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: <20160907160620.GA26308@zach-desktop>
Date:   Wed, 7 Sep 2016 11:06:21 -0500
From:   Zach Brown <zach.brown@...com>
To:     Michal Simek <michal.simek@...inx.com>
CC:     <adrian.hunter@...el.com>, <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>, <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 Wed, Sep 07, 2016 at 07:15:02AM +0200, Michal Simek wrote:
> 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)
> 
> 
> >  };

I'll make sure to fix that if I end up not using the BIT macro. Thank you.
> >  
> >  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.
> 
Sorry for not getting it last time. Your last email cleared it up for me. I
have corrected the issue with my editor. The style will be fixed in the next
version. Thank you for pointing it out.

> Thanks,
> Michal
> 
>