RE: [PATCH V1 1/1] mmc:sdhci-pci-o2micro:fix some SD cards compatibility issue at ddr50 mode

[Christian Loehle]

Just be aware that cards may support one but not the other, so this doesn't come without cost.

-----Original Message-----
From: Chevron Li <chevron.li@xxxxxxxxxxxxxx> 
Sent: Mittwoch, 27. Juli 2022 05:31
To: adrian.hunter@xxxxxxxxx; ulf.hansson@xxxxxxxxxx; linux-mmc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Cc: shaper.liu@xxxxxxxxxxxxxx; shirley.her@xxxxxxxxxxxxxx; xiaoguang.yu@xxxxxxxxxxxxxx
Subject: [PATCH V1 1/1] mmc:sdhci-pci-o2micro:fix some SD cards compatibility issue at ddr50 mode

Bayhub chips have better compatibility support for sdr50 than ddr50 and both mode have the same R/W performance.
Disable ddr50 mode and use sdr50 instead.

Signed-off-by: Chevron Li<chevron.li@xxxxxxxxxxxxxx>
---
Changes on V1:
1.Set quirks2 flag SDHCI_QUIRK2_BROKEN_DDR50 for bayhub chips.
2.Use bayhub hardware input tuning for SDR50 mode instead of standard tuning flow.
---
 drivers/mmc/host/sdhci-pci-o2micro.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-pci-o2micro.c b/drivers/mmc/host/sdhci-pci-o2micro.c
index 0d4d343dbb77..ad457cd9cbaa 100644
--- a/drivers/mmc/host/sdhci-pci-o2micro.c
+++ b/drivers/mmc/host/sdhci-pci-o2micro.c
@@ -317,11 +317,12 @@ static int sdhci_o2_execute_tuning(struct mmc_host *mmc, u32 opcode)
 	u32 reg_val;
 
 	/*
-	 * This handler only implements the eMMC tuning that is specific to
+	 * This handler implements the hardware tuning that is specific to
 	 * this controller.  Fall back to the standard method for other TIMING.
 	 */
 	if ((host->timing != MMC_TIMING_MMC_HS200) &&
-		(host->timing != MMC_TIMING_UHS_SDR104))
+		(host->timing != MMC_TIMING_UHS_SDR104) &&
+		(host->timing != MMC_TIMING_UHS_SDR50))
 		return sdhci_execute_tuning(mmc, opcode);
 
 	if (WARN_ON((opcode != MMC_SEND_TUNING_BLOCK_HS200) && @@ -631,6 +632,8 @@ static int sdhci_pci_o2_probe_slot(struct sdhci_pci_slot *slot)
 		if (reg & 0x1)
 			host->quirks |= SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12;
 
+		host->quirks2 |= SDHCI_QUIRK2_BROKEN_DDR50;
+
 		sdhci_pci_o2_enable_msi(chip, host);
 
 		if (chip->pdev->device == PCI_DEVICE_ID_O2_SEABIRD0) {

base-commit: 68e77ffbfd06ae3ef8f2abf1c3b971383c866983
--
2.32.0

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