Fix V1P8_SIGNAL_ENA

[PATCH v2 0/2] Fix V1P8_SIGNAL_ENA

Posted by Judith Mendez 9 months, 3 weeks ago

There are eMMC boot failures seen with V1P8_SIGNAL_ENA on Kingston
eMMC and variouse types of SD cards on Sitara K3 SoCs due to the
sequencing when enumerating to HS200 mode. Since V1P8_SIGNAL_ENA is
optional for eMMC, do not set V1P8_SIGNAL_ENA by default for eMMC.
For SD cards we shall parse DT for ti,suppress-v1p8-ena property
to determine whether to apply the quirk.

This fix was previously merged in the kernel, but was reverted due
to the "heuristics for enabling the quirk"[0]. This issue is adressed
in this patch series by adding optional ti,suppress-v1p8-ena DT property
to apply the quirk for SD.

Changes since v1:
- Drop patch for High_Speed_ENA
- Add ti,suppress-v1p8-ena for SD cards
- Add binding patch for ti,suppress-v1p8-ena
- Update cover-letter/patch descriptions according to new changes

[0] https://lore.kernel.org/linux-mmc/20250127-am654-mmc-regression-v2-1-9bb39fb12810@solid-run.com/

Judith Mendez (2):
  mmc: sdhci_am654: Add sdhci_am654_start_signal_voltage_switch
  dt-bindings: mmc: sdhci-am654: Add ti,suppress-v1p8-ena

 .../devicetree/bindings/mmc/sdhci-am654.yaml  |  5 +++
 drivers/mmc/host/sdhci_am654.c                | 32 +++++++++++++++++++
 2 files changed, 37 insertions(+)

-- 
2.49.0

Re: [PATCH v2 0/2] Fix V1P8_SIGNAL_ENA

Posted by Francesco Dolcini 9 months, 3 weeks ago

On Thu, Apr 17, 2025 at 01:26:50PM -0500, Judith Mendez wrote:
> There are eMMC boot failures seen with V1P8_SIGNAL_ENA on Kingston
> eMMC and variouse types of SD cards on Sitara K3 SoCs due to the
> sequencing when enumerating to HS200 mode. Since V1P8_SIGNAL_ENA is
> optional for eMMC, do not set V1P8_SIGNAL_ENA by default for eMMC.
> For SD cards we shall parse DT for ti,suppress-v1p8-ena property
> to determine whether to apply the quirk.

I assume this ti,suppress-v1p8-ena should be added to some SoC dtsi, am I
wrong?

Francesco

Re: [PATCH v2 0/2] Fix V1P8_SIGNAL_ENA

Posted by Judith Mendez 9 months, 3 weeks ago

Hi Francesco,

On 4/17/25 2:22 PM, Francesco Dolcini wrote:
> On Thu, Apr 17, 2025 at 01:26:50PM -0500, Judith Mendez wrote:
>> There are eMMC boot failures seen with V1P8_SIGNAL_ENA on Kingston
>> eMMC and variouse types of SD cards on Sitara K3 SoCs due to the
>> sequencing when enumerating to HS200 mode. Since V1P8_SIGNAL_ENA is
>> optional for eMMC, do not set V1P8_SIGNAL_ENA by default for eMMC.
>> For SD cards we shall parse DT for ti,suppress-v1p8-ena property
>> to determine whether to apply the quirk.
> 
> I assume this ti,suppress-v1p8-ena should be added to some SoC dtsi, am I
> wrong?
> 

I was planning to add in a separate series once this was merged but I
can add to v3 no problem, thanks for reviewing.

~ Judith