[U-Boot] [U-BOOT] mmc: sdhci: Enable 8-bit bus width only for 3.0 spec onwards

[Jagannadha Sutradharudu Teki]

Request for an update on this.

Thanks,
Jagan.

> -----Original Message-----
> From: Jagannadha Sutradharudu Teki [mailto:jagannadha.sutradharudu-
> teki at xilinx.com]
> Sent: 21 May 2013 15:02
> To: u-boot at lists.denx.de
> Cc: monstr at monstr.eu; Andy Fleming; Jagannadha Sutradharudu Teki
> Subject: [U-BOOT] mmc: sdhci: Enable 8-bit bus width only for 3.0 spec onwards
>
> CAP register don't have any information for 8-bit buswidth support on 2.0 sdhci
> spec, only from 3.0 onwards bit[18] got this information.
>
> Due to this misassignment in sdhci, mmc is setting 8-bit buswidth using
> mmc_set_bus_width even if controller doesn't support.
> Below change has code information.
> "mmc: Properly determine maximum supported bus width"
> (sha1: 7798f6dbd5e1a3030ed81a81da5dfb57c3307cac)
>
> Bug log: <mmc plus and emmc cards)
> -------
> zynq-uboot> mmcinfo
> Error detected in status(0x208100)!
> Device: zynq_sdhci
> Manufacturer ID: fe
> .....
>
> So enable 8-bit support only for 3.0 spec using CAP and for below 3.0 assign
> mmc->host_caps = MMC_MODE_8BIT on respective platform driver if host have
> a support.
>
> Signed-off-by: Jagannadha Sutradharudu Teki <jaganna at xilinx.com>
> ---
>  drivers/mmc/sdhci.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c index 1eaea04..c5631bf
> 100644
> --- a/drivers/mmc/sdhci.c
> +++ b/drivers/mmc/sdhci.c
> @@ -486,8 +486,10 @@ int add_sdhci(struct sdhci_host *host, u32 max_clk,
> u32 min_clk)
>               mmc->voltages |= host->voltages;
>
>       mmc->host_caps = MMC_MODE_HS | MMC_MODE_HS_52MHz |
> MMC_MODE_4BIT;
> -     if (caps & SDHCI_CAN_DO_8BIT)
> -             mmc->host_caps |= MMC_MODE_8BIT;
> +     if ((host->version & SDHCI_SPEC_VER_MASK) >= SDHCI_SPEC_300) {
> +             if (caps & SDHCI_CAN_DO_8BIT)
> +                     mmc->host_caps |= MMC_MODE_8BIT;
> +     }
>       if (host->host_caps)
>               mmc->host_caps |= host->host_caps;
>
> --
> 1.7.4
>



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