-----Original Message-----
From: Adrian Hunter [mailto:adrian.hunter@intel.com]
Sent: 2021年5月11日 20:41
To: Lucas Stach <l.stach@pengutronix.de>; Bough Chen
[off-list ref]; Ulf Hansson [off-list ref]
Cc: Rob Herring <robh+dt@kernel.org>; dl-linux-imx <redacted>;
kernel@pengutronix.de; linux-mmc@vger.kernel.org;
devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 2/3] mmc: sdhci-esdhc-imx: advertise HS400 mode
through MMC caps

On 11/05/21 11:18 am, Lucas Stach wrote:

quoted

Am Dienstag, dem 11.05.2021 um 03:00 +0000 schrieb Bough Chen:

quoted

quoted

-----Original Message-----
From: Lucas Stach [mailto:l.stach@pengutronix.de]
Sent: 2021年5月11日 3:04
To: Ulf Hansson <redacted>; Adrian Hunter
[off-list ref]; Bough Chen [off-list ref]
Cc: Rob Herring <robh+dt@kernel.org>; dl-linux-imx
[off-list ref]; kernel@pengutronix.de;
linux-mmc@vger.kernel.org; devicetree@vger.kernel.org;
linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/3] mmc: sdhci-esdhc-imx: advertise HS400 mode
through MMC caps

Instead of having an indirection through the SDHCI layer and
emulating a capability bit, that isn't there in hardware, do the
same same thing as

with

quoted

HS400_ES and advertise the support for HS400 directly through the
MMC

caps.

quoted

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
---
 drivers/mmc/host/sdhci-esdhc-imx.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c

b/drivers/mmc/host/sdhci-esdhc-imx.c
index a20459744d21..65a52586db36 100644

--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c

@@ -427,9 +427,6 @@ static u32 esdhc_readl_le(struct sdhci_host

*host, int
reg)
 					|

FIELD_PREP(SDHCI_RETUNING_MODE_MASK,

quoted

 						     SDHCI_TUNING_MODE_3);

-			if (imx_data->socdata->flags & ESDHC_FLAG_HS400)
-				val |= SDHCI_SUPPORT_HS400;
-
 			/*
 			 * Do not advertise faster UHS modes if there are no
 			 * pinctrl states for 100MHz/200MHz.

@@ -1603,7 +1600,7 @@ static int sdhci_esdhc_imx_probe(struct

platform_device *pdev)
 		host->quirks |= SDHCI_QUIRK_BROKEN_ADMA;

 	if (imx_data->socdata->flags & ESDHC_FLAG_HS400)
-		host->quirks2 |= SDHCI_QUIRK2_CAPS_BIT63_FOR_HS400;
+		host->mmc->caps2 |= MMC_CAP2_HS400;

Hi Lucas,

I think patch1 and patch 2 are enough to cover your requirement.
For this patch, I think it's unnecessary, sdhci-esdhc-imx.c need to
reuse sdhci.c as much as possible.
In sdhci.c, already contain the following logic.

         if (host->quirks2 & SDHCI_QUIRK2_CAPS_BIT63_FOR_HS400

&&

quoted

quoted

             (host->caps1 & SDHCI_SUPPORT_HS400))
                 mmc->caps2 |= MMC_CAP2_HS400;

The reason why we directly use host->mmc->caps2 for HS400ES mode is
that sdhci.c do not contain the similar logic.

No, it's not enough. We call mmc_of_parse(), which clears the HS400
flags, before sdhci_setup_host() is called, which will then add the
HS400 flags again. So either I still need to evaluate the DT property
in the esdhc driver to make it return the right emulated SDHCI caps
bit for the HS400 case, or do it like in this patch.

While the way it is done here is a bit of a layering violation between

We see SDHCI as more of a library, not a layer, so this is OK

Okay, I see.
For this patch:
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>

Regards
Haibo

quoted

SDHCI and MMC, it still feels like the cleaner and more straight
forward solution.

Regards,
Lucas