linux-kernel - Re: [PATCH v3 3/5] mmc: dw_mmc: Add exynos resume_noirq callback to clear WAKEUP

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Message-id: <51E4A396.7010202@samsung.com>
Date:	Tue, 16 Jul 2013 10:36:22 +0900
From:	Jaehoon Chung <jh80.chung@...sung.com>
To:	Doug Anderson <dianders@...omium.org>
Cc:	Chris Ball <cjb@...top.org>, Olof Johansson <olof@...om.net>,
	Jaehoon Chung <jh80.chung@...sung.com>,
	Seungwon Jeon <tgih.jun@...sung.com>,
	James Hogan <james.hogan@...tec.com>,
	Grant Grundler <grundler@...omium.org>,
	Alim Akhtar <alim.akhtar@...sung.com>,
	Abhilash Kesavan <a.kesavan@...sung.com>,
	Tomasz Figa <tomasz.figa@...il.com>,
	Kukjin Kim <kgene.kim@...sung.com>, linux-mmc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 3/5] mmc: dw_mmc: Add exynos resume_noirq callback to
 clear WAKEUP_INT

Hi Doug,

I think these patch-set didn't base on latest mmc-next.
If you can rebase on latest mmc-next, it's helpful to me for testing.

Best Regards,
Jaehoon Chung

On 07/11/2013 12:42 AM, Doug Anderson wrote:
> If the WAKEUP_INT is asserted at wakeup and not cleared, we'll end up
> looping around forever.  This has been seen to happen on exynos5420
> silicon despite the fact that we haven't enabled any wakeup events.
> 
> Signed-off-by: Doug Anderson <dianders@...omium.org>
> ---
> Changes in v3: None
> Changes in v2:
> - Use suspend_noirq as per James Hogan.
> 
>  drivers/mmc/host/dw_mmc-exynos.c | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
> index f013e7e..36b9620 100644
> --- a/drivers/mmc/host/dw_mmc-exynos.c
> +++ b/drivers/mmc/host/dw_mmc-exynos.c
> @@ -30,6 +30,7 @@
>  #define SDMMC_CLKSEL_TIMING(x, y, z)	(SDMMC_CLKSEL_CCLK_SAMPLE(x) |	\
>  					SDMMC_CLKSEL_CCLK_DRIVE(y) |	\
>  					SDMMC_CLKSEL_CCLK_DIVIDER(z))
> +#define SDMMC_CLKSEL_WAKEUP_INT		BIT(11)
>  
>  #define SDMMC_CMD_USE_HOLD_REG		BIT(29)
>  
> @@ -102,6 +103,27 @@ static int dw_mci_exynos_setup_clock(struct dw_mci *host)
>  	return 0;
>  }
>  
> +/**
> + * dw_mci_exynos_resume_noirq - Exynos-specific resume code
> + *
> + * We have seen cases (at least on the exynos5420) where turning off the INT
> + * power rail during suspend will leave the WAKEUP_INT bit in the CLKSEL
> + * register asserted.  This bit is 1 to indicate that it fired and we can
> + * clear it by writing a 1 back.  Clear it to prevent interrupts from going off
> + * constantly.
> + */
> +
> +static int dw_mci_exynos_resume_noirq(struct dw_mci *host)
> +{
> +	u32 clksel;
> +
> +	clksel = mci_readl(host, CLKSEL);
> +	if (clksel & SDMMC_CLKSEL_WAKEUP_INT)
> +		mci_writel(host, CLKSEL, clksel);
> +
> +	return 0;
> +}
> +
>  static void dw_mci_exynos_prepare_command(struct dw_mci *host, u32 *cmdr)
>  {
>  	/*
> @@ -165,6 +187,7 @@ static const struct dw_mci_drv_data exynos_drv_data = {
>  	.caps			= exynos_dwmmc_caps,
>  	.init			= dw_mci_exynos_priv_init,
>  	.setup_clock		= dw_mci_exynos_setup_clock,
> +	.resume_noirq		= dw_mci_exynos_resume_noirq,
>  	.prepare_command	= dw_mci_exynos_prepare_command,
>  	.set_ios		= dw_mci_exynos_set_ios,
>  	.parse_dt		= dw_mci_exynos_parse_dt,
> 

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