diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index ee32dd8..84cb8c3 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -623,6 +623,12 @@ static int mmc_sd_init_uhs_card(struct mmc_card *card)
 
 	/* Set current limit for the card */
 	err = sd_set_current_limit(card, status);
+	if (err)
+		goto out;
+
+	/* SPI mode doesn't define CMD19 */
+	if (!mmc_host_is_spi(card->host) && card->host->ops->execute_tuning)
+		err = card->host->ops->execute_tuning(card->host);
 
 out:
 	kfree(status);
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 9176911..85775cf 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -38,6 +38,8 @@
 #define SDHCI_USE_LEDS_CLASS
 #endif
 
+#define MAX_TUNING_LOOP 40
+
 static unsigned int debug_quirks = 0;
 
 static void sdhci_finish_data(struct sdhci_host *);
@@ -968,7 +970,9 @@ static void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
 		flags |= SDHCI_CMD_CRC;
 	if (cmd->flags & MMC_RSP_OPCODE)
 		flags |= SDHCI_CMD_INDEX;
-	if (cmd->data)
+
+	/* CMD19 is special in that the Data Present Select should be set */
+	if (cmd->data || (cmd->opcode == MMC_SEND_TUNING_BLOCK))
 		flags |= SDHCI_CMD_DATA;
 
 	sdhci_writew(host, SDHCI_MAKE_CMD(cmd->opcode, flags), SDHCI_COMMAND);
@@ -1502,12 +1506,162 @@ static int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
 		return 0;
 }
 
+static int sdhci_execute_tuning(struct mmc_host *mmc)
+{
+	struct sdhci_host *host;
+	u16 ctrl;
+	u32 ier;
+	int tuning_loop_counter = MAX_TUNING_LOOP;
+	unsigned long timeout;
+	int err = 0;
+
+	host = mmc_priv(mmc);
+
+	disable_irq(host->irq);
+	spin_lock(&host->lock);
+
+	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+
+	/*
+	 * Host Controller needs tuning only in case of SDR104 mode
+	 * and for SDR50 mode when Use Tuning for SDR50 is set in
+	 * Capabilities register.
+	 */
+	if (((ctrl & SDHCI_CTRL_UHS_MASK) == SDHCI_CTRL_UHS_SDR104) ||
+	    (((ctrl & SDHCI_CTRL_UHS_MASK) == SDHCI_CTRL_UHS_SDR50) &&
+	    (host->flags & SDHCI_SDR50_NEEDS_TUNING)))
+		ctrl |= SDHCI_CTRL_EXEC_TUNING;
+	else {
+		spin_unlock(&host->lock);
+		enable_irq(host->irq);
+		return 0;
+	}
+
+	sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
+
+	/*
+	 * As per the Host Controller spec v3.00, tuning command
+	 * generates Buffer Read Ready interrupt, so enable that.
+	 *
+	 * Note: The spec clearly says that when tuning sequence
+	 * is being performed, the controller does not generate
+	 * interrupts other than Buffer Read Ready interrupt. But
+	 * to make sure we don't hit a controller bug, we _only_
+	 * enable Buffer Read Ready interrupt here.
+	 */
+	ier = sdhci_readl(host, SDHCI_INT_ENABLE);
+	sdhci_clear_set_irqs(host, ier, SDHCI_INT_DATA_AVAIL);
+
+	/*
+	 * Issue CMD19 repeatedly till Execute Tuning is set to 0 or the number
+	 * of loops reaches 40 times or a timeout of 150ms occurs.
+	 */
+	timeout = 150;
+	do {
+		struct mmc_command cmd;
+		struct mmc_request mrq;
+
+		if (!tuning_loop_counter && !timeout)
+			break;
+
+		memset(&cmd, 0, sizeof(struct mmc_command));
+		cmd.opcode = MMC_SEND_TUNING_BLOCK;
+		cmd.arg = 0;
+		cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
+
+		memset(&cmd.resp, 0, sizeof(cmd.resp));
+		cmd.retries = 0;
+
+		cmd.data = NULL;
+		cmd.error = 0;
+
+		memset(&mrq, 0, sizeof(struct mmc_request));
+		mrq.cmd = &cmd;
+		host->mrq = &mrq;
+
+		/*
+		 * In response to CMD19, the card sends 64 bytes of tuning
+		 * block to the Host Controller. So we set the block size
+		 * to 64 here.
+		 */
+		sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 64), SDHCI_BLOCK_SIZE);
+
+		/*
+		 * The tuning block is sent by the card to the host controller.
+		 * So we set the TRNS_READ bit in the Transfer Mode register.
+		 * This also takes care of setting DMA Enable and Multi Block
+		 * Select in the same register to 0.
+		 */
+		sdhci_writew(host, SDHCI_TRNS_READ, SDHCI_TRANSFER_MODE);
+
+		sdhci_send_command(host, &cmd);
+
+		host->cmd = NULL;
+		host->mrq = NULL;
+
+		spin_unlock(&host->lock);
+		enable_irq(host->irq);
+
+		/* Wait for Buffer Read Ready interrupt */
+		wait_event_interruptible_timeout(host->buf_ready_int,
+					(host->tuning_done == 1),
+					msecs_to_jiffies(50));
+		disable_irq(host->irq);
+		spin_lock(&host->lock);
+
+		if (!host->tuning_done) {
+			printk(KERN_INFO DRIVER_NAME ": Timeout waiting for "
+				"Buffer Read Ready interrupt during tuning "
+				"procedure, falling back to fixed sampling "
+				"clock\n");
+			ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+			ctrl &= ~SDHCI_CTRL_TUNED_CLK;
+			ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
+			sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
+
+			err = -EIO;
+			goto out;
+		}
+
+		host->tuning_done = 0;
+
+		ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+		tuning_loop_counter--;
+		timeout--;
+		mdelay(1);
+	} while (ctrl & SDHCI_CTRL_EXEC_TUNING);
+
+	/*
+	 * The Host Driver has exhausted the maximum number of loops allowed,
+	 * so use fixed sampling frequency.
+	 */
+	if (!tuning_loop_counter || !timeout) {
+		ctrl &= ~SDHCI_CTRL_TUNED_CLK;
+		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
+	} else {
+		if (!(ctrl & SDHCI_CTRL_TUNED_CLK)) {
+			printk(KERN_INFO DRIVER_NAME ": Tuning procedure"
+				" failed, falling back to fixed sampling"
+				" clock\n");
+			err = -EIO;
+		}
+	}
+
+out:
+	sdhci_clear_set_irqs(host, SDHCI_INT_DATA_AVAIL, ier);
+	spin_unlock(&host->lock);
+	enable_irq(host->irq);
+
+	return err;
+}
+
 static const struct mmc_host_ops sdhci_ops = {
 	.request	= sdhci_request,
 	.set_ios	= sdhci_set_ios,
 	.get_ro		= sdhci_get_ro,
 	.enable_sdio_irq = sdhci_enable_sdio_irq,
 	.start_signal_voltage_switch	= sdhci_start_signal_voltage_switch,
+	.execute_tuning			= sdhci_execute_tuning,
 };
 
 /*****************************************************************************\
@@ -1725,6 +1879,16 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask)
 {
 	BUG_ON(intmask == 0);
 
+	/* CMD19 generates _only_ Buffer Read Ready interrupt */
+	if (intmask & SDHCI_INT_DATA_AVAIL) {
+		if (SDHCI_GET_CMD(sdhci_readw(host, SDHCI_COMMAND))
+		    == MMC_SEND_TUNING_BLOCK) {
+			host->tuning_done = 1;
+			wake_up(&host->buf_ready_int);
+			return;
+		}
+	}
+
 	if (!host->data) {
 		/*
 		 * The "data complete" interrupt is also used to
@@ -2161,6 +2325,10 @@ int sdhci_add_host(struct sdhci_host *host)
 	if (caps[1] & SDHCI_SUPPORT_DDR50)
 		mmc->caps |= MMC_CAP_UHS_DDR50;
 
+	/* Does the host needs tuning for SDR50? */
+	if (caps[1] & SDHCI_USE_SDR50_TUNING)
+		host->flags |= SDHCI_SDR50_NEEDS_TUNING;
+
 	/* Driver Type(s) (A, C, D) supported by the host */
 	if (caps[1] & SDHCI_DRIVER_TYPE_A)
 		mmc->caps |= MMC_CAP_DRIVER_TYPE_A;
@@ -2314,6 +2482,9 @@ int sdhci_add_host(struct sdhci_host *host)
 
 	setup_timer(&host->timer, sdhci_timeout_timer, (unsigned long)host);
 
+	if (host->version >= SDHCI_SPEC_300)
+		init_waitqueue_head(&host->buf_ready_int);
+
 	ret = request_irq(host->irq, sdhci_irq, IRQF_SHARED,
 		mmc_hostname(mmc), host);
 	if (ret)
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 5b12793..b32fc32 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -161,6 +161,8 @@
 #define   SDHCI_CTRL_DRV_TYPE_A		0x0010
 #define   SDHCI_CTRL_DRV_TYPE_C		0x0020
 #define   SDHCI_CTRL_DRV_TYPE_D		0x0030
+#define  SDHCI_CTRL_EXEC_TUNING		0x0040
+#define  SDHCI_CTRL_TUNED_CLK		0x0080
 #define  SDHCI_CTRL_PRESET_VAL_ENABLE	0x8000
 
 #define SDHCI_CAPABILITIES	0x40
@@ -188,6 +190,7 @@
 #define  SDHCI_DRIVER_TYPE_A	0x00000010
 #define  SDHCI_DRIVER_TYPE_C	0x00000020
 #define  SDHCI_DRIVER_TYPE_D	0x00000040
+#define  SDHCI_USE_SDR50_TUNING	0x00002000
 
 #define SDHCI_CAPABILITIES_1	0x44
 
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 52b5dc9..ca7007f 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -136,6 +136,7 @@ struct mmc_host_ops {
 	void	(*init_card)(struct mmc_host *host, struct mmc_card *card);
 
 	int	(*start_signal_voltage_switch)(struct mmc_host *host, struct mmc_ios *ios);
+	int	(*execute_tuning)(struct mmc_host *host);
 };
 
 struct mmc_card;
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 373b2bf..9fa5a73 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -50,6 +50,7 @@
 #define MMC_SET_BLOCKLEN         16   /* ac   [31:0] block len   R1  */
 #define MMC_READ_SINGLE_BLOCK    17   /* adtc [31:0] data addr   R1  */
 #define MMC_READ_MULTIPLE_BLOCK  18   /* adtc [31:0] data addr   R1  */
+#define MMC_SEND_TUNING_BLOCK    19   /* adtc                    R1  */
 
   /* class 3 */
 #define MMC_WRITE_DAT_UNTIL_STOP 20   /* adtc [31:0] data addr   R1  */
diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
index 92e1c9a..b74c853 100644
--- a/include/linux/mmc/sdhci.h
+++ b/include/linux/mmc/sdhci.h
@@ -111,6 +111,7 @@ struct sdhci_host {
 #define SDHCI_USE_ADMA		(1<<1)	/* Host is ADMA capable */
 #define SDHCI_REQ_USE_DMA	(1<<2)	/* Use DMA for this req. */
 #define SDHCI_DEVICE_DEAD	(1<<3)	/* Device unresponsive */
+#define SDHCI_SDR50_NEEDS_TUNING (1<<4)	/* SDR50 needs tuning */
 
 	unsigned int version;	/* SDHCI spec. version */
 
@@ -147,6 +148,9 @@ struct sdhci_host {
 	unsigned int            ocr_avail_sd;
 	unsigned int            ocr_avail_mmc;
 
+	wait_queue_head_t	buf_ready_int;	/* Waitqueue for Buffer Read Ready interrupt */
+	unsigned int		tuning_done;	/* Condition flag set when CMD19 succeeds */
+
 	unsigned long private[0] ____cacheline_aligned;
 };
 #endif /* __SDHCI_H */
