Hi Philip, > -----Original Message----- > From: Philip Rakity [mailto:prakity@xxxxxxxxxxx] > Sent: Saturday, April 23, 2011 1:57 AM > To: linux-mmc@xxxxxxxxxxxxxxx > Cc: Nath, Arindam > Subject: [PATCH] mmc: 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: Philip Rakity <prakity@xxxxxxxxxxx> > --- > drivers/mmc/core/core.c | 14 ++------------ > drivers/mmc/core/core.h | 2 -- > drivers/mmc/core/mmc.c | 33 ++++++++++++++++++++++++++++----- > include/linux/mmc/host.h | 1 + > 4 files changed, 31 insertions(+), 19 deletions(-) > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c > index 91ab31f..69df00c 100644 > --- a/drivers/mmc/core/core.c > +++ b/drivers/mmc/core/core.c > @@ -720,22 +720,12 @@ void mmc_set_bus_mode(struct mmc_host *host, > unsigned int mode) > } > > /* > - * 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); > } > > /** > diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h > index 6114ca5..c5d0e8b 100644 > --- a/drivers/mmc/core/core.h > +++ b/drivers/mmc/core/core.h > @@ -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); > void mmc_set_timing(struct mmc_host *host, unsigned int timing); > void mmc_set_driver_type(struct mmc_host *host, unsigned int > drv_type); > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c > index ba1c878..f4b675b 100644 > --- a/drivers/mmc/core/mmc.c > +++ b/drivers/mmc/core/mmc.c > @@ -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 +634,12 @@ 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 +673,7 @@ 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 +699,29 @@ 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); Will this call really have any effect? *cmd11* argument is 0, so CMD11 won't be sent in this case. Also since there is no handler in my sdhci_start_signal_voltage_switch() for MMC_SIGNAL_VOLTAGE_120, the function will simply return 0. Thanks, Arindam -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
