linux-kernel - Re: [RESEND PATCH v7 2/2] sdhci-of-arasan: Set controller to test mode when xlnx,fails-without-test-cd is present

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Message-ID: <992df66b-043e-ea1b-d291-a544b0d861d0@intel.com>
Date:   Mon, 19 Sep 2016 10:51:08 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Zach Brown <zach.brown@...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: [RESEND PATCH v7 2/2] sdhci-of-arasan: Set controller to test
 mode when xlnx,fails-without-test-cd is present

On 16/09/16 18:01, 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>

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

> ---
>  drivers/mmc/host/sdhci-of-arasan.c | 27 ++++++++++++++++++++++++++-
>  drivers/mmc/host/sdhci.h           |  2 ++
>  2 files changed, 28 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
> index 33601a8..da8e40a 100644
> --- a/drivers/mmc/host/sdhci-of-arasan.c
> +++ b/drivers/mmc/host/sdhci-of-arasan.c
> @@ -26,6 +26,7 @@
>  #include <linux/phy/phy.h>
>  #include <linux/regmap.h>
>  #include "sdhci-pltfm.h"
> +#include <linux/of.h>
>  
>  #define SDHCI_ARASAN_CLK_CTRL_OFFSET	0x2c
>  #define SDHCI_ARASAN_VENDOR_REGISTER	0x78
> @@ -98,6 +99,10 @@ struct sdhci_arasan_data {
>  
>  	struct regmap	*soc_ctl_base;
>  	const struct sdhci_arasan_soc_ctl_map *soc_ctl_map;
> +	unsigned int	quirks; /* Arasan deviations from spec */
> +
> +/* Controller does not have CD wired and will not function normally without */
> +#define SDHCI_ARASAN_QUIRK_FORCE_CDTEST	BIT(0)
>  };
>  
>  static const struct sdhci_arasan_soc_ctl_map rk3399_soc_ctl_map = {
> @@ -245,12 +250,27 @@ static void sdhci_arasan_hs400_enhanced_strobe(struct mmc_host *mmc,
>  	writel(vendor, host->ioaddr + SDHCI_ARASAN_VENDOR_REGISTER);
>  }
>  
> +void sdhci_arasan_reset(struct sdhci_host *host, u8 mask)
> +{
> +	u8 ctrl;
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
> +
> +	sdhci_reset(host, mask);
> +
> +	if (sdhci_arasan->quirks & SDHCI_ARASAN_QUIRK_FORCE_CDTEST) {
> +		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,
>  };
>  
> @@ -545,6 +565,7 @@ 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));
> @@ -599,6 +620,10 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
>  	}
>  
>  	sdhci_get_of_property(pdev);
> +
> +	if (of_property_read_bool(np, "xlnx,fails-without-test-cd"))
> +		sdhci_arasan->quirks |= SDHCI_ARASAN_QUIRK_FORCE_CDTEST;
> +
>  	pltfm_host->clk = clk_xin;
>  
>  	if (of_device_is_compatible(pdev->dev.of_node,
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index a2bc9e1..c722cd2 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
>  
>  #define SDHCI_POWER_CONTROL	0x29
>  #define  SDHCI_POWER_ON		0x01
>