mmc: sd: add support for driver type selection

This patch adds support for setting driver strength during UHS-I
initialization procedure. Since UHS-I cards set S18A (bit 24) in
response to ACMD41, we use this as a base for UHS-I initialization.
We modify the parameter list of mmc_sd_get_cid() so that we can
save the ROCR from ACMD41 to check whether bit 24 is set.

We decide whether the Host Controller supports A, C, or D driver
type depending on the Capabilities register. Driver type B is
suported by default. We then set the appropriate driver type for
the card using CMD6 mode 1. As per Host Controller spec v3.00, we
set driver type for the host only if Preset Value Enable in the
Host Control2 register is not set. SDHCI_HOST_CONTROL has been
renamed to SDHCI_HOST_CONTROL1 to conform to the spec.

Tested by Zhangfei Gao with a Toshiba uhs card and general hs card,
on mmp2 in SDMA mode.

Signed-off-by: Arindam Nath <arindam.nath@amd.com>
Reviewed-by: Philip Rakity <prakity@marvell.com>
Tested-by: Philip Rakity <prakity@marvell.com>
Acked-by: Zhangfei Gao <zhangfei.gao@marvell.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

5 files changed, 139 insertions, 29 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 5005a63..61c6c0b 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -984,6 +984,15 @@ void mmc_set_timing(struct mmc_host *host, unsigned int timing)
 }
 
 /*
+ * Select appropriate driver type for host.
+ */
+void mmc_set_driver_type(struct mmc_host *host, unsigned int drv_type)
+{
+	host->ios.drv_type = drv_type;
+	mmc_set_ios(host);
+}
+
+/*
  * Apply power to the MMC stack.  This is a two-stage process.
  * First, we enable power to the card without the clock running.
  * We then wait a bit for the power to stabilise.  Finally,
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 7745dea..93f3397 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -43,6 +43,7 @@ void mmc_set_bus_width_ddr(struct mmc_host *host, unsigned int width,
 u32 mmc_select_voltage(struct mmc_host *host, u32 ocr);
 int mmc_set_signal_voltage(struct mmc_host *host, int signal_voltage);
 void mmc_set_timing(struct mmc_host *host, unsigned int timing);
+void mmc_set_driver_type(struct mmc_host *host, unsigned int drv_type);
 
 static inline void mmc_delay(unsigned int ms)
 {
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 8285842..5b7c998 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -400,6 +400,98 @@ out:
 	return err;
 }
 
+static int sd_select_driver_type(struct mmc_card *card, u8 *status)
+{
+	int host_drv_type = 0, card_drv_type = 0;
+	int err;
+
+	/*
+	 * If the host doesn't support any of the Driver Types A,C or D,
+	 * default Driver Type B is used.
+	 */
+	if (!(card->host->caps & (MMC_CAP_DRIVER_TYPE_A | MMC_CAP_DRIVER_TYPE_C
+	    | MMC_CAP_DRIVER_TYPE_D)))
+		return 0;
+
+	if (card->host->caps & MMC_CAP_DRIVER_TYPE_A) {
+		host_drv_type = MMC_SET_DRIVER_TYPE_A;
+		if (card->sw_caps.sd3_drv_type & SD_DRIVER_TYPE_A)
+			card_drv_type = MMC_SET_DRIVER_TYPE_A;
+		else if (card->sw_caps.sd3_drv_type & SD_DRIVER_TYPE_B)
+			card_drv_type = MMC_SET_DRIVER_TYPE_B;
+		else if (card->sw_caps.sd3_drv_type & SD_DRIVER_TYPE_C)
+			card_drv_type = MMC_SET_DRIVER_TYPE_C;
+	} else if (card->host->caps & MMC_CAP_DRIVER_TYPE_C) {
+		host_drv_type = MMC_SET_DRIVER_TYPE_C;
+		if (card->sw_caps.sd3_drv_type & SD_DRIVER_TYPE_C)
+			card_drv_type = MMC_SET_DRIVER_TYPE_C;
+	} else if (!(card->host->caps & MMC_CAP_DRIVER_TYPE_D)) {
+		/*
+		 * If we are here, that means only the default driver type
+		 * B is supported by the host.
+		 */
+		host_drv_type = MMC_SET_DRIVER_TYPE_B;
+		if (card->sw_caps.sd3_drv_type & SD_DRIVER_TYPE_B)
+			card_drv_type = MMC_SET_DRIVER_TYPE_B;
+		else if (card->sw_caps.sd3_drv_type & SD_DRIVER_TYPE_C)
+			card_drv_type = MMC_SET_DRIVER_TYPE_C;
+	}
+
+	err = mmc_sd_switch(card, 1, 2, card_drv_type, status);
+	if (err)
+		return err;
+
+	if ((status[15] & 0xF) != card_drv_type) {
+		printk(KERN_WARNING "%s: Problem setting driver strength!\n",
+			mmc_hostname(card->host));
+		return 0;
+	}
+
+	mmc_set_driver_type(card->host, host_drv_type);
+
+	return 0;
+}
+
+/*
+ * UHS-I specific initialization procedure
+ */
+static int mmc_sd_init_uhs_card(struct mmc_card *card)
+{
+	int err;
+	u8 *status;
+
+	if (!card->scr.sda_spec3)
+		return 0;
+
+	if (!(card->csd.cmdclass & CCC_SWITCH))
+		return 0;
+
+	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;
+	}
+
+	/* Set 4-bit bus width */
+	if ((card->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 out;
+
+		mmc_set_bus_width(card->host, MMC_BUS_WIDTH_4);
+	}
+
+	/* Set the driver strength for the card */
+	err = sd_select_driver_type(card, status);
+
+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],
@@ -448,10 +540,9 @@ struct device_type sd_type = {
 /*
  * Fetch CID from card.
  */
-int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid)
+int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid, u32 *rocr)
 {
 	int err;
-	u32 rocr;
 
 	/*
 	 * Since we're changing the OCR value, we seem to
@@ -485,7 +576,7 @@ int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid)
 		ocr |= SD_OCR_XPC;
 
 try_again:
-	err = mmc_send_app_op_cond(host, ocr, &rocr);
+	err = mmc_send_app_op_cond(host, ocr, rocr);
 	if (err)
 		return err;
 
@@ -493,7 +584,8 @@ try_again:
 	 * In case CCS and S18A in the response is set, start Signal Voltage
 	 * Switch procedure. SPI mode doesn't support CMD11.
 	 */
-	if (!mmc_host_is_spi(host) && ((rocr & 0x41000000) == 0x41000000)) {
+	if (!mmc_host_is_spi(host) && rocr &&
+	   ((*rocr & 0x41000000) == 0x41000000)) {
 		err = mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_180);
 		if (err) {
 			ocr &= ~SD_OCR_S18R;
@@ -628,11 +720,12 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
 	struct mmc_card *card;
 	int err;
 	u32 cid[4];
+	u32 rocr = 0;
 
 	BUG_ON(!host);
 	WARN_ON(!host->claimed);
 
-	err = mmc_sd_get_cid(host, ocr, cid);
+	err = mmc_sd_get_cid(host, ocr, cid, &rocr);
 	if (err)
 		return err;
 
@@ -685,30 +778,37 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
 	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);
+	/* Initialization sequence for UHS-I cards */
+	if (rocr & SD_ROCR_S18A) {
+		err = mmc_sd_init_uhs_card(card);
 		if (err)
 			goto free_card;
+	} else {
+		/*
+		 * 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));
 
-		mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
+		/*
+		 * 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;
diff --git a/drivers/mmc/core/sd.h b/drivers/mmc/core/sd.h
index 3d8800f..4b34b24 100644
--- a/drivers/mmc/core/sd.h
+++ b/drivers/mmc/core/sd.h
@@ -5,7 +5,7 @@
 
 extern struct device_type sd_type;
 
-int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid);
+int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid, u32 *rocr);
 int mmc_sd_get_csd(struct mmc_host *host, struct mmc_card *card);
 void mmc_decode_cid(struct mmc_card *card);
 int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card,
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 1e60959..4d0c15b 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -369,8 +369,8 @@ static int mmc_sdio_init_card(struct mmc_host *host, u32 ocr,
 		goto err;
 	}
 
-	if (ocr & R4_MEMORY_PRESENT
-	    && mmc_sd_get_cid(host, host->ocr & ocr, card->raw_cid) == 0) {
+	if ((ocr & R4_MEMORY_PRESENT) &&
+	    mmc_sd_get_cid(host, host->ocr & ocr, card->raw_cid, NULL) == 0) {
 		card->type = MMC_TYPE_SD_COMBO;
 
 		if (oldcard && (oldcard->type != MMC_TYPE_SD_COMBO ||