Re: [PATCH] mmc: dwmmc: Add quirk for broken Hardware Config

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On 16 July 2012 14:15, Girish K S <girish.shivananjappa@xxxxxxxxxx> wrote:
> In some Soc'S that integrate Designware mmc host controllers, the
> HCON register is broken. The hardware configuration is not
> updated. One specific usecase is the IDMAC. In Exysons5 SoC
> there exist a internal DMA, but the HCON register's DMA_INTERFACE
> field is not set to indicate its existance.
>
> This quirk can be used in such case to force the existance broken
> HCON field.
>
> Signed-off-by: Girish K S <girish.shivananjappa@xxxxxxxxxx>
> ---
This patch is based on Thomas Abraham's patch series for device tree support
>  drivers/mmc/host/dw_mmc-pltfm.c |    5 +++++
>  drivers/mmc/host/dw_mmc.c       |   11 ++++++++++-
>  drivers/mmc/host/dw_mmc.h       |    1 +
>  include/linux/mmc/host.h        |    1 +
>  4 files changed, 17 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/mmc/host/dw_mmc-pltfm.c b/drivers/mmc/host/dw_mmc-pltfm.c
> index 900f412..24ea485 100644
> --- a/drivers/mmc/host/dw_mmc-pltfm.c
> +++ b/drivers/mmc/host/dw_mmc-pltfm.c
> @@ -35,9 +35,14 @@ static unsigned long exynos5250_dwmmc_caps[4] = {
>         MMC_CAP_CMD23,
>  };
>
> +static unsigned long exynos5250_dwmmc_caps2[1] = {
> +       MMC_CAP2_CONFIG_BROKEN,
> +};
> +
>  static struct dw_mci_drv_data exynos5250_drv_data = {
>         .ctrl_type      = DW_MCI_TYPE_EXYNOS5250,
>         .caps           = exynos5250_dwmmc_caps,
> +       .caps2          = exynos5250_dwmmc_caps2,
>  };
>
>  static const struct of_device_id dw_mci_pltfm_match[] = {
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 1a59a92..030224c 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -431,7 +431,13 @@ static int dw_mci_idmac_init(struct dw_mci *host)
>         /* Check if Hardware Configuration Register has support for DMA */
>         dma_support = (mci_readl(host, HCON) >> 16) & 0x3;
>
> -       if (!dma_support || dma_support > 2) {
> +       /*
> +        * In Some of the Soc's the HCON Register is broken. Even though the
> +        * Soc's has a internal DMA the HCON register's DMA field doesnt
> +        * show it. So additional quirk is added for such Soc's
> +        */
> +       if ((!dma_support || dma_support > 2) &&
> +               !((u32)host->drv_data->caps2 & MMC_CAP2_CONFIG_BROKEN)) {
>                 dev_err(&host->dev,
>                         "Host Controller does not support IDMA Tx.\n");
>                 host->dma_ops = NULL;
> @@ -1957,6 +1963,9 @@ static int __init dw_mci_init_slot(struct dw_mci *host, unsigned int id)
>         if (host->pdata->caps2)
>                 mmc->caps2 = host->pdata->caps2;
>
> +       if (host->drv_data->caps2)
> +               mmc->caps2 |= host->drv_data->caps2[ctrl_id];
> +
>         if (host->pdata->get_bus_wd) {
>                 if (host->pdata->get_bus_wd(slot->id) >= 4)
>                         mmc->caps |= MMC_CAP_4_BIT_DATA;
> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
> index 6c17282..8c4810a 100644
> --- a/drivers/mmc/host/dw_mmc.h
> +++ b/drivers/mmc/host/dw_mmc.h
> @@ -203,6 +203,7 @@ extern int dw_mci_resume(struct dw_mci *host);
>  struct dw_mci_drv_data {
>         unsigned long           ctrl_type;
>         unsigned long           *caps;
> +       unsigned long           *caps2;
>  };
>
>  #endif /* _DW_MMC_H_ */
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 65c64ee..ab5c7f9 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -261,6 +261,7 @@ struct mmc_host {
>  #define MMC_CAP2_HC_ERASE_SZ   (1 << 9)        /* High-capacity erase size */
>  #define MMC_CAP2_CD_ACTIVE_HIGH        (1 << 10)       /* Card-detect signal active high */
>  #define MMC_CAP2_RO_ACTIVE_HIGH        (1 << 11)       /* Write-protect signal active high */
> +#define MMC_CAP2_CONFIG_BROKEN (1 << 12)       /* Broken Config Register */
>
>         mmc_pm_flag_t           pm_caps;        /* supported pm features */
>         unsigned int        power_notify_type;
> --
> 1.7.4.1
>
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