mmc: host: Wait for Vdd to settle on card power off

[PATCH v2] mmc: host: Wait for Vdd to settle on card power off

Posted by Erick Shepherd 9 months, 1 week ago

The SD spec version 6.0 section 6.4.1.5 requires that Vdd must be
lowered to less than 0.5V for a minimum of 1 ms when powering off a
card. Increase wait to 15 ms so that voltage has time to drain down
to 0.5V and cards can power off correctly. Issues with voltage drain
time were only observed on Apollo Lake and Bay Trail host controllers
so this fix is limited to those devices.

Signed-off-by: Erick Shepherd <erick.shepherd@ni.com>
---
 drivers/mmc/host/sdhci-pci-core.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
index 1f0bd723f011..b1f7c11ea61e 100644
--- a/drivers/mmc/host/sdhci-pci-core.c
+++ b/drivers/mmc/host/sdhci-pci-core.c
@@ -610,9 +610,12 @@ static void sdhci_intel_set_power(struct sdhci_host *host, unsigned char mode,
 
 	sdhci_set_power(host, mode, vdd);
 
-	if (mode == MMC_POWER_OFF)
+	if (mode == MMC_POWER_OFF) {
+		if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_APL_SD ||
+		    slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_BYT_SD)
+			usleep_range(15000, 17500);
 		return;
-
+	}
 	/*
 	 * Bus power might not enable after D3 -> D0 transition due to the
 	 * present state not yet having propagated. Retry for up to 2ms.
-- 
2.43.0

Re: [PATCH v2] mmc: host: Wait for Vdd to settle on card power off

Posted by Adrian Hunter 9 months ago

On 14/03/25 21:50, Erick Shepherd wrote:
> The SD spec version 6.0 section 6.4.1.5 requires that Vdd must be
> lowered to less than 0.5V for a minimum of 1 ms when powering off a
> card. Increase wait to 15 ms so that voltage has time to drain down
> to 0.5V and cards can power off correctly. Issues with voltage drain
> time were only observed on Apollo Lake and Bay Trail host controllers
> so this fix is limited to those devices.
> 
> Signed-off-by: Erick Shepherd <erick.shepherd@ni.com>

Can we leave a blank line after the block.  It was that way before.

With that, you can add:

Acked-by: Adrian Hunter <adrian.hunter@intel.com>

> ---
>  drivers/mmc/host/sdhci-pci-core.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
> index 1f0bd723f011..b1f7c11ea61e 100644
> --- a/drivers/mmc/host/sdhci-pci-core.c
> +++ b/drivers/mmc/host/sdhci-pci-core.c
> @@ -610,9 +610,12 @@ static void sdhci_intel_set_power(struct sdhci_host *host, unsigned char mode,
>  
>  	sdhci_set_power(host, mode, vdd);
>  
> -	if (mode == MMC_POWER_OFF)
> +	if (mode == MMC_POWER_OFF) {
> +		if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_APL_SD ||
> +		    slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_BYT_SD)
> +			usleep_range(15000, 17500);
>  		return;
> -
> +	}

Blank line here

>  	/*
>  	 * Bus power might not enable after D3 -> D0 transition due to the
>  	 * present state not yet having propagated. Retry for up to 2ms.

Re: [PATCH v2] mmc: host: Wait for Vdd to settle on card power off

Posted by Ulf Hansson 9 months ago

On Thu, 20 Mar 2025 at 08:26, Adrian Hunter <adrian.hunter@intel.com> wrote:
>
> On 14/03/25 21:50, Erick Shepherd wrote:
> > The SD spec version 6.0 section 6.4.1.5 requires that Vdd must be
> > lowered to less than 0.5V for a minimum of 1 ms when powering off a
> > card. Increase wait to 15 ms so that voltage has time to drain down
> > to 0.5V and cards can power off correctly. Issues with voltage drain
> > time were only observed on Apollo Lake and Bay Trail host controllers
> > so this fix is limited to those devices.
> >
> > Signed-off-by: Erick Shepherd <erick.shepherd@ni.com>
>
> Can we leave a blank line after the block.  It was that way before.
>
> With that, you can add:
>
> Acked-by: Adrian Hunter <adrian.hunter@intel.com>

Applied for next with the suggested change, thanks!

Kind regards
Uffe


>
> > ---
> >  drivers/mmc/host/sdhci-pci-core.c | 7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
> > index 1f0bd723f011..b1f7c11ea61e 100644
> > --- a/drivers/mmc/host/sdhci-pci-core.c
> > +++ b/drivers/mmc/host/sdhci-pci-core.c
> > @@ -610,9 +610,12 @@ static void sdhci_intel_set_power(struct sdhci_host *host, unsigned char mode,
> >
> >       sdhci_set_power(host, mode, vdd);
> >
> > -     if (mode == MMC_POWER_OFF)
> > +     if (mode == MMC_POWER_OFF) {
> > +             if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_APL_SD ||
> > +                 slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_BYT_SD)
> > +                     usleep_range(15000, 17500);
> >               return;
> > -
> > +     }
>
> Blank line here
>
> >       /*
> >        * Bus power might not enable after D3 -> D0 transition due to the
> >        * present state not yet having propagated. Retry for up to 2ms.
>