RE: [PATCH] sdhci: Add quirk and device tree parameter to force SD test mode

[Haibo Chen]

> -----Original Message-----
> From: linux-mmc-owner@xxxxxxxxxxxxxxx [mailto:linux-mmc-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Zach Brown
> Sent: Tuesday, August 23, 2016 6:56 AM
> To: adrian.hunter@xxxxxxxxx
> Cc: ulf.hansson@xxxxxxxxxx; mark.rutland@xxxxxxx; robh+dt@xxxxxxxxxx;
> linux-mmc@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH] sdhci: Add quirk and device tree parameter to force SD test
> mode
> 
> From: Jaeden Amero <jaeden.amero@xxxxxx>
> 
> On some devices, CD is broken so that we must force the SDHCI into test mode
> and set CD, so that it always detects an SD card as present.
> 
> In order to get a device with broken CD working, we had previously always set
> the SDHCI into test mode. Unfortunately, this had the side effect of making all
> SD cards used with our Linux kernels undetectable and non-removable.

Why not use the poll mode? You can set the flag MMC_CAP_NEEDS_POLL, then 
the mmc core will detect the card every second.

> 
> By making this "SD test mode" setting optional via a quirk, we can avoid this
> side effect for devices other than the device with broken CD.
> Additionally, we add a device parameter to sdhci-pltfm to allow all SDHCI
> drivers to enable this quirk.
> 
> Signed-off-by: Jaeden Amero <jaeden.amero@xxxxxx>
> Signed-off-by: Zach Brown <zach.brown@xxxxxx>
> ---
>  Documentation/devicetree/bindings/mmc/mmc.txt | 2 ++
>  drivers/mmc/host/sdhci-pltfm.c                | 4 ++++
>  drivers/mmc/host/sdhci.c                      | 9 +++++++++
>  drivers/mmc/host/sdhci.h                      | 4 ++++
>  4 files changed, 19 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt
> b/Documentation/devicetree/bindings/mmc/mmc.txt
> index 22d1e1f..3a9be41 100644
> --- a/Documentation/devicetree/bindings/mmc/mmc.txt
> +++ b/Documentation/devicetree/bindings/mmc/mmc.txt
> @@ -52,6 +52,8 @@ Optional properties:
>  - no-sdio: controller is limited to send sdio cmd during initialization
>  - no-sd: controller is limited to send sd cmd during initialization
>  - no-mmc: controller is limited to send mmc cmd during initialization
> +- force-sd-cd-test-mode: card detection is broken on device, force cd
> +test
> +  enable and cd test inserted so host will always detect a card.
> 
>  *NOTE* on CD and WP polarity. To use common for all SD/MMC host
> controllers line  polarity properties, we have to fix the meaning of the "normal"
> and "inverted"
> diff --git a/drivers/mmc/host/sdhci-pltfm.c b/drivers/mmc/host/sdhci-pltfm.c
> index 1d17dcf..056d101 100644
> --- a/drivers/mmc/host/sdhci-pltfm.c
> +++ b/drivers/mmc/host/sdhci-pltfm.c
> @@ -87,6 +87,10 @@ void sdhci_get_of_property(struct platform_device
> *pdev)
>  	if (of_get_property(np, "broken-cd", NULL))
>  		host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
> 
> +	if (of_get_property(np, "force-sd-cd-test-mode", NULL))
> +		host->quirks2 |=
> +			SDHCI_QUIRK2_MUST_FORCE_SD_CD_TEST_MODE;
> +
>  	if (of_get_property(np, "no-1-8-v", NULL))
>  		host->quirks2 |= SDHCI_QUIRK2_NO_1_8_V;
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index
> cd65d47..2f4c6f9 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -117,6 +117,15 @@ static inline bool sdhci_data_line_cmd(struct
> mmc_command *cmd)  static void sdhci_set_card_detection(struct sdhci_host
> *host, bool enable)  {
>  	u32 present;
> +	u8  ctrl;
> +
> +	if (host->quirks2 & SDHCI_QUIRK2_MUST_FORCE_SD_CD_TEST_MODE)
> {
> +		/* Put the card in test mode, with card inserted */
> +		ctrl = sdhci_readl(host, SDHCI_HOST_CONTROL);
> +		ctrl |= SDHCI_CTRL_CD_TEST_INSERTED |
> +			SDHCI_CTRL_CD_TEST_ENABLE;
> +		sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
> +	}
> 
>  	if ((host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION) ||
>  	    !mmc_card_is_removable(host->mmc))
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index
> 0411c9f..dd609b2 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -84,6 +84,8 @@
>  #define   SDHCI_CTRL_ADMA32	0x10
>  #define   SDHCI_CTRL_ADMA64	0x18
>  #define   SDHCI_CTRL_8BITBUS	0x20
> +#define  SDHCI_CTRL_CD_TEST_INSERTED	0x40
> +#define  SDHCI_CTRL_CD_TEST_ENABLE	0x80
> 
>  #define SDHCI_POWER_CONTROL	0x29
>  #define  SDHCI_POWER_ON		0x01
> @@ -422,6 +424,8 @@ struct sdhci_host {
>  #define SDHCI_QUIRK2_ACMD23_BROKEN			(1<<14)
>  /* Broken Clock divider zero in controller */
>  #define SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN		(1<<15)
> +/* Controller must support device with broken CD */
> +#define SDHCI_QUIRK2_MUST_FORCE_SD_CD_TEST_MODE		(1<<16)
> 
>  	int irq;		/* Device IRQ */
>  	void __iomem *ioaddr;	/* Mapped address */
> --
> 2.7.4
> 
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