(struct mmc_host *host, u32 ocr)
 {
 	int err;

 	BUG_ON(!host);
 	WARN_ON(!host->claimed);

 	mmc_sd_attach_bus_ops(host);

 	/*
 	 * We need to get OCR a different way for SPI.
 	 */
 	if (mmc_host_is_spi(host)) {
 		mmc_go_idle(host);

 		err = mmc_spi_read_ocr(host, 0, &ocr);
 		if (err)
 			goto err;
 	}

 	/*
 	 * Sanity check the voltages that the card claims to
 	 * support.
 	 */
 	if (ocr & 0x7F) {
 		printk(KERN_WARNING "%s: card claims to support voltages "
 		       "below the defined range. These will be ignored.\n",
 		       mmc_hostname(host));
 		ocr &= ~0x7F;
 	}

 	if (ocr & MMC_VDD_165_195) {
 		printk(KERN_WARNING "%s: SD card claims to support the "
 		       "incompletely defined 'low voltage range'. This "
 		       "will be ignored.\n", mmc_hostname(host));
 		ocr &= ~MMC_VDD_165_195;
 	}

 	host->ocr = mmc_select_voltage(host, ocr);

 	/*
 	 * Can we support the voltage(s) of the card(s)?
 	 */
 	if (!host->ocr) {
 		err = -EINVAL;
 		goto err;
 	}

 	/*
 	 * Detect and init the card.
 	 */
 	err = mmc_sd_init_card(host, host->ocr, NULL);
 	if (err)
 		goto err;

 	mmc_release_host(host);

 	err = mmc_add_card(host->card);
 	if (err)
 		goto remove_card;

 	return 0;

 remove_card:
 	mmc_remove_card(host->card);
 	host->card = NULL;
 	mmc_claim_host(host);
 err:
 	mmc_detach_bus(host);
 	mmc_release_host(host);

 	printk(KERN_ERR "%s: error %d whilst initialising SD card\n",
 		mmc_hostname(host), err);

 	return err;
 }
	/*
	* linux/drivers/mmc/core/sd.c
	*
	* Copyright (C) 2003-2004 Russell King, All Rights Reserved.
	* SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
	* Copyright (C) 2005-2007 Pierre Ossman, All Rights Reserved.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/err.h>
	#include <linux/slab.h>

	#include <linux/mmc/host.h>
	#include <linux/mmc/card.h>
	#include <linux/mmc/mmc.h>
	#include <linux/mmc/sd.h>

	#include "core.h"
	#include "bus.h"
	#include "mmc_ops.h"
	#include "sd_ops.h"

	static const unsigned int tran_exp[] = {
	10000, 100000, 1000000, 10000000,
	0, 0, 0, 0
	};

	static const unsigned char tran_mant[] = {
	0, 10, 12, 13, 15, 20, 25, 30,
	35, 40, 45, 50, 55, 60, 70, 80,
	};

	static const unsigned int tacc_exp[] = {
	1, 10, 100, 1000, 10000, 100000, 1000000, 10000000,
	};

	static const unsigned int tacc_mant[] = {
	0, 10, 12, 13, 15, 20, 25, 30,
	35, 40, 45, 50, 55, 60, 70, 80,
	};

	#define UNSTUFF_BITS(resp,start,size) \
	({ \
	const int __size = size; \
	const u32 __mask = (__size < 32 ? 1 << __size : 0) - 1; \
	const int __off = 3 - ((start) / 32); \
	const int __shft = (start) & 31; \
	u32 __res; \
	\
	__res = resp[__off] >> __shft; \
	if (__size + __shft > 32) \
	__res \|= resp[__off-1] << ((32 - __shft) % 32); \
	__res & __mask; \
	})

	/*
	* Given the decoded CSD structure, decode the raw CID to our CID structure.
	*/
	void mmc_decode_cid(struct mmc_card *card)
	{
	u32 *resp = card->raw_cid;

	memset(&card->cid, 0, sizeof(struct mmc_cid));

	/*
	* SD doesn't currently have a version field so we will
	* have to assume we can parse this.
	*/
	card->cid.manfid = UNSTUFF_BITS(resp, 120, 8);
	card->cid.oemid = UNSTUFF_BITS(resp, 104, 16);
	card->cid.prod_name[0] = UNSTUFF_BITS(resp, 96, 8);
	card->cid.prod_name[1] = UNSTUFF_BITS(resp, 88, 8);
	card->cid.prod_name[2] = UNSTUFF_BITS(resp, 80, 8);
	card->cid.prod_name[3] = UNSTUFF_BITS(resp, 72, 8);
	card->cid.prod_name[4] = UNSTUFF_BITS(resp, 64, 8);
	card->cid.hwrev = UNSTUFF_BITS(resp, 60, 4);
	card->cid.fwrev = UNSTUFF_BITS(resp, 56, 4);
	card->cid.serial = UNSTUFF_BITS(resp, 24, 32);
	card->cid.year = UNSTUFF_BITS(resp, 12, 8);
	card->cid.month = UNSTUFF_BITS(resp, 8, 4);

	card->cid.year += 2000; /* SD cards year offset */
	}

	/*
	* Given a 128-bit response, decode to our card CSD structure.
	*/
	static int mmc_decode_csd(struct mmc_card *card)
	{
	struct mmc_csd *csd = &card->csd;
	unsigned int e, m, csd_struct;
	u32 *resp = card->raw_csd;

	csd_struct = UNSTUFF_BITS(resp, 126, 2);

	switch (csd_struct) {
	case 0:
	m = UNSTUFF_BITS(resp, 115, 4);
	e = UNSTUFF_BITS(resp, 112, 3);
	csd->tacc_ns = (tacc_exp[e] * tacc_mant[m] + 9) / 10;
	csd->tacc_clks = UNSTUFF_BITS(resp, 104, 8) * 100;

	m = UNSTUFF_BITS(resp, 99, 4);
	e = UNSTUFF_BITS(resp, 96, 3);
	csd->max_dtr = tran_exp[e] * tran_mant[m];
	csd->cmdclass = UNSTUFF_BITS(resp, 84, 12);

	e = UNSTUFF_BITS(resp, 47, 3);
	m = UNSTUFF_BITS(resp, 62, 12);
	csd->capacity = (1 + m) << (e + 2);

	csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
	csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
	csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
	csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
	csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3);
	csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
	csd->write_partial = UNSTUFF_BITS(resp, 21, 1);

	if (UNSTUFF_BITS(resp, 46, 1)) {
	csd->erase_size = 1;
	} else if (csd->write_blkbits >= 9) {
	csd->erase_size = UNSTUFF_BITS(resp, 39, 7) + 1;
	csd->erase_size <<= csd->write_blkbits - 9;
	}
	break;
	case 1:
	/*
	* This is a block-addressed SDHC card. Most
	* interesting fields are unused and have fixed
	* values. To avoid getting tripped by buggy cards,
	* we assume those fixed values ourselves.
	*/
	mmc_card_set_blockaddr(card);

	csd->tacc_ns = 0; /* Unused */
	csd->tacc_clks = 0; /* Unused */

	m = UNSTUFF_BITS(resp, 99, 4);
	e = UNSTUFF_BITS(resp, 96, 3);
	csd->max_dtr = tran_exp[e] * tran_mant[m];
	csd->cmdclass = UNSTUFF_BITS(resp, 84, 12);

	m = UNSTUFF_BITS(resp, 48, 22);
	csd->capacity = (1 + m) << 10;

	csd->read_blkbits = 9;
	csd->read_partial = 0;
	csd->write_misalign = 0;
	csd->read_misalign = 0;
	csd->r2w_factor = 4; /* Unused */
	csd->write_blkbits = 9;
	csd->write_partial = 0;
	csd->erase_size = 1;
	break;
	default:
	printk(KERN_ERR "%s: unrecognised CSD structure version %d\n",
	mmc_hostname(card->host), csd_struct);
	return -EINVAL;
	}

	card->erase_size = csd->erase_size;

	return 0;
	}

	/*
	* Given a 64-bit response, decode to our card SCR structure.
	*/
	static int mmc_decode_scr(struct mmc_card *card)
	{
	struct sd_scr *scr = &card->scr;
	unsigned int scr_struct;
	u32 resp[4];

	resp[3] = card->raw_scr[1];
	resp[2] = card->raw_scr[0];

	scr_struct = UNSTUFF_BITS(resp, 60, 4);
	if (scr_struct != 0) {
	printk(KERN_ERR "%s: unrecognised SCR structure version %d\n",
	mmc_hostname(card->host), scr_struct);
	return -EINVAL;
	}

	scr->sda_vsn = UNSTUFF_BITS(resp, 56, 4);
	scr->bus_widths = UNSTUFF_BITS(resp, 48, 4);

	if (UNSTUFF_BITS(resp, 55, 1))
	card->erased_byte = 0xFF;
	else
	card->erased_byte = 0x0;

	return 0;
	}

	/*
	* Fetch and process SD Status register.
	*/
	static int mmc_read_ssr(struct mmc_card *card)
	{
	unsigned int au, es, et, eo;
	int err, i;
	u32 *ssr;

	if (!(card->csd.cmdclass & CCC_APP_SPEC)) {
	printk(KERN_WARNING "%s: card lacks mandatory SD Status "
	"function.\n", mmc_hostname(card->host));
	return 0;
	}

	ssr = kmalloc(64, GFP_KERNEL);
	if (!ssr)
	return -ENOMEM;

	err = mmc_app_sd_status(card, ssr);
	if (err) {
	printk(KERN_WARNING "%s: problem reading SD Status "
	"register.\n", mmc_hostname(card->host));
	err = 0;
	goto out;
	}

	for (i = 0; i < 16; i++)
	ssr[i] = be32_to_cpu(ssr[i]);

	/*
	* UNSTUFF_BITS only works with four u32s so we have to offset the
	* bitfield positions accordingly.
	*/
	au = UNSTUFF_BITS(ssr, 428 - 384, 4);
	if (au > 0 \|\| au <= 9) {
	card->ssr.au = 1 << (au + 4);
	es = UNSTUFF_BITS(ssr, 408 - 384, 16);
	et = UNSTUFF_BITS(ssr, 402 - 384, 6);
	eo = UNSTUFF_BITS(ssr, 400 - 384, 2);
	if (es && et) {
	card->ssr.erase_timeout = (et * 1000) / es;
	card->ssr.erase_offset = eo * 1000;
	}
	} else {
	printk(KERN_WARNING "%s: SD Status: Invalid Allocation Unit "
	"size.\n", mmc_hostname(card->host));
	}
	out:
	kfree(ssr);
	return err;
	}

	/*
	* Fetches and decodes switch information
	*/
	static int mmc_read_switch(struct mmc_card *card)
	{
	int err;
	u8 *status;

	if (card->scr.sda_vsn < SCR_SPEC_VER_1)
	return 0;

	if (!(card->csd.cmdclass & CCC_SWITCH)) {
	printk(KERN_WARNING "%s: card lacks mandatory switch "
	"function, performance might suffer.\n",
	mmc_hostname(card->host));
	return 0;
	}

	err = -EIO;

	status = kmalloc(64, GFP_KERNEL);
	if (!status) {
	printk(KERN_ERR "%s: could not allocate a buffer for "
	"switch capabilities.\n", mmc_hostname(card->host));
	return -ENOMEM;
	}

	err = mmc_sd_switch(card, 0, 0, 1, status);
	if (err) {
	/* If the host or the card can't do the switch,
	* fail more gracefully. */
	if ((err != -EINVAL)
	&& (err != -ENOSYS)
	&& (err != -EFAULT))
	goto out;

	printk(KERN_WARNING "%s: problem reading switch "
	"capabilities, performance might suffer.\n",
	mmc_hostname(card->host));
	err = 0;

	goto out;
	}

	if (status[13] & 0x02)
	card->sw_caps.hs_max_dtr = 50000000;

	out:
	kfree(status);

	return err;
	}

	/*
	* Test if the card supports high-speed mode and, if so, switch to it.
	*/
	int mmc_sd_switch_hs(struct mmc_card *card)
	{
	int err;
	u8 *status;

	if (card->scr.sda_vsn < SCR_SPEC_VER_1)
	return 0;

	if (!(card->csd.cmdclass & CCC_SWITCH))
	return 0;

	if (!(card->host->caps & MMC_CAP_SD_HIGHSPEED))
	return 0;

	if (card->sw_caps.hs_max_dtr == 0)
	return 0;

	err = -EIO;

	status = kmalloc(64, GFP_KERNEL);
	if (!status) {
	printk(KERN_ERR "%s: could not allocate a buffer for "
	"switch capabilities.\n", mmc_hostname(card->host));
	return -ENOMEM;
	}

	err = mmc_sd_switch(card, 1, 0, 1, status);
	if (err)
	goto out;

	if ((status[16] & 0xF) != 1) {
	printk(KERN_WARNING "%s: Problem switching card "
	"into high-speed mode!\n",
	mmc_hostname(card->host));
	err = 0;
	} else {
	err = 1;
	}

	out:
	kfree(status);

	return err;
	}

	MMC_DEV_ATTR(cid, "%08x%08x%08x%08x\n", card->raw_cid[0], card->raw_cid[1],
	card->raw_cid[2], card->raw_cid[3]);
	MMC_DEV_ATTR(csd, "%08x%08x%08x%08x\n", card->raw_csd[0], card->raw_csd[1],
	card->raw_csd[2], card->raw_csd[3]);
	MMC_DEV_ATTR(scr, "%08x%08x\n", card->raw_scr[0], card->raw_scr[1]);
	MMC_DEV_ATTR(date, "%02d/%04d\n", card->cid.month, card->cid.year);
	MMC_DEV_ATTR(erase_size, "%u\n", card->erase_size << 9);
	MMC_DEV_ATTR(preferred_erase_size, "%u\n", card->pref_erase << 9);
	MMC_DEV_ATTR(fwrev, "0x%x\n", card->cid.fwrev);
	MMC_DEV_ATTR(hwrev, "0x%x\n", card->cid.hwrev);
	MMC_DEV_ATTR(manfid, "0x%06x\n", card->cid.manfid);
	MMC_DEV_ATTR(name, "%s\n", card->cid.prod_name);
	MMC_DEV_ATTR(oemid, "0x%04x\n", card->cid.oemid);
	MMC_DEV_ATTR(serial, "0x%08x\n", card->cid.serial);


	static struct attribute *sd_std_attrs[] = {
	&dev_attr_cid.attr,
	&dev_attr_csd.attr,
	&dev_attr_scr.attr,
	&dev_attr_date.attr,
	&dev_attr_erase_size.attr,
	&dev_attr_preferred_erase_size.attr,
	&dev_attr_fwrev.attr,
	&dev_attr_hwrev.attr,
	&dev_attr_manfid.attr,
	&dev_attr_name.attr,
	&dev_attr_oemid.attr,
	&dev_attr_serial.attr,
	NULL,
	};

	static struct attribute_group sd_std_attr_group = {
	.attrs = sd_std_attrs,
	};

	static const struct attribute_group *sd_attr_groups[] = {
	&sd_std_attr_group,
	NULL,
	};

	struct device_type sd_type = {
	.groups = sd_attr_groups,
	};

	/*
	* Fetch CID from card.
	*/
	int mmc_sd_get_cid(struct mmc_host host, u32 ocr, u32 cid)
	{
	int err;

	/*
	* Since we're changing the OCR value, we seem to
	* need to tell some cards to go back to the idle
	* state. We wait 1ms to give cards time to
	* respond.
	*/
	mmc_go_idle(host);

	/*
	* If SD_SEND_IF_COND indicates an SD 2.0
	* compliant card and we should set bit 30
	* of the ocr to indicate that we can handle
	* block-addressed SDHC cards.
	*/
	err = mmc_send_if_cond(host, ocr);
	if (!err)
	ocr \|= 1 << 30;

	err = mmc_send_app_op_cond(host, ocr, NULL);
	if (err)
	return err;

	if (mmc_host_is_spi(host))
	err = mmc_send_cid(host, cid);
	else
	err = mmc_all_send_cid(host, cid);

	return err;
	}

	int mmc_sd_get_csd(struct mmc_host host, struct mmc_card card)
	{
	int err;

	/*
	* Fetch CSD from card.
	*/
	err = mmc_send_csd(card, card->raw_csd);
	if (err)
	return err;

	err = mmc_decode_csd(card);
	if (err)
	return err;

	return 0;
	}

	int mmc_sd_setup_card(struct mmc_host host, struct mmc_card card,
	bool reinit)
	{
	int err;

	if (!reinit) {
	/*
	* Fetch SCR from card.
	*/
	err = mmc_app_send_scr(card, card->raw_scr);
	if (err)
	return err;

	err = mmc_decode_scr(card);
	if (err)
	return err;

	/*
	* Fetch and process SD Status register.
	*/
	err = mmc_read_ssr(card);
	if (err)
	return err;

	/* Erase init depends on CSD and SSR */
	mmc_init_erase(card);

	/*
	* Fetch switch information from card.
	*/
	err = mmc_read_switch(card);
	if (err)
	return err;
	}

	/*
	* For SPI, enable CRC as appropriate.
	* This CRC enable is located AFTER the reading of the
	* card registers because some SDHC cards are not able
	* to provide valid CRCs for non-512-byte blocks.
	*/
	if (mmc_host_is_spi(host)) {
	err = mmc_spi_set_crc(host, use_spi_crc);
	if (err)
	return err;
	}

	/*
	* Check if read-only switch is active.
	*/
	if (!reinit) {
	int ro = -1;

	if (host->ops->get_ro)
	ro = host->ops->get_ro(host);

	if (ro < 0) {
	printk(KERN_WARNING "%s: host does not "
	"support reading read-only "
	"switch. assuming write-enable.\n",
	mmc_hostname(host));
	} else if (ro > 0) {
	mmc_card_set_readonly(card);
	}
	}

	return 0;
	}

	unsigned mmc_sd_get_max_clock(struct mmc_card *card)
	{
	unsigned max_dtr = (unsigned int)-1;

	if (mmc_card_highspeed(card)) {
	if (max_dtr > card->sw_caps.hs_max_dtr)
	max_dtr = card->sw_caps.hs_max_dtr;
	} else if (max_dtr > card->csd.max_dtr) {
	max_dtr = card->csd.max_dtr;
	}

	return max_dtr;
	}

	void mmc_sd_go_highspeed(struct mmc_card *card)
	{
	mmc_card_set_highspeed(card);
	mmc_set_timing(card->host, MMC_TIMING_SD_HS);
	}

	/*
	* Handle the detection and initialisation of a card.
	*
	* In the case of a resume, "oldcard" will contain the card
	* we're trying to reinitialise.
	*/
	static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
	struct mmc_card *oldcard)
	{
	struct mmc_card *card;
	int err;
	u32 cid[4];

	BUG_ON(!host);
	WARN_ON(!host->claimed);

	err = mmc_sd_get_cid(host, ocr, cid);
	if (err)
	return err;

	if (oldcard) {
	if (memcmp(cid, oldcard->raw_cid, sizeof(cid)) != 0)
	return -ENOENT;

	card = oldcard;
	} else {
	/*
	* Allocate card structure.
	*/
	card = mmc_alloc_card(host, &sd_type);
	if (IS_ERR(card))
	return PTR_ERR(card);

	card->type = MMC_TYPE_SD;
	memcpy(card->raw_cid, cid, sizeof(card->raw_cid));
	}

	/*
	* For native busses: get card RCA and quit open drain mode.
	*/
	if (!mmc_host_is_spi(host)) {
	err = mmc_send_relative_addr(host, &card->rca);
	if (err)
	return err;

	mmc_set_bus_mode(host, MMC_BUSMODE_PUSHPULL);
	}

	if (!oldcard) {
	err = mmc_sd_get_csd(host, card);
	if (err)
	return err;

	mmc_decode_cid(card);
	}

	/*
	* Select card, as all following commands rely on that.
	*/
	if (!mmc_host_is_spi(host)) {
	err = mmc_select_card(card);
	if (err)
	return err;
	}

	err = mmc_sd_setup_card(host, card, oldcard != NULL);
	if (err)
	goto free_card;

	/*
	* Attempt to change to high-speed (if supported)
	*/
	err = mmc_sd_switch_hs(card);
	if (err > 0)
	mmc_sd_go_highspeed(card);
	else if (err)
	goto free_card;

	/*
	* Set bus speed.
	*/
	mmc_set_clock(host, mmc_sd_get_max_clock(card));

	/*
	* Switch to wider bus (if supported).
	*/
	if ((host->caps & MMC_CAP_4_BIT_DATA) &&
	(card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
	err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
	if (err)
	goto free_card;

	mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
	}

	host->card = card;
	return 0;

	free_card:
	if (!oldcard)
	mmc_remove_card(card);

	return err;
	}

	/*
	* Host is being removed. Free up the current card.
	*/
	static void mmc_sd_remove(struct mmc_host *host)
	{
	BUG_ON(!host);
	BUG_ON(!host->card);

	mmc_remove_card(host->card);
	host->card = NULL;
	}

	/*
	* Card detection callback from host.
	*/
	static void mmc_sd_detect(struct mmc_host *host)
	{
	int err;

	BUG_ON(!host);
	BUG_ON(!host->card);

	mmc_claim_host(host);

	/*
	* Just check if our card has been removed.
	*/
	err = mmc_send_status(host->card, NULL);

	mmc_release_host(host);

	if (err) {
	mmc_sd_remove(host);

	mmc_claim_host(host);
	mmc_detach_bus(host);
	mmc_release_host(host);
	}
	}

	/*
	* Suspend callback from host.
	*/
	static int mmc_sd_suspend(struct mmc_host *host)
	{
	BUG_ON(!host);
	BUG_ON(!host->card);

	mmc_claim_host(host);
	if (!mmc_host_is_spi(host))
	mmc_deselect_cards(host);
	host->card->state &= ~MMC_STATE_HIGHSPEED;
	mmc_release_host(host);

	return 0;
	}

	/*
	* Resume callback from host.
	*
	* This function tries to determine if the same card is still present
	* and, if so, restore all state to it.
	*/
	static int mmc_sd_resume(struct mmc_host *host)
	{
	int err;

	BUG_ON(!host);
	BUG_ON(!host->card);

	mmc_claim_host(host);
	err = mmc_sd_init_card(host, host->ocr, host->card);
	mmc_release_host(host);

	return err;
	}

	static void mmc_sd_power_restore(struct mmc_host *host)
	{
	host->card->state &= ~MMC_STATE_HIGHSPEED;
	mmc_claim_host(host);
	mmc_sd_init_card(host, host->ocr, host->card);
	mmc_release_host(host);
	}

	static const struct mmc_bus_ops mmc_sd_ops = {
	.remove = mmc_sd_remove,
	.detect = mmc_sd_detect,
	.suspend = NULL,
	.resume = NULL,
	.power_restore = mmc_sd_power_restore,
	};

	static const struct mmc_bus_ops mmc_sd_ops_unsafe = {
	.remove = mmc_sd_remove,
	.detect = mmc_sd_detect,
	.suspend = mmc_sd_suspend,
	.resume = mmc_sd_resume,
	.power_restore = mmc_sd_power_restore,
	};

	static void mmc_sd_attach_bus_ops(struct mmc_host *host)
	{
	const struct mmc_bus_ops *bus_ops;

	if (host->caps & MMC_CAP_NONREMOVABLE \|\| !mmc_assume_removable)
	bus_ops = &mmc_sd_ops_unsafe;
	else
	bus_ops = &mmc_sd_ops;
	mmc_attach_bus(host, bus_ops);
	}

	/*
	* Starting point for SD card init.
	*/
	int mmc_attach_sd(struct mmc_host *host, u32 ocr)
	{
	int err;

	BUG_ON(!host);
	WARN_ON(!host->claimed);

	mmc_sd_attach_bus_ops(host);

	/*
	* We need to get OCR a different way for SPI.
	*/
	if (mmc_host_is_spi(host)) {
	mmc_go_idle(host);

	err = mmc_spi_read_ocr(host, 0, &ocr);
	if (err)
	goto err;
	}

	/*
	* Sanity check the voltages that the card claims to
	* support.
	*/
	if (ocr & 0x7F) {
	printk(KERN_WARNING "%s: card claims to support voltages "
	"below the defined range. These will be ignored.\n",
	mmc_hostname(host));
	ocr &= ~0x7F;
	}

	if (ocr & MMC_VDD_165_195) {
	printk(KERN_WARNING "%s: SD card claims to support the "
	"incompletely defined 'low voltage range'. This "
	"will be ignored.\n", mmc_hostname(host));
	ocr &= ~MMC_VDD_165_195;
	}

	host->ocr = mmc_select_voltage(host, ocr);

	/*
	* Can we support the voltage(s) of the card(s)?
	*/
	if (!host->ocr) {
	err = -EINVAL;
	goto err;
	}

	/*
	* Detect and init the card.
	*/
	err = mmc_sd_init_card(host, host->ocr, NULL);
	if (err)
	goto err;

	mmc_release_host(host);

	err = mmc_add_card(host->card);
	if (err)
	goto remove_card;

	return 0;

	remove_card:
	mmc_remove_card(host->card);
	host->card = NULL;
	mmc_claim_host(host);
	err:
	mmc_detach_bus(host);
	mmc_release_host(host);

	printk(KERN_ERR "%s: error %d whilst initialising SD card\n",
	mmc_hostname(host), err);

	return err;
	}