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Commit 4c4cb171 authored by Philip Rakity's avatar Philip Rakity Committed by Chris Ball
Browse files

mmc: core: add support for eMMC Dual Data Rate 



eMMC voltage change not required for 1.8V.  3.3V and 1.8V vcc
are capable of doing DDR. vccq of 1.8v is not required.

Signed-off-by: default avatarPhilip Rakity <prakity@marvell.com>
Reviewed-by: default avatarArindam Nath <arindam.nath@amd.com>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 261bbd46

drivers/mmc/core/core.c

+2 −12
Original line number Diff line number Diff line
@@ -717,23 +717,13 @@ void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode) 
	mmc_set_ios(host);

}



/*

 * Change data bus width and DDR mode of a host.

 */

void mmc_set_bus_width_ddr(struct mmc_host *host, unsigned int width,

			   unsigned int ddr)

{

	host->ios.bus_width = width;

	host->ios.ddr = ddr;

	mmc_set_ios(host);

}



/*

 * Change data bus width of a host.

 */

void mmc_set_bus_width(struct mmc_host *host, unsigned int width)

{

	mmc_set_bus_width_ddr(host, width, MMC_SDR_MODE);

	host->ios.bus_width = width;

	mmc_set_ios(host);

}



/**

drivers/mmc/core/core.h

+0 −2
Original line number Diff line number Diff line
@@ -38,8 +38,6 @@ void mmc_ungate_clock(struct mmc_host *host); 
void mmc_set_ungated(struct mmc_host *host);

void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode);

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,

			   bool cmd11);

drivers/mmc/core/mmc.c

+30 −5
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include "core.h"

#include "bus.h"

#include "mmc_ops.h"

#include "sd_ops.h"



static const unsigned int tran_exp[] = {

	10000,		100000,		1000000,	10000000,
@@ -633,10 +634,14 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr, 
	 */

	if (mmc_card_highspeed(card)) {

		if ((card->ext_csd.card_type & EXT_CSD_CARD_TYPE_DDR_1_8V)

			&& (host->caps & (MMC_CAP_1_8V_DDR)))

			&& ((host->caps & (MMC_CAP_1_8V_DDR |

			     MMC_CAP_UHS_DDR50))

				== (MMC_CAP_1_8V_DDR | MMC_CAP_UHS_DDR50)))

				ddr = MMC_1_8V_DDR_MODE;

		else if ((card->ext_csd.card_type & EXT_CSD_CARD_TYPE_DDR_1_2V)

			&& (host->caps & (MMC_CAP_1_2V_DDR)))

			&& ((host->caps & (MMC_CAP_1_2V_DDR |

			     MMC_CAP_UHS_DDR50))

				== (MMC_CAP_1_2V_DDR | MMC_CAP_UHS_DDR50)))

				ddr = MMC_1_2V_DDR_MODE;

	}
@@ -670,8 +675,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr, 
					 ext_csd_bits[idx][0],

					 0);

			if (!err) {

				mmc_set_bus_width_ddr(card->host,

						      bus_width, MMC_SDR_MODE);

				mmc_set_bus_width(card->host, bus_width);

				/*

				 * If controller can't handle bus width test,

				 * use the highest bus width to maintain
@@ -697,8 +701,29 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr, 
				1 << bus_width, ddr);

			goto free_card;

		} else if (ddr) {

			/*

			 * eMMC cards can support 3.3V to 1.2V i/o (vccq)

			 * signaling.

			 *

			 * EXT_CSD_CARD_TYPE_DDR_1_8V means 3.3V or 1.8V vccq.

			 *

			 * 1.8V vccq at 3.3V core voltage (vcc) is not required

			 * in the JEDEC spec for DDR.

			 *

			 * Do not force change in vccq since we are obviously

			 * working and no change to vccq is needed.

			 *

			 * WARNING: eMMC rules are NOT the same as SD DDR

			 */

			if (ddr == EXT_CSD_CARD_TYPE_DDR_1_2V) {

				err = mmc_set_signal_voltage(host,

					MMC_SIGNAL_VOLTAGE_120, 0);

				if (err)

					goto err;

			}

			mmc_card_set_ddr_mode(card);

			mmc_set_bus_width_ddr(card->host, bus_width, ddr);

			mmc_set_timing(card->host, MMC_TIMING_UHS_DDR50);

			mmc_set_bus_width(card->host, bus_width);

		}

	}

include/linux/mmc/host.h

+1 −0
Original line number Diff line number Diff line
@@ -66,6 +66,7 @@ struct mmc_ios { 


#define MMC_SIGNAL_VOLTAGE_330	0

#define MMC_SIGNAL_VOLTAGE_180	1

#define MMC_SIGNAL_VOLTAGE_120	2



	unsigned char	drv_type;		/* driver type (A, B, C, D) */