Re: [PATCH 1/3] mmc: core: need do mmc_power_cycle in mmc_sdio_resend_if_cond
From: Matthias Kaehlcke
Date: Mon Apr 20 2020 - 15:15:24 EST
Hi,
On Tue, Apr 14, 2020 at 11:40:09AM +0800, Yong Mao wrote:
> From: yong mao <yong.mao@xxxxxxxxxxxx>
>
> When mmc_sdio_resned_if_cond is invoked, it indicates the SDIO
> device is not in the right state. In this condition, the previous
> implementation of mmc_sdio_resend_if_cond can't make sure SDIO
> device be back to idle state. mmc_power_cycle can reset the SDIO
> device by HW and also make sure SDIO device enter to idle state
> correctly.
>
> Signed-off-by: Yong Mao <yong.mao@xxxxxxxxxxxx>
> ---
> drivers/mmc/core/sdio.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
> index ebb387a..ada0a80 100644
> --- a/drivers/mmc/core/sdio.c
> +++ b/drivers/mmc/core/sdio.c
> @@ -546,6 +546,7 @@ static int mmc_sdio_init_uhs_card(struct mmc_card *card)
> static void mmc_sdio_resend_if_cond(struct mmc_host *host,
> struct mmc_card *card)
> {
> + mmc_power_cycle(host, host->card->ocr);
My MMC/SDIO background is limited, but it seems this isn't needed for the
vast majority of SDIO devices, otherwise it probably would have been added
earlier. I wonder if it would make sense to make the power cycle
conditional through a quirk, to limit it to the devices that need it.
> sdio_reset(host);
> mmc_go_idle(host);
> mmc_send_if_cond(host, host->ocr_avail);
> --
> 1.9.1