linux-kernel - Re: [PATCH v4] mmc: sdhci-of-esdhc: fixup PRESENT

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Date:   Tue, 15 Nov 2016 12:25:32 +0200
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Michael Walle <michael@...le.cc>, linux-kernel@...r.kernel.org
Cc:     linux-mmc@...r.kernel.org, Ulf Hansson <ulf.hansson@...aro.org>,
        yangbo lu <yangbo.lu@....com>,
        Alexander Stein <alexander.stein@...tec-electronic.com>
Subject: Re: [PATCH v4] mmc: sdhci-of-esdhc: fixup PRESENT_STATE read

On 15/11/16 12:13, Michael Walle wrote:
> 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()")
> Acked-by: Yangbo Lu <yangbo.lu@....com>

Acked-by: Adrian Hunter <adrian.hunter@...el.com>

> ---
> v4:
>  - add and use SDHCI_CMD_LVL macro
>  - fix typo in comment, thanks alex
>  - add acked-by
> 
> v3:
>  - explain the bits in the comments
>  - use bits[19:0] from the original value, all other will be taken from the
>    fixup value.
> 
> 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 | 14 ++++++++++++++
>  drivers/mmc/host/sdhci.h          |  1 +
>  2 files changed, 15 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-of-esdhc.c
> index fb71c86..1bb11e4 100644
> --- a/drivers/mmc/host/sdhci-of-esdhc.c
> +++ b/drivers/mmc/host/sdhci-of-esdhc.c
> @@ -66,6 +66,20 @@ static u32 esdhc_readl_fixup(struct sdhci_host *host,
>  			return ret;
>  		}
>  	}
> +	/*
> +	 * The DAT[3:0] line signal levels and the CMD line signal level are
> +	 * not compatible with standard SDHC register. The line signal levels
> +	 * DAT[7:0] are at bits 31:24 and the command line signal level is at
> +	 * bit 23. All other bits are the same as in the standard SDHC
> +	 * register.
> +	 */
> +	if (spec_reg == SDHCI_PRESENT_STATE) {
> +		ret = value & 0x000fffff;
> +		ret |= (value >> 4) & SDHCI_DATA_LVL_MASK;
> +		ret |= (value << 1) & SDHCI_CMD_LVL;
> +		return ret;
> +	}
> +
>  	ret = value;
>  	return ret;
>  }
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index c722cd2..ea38962 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -73,6 +73,7 @@
>  #define  SDHCI_DATA_LVL_MASK	0x00F00000
>  #define   SDHCI_DATA_LVL_SHIFT	20
>  #define   SDHCI_DATA_0_LVL_MASK	0x00100000
> +#define  SDHCI_CMD_LVL		0x01000000
>  
>  #define SDHCI_HOST_CONTROL	0x28
>  #define  SDHCI_CTRL_LED		0x01
>