Re: sdhci-omap: issues with PM features since 5.16

[Tony Lindgren <tony@atomide.com>]

Hi,

Adding the linux-mmc folks to Cc too.

* Romain Naour <romain.naour@smile.fr> [240130 11:20]:
> Le 29/01/2024 à 18:42, Romain Naour a écrit :
> > Le 29/01/2024 à 12:17, Tony Lindgren a écrit :
> >> So I'm still guessing your issue is with emmc not getting reinitialized
> >> properly as there's no mmc-pwrseq-emmc configured. Can you give it a
> >> try? See am5729-beagleboneai.dts for an example.
> 
> I can't add such mmc-pwrseq-emmc on the custom board, there is no gpio available
> to reset the emmc device.
> 
> To resume:
> - the emmc doesn't work with mmc-hs200-1_8v mode with PM runtime enabled
> - the emmc works with mmc-hs200-1_8v mode without PM runtime (patch series reverted)
> - the emmc works with mmc-ddr-1_8v mode with PM runtime enabled
> 
> AFAIU the hs200 mode requires some pin iodelay tuning (SDHCI_OMAP_REQUIRE_IODELAY)
> is sdhci_omap_runtime_{suspend,resume} needs to take care of that?
> 
> The mmc2 clock seems idle when mmc-hs200-1_8v and PM runtime are used.
> 
> omapconf dump prcm l3init
> 
> (mmc2 clock idle)
> | CM_L3INIT_MMC2_CLKCTRL           | 0x4A009330   | 0x01070000 |
> 
> (mmc2 clock running)
> | CM_L3INIT_MMC2_CLKCTRL           | 0x4A009330   | 0x01040002 |
> 
> Thoughts?

OK so if the emmc reset gpio is not available, seems we should do something
like the following patch to not set MMC_CAP_POWER_OFF_CARD unless the
cap-power-off-card devicetree property is set.

Care to give it a try and see if it helps?

Regards,

Tony

8< ----------------
diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c
--- a/drivers/mmc/host/sdhci-omap.c
+++ b/drivers/mmc/host/sdhci-omap.c
@@ -1339,8 +1339,11 @@ static int sdhci_omap_probe(struct platform_device *pdev)
 	/* R1B responses is required to properly manage HW busy detection. */
 	mmc->caps |= MMC_CAP_NEED_RSP_BUSY;
 
-	/* Allow card power off and runtime PM for eMMC/SD card devices */
-	mmc->caps |= MMC_CAP_POWER_OFF_CARD | MMC_CAP_AGGRESSIVE_PM;
+	/*
+	 * Allow runtime PM for eMMC/SD card devices. Note that to power off
+	 * the card, the devicetree property cap-power-off-card must be set.
+	 */
+	mmc->caps |= MMC_CAP_AGGRESSIVE_PM;
 
 	ret = sdhci_setup_host(host);
 	if (ret)
-- 
2.43.0