linux-kernel - RE: [PATCH v2] mmc: sdhci-of-esdhc: fixup PRESENT

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Date:   Mon, 14 Nov 2016 03:00:03 +0000
From:   "Y.B. Lu" <yangbo.lu@....com>
To:     Michael Walle <michael@...le.cc>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        yangbo lu <yangbo.lu@...escale.com>
Subject: RE: [PATCH v2] mmc: sdhci-of-esdhc: fixup PRESENT_STATE read

> -----Original Message-----
> From: Michael Walle [mailto:michael@...le.cc]
> Sent: Saturday, November 12, 2016 12:04 AM
> To: linux-kernel@...r.kernel.org
> Cc: linux-mmc@...r.kernel.org; Ulf Hansson; Adrian Hunter; yangbo lu;
> Michael Walle
> Subject: [PATCH v2] mmc: sdhci-of-esdhc: fixup PRESENT_STATE read
> 
> Since commit 87a18a6a5652 ("mmc: mmc: Use ->card_busy() to detect busy
> cards in __mmc_switch()") the ESDHC driver is broken:
>   mmc0: Card stuck in programming state! __mmc_switch
>   mmc0: error -110 whilst initialising MMC card
> 
> Since this commit __mmc_switch() uses ->card_busy(), which is
> sdhci_card_busy() for the esdhc driver. sdhci_card_busy() uses the
> PRESENT_STATE register, specifically the DAT0 signal level bit. But the
> ESDHC uses a non-conformant PRESENT_STATE register, thus a read fixup is
> required to make the driver work again.
> 
> Signed-off-by: Michael Walle <michael@...le.cc>
> Fixes: 87a18a6a5652 ("mmc: mmc: Use ->card_busy() to detect busy cards in
> __mmc_switch()")
> ---
> v2:
>  - use lower bits of the original value (that was actually a typo)
>  - add fixes tag
>  - fix typo
> 
>  drivers/mmc/host/sdhci-of-esdhc.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-
> of-esdhc.c
> index fb71c86..f9c84bb 100644
> --- a/drivers/mmc/host/sdhci-of-esdhc.c
> +++ b/drivers/mmc/host/sdhci-of-esdhc.c
> @@ -66,6 +66,18 @@ static u32 esdhc_readl_fixup(struct sdhci_host *host,
>  			return ret;
>  		}
>  	}
> +	/*
> +	 * The DAT[3:0] line signal levels and the CMD line signal level is
> +	 * not compatible with standard SDHC register. Move the
> corresponding
> +	 * bits around.
> +	 */
> +	if (spec_reg == SDHCI_PRESENT_STATE) {
> +		ret = value & ~0xf8000000;

[Lu Yangbo-B47093] I think the bits which should be cleaned before following '|=' are 0x01f00000 not 0xf8000000, right?
:)

> +		ret |= (value >> 4) & SDHCI_DATA_LVL_MASK;
> +		ret |= (value << 1) & 0x01000000;
> +		return ret;
> +	}
> +
>  	ret = value;
>  	return ret;
>  }
> --
> 2.1.4