There are MMC boot failures seen with V1P8_SIGNAL_ENA on Kingston eMMC and
Microcenter/Patriot SD cards on am62* Sitara K3 boards due to the HS200
initialization sequence involving V1P8_SIGNAL_ENA. Since V1P8_SIGNAL_ENA
is optional for eMMC and only affects timing for host controllers using
ti,am62-sdhci compatible so far, add a new platform data structure for am62
compatible and append the new SDHCI_QUIRK2_SUPPRESS_V1P8_ENA 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 the quirk based on compatible string,
ensuring the quirk is never applied to devices with internal LDOs, then
V1P8_SIGNAL_ENA also has a voltage component tied to it.

Changes since v3 RESEND:
- apply the quirk based on compatible string instead of based on bus
  width or DT property
- rephrase commit descriptions and cover-letter descriptions based on
  new implementation.

Link to v3 RESEND:
https://lore.kernel.org/linux-mmc/8678d284-db12-451a-b789-2b75f9932f9f@ti.com
Link to v2:
https://lore.kernel.org/linux-mmc/20250417182652.3521104-1-jm@ti.com/
Link to v1:
https://lore.kernel.org/linux-mmc/20250407222702.2199047-1-jm@ti.com/

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

Judith Mendez (2):
  mmc: sdhci: Add a quirk for suppressing V1P8_SIGNAL_ENA
  mmc: sdhci_am654: Add SDHCI_QUIRK2_SUPPRESS_V1P8_ENA quirk to am62
    compatible

 drivers/mmc/host/sdhci.c       |  8 +++++---
 drivers/mmc/host/sdhci.h       |  2 ++
 drivers/mmc/host/sdhci_am654.c | 14 +++++++++++++-
 3 files changed, 20 insertions(+), 4 deletions(-)


base-commit: 1be38f81251f6d276713c259ecf4414f82f22c29
-- 
2.49.0

Hi all,

On 4/24/2025 1:00 PM, Judith Mendez wrote:
> There are MMC boot failures seen with V1P8_SIGNAL_ENA on Kingston eMMC and
> Microcenter/Patriot SD cards on am62* Sitara K3 boards due to the HS200
> initialization sequence involving V1P8_SIGNAL_ENA. Since V1P8_SIGNAL_ENA
> is optional for eMMC and only affects timing for host controllers using
> ti,am62-sdhci compatible so far, add a new platform data structure for am62
> compatible and append the new SDHCI_QUIRK2_SUPPRESS_V1P8_ENA 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 the quirk based on compatible string,
> ensuring the quirk is never applied to devices with internal LDOs, then
> V1P8_SIGNAL_ENA also has a voltage component tied to it.

Gentle ping on this, are there any comments or any issues with this
type of implementation?

Thanks,

~ Judith

On Mon, 5 May 2025 at 23:24, Mendez, Judith <jm@ti.com> wrote:
>
> Hi all,
>
> On 4/24/2025 1:00 PM, Judith Mendez wrote:
> > There are MMC boot failures seen with V1P8_SIGNAL_ENA on Kingston eMMC and
> > Microcenter/Patriot SD cards on am62* Sitara K3 boards due to the HS200
> > initialization sequence involving V1P8_SIGNAL_ENA. Since V1P8_SIGNAL_ENA
> > is optional for eMMC and only affects timing for host controllers using
> > ti,am62-sdhci compatible so far, add a new platform data structure for am62
> > compatible and append the new SDHCI_QUIRK2_SUPPRESS_V1P8_ENA 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 the quirk based on compatible string,
> > ensuring the quirk is never applied to devices with internal LDOs, then
> > V1P8_SIGNAL_ENA also has a voltage component tied to it.
>
> Gentle ping on this, are there any comments or any issues with this
> type of implementation?

It looks reasonable to me. Although, in general I think we are trying
to avoid adding new sdhci quirks, perhaps there are good reasons to do
it in this case.

I am deferring to Adrian to make the decision.

Kind regards
Uffe

On 07/05/2025 13:14, Ulf Hansson wrote:
> On Mon, 5 May 2025 at 23:24, Mendez, Judith <jm@ti.com> wrote:
>>
>> Hi all,
>>
>> On 4/24/2025 1:00 PM, Judith Mendez wrote:
>>> There are MMC boot failures seen with V1P8_SIGNAL_ENA on Kingston eMMC and
>>> Microcenter/Patriot SD cards on am62* Sitara K3 boards due to the HS200
>>> initialization sequence involving V1P8_SIGNAL_ENA. Since V1P8_SIGNAL_ENA
>>> is optional for eMMC and only affects timing for host controllers using
>>> ti,am62-sdhci compatible so far, add a new platform data structure for am62
>>> compatible and append the new SDHCI_QUIRK2_SUPPRESS_V1P8_ENA 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 the quirk based on compatible string,
>>> ensuring the quirk is never applied to devices with internal LDOs, then
>>> V1P8_SIGNAL_ENA also has a voltage component tied to it.
>>
>> Gentle ping on this, are there any comments or any issues with this
>> type of implementation?
> 
> It looks reasonable to me. Although, in general I think we are trying
> to avoid adding new sdhci quirks, perhaps there are good reasons to do
> it in this case.

Yes, we want to avoid new quirks in sdhci.c.

Judith, can you do it like in V3? i.e. in sdhci_am654.c with
SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA and sdhci_am654_start_signal_voltage_switch()