From: "Subhash Jadavani" <subhashj@codeaurora.org>
To: arindam.nath@amd.com
Cc: linux-mmc@vger.kernel.org, linux-arm-msm@vger.kernel.org,
Subhash Jadavani <subhashj@codeaurora.org>
Subject: Re: [PATCH v2 1/1] mmc: sd: UHS-I bus speed should be set last in UHS initialization
Date: Mon, 22 Aug 2011 02:47:16 -0700 (PDT) [thread overview]
Message-ID: <9ee37b38ae8b93ce66b7b9daa0d08d9f.squirrel@www.codeaurora.org> (raw)
In-Reply-To: <1312872571-12091-1-git-send-email-subhashj@codeaurora.org>
Hi Arindam,
Can you please check if this patch looks ok or not?
Regards,
Subhash
> 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 | 81
> ++++++++++++++++++++++++++++++++-----------------
> 1 files changed, 53 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
> index e2dcf23..2191dda 100644
> --- a/drivers/mmc/core/sd.c
> +++ b/drivers/mmc/core/sd.c
> @@ -459,56 +459,75 @@ 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 void sd_update_bus_speed_mode(struct mmc_card *card)
> {
> - unsigned int bus_speed = 0, timing = 0;
> - 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_SDR12 | MMC_CAP_UHS_SDR25 |
> - MMC_CAP_UHS_SDR50 | MMC_CAP_UHS_SDR104 | MMC_CAP_UHS_DDR50)))
> - return 0;
> + MMC_CAP_UHS_SDR50 | MMC_CAP_UHS_SDR104 | MMC_CAP_UHS_DDR50))) {
> + card->sd_bus_speed = 0;
> + return;
> + }
>
> 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;
> + card->sd_bus_speed = UHS_SDR104_BUS_SPEED;
> } 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;
> + card->sd_bus_speed = UHS_DDR50_BUS_SPEED;
> } 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;
> + card->sd_bus_speed = UHS_SDR50_BUS_SPEED;
> } 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;
> + card->sd_bus_speed = UHS_SDR25_BUS_SPEED;
> } 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;
> + card->sd_bus_speed = UHS_SDR12_BUS_SPEED;
> + }
> +}
> +
> +static int sd_set_bus_speed_mode(struct mmc_card *card, u8 *status)
> +{
> + int err;
> + unsigned int timing = 0;
> +
> + switch (card->sd_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;
> - err = mmc_sd_switch(card, 1, 0, bus_speed, status);
> + err = mmc_sd_switch(card, 1, 0, card->sd_bus_speed, status);
> if (err)
> return err;
>
> - if ((status[16] & 0xF) != bus_speed)
> + if ((status[16] & 0xF) != card->sd_bus_speed)
> printk(KERN_WARNING "%s: Problem setting bus speed mode!\n",
> mmc_hostname(card->host));
> else {
> @@ -608,18 +627,24 @@ static int mmc_sd_init_uhs_card(struct mmc_card
> *card)
> mmc_set_bus_width(card->host, MMC_BUS_WIDTH_4);
> }
>
> + /*
> + * Select the bus speed mode depending on host
> + * and card capability.
> + */
> + sd_update_bus_speed_mode(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);
> + /* 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.
>
>
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
next prev parent reply other threads:[~2011-08-22 9:47 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-09 6:49 [PATCH v2 1/1] mmc: sd: UHS-I bus speed should be set last in UHS initialization Subhash Jadavani
2011-08-22 9:47 ` Subhash Jadavani [this message]
[not found] ` <000201cc6189$fdb73d40$f925b7c0$@org>
2011-08-23 12:14 ` Nath, Arindam
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