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SubjectRe: [PATCH v2] mmc: host: sdhci-sprd: Fix the incorrect soft reset operation when runtime resuming
On Tue, 16 Jul 2019 at 16:24, Adrian Hunter <adrian.hunter@intel.com> wrote:
>
> On 16/07/19 10:31 AM, Baolin Wang wrote:
> > In sdhci_runtime_resume_host() function, we will always do software reset
> > for all, which will cause Spreadtrum host controller work abnormally after
> > resuming.
> >
> > Thus for Spreadtrum platform that do not power down the SD/eMMC card during
> > runtime suspend, we should not do software reset for all. To fix this
> > issue, adding a specific reset operation that add one condition to validate
> > the MMC_CAP_AGGRESSIVE_PM to decide if we can do software reset for all or
> > just reset command and data lines.
> >
> > Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> > ---
> > Changes from v1:
> > - Add a specific reset operation instead of changing the core to avoid
> > affecting other hardware.
> > ---
> > drivers/mmc/host/sdhci-sprd.c | 38 +++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 37 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-sprd.c b/drivers/mmc/host/sdhci-sprd.c
> > index 603a5d9..174b566 100644
> > --- a/drivers/mmc/host/sdhci-sprd.c
> > +++ b/drivers/mmc/host/sdhci-sprd.c
> > @@ -373,6 +373,42 @@ static unsigned int sdhci_sprd_get_max_timeout_count(struct sdhci_host *host)
> > return 1 << 31;
> > }
> >
> > +static void sdhci_sprd_reset(struct sdhci_host *host, u8 mask)
> > +{
> > + struct mmc_host *mmc = host->mmc;
> > + ktime_t timeout;
> > +
> > + /*
> > + * When try to reset controller after runtime suspend, we should not
> > + * reset for all if the SD/eMMC card is not power down, just reset
> > + * command and data lines instead. Otherwise will meet some strange
> > + * behaviors for Spreadtrum host controller.
> > + */
> > + if (host->runtime_suspended && (mask & SDHCI_RESET_ALL) &&
> > + !(mmc->caps & MMC_CAP_AGGRESSIVE_PM))
> > + mask = SDHCI_RESET_CMD | SDHCI_RESET_DATA;
> > +
>
> Here you could just call sdhci_reset(host, mask) instead of below.

Ah, right. Thanks for your comment.

>
> > + sdhci_writeb(host, mask, SDHCI_SOFTWARE_RESET);
> > +
> > + /* Wait max 100 ms */
> > + timeout = ktime_add_ms(ktime_get(), 100);
> > +
> > + /* hw clears the bit when it's done */
> > + while (1) {
> > + bool timedout = ktime_after(ktime_get(), timeout);
> > +
> > + if (!(sdhci_readb(host, SDHCI_SOFTWARE_RESET) & mask))
> > + break;
> > + if (timedout) {
> > + pr_err("%s: Reset 0x%x never completed.\n",
> > + mmc_hostname(host->mmc), (int)mask);
> > + sdhci_dumpregs(host);
> > + return;
> > + }
> > + udelay(10);
> > + }
> > +}
> > +
> > static struct sdhci_ops sdhci_sprd_ops = {
> > .read_l = sdhci_sprd_readl,
> > .write_l = sdhci_sprd_writel,
> > @@ -381,7 +417,7 @@ static unsigned int sdhci_sprd_get_max_timeout_count(struct sdhci_host *host)
> > .get_max_clock = sdhci_sprd_get_max_clock,
> > .get_min_clock = sdhci_sprd_get_min_clock,
> > .set_bus_width = sdhci_set_bus_width,
> > - .reset = sdhci_reset,
> > + .reset = sdhci_sprd_reset,
> > .set_uhs_signaling = sdhci_sprd_set_uhs_signaling,
> > .hw_reset = sdhci_sprd_hw_reset,
> > .get_max_timeout_count = sdhci_sprd_get_max_timeout_count,
> >
>


--
Baolin Wang
Best Regards

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