RE: [PATCH v1 1/1] mmc: sd: UHS-I bus speed should be set last in UHS initialization

Subhash Jadavani
2011-08-05T16:25:09Z

Chris, Arindam, Philip,

Please let me know you comments on this reworked patch.

Regards,
Subhash

> -----Original Message-----
> From: linux-arm-msm-owner@vger.kernel.org [mailto:linux-arm-msm-
> owner@vger.kernel.org] On Behalf Of Subhash Jadavani
> Sent: Thursday, August 04, 2011 4:08 PM
> To: linux-mmc@vger.kernel.org
> Cc: linux-arm-msm@vger.kernel.org; Subhash Jadavani
> Subject: [PATCH v1 1/1] mmc: sd: UHS-I bus speed should be set last in
> UHS initialization
>
> mmc_sd_init_uhs_card function sets the driver type, current limit
> and bus speed mode on card as well as on host controller side.
>
> Currently bus speed mode is set by sending CMD6 to card and
> immediately setting the timing mode in host controller. But
> then before initiating tuning sequence, it also tries to set
> current limit by sending CMD6 to card which results in data
> timeout errors in controller if bus speed mode is SDR50/SDR104 mode.
>
> So basically bus speed mode should be set only after current limit
> is set in the card and immediately after setting the bus speed mode,
> tuning sequence should be initiated.
>
> Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
> ---
> drivers/mmc/core/sd.c | 65 ++++++++++++++++++++++++++++++++++-------
> --------
> 1 files changed, 45 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
> index ff27741..769e587 100644
> --- a/drivers/mmc/core/sd.c
> +++ b/drivers/mmc/core/sd.c
> @@ -459,10 +459,9 @@ 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)
> +static int sd_get_bus_speed_mode(struct mmc_card *card)
> {
> - unsigned int bus_speed = 0, timing = 0;
> - int err;
> + int bus_speed = 0;
>
> /*
> * If the host doesn't support any of the UHS-I modes, fallback
> on
> @@ -475,32 +474,57 @@ static int sd_set_bus_speed_mode(struct mmc_card
> *card, u8 *status)
> if ((card->host->caps & MMC_CAP_UHS_SDR104) &&
> (card->sw_caps.sd3_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->host->caps & MMC_CAP_UHS_DDR50) &&
> (card->sw_caps.sd3_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->host->caps & (MMC_CAP_UHS_SDR104 |
> MMC_CAP_UHS_SDR50)) && (card->sw_caps.sd3_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->host->caps & (MMC_CAP_UHS_SDR104 |
> MMC_CAP_UHS_SDR50 | MMC_CAP_UHS_SDR25)) &&
> (card->sw_caps.sd3_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_SDR104 |
> MMC_CAP_UHS_SDR50 | MMC_CAP_UHS_SDR25 |
> MMC_CAP_UHS_SDR12)) && (card->sw_caps.sd3_bus_mode &
> SD_MODE_UHS_SDR12)) {
> bus_speed = UHS_SDR12_BUS_SPEED;
> - timing = MMC_TIMING_UHS_SDR12;
> - card->sw_caps.uhs_max_dtr = UHS_SDR12_MAX_DTR;
> + }
> +
> + return bus_speed;
> +}
> +
> +static int sd_set_bus_speed_mode(struct mmc_card *card, u8 *status)
> +{
> + int err, bus_speed;
> + unsigned int timing = 0;
> +
> + bus_speed = sd_get_bus_speed_mode(card);
> +
> + switch (bus_speed) {
> + case UHS_SDR104_BUS_SPEED:
> + timing = MMC_TIMING_UHS_SDR104;
> + card->sw_caps.uhs_max_dtr = UHS_SDR104_MAX_DTR;
> + break;
> + case UHS_DDR50_BUS_SPEED:
> + timing = MMC_TIMING_UHS_DDR50;
> + card->sw_caps.uhs_max_dtr = UHS_DDR50_MAX_DTR;
> + break;
> + case UHS_SDR50_BUS_SPEED:
> + timing = MMC_TIMING_UHS_SDR50;
> + card->sw_caps.uhs_max_dtr = UHS_SDR50_MAX_DTR;
> + break;
> + case UHS_SDR25_BUS_SPEED:
> + timing = MMC_TIMING_UHS_SDR25;
> + card->sw_caps.uhs_max_dtr = UHS_SDR25_MAX_DTR;
> + break;
> + case UHS_SDR12_BUS_SPEED:
> + timing = MMC_TIMING_UHS_SDR12;
> + card->sw_caps.uhs_max_dtr = UHS_SDR12_MAX_DTR;
> + break;
> + default:
> + return 0;
> }
>
> card->sd_bus_speed = bus_speed;
> @@ -522,6 +546,7 @@ static int sd_set_bus_speed_mode(struct mmc_card
> *card, u8 *status)
> static int sd_set_current_limit(struct mmc_card *card, u8 *status)
> {
> int current_limit = 0;
> + unsigned int bus_speed = sd_get_bus_speed_mode(card);
> int err;
>
> /*
> @@ -529,9 +554,9 @@ static int sd_set_current_limit(struct mmc_card
> *card, u8 *status)
> * bus speed modes. For other bus speed modes, we set the default
> * current limit of 200mA.
> */
> - if ((card->sd_bus_speed == UHS_SDR50_BUS_SPEED) ||
> - (card->sd_bus_speed == UHS_SDR104_BUS_SPEED) ||
> - (card->sd_bus_speed == UHS_DDR50_BUS_SPEED)) {
> + if ((bus_speed == UHS_SDR50_BUS_SPEED) ||
> + (bus_speed == UHS_SDR104_BUS_SPEED) ||
> + (bus_speed == UHS_DDR50_BUS_SPEED)) {
> if (card->host->caps & MMC_CAP_MAX_CURRENT_800) {
> if (card->sw_caps.sd3_curr_limit &
> SD_MAX_CURRENT_800)
> current_limit = SD_SET_CURRENT_LIMIT_800;
> @@ -613,13 +638,13 @@ static int mmc_sd_init_uhs_card(struct mmc_card
> *card)
> if (err)
> goto out;
>
> - /* Set bus speed mode of the card */
> - err = sd_set_bus_speed_mode(card, status);
> + /* Set current limit for the card */
> + err = sd_set_current_limit(card, status);
> if (err)
> goto out;
>
> - /* Set current limit for the card */
> - err = sd_set_current_limit(card, status);
> + /* Set bus speed mode of the card */
> + err = sd_set_bus_speed_mode(card, status);
> if (err)
> goto out;
>
> --
> 1.7.1.1
>
> --
> Sent by a consultant of the Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
> Forum.
>
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