mmc: sdhci: Add support for "Tuning Error" interrupts

Most Bay Trail devices do not enable UHS modes for the external sdcard slot
the Lenovo Yoga Tablet 2 830 / 1050 and Lenovo Yoga Tablet 2 Pro 1380 (8",
10" and 13") models however do enable this.

Using a UHS cards in these tablets results in errors like this one:

[  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: ============================================

which results in IO errors leading to issues accessing the sdcard.

0x04000000 is a so-called "Tuning Error" which sofar the SDHCI driver
does not support / enable. Modify the IRQ handler to process these.

This fixes UHS microsd cards not working with these tablets.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Hans de Goede <[email protected]>
Signed-off-by: Adrian Hunter <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Ulf Hansson <[email protected]>

Author: ahunter6

drivers/mmc/host/sdhci.c

@@ -3439,12 +3439,18 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask)
 		host->data->error = -EILSEQ;
 		if (!mmc_op_tuning(SDHCI_GET_CMD(sdhci_readw(host, SDHCI_COMMAND))))
 			sdhci_err_stats_inc(host, DAT_CRC);
-	} else if ((intmask & SDHCI_INT_DATA_CRC) &&
+	} else if ((intmask & (SDHCI_INT_DATA_CRC | SDHCI_INT_TUNING_ERROR)) &&
 		SDHCI_GET_CMD(sdhci_readw(host, SDHCI_COMMAND))
 			!= MMC_BUS_TEST_R) {
 		host->data->error = -EILSEQ;
 		if (!mmc_op_tuning(SDHCI_GET_CMD(sdhci_readw(host, SDHCI_COMMAND))))
 			sdhci_err_stats_inc(host, DAT_CRC);
+		if (intmask & SDHCI_INT_TUNING_ERROR) {
+			u16 ctrl2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+
+			ctrl2 &= ~SDHCI_CTRL_TUNED_CLK;
+			sdhci_writew(host, ctrl2, SDHCI_HOST_CONTROL2);
+		}
 	} else if (intmask & SDHCI_INT_ADMA_ERROR) {
 		pr_err("%s: ADMA error: 0x%08x\n", mmc_hostname(host->mmc),
 		       intmask);
@@ -3979,7 +3985,7 @@ bool sdhci_cqe_irq(struct sdhci_host *host, u32 intmask, int *cmd_error,
 	} else
 		*cmd_error = 0;
 
-	if (intmask & (SDHCI_INT_DATA_END_BIT | SDHCI_INT_DATA_CRC)) {
+	if (intmask & (SDHCI_INT_DATA_END_BIT | SDHCI_INT_DATA_CRC | SDHCI_INT_TUNING_ERROR)) {
 		*data_error = -EILSEQ;
 		if (!mmc_op_tuning(SDHCI_GET_CMD(sdhci_readw(host, SDHCI_COMMAND))))
 			sdhci_err_stats_inc(host, DAT_CRC);

drivers/mmc/host/sdhci.h

@@ -158,6 +158,7 @@
 #define  SDHCI_INT_BUS_POWER	0x00800000
 #define  SDHCI_INT_AUTO_CMD_ERR	0x01000000
 #define  SDHCI_INT_ADMA_ERROR	0x02000000
+#define  SDHCI_INT_TUNING_ERROR	0x04000000
 
 #define  SDHCI_INT_NORMAL_MASK	0x00007FFF
 #define  SDHCI_INT_ERROR_MASK	0xFFFF8000
@@ -169,7 +170,7 @@
 		SDHCI_INT_DATA_AVAIL | SDHCI_INT_SPACE_AVAIL | \
 		SDHCI_INT_DATA_TIMEOUT | SDHCI_INT_DATA_CRC | \
 		SDHCI_INT_DATA_END_BIT | SDHCI_INT_ADMA_ERROR | \
-		SDHCI_INT_BLK_GAP)
+		SDHCI_INT_BLK_GAP | SDHCI_INT_TUNING_ERROR)
 #define SDHCI_INT_ALL_MASK	((unsigned int)-1)
 
 #define SDHCI_CQE_INT_ERR_MASK ( \