Re: Adding aliases to mmc

[Dirk Behme <dirk.behme-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Hi Fabio,

Am 18.09.2013 02:06, schrieb Fabio Estevam:
> Hi Dirk,
>
> On Tue, Sep 17, 2013 at 3:04 PM, Fabio Estevam <festevam-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> Hi Dirk,
>>
>> I have adapted your patch at:
>> http://lists.infradead.org/pipermail/linux-arm-kernel/2012-July/111022.html
>>
>> and tested it on 3.12-rc1 on a mx6qsabresd board.
>>
>> Do you have plans to submit it? Maybe as a RFC?
>>
>> It solves the mmcblkX order issue on my tests and it would be nice we
>> could have this problem addressed.
>
> I simplied your patch a bit:
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 1a3163f..94f842b 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -2026,7 +2026,7 @@ static struct mmc_blk_data
> *mmc_blk_alloc_req(struct mmc_card *card,
>       struct mmc_blk_data *md;
>       int devidx, ret;
>
> -    devidx = find_first_zero_bit(dev_use, max_devices);
> +    devidx = find_next_zero_bit(dev_use, max_devices, card->host->devidx);
>       if (devidx >= max_devices)
>           return ERR_PTR(-ENOSPC);
>       __set_bit(devidx, dev_use);
> @@ -2044,7 +2044,8 @@ static struct mmc_blk_data
> *mmc_blk_alloc_req(struct mmc_card *card,
>        * index anymore so we keep track of a name index.
>        */
>       if (!subname) {
> -        md->name_idx = find_first_zero_bit(name_use, max_devices);
> +        md->name_idx = find_next_zero_bit(name_use, max_devices,
> +                card->host->devidx);
>           __set_bit(md->name_idx, name_use);
>       } else
>           md->name_idx = ((struct mmc_blk_data *)
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c
> b/drivers/mmc/host/sdhci-esdhc-imx.c
> index abc8cf0..e11a6af 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -524,8 +524,9 @@ static int sdhci_esdhc_imx_probe(struct
> platform_device *pdev)
>       struct sdhci_pltfm_host *pltfm_host;
>       struct sdhci_host *host;
>       struct esdhc_platform_data *boarddata;
> -    int err;
> +    int err, ret;
>       struct pltfm_imx_data *imx_data;
> +    struct device_node *np = pdev->dev.of_node;
>
>       host = sdhci_pltfm_init(pdev, &sdhci_esdhc_imx_pdata, 0);
>       if (IS_ERR(host))
> @@ -602,6 +603,13 @@ static int sdhci_esdhc_imx_probe(struct
> platform_device *pdev)
>                       host->mmc->parent->platform_data);
>       }
>
> +
> +    if (np) {
> +        ret = of_alias_get_id(np, "mmcblk");
> +        if (ret >= 0)
> +            host->mmc->devidx = ret;
> +    }
> +
>       /* write_protect */
>       if (boarddata->wp_type == ESDHC_WP_GPIO) {
>           err = mmc_gpio_request_ro(host->mmc, boarddata->wp_gpio);
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 3b0c33a..8209f72 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -362,6 +362,8 @@ struct mmc_host {
>
>       unsigned int        slotno;    /* used for sdio acpi binding */
>
> +    /* preferred mmc block device index (mmcblkX) */
> +    unsigned int        devidx;
>       unsigned long        private[0] ____cacheline_aligned;
>   };
>
> What do you think?

Do you like to send this as a proper patch? Following the recent 
discussion it sounds to me that there is really some need for 
something like this. Then we could discuss the technical details.

Best regards

Dirk

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