6 files changed, 525 insertions, 1 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 83240faa1dc8..5db49b124ffa 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1050,6 +1050,352 @@ void mmc_detect_change(struct mmc_host *host, unsigned long delay)
 
 EXPORT_SYMBOL(mmc_detect_change);
 
+void mmc_init_erase(struct mmc_card *card)
+{
+	unsigned int sz;
+
+	if (is_power_of_2(card->erase_size))
+		card->erase_shift = ffs(card->erase_size) - 1;
+	else
+		card->erase_shift = 0;
+
+	/*
+	 * It is possible to erase an arbitrarily large area of an SD or MMC
+	 * card.  That is not desirable because it can take a long time
+	 * (minutes) potentially delaying more important I/O, and also the
+	 * timeout calculations become increasingly hugely over-estimated.
+	 * Consequently, 'pref_erase' is defined as a guide to limit erases
+	 * to that size and alignment.
+	 *
+	 * For SD cards that define Allocation Unit size, limit erases to one
+	 * Allocation Unit at a time.  For MMC cards that define High Capacity
+	 * Erase Size, whether it is switched on or not, limit to that size.
+	 * Otherwise just have a stab at a good value.  For modern cards it
+	 * will end up being 4MiB.  Note that if the value is too small, it
+	 * can end up taking longer to erase.
+	 */
+	if (mmc_card_sd(card) && card->ssr.au) {
+		card->pref_erase = card->ssr.au;
+		card->erase_shift = ffs(card->ssr.au) - 1;
+	} else if (card->ext_csd.hc_erase_size) {
+		card->pref_erase = card->ext_csd.hc_erase_size;
+	} else {
+		sz = (card->csd.capacity << (card->csd.read_blkbits - 9)) >> 11;
+		if (sz < 128)
+			card->pref_erase = 512 * 1024 / 512;
+		else if (sz < 512)
+			card->pref_erase = 1024 * 1024 / 512;
+		else if (sz < 1024)
+			card->pref_erase = 2 * 1024 * 1024 / 512;
+		else
+			card->pref_erase = 4 * 1024 * 1024 / 512;
+		if (card->pref_erase < card->erase_size)
+			card->pref_erase = card->erase_size;
+		else {
+			sz = card->pref_erase % card->erase_size;
+			if (sz)
+				card->pref_erase += card->erase_size - sz;
+		}
+	}
+}
+
+static void mmc_set_mmc_erase_timeout(struct mmc_card *card,
+				      struct mmc_command *cmd,
+				      unsigned int arg, unsigned int qty)
+{
+	unsigned int erase_timeout;
+
+	if (card->ext_csd.erase_group_def & 1) {
+		/* High Capacity Erase Group Size uses HC timeouts */
+		if (arg == MMC_TRIM_ARG)
+			erase_timeout = card->ext_csd.trim_timeout;
+		else
+			erase_timeout = card->ext_csd.hc_erase_timeout;
+	} else {
+		/* CSD Erase Group Size uses write timeout */
+		unsigned int mult = (10 << card->csd.r2w_factor);
+		unsigned int timeout_clks = card->csd.tacc_clks * mult;
+		unsigned int timeout_us;
+
+		/* Avoid overflow: e.g. tacc_ns=80000000 mult=1280 */
+		if (card->csd.tacc_ns < 1000000)
+			timeout_us = (card->csd.tacc_ns * mult) / 1000;
+		else
+			timeout_us = (card->csd.tacc_ns / 1000) * mult;
+
+		/*
+		 * ios.clock is only a target.  The real clock rate might be
+		 * less but not that much less, so fudge it by multiplying by 2.
+		 */
+		timeout_clks <<= 1;
+		timeout_us += (timeout_clks * 1000) /
+			      (card->host->ios.clock / 1000);
+
+		erase_timeout = timeout_us / 1000;
+
+		/*
+		 * Theoretically, the calculation could underflow so round up
+		 * to 1ms in that case.
+		 */
+		if (!erase_timeout)
+			erase_timeout = 1;
+	}
+
+	/* Multiplier for secure operations */
+	if (arg & MMC_SECURE_ARGS) {
+		if (arg == MMC_SECURE_ERASE_ARG)
+			erase_timeout *= card->ext_csd.sec_erase_mult;
+		else
+			erase_timeout *= card->ext_csd.sec_trim_mult;
+	}
+
+	erase_timeout *= qty;
+
+	/*
+	 * Ensure at least a 1 second timeout for SPI as per
+	 * 'mmc_set_data_timeout()'
+	 */
+	if (mmc_host_is_spi(card->host) && erase_timeout < 1000)
+		erase_timeout = 1000;
+
+	cmd->erase_timeout = erase_timeout;
+}
+
+static void mmc_set_sd_erase_timeout(struct mmc_card *card,
+				     struct mmc_command *cmd, unsigned int arg,
+				     unsigned int qty)
+{
+	if (card->ssr.erase_timeout) {
+		/* Erase timeout specified in SD Status Register (SSR) */
+		cmd->erase_timeout = card->ssr.erase_timeout * qty +
+				     card->ssr.erase_offset;
+	} else {
+		/*
+		 * Erase timeout not specified in SD Status Register (SSR) so
+		 * use 250ms per write block.
+		 */
+		cmd->erase_timeout = 250 * qty;
+	}
+
+	/* Must not be less than 1 second */
+	if (cmd->erase_timeout < 1000)
+		cmd->erase_timeout = 1000;
+}
+
+static void mmc_set_erase_timeout(struct mmc_card *card,
+				  struct mmc_command *cmd, unsigned int arg,
+				  unsigned int qty)
+{
+	if (mmc_card_sd(card))
+		mmc_set_sd_erase_timeout(card, cmd, arg, qty);
+	else
+		mmc_set_mmc_erase_timeout(card, cmd, arg, qty);
+}
+
+static int mmc_do_erase(struct mmc_card *card, unsigned int from,
+			unsigned int to, unsigned int arg)
+{
+	struct mmc_command cmd;
+	unsigned int qty = 0;
+	int err;
+
+	/*
+	 * qty is used to calculate the erase timeout which depends on how many
+	 * erase groups (or allocation units in SD terminology) are affected.
+	 * We count erasing part of an erase group as one erase group.
+	 * For SD, the allocation units are always a power of 2.  For MMC, the
+	 * erase group size is almost certainly also power of 2, but it does not
+	 * seem to insist on that in the JEDEC standard, so we fall back to
+	 * division in that case.  SD may not specify an allocation unit size,
+	 * in which case the timeout is based on the number of write blocks.
+	 *
+	 * Note that the timeout for secure trim 2 will only be correct if the
+	 * number of erase groups specified is the same as the total of all
+	 * preceding secure trim 1 commands.  Since the power may have been
+	 * lost since the secure trim 1 commands occurred, it is generally
+	 * impossible to calculate the secure trim 2 timeout correctly.
+	 */
+	if (card->erase_shift)
+		qty += ((to >> card->erase_shift) -
+			(from >> card->erase_shift)) + 1;
+	else if (mmc_card_sd(card))
+		qty += to - from + 1;
+	else
+		qty += ((to / card->erase_size) -
+			(from / card->erase_size)) + 1;
+
+	if (!mmc_card_blockaddr(card)) {
+		from <<= 9;
+		to <<= 9;
+	}
+
+	memset(&cmd, 0, sizeof(struct mmc_command));
+	if (mmc_card_sd(card))
+		cmd.opcode = SD_ERASE_WR_BLK_START;
+	else
+		cmd.opcode = MMC_ERASE_GROUP_START;
+	cmd.arg = from;
+	cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
+	err = mmc_wait_for_cmd(card->host, &cmd, 0);
+	if (err) {
+		printk(KERN_ERR "mmc_erase: group start error %d, "
+		       "status %#x\n", err, cmd.resp[0]);
+		err = -EINVAL;
+		goto out;
+	}
+
+	memset(&cmd, 0, sizeof(struct mmc_command));
+	if (mmc_card_sd(card))
+		cmd.opcode = SD_ERASE_WR_BLK_END;
+	else
+		cmd.opcode = MMC_ERASE_GROUP_END;
+	cmd.arg = to;
+	cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
+	err = mmc_wait_for_cmd(card->host, &cmd, 0);
+	if (err) {
+		printk(KERN_ERR "mmc_erase: group end error %d, status %#x\n",
+		       err, cmd.resp[0]);
+		err = -EINVAL;
+		goto out;
+	}
+
+	memset(&cmd, 0, sizeof(struct mmc_command));
+	cmd.opcode = MMC_ERASE;
+	cmd.arg = arg;
+	cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
+	mmc_set_erase_timeout(card, &cmd, arg, qty);
+	err = mmc_wait_for_cmd(card->host, &cmd, 0);
+	if (err) {
+		printk(KERN_ERR "mmc_erase: erase error %d, status %#x\n",
+		       err, cmd.resp[0]);
+		err = -EIO;
+		goto out;
+	}
+
+	if (mmc_host_is_spi(card->host))
+		goto out;
+
+	do {
+		memset(&cmd, 0, sizeof(struct mmc_command));
+		cmd.opcode = MMC_SEND_STATUS;
+		cmd.arg = card->rca << 16;
+		cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
+		/* Do not retry else we can't see errors */
+		err = mmc_wait_for_cmd(card->host, &cmd, 0);
+		if (err || (cmd.resp[0] & 0xFDF92000)) {
+			printk(KERN_ERR "error %d requesting status %#x\n",
+				err, cmd.resp[0]);
+			err = -EIO;
+			goto out;
+		}
+	} while (!(cmd.resp[0] & R1_READY_FOR_DATA) ||
+		 R1_CURRENT_STATE(cmd.resp[0]) == 7);
+out:
+	return err;
+}
+
+/**
+ * mmc_erase - erase sectors.
+ * @card: card to erase
+ * @from: first sector to erase
+ * @nr: number of sectors to erase
+ * @arg: erase command argument (SD supports only %MMC_ERASE_ARG)
+ *
+ * Caller must claim host before calling this function.
+ */
+int mmc_erase(struct mmc_card *card, unsigned int from, unsigned int nr,
+	      unsigned int arg)
+{
+	unsigned int rem, to = from + nr;
+
+	if (!(card->host->caps & MMC_CAP_ERASE) ||
+	    !(card->csd.cmdclass & CCC_ERASE))
+		return -EOPNOTSUPP;
+
+	if (!card->erase_size)
+		return -EOPNOTSUPP;
+
+	if (mmc_card_sd(card) && arg != MMC_ERASE_ARG)
+		return -EOPNOTSUPP;
+
+	if ((arg & MMC_SECURE_ARGS) &&
+	    !(card->ext_csd.sec_feature_support & EXT_CSD_SEC_ER_EN))
+		return -EOPNOTSUPP;
+
+	if ((arg & MMC_TRIM_ARGS) &&
+	    !(card->ext_csd.sec_feature_support & EXT_CSD_SEC_GB_CL_EN))
+		return -EOPNOTSUPP;
+
+	if (arg == MMC_SECURE_ERASE_ARG) {
+		if (from % card->erase_size || nr % card->erase_size)
+			return -EINVAL;
+	}
+
+	if (arg == MMC_ERASE_ARG) {
+		rem = from % card->erase_size;
+		if (rem) {
+			rem = card->erase_size - rem;
+			from += rem;
+			if (nr > rem)
+				nr -= rem;
+			else
+				return 0;
+		}
+		rem = nr % card->erase_size;
+		if (rem)
+			nr -= rem;
+	}
+
+	if (nr == 0)
+		return 0;
+
+	to = from + nr;
+
+	if (to <= from)
+		return -EINVAL;
+
+	/* 'from' and 'to' are inclusive */
+	to -= 1;
+
+	return mmc_do_erase(card, from, to, arg);
+}
+EXPORT_SYMBOL(mmc_erase);
+
+int mmc_can_erase(struct mmc_card *card)
+{
+	if ((card->host->caps & MMC_CAP_ERASE) &&
+	    (card->csd.cmdclass & CCC_ERASE) && card->erase_size)
+		return 1;
+	return 0;
+}
+EXPORT_SYMBOL(mmc_can_erase);
+
+int mmc_can_trim(struct mmc_card *card)
+{
+	if (card->ext_csd.sec_feature_support & EXT_CSD_SEC_GB_CL_EN)
+		return 1;
+	return 0;
+}
+EXPORT_SYMBOL(mmc_can_trim);
+
+int mmc_can_secure_erase_trim(struct mmc_card *card)
+{
+	if (card->ext_csd.sec_feature_support & EXT_CSD_SEC_ER_EN)
+		return 1;
+	return 0;
+}
+EXPORT_SYMBOL(mmc_can_secure_erase_trim);
+
+int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,
+			    unsigned int nr)
+{
+	if (!card->erase_size)
+		return 0;
+	if (from % card->erase_size || nr % card->erase_size)
+		return 0;
+	return 1;
+}
+EXPORT_SYMBOL(mmc_erase_group_aligned);
 
 void mmc_rescan(struct work_struct *work)
 {
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index a811c52a1659..9d9eef50e5d1 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -29,6 +29,8 @@ struct mmc_bus_ops {
 void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);
 void mmc_detach_bus(struct mmc_host *host);
 
+void mmc_init_erase(struct mmc_card *card);
+
 void mmc_set_chip_select(struct mmc_host *host, int mode);
 void mmc_set_clock(struct mmc_host *host, unsigned int hz);
 void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode);
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index ccba3869c029..6909a54c39be 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -108,13 +108,23 @@ static int mmc_decode_cid(struct mmc_card *card)
 	return 0;
 }
 
+static void mmc_set_erase_size(struct mmc_card *card)
+{
+	if (card->ext_csd.erase_group_def & 1)
+		card->erase_size = card->ext_csd.hc_erase_size;
+	else
+		card->erase_size = card->csd.erase_size;
+
+	mmc_init_erase(card);
+}
+
 /*
  * 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;
+	unsigned int e, m, a, b;
 	u32 *resp = card->raw_csd;
 
 	/*
@@ -152,6 +162,13 @@ static int mmc_decode_csd(struct mmc_card *card)
 	csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
 	csd->write_partial = UNSTUFF_BITS(resp, 21, 1);
 
+	if (csd->write_blkbits >= 9) {
+		a = UNSTUFF_BITS(resp, 42, 5);
+		b = UNSTUFF_BITS(resp, 37, 5);
+		csd->erase_size = (a + 1) * (b + 1);
+		csd->erase_size <<= csd->write_blkbits - 9;
+	}
+
 	return 0;
 }
 
@@ -261,8 +278,30 @@ static int mmc_read_ext_csd(struct mmc_card *card)
 		if (sa_shift > 0 && sa_shift <= 0x17)
 			card->ext_csd.sa_timeout =
 					1 << ext_csd[EXT_CSD_S_A_TIMEOUT];
+		card->ext_csd.erase_group_def =
+			ext_csd[EXT_CSD_ERASE_GROUP_DEF];
+		card->ext_csd.hc_erase_timeout = 300 *
+			ext_csd[EXT_CSD_ERASE_TIMEOUT_MULT];
+		card->ext_csd.hc_erase_size =
+			ext_csd[EXT_CSD_HC_ERASE_GRP_SIZE] << 10;
+	}
+
+	if (card->ext_csd.rev >= 4) {
+		card->ext_csd.sec_trim_mult =
+			ext_csd[EXT_CSD_SEC_TRIM_MULT];
+		card->ext_csd.sec_erase_mult =
+			ext_csd[EXT_CSD_SEC_ERASE_MULT];
+		card->ext_csd.sec_feature_support =
+			ext_csd[EXT_CSD_SEC_FEATURE_SUPPORT];
+		card->ext_csd.trim_timeout = 300 *
+			ext_csd[EXT_CSD_TRIM_MULT];
 	}
 
+	if (ext_csd[EXT_CSD_ERASED_MEM_CONT])
+		card->erased_byte = 0xFF;
+	else
+		card->erased_byte = 0x0;
+
 out:
 	kfree(ext_csd);
 
@@ -274,6 +313,8 @@ MMC_DEV_ATTR(cid, "%08x%08x%08x%08x\n", card->raw_cid[0], card->raw_cid[1],
 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(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);
@@ -285,6 +326,8 @@ static struct attribute *mmc_std_attrs[] = {
 	&dev_attr_cid.attr,
 	&dev_attr_csd.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,
@@ -421,6 +464,8 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 		err = mmc_read_ext_csd(card);
 		if (err)
 			goto free_card;
+		/* Erase size depends on CSD and Extended CSD */
+		mmc_set_erase_size(card);
 	}
 
 	/*
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index e6d7d9fab446..0f5241085557 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -119,6 +119,13 @@ static int mmc_decode_csd(struct mmc_card *card)
 		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:
 		/*
@@ -147,6 +154,7 @@ static int mmc_decode_csd(struct mmc_card *card)
 		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",
@@ -154,6 +162,8 @@ static int mmc_decode_csd(struct mmc_card *card)
 		return -EINVAL;
 	}
 
+	card->erase_size = csd->erase_size;
+
 	return 0;
 }
 
@@ -179,10 +189,68 @@ static int mmc_decode_scr(struct mmc_card *card)
 	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)
@@ -289,6 +357,8 @@ 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);
@@ -302,6 +372,8 @@ static struct attribute *sd_std_attrs[] = {
 	&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,
@@ -397,6 +469,16 @@ int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card,
 			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);
diff --git a/drivers/mmc/core/sd_ops.c b/drivers/mmc/core/sd_ops.c
index 63772e7e7608..797cdb5887fd 100644
--- a/drivers/mmc/core/sd_ops.c
+++ b/drivers/mmc/core/sd_ops.c
@@ -346,3 +346,51 @@ int mmc_sd_switch(struct mmc_card *card, int mode, int group,
 	return 0;
 }
 
+int mmc_app_sd_status(struct mmc_card *card, void *ssr)
+{
+	int err;
+	struct mmc_request mrq;
+	struct mmc_command cmd;
+	struct mmc_data data;
+	struct scatterlist sg;
+
+	BUG_ON(!card);
+	BUG_ON(!card->host);
+	BUG_ON(!ssr);
+
+	/* NOTE: caller guarantees ssr is heap-allocated */
+
+	err = mmc_app_cmd(card->host, card);
+	if (err)
+		return err;
+
+	memset(&mrq, 0, sizeof(struct mmc_request));
+	memset(&cmd, 0, sizeof(struct mmc_command));
+	memset(&data, 0, sizeof(struct mmc_data));
+
+	mrq.cmd = &cmd;
+	mrq.data = &data;
+
+	cmd.opcode = SD_APP_SD_STATUS;
+	cmd.arg = 0;
+	cmd.flags = MMC_RSP_SPI_R2 | MMC_RSP_R1 | MMC_CMD_ADTC;
+
+	data.blksz = 64;
+	data.blocks = 1;
+	data.flags = MMC_DATA_READ;
+	data.sg = &sg;
+	data.sg_len = 1;
+
+	sg_init_one(&sg, ssr, 64);
+
+	mmc_set_data_timeout(&data, card);
+
+	mmc_wait_for_req(card->host, &mrq);
+
+	if (cmd.error)
+		return cmd.error;
+	if (data.error)
+		return data.error;
+
+	return 0;
+}
diff --git a/drivers/mmc/core/sd_ops.h b/drivers/mmc/core/sd_ops.h
index 9742d8a30664..ffc2305d905f 100644
--- a/drivers/mmc/core/sd_ops.h
+++ b/drivers/mmc/core/sd_ops.h
@@ -19,6 +19,7 @@ int mmc_send_relative_addr(struct mmc_host *host, unsigned int *rca);
 int mmc_app_send_scr(struct mmc_card *card, u32 *scr);
 int mmc_sd_switch(struct mmc_card *card, int mode, int group,
 	u8 value, u8 *resp);
+int mmc_app_sd_status(struct mmc_card *card, void *ssr);
 
 #endif