[PATCH 04/30] mci: tuning: fix fallback to DDR52

Ahmad Fatoum a.fatoum at pengutronix.de
Mon May 5 05:06:07 PDT 2025


When CONFIG_MCI_TUNING is enabled, but a card mmc_card_hs200 return
false, the fallback currently puts the card into high speed mode instead
of DDR52, which would've been the next best thing.

Rework the code to fix this.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 drivers/mci/mci-core.c | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/drivers/mci/mci-core.c b/drivers/mci/mci-core.c
index 54d3fab4f10c..bb345dc5454e 100644
--- a/drivers/mci/mci-core.c
+++ b/drivers/mci/mci-core.c
@@ -1781,34 +1781,35 @@ static int mci_startup_mmc(struct mci *mci)
 	}
 
 	if (IS_ENABLED(CONFIG_MCI_TUNING)) {
-		/*
-		 * Select timing interface
-		 */
+		dev_dbg(&mci->dev, "select timing %s\n", mci_timing_tostr(host->ios.timing));
+
 		ret = mmc_select_timing(mci);
 		if (ret)
 			return ret;
 
-		if (mmc_card_hs200(mci))
+		if (mmc_card_hs200(mci)) {
 			ret = mmc_hs200_tuning(mci);
+			if (!ret) {
+				dev_dbg(&mci->dev, "HS200 tuning succeeded\n");
+				return 0;
+			}
+
+			dev_dbg(&mci->dev, "HS200 tuning failed, falling back to HS\n");
 
-		if (ret) {
 			host->ios.timing = MMC_TIMING_MMC_HS;
 			mci_switch(mci, EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS);
 		}
 	}
 
-	if (ret || !IS_ENABLED(CONFIG_MCI_TUNING)) {
-		mci_set_clock(mci, mci->tran_speed);
+	mci_set_clock(mci, mci->tran_speed);
 
-		/* find out maximum bus width and then try DDR if supported */
-		ret = mci_mmc_select_bus_width(mci);
-		if (ret > MMC_BUS_WIDTH_1 && mci->tran_speed == 52000000)
-			ret = mci_mmc_select_hs_ddr(mci);
+	/* find out maximum bus width and then try DDR if supported */
+	ret = mci_mmc_select_bus_width(mci);
+	if (ret > MMC_BUS_WIDTH_1 && mci->tran_speed == 52000000)
+		ret = mci_mmc_select_hs_ddr(mci);
 
-		if (ret < 0) {
-			dev_warn(&mci->dev, "Changing MMC bus width failed: %d\n", ret);
-		}
-	}
+	if (ret < 0)
+		dev_warn(&mci->dev, "Changing MMC bus width failed: %d\n", ret);
 
 	return ret >= MMC_BUS_WIDTH_1 ? 0 : ret;
 }
-- 
2.39.5




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