linux-kernel - Re: [PATCH v4 2/2] sdhci-of-arasan: Set controller to test mode when xlnx-fails-without-test-cd is present

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Message-ID: <43273dd9-16d9-e6cb-49cd-fb924310a386@xilinx.com>
Date:   Wed, 7 Sep 2016 07:15:02 +0200
From:   Michal Simek <michal.simek@...inx.com>
To:     Zach Brown <zach.brown@...com>, <adrian.hunter@...el.com>
CC:     <robh+dt@...nel.org>, <ulf.hansson@...aro.org>,
        <mark.rutland@....com>, <linux-mmc@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <michal.simek@...inx.com>, <soren.brinkmann@...inx.com>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v4 2/2] sdhci-of-arasan: Set controller to test mode when
 xlnx-fails-without-test-cd is present

On 6.9.2016 22:34, Zach Brown wrote:
> The sdhci controller on xilinx zynq devices will not function unless
> the CD bit is provided. http://www.xilinx.com/support/answers/61064.html
> In cases where it is impossible to provide the CD bit in hardware,
> setting the controller to test mode and then setting inserted to true
> will get the controller to function without the CD bit.
> 
> When the device has the property xlnx-fails-without-test-cd the driver
> changes the controller to test mode and sets test inserted to true to
> make the controller function.
> 
> Signed-off-by: Zach Brown <zach.brown@...com>
> ---
>  drivers/mmc/host/sdhci-of-arasan.c | 34 +++++++++++++++++++++++++++++++++-
>  drivers/mmc/host/sdhci.h           |  2 ++
>  2 files changed, 35 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
> index b6f4c1d..63b0c2a 100644
> --- a/drivers/mmc/host/sdhci-of-arasan.c
> +++ b/drivers/mmc/host/sdhci-of-arasan.c
> @@ -23,6 +23,7 @@
>  #include <linux/of_device.h>
>  #include <linux/phy/phy.h>
>  #include "sdhci-pltfm.h"
> +#include <linux/of.h>
>  
>  #define SDHCI_ARASAN_CLK_CTRL_OFFSET	0x2c
>  
> @@ -38,6 +39,10 @@
>  struct sdhci_arasan_data {
>  	struct clk	*clk_ahb;
>  	struct phy	*phy;
> +	unsigned int arasan_quirks; /* Arasan deviations from spec */
> +
> +/* Controller does not have CD wired and will not function normally without */
> +#define SDHCI_ARASAN_QUIRK_FAILS_WITHOUT_TEST_CD (1<<0)

Also here. If it is fine not to use BIT macro here you should at least
fix coding style (1 << 0)


>  };
>  
>  static unsigned int sdhci_arasan_get_timeout_clock(struct sdhci_host *host)
> @@ -79,12 +84,32 @@ static void sdhci_arasan_set_clock(struct sdhci_host *host, unsigned int clock)
>  	}
>  }
>  
> +void sdhci_arasan_reset(struct sdhci_host *host, u8 mask)
> +{
> +	u8 ctrl;
> +	struct sdhci_pltfm_host *pltfm_host;
> +	struct sdhci_arasan_data *sdhci_arasan;
> +
> +	sdhci_reset(host, mask);
> +
> +	pltfm_host = sdhci_priv(host);
> +	sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
> +
> +	if (sdhci_arasan->arasan_quirks &
> +	     SDHCI_ARASAN_QUIRK_FAILS_WITHOUT_TEST_CD) {
> +		ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
> +		ctrl |= SDHCI_CTRL_CDTEST_INS |
> +			SDHCI_CTRL_CDTEST_EN;
> +		sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
> +	}
> +}
> +
>  static struct sdhci_ops sdhci_arasan_ops = {
>  	.set_clock = sdhci_arasan_set_clock,
>  	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
>  	.get_timeout_clock = sdhci_arasan_get_timeout_clock,
>  	.set_bus_width = sdhci_set_bus_width,
> -	.reset = sdhci_reset,
> +	.reset = sdhci_arasan_reset,
>  	.set_uhs_signaling = sdhci_set_uhs_signaling,
>  };
>  
> @@ -179,6 +204,7 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
>  	struct sdhci_host *host;
>  	struct sdhci_pltfm_host *pltfm_host;
>  	struct sdhci_arasan_data *sdhci_arasan;
> +	struct device_node *np = pdev->dev.of_node;
>  
>  	host = sdhci_pltfm_init(pdev, &sdhci_arasan_pdata,
>  				sizeof(*sdhci_arasan));
> @@ -215,6 +241,12 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
>  	}
>  
>  	sdhci_get_of_property(pdev);
> +
> +	if (of_get_property(np, "xlnx-fails-without-test-cd", NULL)) {
> +		sdhci_arasan->arasan_quirks |=
> +				SDHCI_ARASAN_QUIRK_FAILS_WITHOUT_TEST_CD;
> +	}
> +
>  	pltfm_host->clk = clk_xin;
>  
>  	ret = mmc_of_parse(host->mmc);
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 609f87c..ac0ba18 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_CDTEST_INS   0x40
> +#define  SDHCI_CTRL_CDTEST_EN    0x80

The issue is still present here.

Thanks,
Michal