On Wed, August 07, 2013, 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 due
> to a silicon errata. It is safe to do on all exynos variants.
>
> Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx>
> ---
> Changes in v4:
> - Take Seungwon's suggestion and don't add any dw_mmc-pltfm code.
>
> Changes in v3:
> - Add freeze/thaw and poweroff/restore noirq entries.
>
> Changes in v2:
> - Use suspend_noirq as per James Hogan.
>
> drivers/mmc/host/dw_mmc-exynos.c | 51 ++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 49 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
> index 866edef..0c1f192 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 EXYNOS4210_FIXED_CIU_CLK_DIV 2
> #define EXYNOS4412_FIXED_CIU_CLK_DIV 4
> @@ -100,6 +101,30 @@ static int dw_mci_exynos_setup_clock(struct dw_mci *host)
> return 0;
> }
>
> +/**
> + * dw_mci_exynos_resume_noirq - Exynos-specific resume code
> + *
> + * On exynos5420 there is a silicon errata that will sometimes 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.
> + *
> + * We run this code on all exynos variants because it doesn't hurt and the bug
> + * may be more widespread than just exynos5420.
I guess just above comment can be removed. (Not be widespread)
Updating the origin value of CLKSEL looks like no harm while SDMMC_CLKSEL_WAKEUP_INT is cleared.
> + */
> +
> +static int dw_mci_exynos_resume_noirq(struct device *dev)
> +{
> + struct dw_mci *host = dev_get_drvdata(dev);
> + 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)
> {
> /*
> @@ -187,17 +212,39 @@ static int dw_mci_exynos_probe(struct platform_device *pdev)
> return dw_mci_pltfm_register(pdev, drv_data);
> }
>
> +static struct dev_pm_ops dw_mci_exynos_pmops;
> +
> static struct platform_driver dw_mci_exynos_pltfm_driver = {
> .probe = dw_mci_exynos_probe,
> .remove = __exit_p(dw_mci_pltfm_remove),
> .driver = {
> .name = "dwmmc_exynos",
> .of_match_table = dw_mci_exynos_match,
> - .pm = &dw_mci_pltfm_pmops,
> + .pm = &dw_mci_exynos_pmops,
> },
> };
>
> -module_platform_driver(dw_mci_exynos_pltfm_driver);
> +static int __init dw_mci_exynos_init(void)
> +{
> + /* Add a "noirq" resume to platform pmops */
> + memcpy(&dw_mci_exynos_pmops, &dw_mci_pltfm_pmops,
> + sizeof(dw_mci_exynos_pmops));
> + WARN_ON(dw_mci_exynos_pmops.resume_noirq ||
> + dw_mci_exynos_pmops.thaw_noirq ||
> + dw_mci_exynos_pmops.restore_noirq);
> + dw_mci_exynos_pmops.resume_noirq = dw_mci_exynos_resume_noirq;
> + dw_mci_exynos_pmops.thaw_noirq = dw_mci_exynos_resume_noirq;
> + dw_mci_exynos_pmops.restore_noirq = dw_mci_exynos_resume_noirq;
If CONFIG_PM_SLEEP is not defined, we don't need to add it.
And also, instead of reusing dw_mci_pltfm_pmops, how about defining dw_mci_exynos_pmops's own?
Of course, suspend/resume will not different with dw_mci_pltfm* just now.
But specific code for exynos would be added soon.
Thanks,
Seungwon Jeon
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