3 files changed, 67 insertions, 2 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 1dbc18576219..5005a6323165 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -942,6 +942,38 @@ u32 mmc_select_voltage(struct mmc_host *host, u32 ocr)
 	return ocr;
 }
 
+int mmc_set_signal_voltage(struct mmc_host *host, int signal_voltage)
+{
+	struct mmc_command cmd = {0};
+	int err = 0;
+
+	BUG_ON(!host);
+
+	/*
+	 * Send CMD11 only if the request is to switch the card to
+	 * 1.8V signalling.
+	 */
+	if (signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
+		cmd.opcode = SD_SWITCH_VOLTAGE;
+		cmd.arg = 0;
+		cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
+
+		err = mmc_wait_for_cmd(host, &cmd, 0);
+		if (err)
+			return err;
+
+		if (!mmc_host_is_spi(host) && (cmd.resp[0] & R1_ERROR))
+			return -EIO;
+	}
+
+	host->ios.signal_voltage = signal_voltage;
+
+	if (host->ops->start_signal_voltage_switch)
+		err = host->ops->start_signal_voltage_switch(host, &host->ios);
+
+	return err;
+}
+
 /*
  * Select timing parameters for host.
  */
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index ca1fdde29df6..7745dea430b8 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -41,6 +41,7 @@ void mmc_set_bus_width(struct mmc_host *host, unsigned int width);
 void mmc_set_bus_width_ddr(struct mmc_host *host, unsigned int width,
 			   unsigned int ddr);
 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);
 
 static inline void mmc_delay(unsigned int ms)
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 6dac89fe0535..b0cd285d272a 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -403,6 +403,7 @@ struct device_type sd_type = {
 int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid)
 {
 	int err;
+	u32 rocr;
 
 	/*
 	 * Since we're changing the OCR value, we seem to
@@ -420,12 +421,38 @@ int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid)
 	 */
 	err = mmc_send_if_cond(host, ocr);
 	if (!err)
-		ocr |= 1 << 30;
+		ocr |= SD_OCR_CCS;
 
-	err = mmc_send_app_op_cond(host, ocr, NULL);
+	/*
+	 * If the host supports one of UHS-I modes, request the card
+	 * to switch to 1.8V signaling level.
+	 */
+	if (host->caps & (MMC_CAP_UHS_SDR12 | MMC_CAP_UHS_SDR25 |
+	    MMC_CAP_UHS_SDR50 | MMC_CAP_UHS_SDR104 | MMC_CAP_UHS_DDR50))
+		ocr |= SD_OCR_S18R;
+
+	/* If the host can supply more than 150mA, XPC should be set to 1. */
+	if (host->caps & (MMC_CAP_SET_XPC_330 | MMC_CAP_SET_XPC_300 |
+	    MMC_CAP_SET_XPC_180))
+		ocr |= SD_OCR_XPC;
+
+try_again:
+	err = mmc_send_app_op_cond(host, ocr, &rocr);
 	if (err)
 		return err;
 
+	/*
+	 * 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)) {
+		err = mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_180);
+		if (err) {
+			ocr &= ~SD_OCR_S18R;
+			goto try_again;
+		}
+	}
+
 	if (mmc_host_is_spi(host))
 		err = mmc_send_cid(host, cid);
 	else
@@ -773,6 +800,11 @@ int mmc_attach_sd(struct mmc_host *host)
 	BUG_ON(!host);
 	WARN_ON(!host->claimed);
 
+	/* Make sure we are at 3.3V signalling voltage */
+	err = mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330);
+	if (err)
+		return err;
+
 	err = mmc_send_app_op_cond(host, 0, &ocr);
 	if (err)
 		return err;