mmc: sd: Fix inconsistent sd3_bus_mode with failed voltage switch

-----Original Message-----
From: Adrian Hunter <[email protected]>
Sent: Monday, August 15, 2022 4:33 PM
To: Ulf Hansson <[email protected]>
Cc: linux-mmc <[email protected]>; Seunghui Lee <[email protected]>; DooHyun Hwang <[email protected]>
Subject: [PATCH 1/2] mmc: sd: Fix 1.8V workaround branch

When introduced, upon success, the 1.8V fixup workaround in mmc_sd_init_card() would branch to practically the end of the function, to a label named "done". Unfortunately, perhaps due to the label name, over time new code has been added that really should have come after "done" not before it. Move the label to the correct place and rename it "cont".

Fixes 045d705dc1fb ("mmc: core: Enable the MMC host software queue for

the SD card")

Signed-off-by Adrian Hunter <[email protected]>

---
 drivers/mmc/core/sd.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

drivers/mmc/core/sd.c index renamed from drivers/mmc/core/sd.c +0 -0

cee4c0b59f43..bc84d7dfc8e1 100644

drivers/mmc/core/sd.c +2 -2

@@ -1498,7 +1498,7 @@ static int mmc_sd_init_card(struct mmc_host *host,
 u32 ocr,
 					mmc_remove_card(card);
 				goto retry;
 			}
-			goto done;
+			goto cont;
 		}
 	}

@@ -1534,7 +1534,7 @@ static int mmc_sd_init_card(struct mmc_host *host,
 u32 ocr,
 			mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
 		}
 	}
-
+cont:
 	if (!oldcard) {
 		/* Read/parse the extension registers. */

drivers/mmc/core/sd.c +1 -2

 		err = sd_read_ext_regs(card);

@@ -1566,7 +1566,7 @@ static int mmc_sd_init_card(struct mmc_host *host,
 u32 ocr,
 		err = -EINVAL;
 		goto free_card;
 	}
-done:
+
 	host->card = card;
 	return 0;
 
--

2.25.1

-----Original Message-----
From: Adrian Hunter <[email protected]>
Sent: Monday, August 15, 2022 4:33 PM
To: Ulf Hansson <[email protected]>
Cc: linux-mmc <[email protected]>; Seunghui Lee <[email protected]>; DooHyun Hwang <[email protected]>
Subject: [PATCH 2/2] mmc: sd: Fix inconsistent sd3_bus_mode with failed voltage switch

If re-initialization results is a different signal voltage, because the voltage switch failed previously but not this time (or vice versa), then sd3_bus_mode will be inconsistent with the card because the SD_SWITCH command is done only upon first initialization.

Fix by always reading SD_SWITCH information during re-initialization which also means it does not need to be re-read later for the 1.8V fixup workaround.

Note, brief testing showed SD_SWITCH took about 1.8ms to 2ms which added about 1% to 1.5% to the re-initialization time, so not particularly significant.

Reported-by Seunghui Lee <[email protected]>

Signed-off-by Adrian Hunter <[email protected]>

---
 drivers/mmc/core/sd.c | 42 ++++++++++++++++--------------------------
 1 file changed, 16 insertions(+), 26 deletions(-)

drivers/mmc/core/sd.c index renamed from drivers/mmc/core/sd.c +0 -0

bc84d7dfc8e1..06aa62ce0ed1 100644

drivers/mmc/core/sd.c +2 -7

@@ -949,15 +949,16 @@ int mmc_sd_setup_card(struct mmc_host *host, struct
 mmc_card *card,
 
 		/* Erase init depends on CSD and SSR */
 		mmc_init_erase(card);
-
-		/*
-		 * Fetch switch information from card.
-		 */
-		err = mmc_read_switch(card);
-		if (err)
-			return err;
 	}
 
+	/*
+	 * Fetch switch information from card. Note, sd3_bus_mode can

change if

drivers/mmc/core/sd.c +7 -0

+	 * voltage switch outcome changes, so do this always.
+	 */
+	err = mmc_read_switch(card);
+	if (err)
+		return err;
+
 	/*
 	 * For SPI, enable CRC as appropriate.
 	 * This CRC enable is located AFTER the reading of the @@ -1480,26
+1481,15 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
 	if (!v18_fixup_failed && !mmc_host_is_spi(host) &&

mmc_host_uhs(host) &&

drivers/mmc/core/sd.c +8 -20

 	    mmc_sd_card_using_v18(card) &&
 	    host->ios.signal_voltage != MMC_SIGNAL_VOLTAGE_180) {
-		/*
-		 * Re-read switch information in case it has changed since
-		 * oldcard was initialized.
-		 */
-		if (oldcard) {
-			err = mmc_read_switch(card);
-			if (err)
-				goto free_card;
-		}
-		if (mmc_sd_card_using_v18(card)) {
-			if (mmc_host_set_uhs_voltage(host) ||
-			    mmc_sd_init_uhs_card(card)) {
-				v18_fixup_failed = true;
-				mmc_power_cycle(host, ocr);
-				if (!oldcard)
-					mmc_remove_card(card);
-				goto retry;
-			}
-			goto cont;
+		if (mmc_host_set_uhs_voltage(host) ||
+		    mmc_sd_init_uhs_card(card)) {
+			v18_fixup_failed = true;
+			mmc_power_cycle(host, ocr);
+			if (!oldcard)
+				mmc_remove_card(card);
+			goto retry;
 		}
+		goto cont;
 	}
 
 	/* Initialization sequence for UHS-I cards */
--

2.25.1

Hi

Here are 2 SD card fixes prompted by the following email thread:

        https://lore.kernel.org/linux-mmc/[email protected]/T/#u

Adrian Hunter (2):
mmc: sd: Fix 1.8V workaround branch
mmc: sd: Fix inconsistent sd3_bus_mode with failed voltage switch

 drivers/mmc/core/sd.c | 46 ++++++++++++++++++----------------------------
 1 file changed, 18 insertions(+), 28 deletions(-)