Re: [PATCH V2] mmc: sdhci-msm: Disable CQE during SDHC reset

[Veerabhadrarao Badiganti]

Hi Adrian

On 3/4/2020 5:58 PM, Adrian Hunter wrote:
> On 4/03/20 1:54 pm, Veerabhadrarao Badiganti wrote:
> > When SDHC gets reset (E.g. in suspend path), CQE also gets reset
> > and goes to disable state. But s/w state still points it as CQE
> > is in enabled state. Since s/w and h/w states goes out of sync,
> > it results in s/w request timeout for subsequent CQE requests.
> >
> > To synchronize CQE s/w and h/w state during SDHC reset,
> > explicitly disable CQE after reset.
> Shouldn't you be calling cqhci_suspend() / cqhci_resume() in the suspend and
> resume paths?

This issue is seen during mmc runtime suspend. I can add it 
sdhci_msm_runtime_suspend

but sdhci_msm runtime delay is aggressive, its 50ms. It may get invoked 
very frequently.

So Im of the opinion that disabling CQE very often from platform runtime 
suspend is overkill.

> > Signed-off-by: Veerabhadrarao Badiganti <vbadigan@xxxxxxxxxxxxxx>
> > ---
> > Changes since V1:
> > 	- Disable CQE only when SDHC undergoes s/w reset for all.
> > ---
> >   drivers/mmc/host/sdhci-msm.c | 9 ++++++++-
> >   1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> > index 53b79ee..75929d3 100644
> > --- a/drivers/mmc/host/sdhci-msm.c
> > +++ b/drivers/mmc/host/sdhci-msm.c
> > @@ -1823,6 +1823,13 @@ static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
> >   	pr_debug("%s: supported caps: 0x%08x\n", mmc_hostname(mmc), caps);
> >   }
> >   
> > +static void sdhci_msm_reset(struct sdhci_host *host, u8 mask)
> > +{
> > +	sdhci_reset(host, mask);
> > +	if ((host->mmc->caps2 & MMC_CAP2_CQE) && (mask & SDHCI_RESET_ALL))
> > +		cqhci_suspend(host->mmc);
> > +}
> > +
> >   static const struct sdhci_msm_variant_ops mci_var_ops = {
> >   	.msm_readl_relaxed = sdhci_msm_mci_variant_readl_relaxed,
> >   	.msm_writel_relaxed = sdhci_msm_mci_variant_writel_relaxed,
> > @@ -1861,7 +1868,7 @@ static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
> >   MODULE_DEVICE_TABLE(of, sdhci_msm_dt_match);
> >   
> >   static const struct sdhci_ops sdhci_msm_ops = {
> > -	.reset = sdhci_reset,
> > +	.reset = sdhci_msm_reset,
> >   	.set_clock = sdhci_msm_set_clock,
> >   	.get_min_clock = sdhci_msm_get_min_clock,
> >   	.get_max_clock = sdhci_msm_get_max_clock,