[PATCH v2 4/6] mmc: sdhci-acpi: Disable UHS/1.8V modes on Lenovo Yoga Tablet 2 series sdcard slot

[Hans de Goede <hdegoede@redhat.com>]

Unlike all other Bay Trail devices I have (quite a few) the BIOS on
the Lenovo Yoga Tablet 2 830 / 1050 and Lenovo Yoga Tablet 2 Pro 1380 (8",
10" and 13") models sets the SDHCI_SUPPORT_DDR50 bit in the sdcard slots'
SDHCI controller's Caps_1 register which causes Linux to try and use
UHS SDR12 / SDR25 and DDR50 modes on UHS cards.

These tablets do have 1.8V signalling implemented in the hw level through
the Bay Trail SoC's SD3_1P8EN pin. But trying to use UHS modes leads to
lots of errors like these:

[  225.272001] mmc2: Unexpected interrupt 0x04000000.
[  225.272024] mmc2: sdhci: ============ SDHCI REGISTER DUMP ===========
[  225.272034] mmc2: sdhci: Sys addr:  0x0712c400 | Version:  0x0000b502
[  225.272044] mmc2: sdhci: Blk size:  0x00007200 | Blk cnt:  0x00000007
[  225.272054] mmc2: sdhci: Argument:  0x00000000 | Trn mode: 0x00000023
[  225.272064] mmc2: sdhci: Present:   0x01e20002 | Host ctl: 0x00000016
[  225.272073] mmc2: sdhci: Power:     0x0000000f | Blk gap:  0x00000000
[  225.272082] mmc2: sdhci: Wake-up:   0x00000000 | Clock:    0x00000107
[  225.272092] mmc2: sdhci: Timeout:   0x0000000e | Int stat: 0x00000001
[  225.272101] mmc2: sdhci: Int enab:  0x03ff000b | Sig enab: 0x03ff000b
[  225.272110] mmc2: sdhci: ACmd stat: 0x00000000 | Slot int: 0x00000001
[  225.272119] mmc2: sdhci: Caps:      0x076864b2 | Caps_1:   0x00000004
[  225.272129] mmc2: sdhci: Cmd:       0x00000c1b | Max curr: 0x00000000
[  225.272138] mmc2: sdhci: Resp[0]:   0x00000c00 | Resp[1]:  0x00000000
[  225.272147] mmc2: sdhci: Resp[2]:   0x00000000 | Resp[3]:  0x00000900
[  225.272155] mmc2: sdhci: Host ctl2: 0x0000000c
[  225.272164] mmc2: sdhci: ADMA Err:  0x00000003 | ADMA Ptr: 0x0712c200
[  225.272172] mmc2: sdhci: ============================================

Since SDHCI_QUIRK2_PRESET_VALUE_BROKEN is set in the quirks2 field of
the sdhci_acpi_slot_int_emmc struct, I tried setting that in the quirks2
field of the sdhci_acpi_slot_int_sd struct too and that does makes things
mostly work. But the above error still sometimes happen and regularly
access to the card simply freezes for seconds, which are problems which
do not happen with the non UHS SDR50 mode.

Add a new DMI_QUIRK_SD_NO_1_8_V DMI quirk flag and set that for these
tablets to disable sdcard slot UHS modes by setting SDHCI_QUIRK2_NO_1_8_V
for the sdcard slot when this quirk is set.

Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Note a possible alternative approach would be to simply always set
SDHCI_QUIRK2_NO_1_8_V for the sdcard slot on all Bay Trail models
but that seems like a bit of a big hammer for a problem only seen
on these specific models and maybe there are Bay Trail models out
there with working UHS modes for their sdcard slot.
---
Changes in v2:
- Clarify commit message
---
 drivers/mmc/host/sdhci-acpi.c | 29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c
index c0d77f589deb..233af36d55a9 100644
--- a/drivers/mmc/host/sdhci-acpi.c
+++ b/drivers/mmc/host/sdhci-acpi.c
@@ -80,7 +80,8 @@ struct sdhci_acpi_host {
 enum {
 	DMI_QUIRK_RESET_SD_SIGNAL_VOLT_ON_SUSP			= BIT(0),
 	DMI_QUIRK_SD_NO_WRITE_PROTECT				= BIT(1),
-	DMI_QUIRK_SD_CD_ACTIVE_HIGH				= BIT(2),
+	DMI_QUIRK_SD_NO_1_8_V					= BIT(2),
+	DMI_QUIRK_SD_CD_ACTIVE_HIGH				= BIT(3),
 };
 
 static inline void *sdhci_acpi_priv(struct sdhci_acpi_host *c)
@@ -751,12 +752,15 @@ static const struct dmi_system_id sdhci_acpi_quirks[] = {
 	{
 		/*
 		 * Lenovo Yoga Tablet 2 Pro 1380F/L (13" Android version) this
-		 * has broken WP reporting and an inverted CD signal.
+		 * has broken WP reporting, an inverted CD signal and claims
+		 * to support UHS modes but they do not work.
 		 * Note this has more or less the same BIOS as the Lenovo Yoga
 		 * Tablet 2 830F/L or 1050F/L (8" and 10" Android), but unlike
 		 * the 830 / 1050 models which share the same mainboard this
 		 * model has a different mainboard and the inverted CD and
 		 * broken WP are unique to this board.
+		 * This match for the 13" model MUST come before the 8" + 10"
+		 * match since that one will also match the 13" model!
 		 */
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "Intel Corp."),
@@ -766,7 +770,23 @@ static const struct dmi_system_id sdhci_acpi_quirks[] = {
 			DMI_MATCH(DMI_BIOS_VERSION, "BLADE_21.X64.0005.R00.1504101516"),
 		},
 		.driver_data = (void *)(DMI_QUIRK_SD_NO_WRITE_PROTECT |
-					DMI_QUIRK_SD_CD_ACTIVE_HIGH),
+					DMI_QUIRK_SD_CD_ACTIVE_HIGH |
+					DMI_QUIRK_SD_NO_1_8_V),
+	},
+	{
+		/*
+		 * Lenovo Yoga Tablet 2 830F/L or 1050F/L (The 8" and 10"
+		 * Lenovo Yoga Tablet 2 use the same mainboard) These claim
+		 * to support UHS modes but they do not work.
+		 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Intel Corp."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "VALLEYVIEW C0 PLATFORM"),
+			DMI_MATCH(DMI_BOARD_NAME, "BYT-T FFD8"),
+			/* Partial match on beginning of BIOS version */
+			DMI_MATCH(DMI_BIOS_VERSION, "BLADE_21"),
+		},
+		.driver_data = (void *)DMI_QUIRK_SD_NO_1_8_V,
 	},
 	{
 		/*
@@ -904,6 +924,9 @@ static int sdhci_acpi_probe(struct platform_device *pdev)
 
 		if (quirks & DMI_QUIRK_SD_NO_WRITE_PROTECT)
 			host->mmc->caps2 |= MMC_CAP2_NO_WRITE_PROTECT;
+
+		if (quirks & DMI_QUIRK_SD_NO_1_8_V)
+			host->quirks2 |= SDHCI_QUIRK2_NO_1_8_V;
 	}
 
 	err = sdhci_setup_host(host);
-- 
2.44.0