[PATCH] mmc: sdhci-of-at91: force card detect value for non removable devices

[PATCH] mmc: sdhci-of-at91: force card detect value for non removable devices

[Ludovic Desroches]

When the device is non removable, the card detect signal is often use
for another purpose i.e. muxed to another SoC peripheral or used as a
GPIO. It could lead to wrong behaviors depending the defaut value of
this signal if not muxed to the SDHCI controller.

Fixes: bb5f8ea4d514 ("mmc: sdhci-of-at91: introduce driver for the Atmel SDMMC")
Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
---
 drivers/mmc/host/sdhci-of-at91.c | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
index 88e9b5f35a62..6a389f35396e 100644
--- a/drivers/mmc/host/sdhci-of-at91.c
+++ b/drivers/mmc/host/sdhci-of-at91.c
@@ -31,6 +31,7 @@
 
 #define SDMMC_MC1R	0x204
 #define		SDMMC_MC1R_DDR		BIT(3)
+#define		SDMMC_MC1R_FCD		BIT(7)
 #define SDMMC_CACR	0x230
 #define		SDMMC_CACR_CAPWREN	BIT(0)
 #define		SDMMC_CACR_KEY		(0x46 << 8)
@@ -44,6 +45,15 @@ struct sdhci_at91_priv {
 	bool restore_needed;
 };
 
+static void sdhci_at91_set_force_card_detect(struct sdhci_host *host)
+{
+	u8 mc1r;
+
+	mc1r = readb(host->ioaddr + SDMMC_MC1R);
+	mc1r |= SDMMC_MC1R_FCD;
+	writeb(mc1r, host->ioaddr + SDMMC_MC1R);
+}
+
 static void sdhci_at91_set_clock(struct sdhci_host *host, unsigned int clock)
 {
 	u16 clk;
@@ -111,10 +121,18 @@ void sdhci_at91_set_uhs_signaling(struct sdhci_host *host, unsigned int timing)
 	sdhci_set_uhs_signaling(host, timing);
 }
 
+static void sdhci_at91_reset(struct sdhci_host *host, u8 mask)
+{
+	sdhci_reset(host, mask);
+
+	if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
+		sdhci_at91_set_force_card_detect(host);
+}
+
 static const struct sdhci_ops sdhci_at91_sama5d2_ops = {
 	.set_clock		= sdhci_at91_set_clock,
 	.set_bus_width		= sdhci_set_bus_width,
-	.reset			= sdhci_reset,
+	.reset			= sdhci_at91_reset,
 	.set_uhs_signaling	= sdhci_at91_set_uhs_signaling,
 	.set_power		= sdhci_at91_set_power,
 };
@@ -369,6 +387,22 @@ static int sdhci_at91_probe(struct platform_device *pdev)
 		host->quirks &= ~SDHCI_QUIRK_BROKEN_CARD_DETECTION;
 	}
 
+	/*
+	 * If the device attached to the MMC bus is not removable, it is safer
+	 * to set the Force Card Detect bit. People often don't connect the
+	 * card detect signal and use this pin for another purpose. If the card
+	 * detect pin is not muxed to SDHCI controller, a default value is
+	 * used. This value can be different from a SoC revision to another
+	 * one. Problems come when this default value is not card present. To
+	 * avoid this case, if the device is non removable then the card
+	 * detection procedure using the SDMCC_CD signal is bypassed.
+	 * This bit is resetted when a software reset for all command is
+	 * performed so we need to implement our own reset function to set back
+	 * this bit.
+	 */
+	if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
+		sdhci_at91_set_force_card_detect(host);
+
 	pm_runtime_put_autosuspend(&pdev->dev);
 
 	return 0;
-- 
2.12.2

Re: [PATCH] mmc: sdhci-of-at91: force card detect value for non removable devices

[Adrian Hunter]

On 26/07/17 17:02, Ludovic Desroches wrote:
> When the device is non removable, the card detect signal is often use

use -> used

> for another purpose i.e. muxed to another SoC peripheral or used as a
> GPIO. It could lead to wrong behaviors depending the defaut value of

defaut -> default

> this signal if not muxed to the SDHCI controller.
> 
> Fixes: bb5f8ea4d514 ("mmc: sdhci-of-at91: introduce driver for the Atmel SDMMC")
> Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>

Apart from spelling

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

> ---
>  drivers/mmc/host/sdhci-of-at91.c | 36 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 35 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
> index 88e9b5f35a62..6a389f35396e 100644
> --- a/drivers/mmc/host/sdhci-of-at91.c
> +++ b/drivers/mmc/host/sdhci-of-at91.c
> @@ -31,6 +31,7 @@
>  
>  #define SDMMC_MC1R	0x204
>  #define		SDMMC_MC1R_DDR		BIT(3)
> +#define		SDMMC_MC1R_FCD		BIT(7)
>  #define SDMMC_CACR	0x230
>  #define		SDMMC_CACR_CAPWREN	BIT(0)
>  #define		SDMMC_CACR_KEY		(0x46 << 8)
> @@ -44,6 +45,15 @@ struct sdhci_at91_priv {
>  	bool restore_needed;
>  };
>  
> +static void sdhci_at91_set_force_card_detect(struct sdhci_host *host)
> +{
> +	u8 mc1r;
> +
> +	mc1r = readb(host->ioaddr + SDMMC_MC1R);
> +	mc1r |= SDMMC_MC1R_FCD;
> +	writeb(mc1r, host->ioaddr + SDMMC_MC1R);
> +}
> +
>  static void sdhci_at91_set_clock(struct sdhci_host *host, unsigned int clock)
>  {
>  	u16 clk;
> @@ -111,10 +121,18 @@ void sdhci_at91_set_uhs_signaling(struct sdhci_host *host, unsigned int timing)
>  	sdhci_set_uhs_signaling(host, timing);
>  }
>  
> +static void sdhci_at91_reset(struct sdhci_host *host, u8 mask)
> +{
> +	sdhci_reset(host, mask);
> +
> +	if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
> +		sdhci_at91_set_force_card_detect(host);
> +}
> +
>  static const struct sdhci_ops sdhci_at91_sama5d2_ops = {
>  	.set_clock		= sdhci_at91_set_clock,
>  	.set_bus_width		= sdhci_set_bus_width,
> -	.reset			= sdhci_reset,
> +	.reset			= sdhci_at91_reset,
>  	.set_uhs_signaling	= sdhci_at91_set_uhs_signaling,
>  	.set_power		= sdhci_at91_set_power,
>  };
> @@ -369,6 +387,22 @@ static int sdhci_at91_probe(struct platform_device *pdev)
>  		host->quirks &= ~SDHCI_QUIRK_BROKEN_CARD_DETECTION;
>  	}
>  
> +	/*
> +	 * If the device attached to the MMC bus is not removable, it is safer
> +	 * to set the Force Card Detect bit. People often don't connect the
> +	 * card detect signal and use this pin for another purpose. If the card
> +	 * detect pin is not muxed to SDHCI controller, a default value is
> +	 * used. This value can be different from a SoC revision to another
> +	 * one. Problems come when this default value is not card present. To
> +	 * avoid this case, if the device is non removable then the card
> +	 * detection procedure using the SDMCC_CD signal is bypassed.
> +	 * This bit is resetted when a software reset for all command is

resetted -> reset

> +	 * performed so we need to implement our own reset function to set back
> +	 * this bit.
> +	 */
> +	if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
> +		sdhci_at91_set_force_card_detect(host);
> +
>  	pm_runtime_put_autosuspend(&pdev->dev);
>  
>  	return 0;
> 

Re: [PATCH] mmc: sdhci-of-at91: force card detect value for non removable devices

[Ulf Hansson]

On 26 July 2017 at 16:02, Ludovic Desroches
<ludovic.desroches@microchip.com> wrote:
> When the device is non removable, the card detect signal is often use
> for another purpose i.e. muxed to another SoC peripheral or used as a
> GPIO. It could lead to wrong behaviors depending the defaut value of
> this signal if not muxed to the SDHCI controller.
>
> Fixes: bb5f8ea4d514 ("mmc: sdhci-of-at91: introduce driver for the Atmel SDMMC")
> Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>

Thanks, applied for fixes and added a stable tag.

I also fixed some spellings according to the comments from Adrian.

Kind regards
Uffe

> ---
>  drivers/mmc/host/sdhci-of-at91.c | 36 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
> index 88e9b5f35a62..6a389f35396e 100644
> --- a/drivers/mmc/host/sdhci-of-at91.c
> +++ b/drivers/mmc/host/sdhci-of-at91.c
> @@ -31,6 +31,7 @@
>
>  #define SDMMC_MC1R     0x204
>  #define                SDMMC_MC1R_DDR          BIT(3)
> +#define                SDMMC_MC1R_FCD          BIT(7)
>  #define SDMMC_CACR     0x230
>  #define                SDMMC_CACR_CAPWREN      BIT(0)
>  #define                SDMMC_CACR_KEY          (0x46 << 8)
> @@ -44,6 +45,15 @@ struct sdhci_at91_priv {
>         bool restore_needed;
>  };
>
> +static void sdhci_at91_set_force_card_detect(struct sdhci_host *host)
> +{
> +       u8 mc1r;
> +
> +       mc1r = readb(host->ioaddr + SDMMC_MC1R);
> +       mc1r |= SDMMC_MC1R_FCD;
> +       writeb(mc1r, host->ioaddr + SDMMC_MC1R);
> +}
> +
>  static void sdhci_at91_set_clock(struct sdhci_host *host, unsigned int clock)
>  {
>         u16 clk;
> @@ -111,10 +121,18 @@ void sdhci_at91_set_uhs_signaling(struct sdhci_host *host, unsigned int timing)
>         sdhci_set_uhs_signaling(host, timing);
>  }
>
> +static void sdhci_at91_reset(struct sdhci_host *host, u8 mask)
> +{
> +       sdhci_reset(host, mask);
> +
> +       if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
> +               sdhci_at91_set_force_card_detect(host);
> +}
> +
>  static const struct sdhci_ops sdhci_at91_sama5d2_ops = {
>         .set_clock              = sdhci_at91_set_clock,
>         .set_bus_width          = sdhci_set_bus_width,
> -       .reset                  = sdhci_reset,
> +       .reset                  = sdhci_at91_reset,
>         .set_uhs_signaling      = sdhci_at91_set_uhs_signaling,
>         .set_power              = sdhci_at91_set_power,
>  };
> @@ -369,6 +387,22 @@ static int sdhci_at91_probe(struct platform_device *pdev)
>                 host->quirks &= ~SDHCI_QUIRK_BROKEN_CARD_DETECTION;
>         }
>
> +       /*
> +        * If the device attached to the MMC bus is not removable, it is safer
> +        * to set the Force Card Detect bit. People often don't connect the
> +        * card detect signal and use this pin for another purpose. If the card
> +        * detect pin is not muxed to SDHCI controller, a default value is
> +        * used. This value can be different from a SoC revision to another
> +        * one. Problems come when this default value is not card present. To
> +        * avoid this case, if the device is non removable then the card
> +        * detection procedure using the SDMCC_CD signal is bypassed.
> +        * This bit is resetted when a software reset for all command is
> +        * performed so we need to implement our own reset function to set back
> +        * this bit.
> +        */
> +       if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
> +               sdhci_at91_set_force_card_detect(host);
> +
>         pm_runtime_put_autosuspend(&pdev->dev);
>
>         return 0;
> --
> 2.12.2
>