Re: [PATCH 06/12] mmc: sd: add support for uhs bus speed mode selection

Philip Rakity
2011-03-09T21:46:42Z

On Feb 15, 2011, at 1:35 AM, Arindam Nath wrote:

> This patch adds support for setting UHS-I bus speed mode during UHS-I
> initialization procedure. Since both the host and card can support
> more than one bus speed, we select the highest speed based on both of
> their capabilities. First we set the bus speed mode for the card using
> CMD6 mode 1, and then we program the host controller to support the
> required speed mode. We also set High Speed Enable in case one of the
> UHS-I modes is selected. Since MMC_TIMING_UHS_SDR25 is same as
> MMC_TIMING_SD_HS, we don't need to set the SDHCI_CTRL_HISPD flag for
> UHS SDR25 again. We also take care to reset SD clock before setting
> UHS mode in the Host Control2 register, and then re-enable it as per
> the Host Controller spec v3.00. We set the clock frequency for the
> UHS-I mode selected.
>
> Signed-off-by: Arindam Nath <arindam.nath@amd.com>
> ---
> drivers/mmc/core/sd.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++
> drivers/mmc/host/sdhci.c | 32 +++++++++++++++++-
> drivers/mmc/host/sdhci.h | 5 +++
> include/linux/mmc/card.h | 16 +++++++++
> include/linux/mmc/host.h | 4 ++
> 5 files changed, 137 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
> index 9e4574d..e681385 100644
> --- a/drivers/mmc/core/sd.c
> +++ b/drivers/mmc/core/sd.c
> @@ -464,6 +464,83 @@ static int sd_select_driver_type(struct mmc_card *card, u8 *status)
> return 0;
> }
>
> +static int sd_set_bus_speed_mode(struct mmc_card *card, u8 *status)
> +{
> + unsigned int bus_speed, timing;

warning may not be initialized. bus_speed

> + int err;
> +
> + /*
> + * If the host doesn't support any of the UHS-I modes, fallback on
> + * default speed.
> + */
> + if (!(card->host->caps & (MMC_CAP_UHS_SDR50 | MMC_CAP_UHS_SDR104 |
> + MMC_CAP_UHS_DDR50)))
> + return 0;
> +
> + if (card->host->caps & MMC_CAP_UHS_SDR104) {
> + if (card->sw_caps.uhs_bus_mode & SD_MODE_UHS_SDR104) {
> + bus_speed = UHS_SDR104_BUS_SPEED;
> + timing = MMC_TIMING_UHS_SDR104;
> + card->sw_caps.uhs_max_dtr = UHS_SDR104_MAX_DTR;
> + } else if (card->sw_caps.uhs_bus_mode & SD_MODE_UHS_SDR50) {
> + bus_speed = UHS_SDR50_BUS_SPEED;
> + timing = MMC_TIMING_UHS_SDR50;
> + card->sw_caps.uhs_max_dtr = UHS_SDR50_MAX_DTR;
> + } else if (card->sw_caps.uhs_bus_mode & SD_MODE_UHS_DDR50) {
> + bus_speed = UHS_DDR50_BUS_SPEED;
> + timing = MMC_TIMING_UHS_DDR50;
> + card->sw_caps.uhs_max_dtr = UHS_DDR50_MAX_DTR;
> + } else if (card->sw_caps.uhs_bus_mode & SD_MODE_UHS_SDR25) {
> + bus_speed = UHS_SDR25_BUS_SPEED;
> + timing = MMC_TIMING_UHS_SDR25;
> + card->sw_caps.uhs_max_dtr = UHS_SDR25_MAX_DTR;
> + }
> + } else if (card->host->caps & MMC_CAP_UHS_SDR50) {
> + if ((card->sw_caps.uhs_bus_mode & SD_MODE_UHS_SDR104) ||
> + (card->sw_caps.uhs_bus_mode & SD_MODE_UHS_SDR50)) {
> + bus_speed = UHS_SDR50_BUS_SPEED;
> + timing = MMC_TIMING_UHS_SDR50;
> + card->sw_caps.uhs_max_dtr = UHS_SDR50_MAX_DTR;
> + } else if (card->sw_caps.uhs_bus_mode & SD_MODE_UHS_DDR50) {
> + bus_speed = UHS_DDR50_BUS_SPEED;
> + timing = MMC_TIMING_UHS_DDR50;
> + card->sw_caps.uhs_max_dtr = UHS_DDR50_MAX_DTR;
> + } else if (card->sw_caps.uhs_bus_mode & SD_MODE_UHS_SDR25) {
> + bus_speed = UHS_SDR25_BUS_SPEED;
> + timing = MMC_TIMING_UHS_SDR25;
> + card->sw_caps.uhs_max_dtr = UHS_SDR25_MAX_DTR;
> + }
> + } else if (card->host->caps & MMC_CAP_UHS_DDR50) {
> + if ((card->sw_caps.uhs_bus_mode & SD_MODE_UHS_SDR104) ||
> + (card->sw_caps.uhs_bus_mode & SD_MODE_UHS_SDR50) ||
> + (card->sw_caps.uhs_bus_mode & SD_MODE_UHS_DDR50)) {
> + bus_speed = UHS_DDR50_BUS_SPEED;
> + timing = MMC_TIMING_UHS_DDR50;
> + card->sw_caps.uhs_max_dtr = UHS_DDR50_MAX_DTR;
> + } else if (card->sw_caps.uhs_bus_mode & SD_MODE_UHS_SDR25) {
> + bus_speed = UHS_SDR25_BUS_SPEED;
> + timing = MMC_TIMING_UHS_SDR25;
> + card->sw_caps.uhs_max_dtr = UHS_SDR25_MAX_DTR;
> + }
> + }
> +
> + err = mmc_sd_switch(card, 1, 0, bus_speed, status);
> + if (err)
> + return err;
> +
> + if ((status[16] & 0xF) != bus_speed)
> + printk(KERN_WARNING "%s: Problem setting bus speed mode!\n",
> + mmc_hostname(card->host));
> + else {
> + if (bus_speed) {
> + mmc_set_timing(card->host, timing);
> + mmc_set_clock(card->host, card->sw_caps.uhs_max_dtr);
> + }
> + }
> +
> + return 0;
> +}
> +
> /*
> * UHS-I specific initialization procedure
> */
> @@ -499,6 +576,11 @@ static int mmc_sd_init_uhs_card(struct mmc_card *card)
>
> /* Set the driver strength for the card */
> err = sd_select_driver_type(card, status);
> + if (err)
> + goto out;
> +
> + /* Set bus speed mode of the card */
> + err = sd_set_bus_speed_mode(card, status);
>
> out:
> kfree(status);
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 5db0109..ae91c6b 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1281,7 +1281,13 @@ static void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> ctrl &= ~SDHCI_CTRL_HISPD;
>
> if (host->version >= SDHCI_SPEC_300) {
> - u16 ctrl_2;
> + u16 clk, ctrl_2;
> +
> + /* In case of UHS-I modes, set High Speed Enable */
> + if ((ios->timing == MMC_TIMING_UHS_SDR50) ||
> + (ios->timing == MMC_TIMING_UHS_SDR104) ||
> + (ios->timing == MMC_TIMING_UHS_DDR50))
> + ctrl |= SDHCI_CTRL_HISPD;
>
> ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> if (!(ctrl_2 & SDHCI_CTRL_PRESET_VAL_ENABLE)) {
> @@ -1303,7 +1309,6 @@ static void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> * need to reset SD Clock Enable before changing High
> * Speed Enable to avoid generating clock gliches.
> */
> - u16 clk;
>
> /* Reset SD Clock Enable */
> clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
> @@ -1316,6 +1321,29 @@ static void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> clk |= SDHCI_CLOCK_CARD_EN;
> sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
> }
> +
> + ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> +
> + /* Select Bus Speed Mode for host */
> + if (ios->timing == MMC_TIMING_UHS_SDR25)
> + ctrl_2 |= SDHCI_CTRL_UHS_SDR25;
> + else if (ios->timing == MMC_TIMING_UHS_SDR50)
> + ctrl_2 |= SDHCI_CTRL_UHS_SDR50;
> + else if (ios->timing == MMC_TIMING_UHS_SDR104)
> + ctrl_2 |= SDHCI_CTRL_UHS_SDR104;
> + else if (ios->timing == MMC_TIMING_UHS_DDR50)
> + ctrl_2 |= SDHCI_CTRL_UHS_DDR50;
> +
> + /* Reset SD Clock Enable */
> + clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
> + clk &= ~SDHCI_CLOCK_CARD_EN;
> + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
> +
> + sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
> +
> + /* Re-enable SD Clock */
> + clk |= SDHCI_CLOCK_CARD_EN;
> + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
> } else
> sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL1);
>
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index a407b5b..5bf244d 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -150,6 +150,11 @@
> #define SDHCI_ACMD12_ERR 0x3C
>
> #define SDHCI_HOST_CONTROL2 0x3E
> +#define SDHCI_CTRL_UHS_SDR12 0x0000
> +#define SDHCI_CTRL_UHS_SDR25 0x0001
> +#define SDHCI_CTRL_UHS_SDR50 0x0002
> +#define SDHCI_CTRL_UHS_SDR104 0x0003
> +#define SDHCI_CTRL_UHS_DDR50 0x0004
> #define SDHCI_CTRL_VDD_180 0x0008
> #define SDHCI_CTRL_DRV_TYPE_B 0x0000
> #define SDHCI_CTRL_DRV_TYPE_A 0x0010
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index 2d7f7a3..0b24c41 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -75,7 +75,23 @@ struct sd_ssr {
>
> struct sd_switch_caps {
> unsigned int hs_max_dtr;
> + unsigned int uhs_max_dtr;
> +#define UHS_SDR104_MAX_DTR 208000000
> +#define UHS_SDR50_MAX_DTR 100000000
> +#define UHS_DDR50_MAX_DTR 50000000
> +#define UHS_SDR25_MAX_DTR 50000000
> unsigned int uhs_bus_mode;
> +#define UHS_SDR12_BUS_SPEED 0
> +#define UHS_SDR25_BUS_SPEED 1
> +#define UHS_SDR50_BUS_SPEED 2
> +#define UHS_SDR104_BUS_SPEED 3
> +#define UHS_DDR50_BUS_SPEED 4
> +
> +#define SD_MODE_UHS_SDR12 (1 << UHS_SDR12_BUS_SPEED)
> +#define SD_MODE_UHS_SDR25 (1 << UHS_SDR25_BUS_SPEED)
> +#define SD_MODE_UHS_SDR50 (1 << UHS_SDR50_BUS_SPEED)
> +#define SD_MODE_UHS_SDR104 (1 << UHS_SDR104_BUS_SPEED)
> +#define SD_MODE_UHS_DDR50 (1 << UHS_DDR50_BUS_SPEED)
> unsigned int uhs_drv_type;
> #define SD_DRIVER_TYPE_B 0x01
> #define SD_DRIVER_TYPE_A 0x02
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index e6ae4c4..0a21839 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -50,6 +50,10 @@ struct mmc_ios {
> #define MMC_TIMING_LEGACY 0
> #define MMC_TIMING_MMC_HS 1
> #define MMC_TIMING_SD_HS 2
> +#define MMC_TIMING_UHS_SDR25 MMC_TIMING_SD_HS
> +#define MMC_TIMING_UHS_SDR50 3
> +#define MMC_TIMING_UHS_SDR104 4
> +#define MMC_TIMING_UHS_DDR50 5
>
> unsigned char ddr; /* dual data rate used */
>
> --
> 1.7.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html