mmc: mtk-sd: Add condition to enable 'single' burst type

This change add a condition for 'single' burst type selection.

Read AXI_LEN field from EMMC50_CFG2(AHB2AXI wrapper) register, if the
value is not 0, it means the HWIP is using AXI as AMBA bus, which do
not support 'single' burst type.

Suggested-by: AngeloGioacchino Del Regno <[email protected]>
Signed-off-by: Axe Yang <[email protected]>
Reviewed-by: AngeloGioacchino Del Regno <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Ulf Hansson <[email protected]>

Author: Axe Yang

drivers/mmc/host/mtk-sd.c

@@ -84,6 +84,7 @@
 #define EMMC51_CFG0	 0x204
 #define EMMC50_CFG0      0x208
 #define EMMC50_CFG1      0x20c
+#define EMMC50_CFG2      0x21c
 #define EMMC50_CFG3      0x220
 #define SDC_FIFO_CFG     0x228
 #define CQHCI_SETTING	 0x7fc
@@ -306,7 +307,10 @@
 /* EMMC50_CFG1 mask */
 #define EMMC50_CFG1_DS_CFG        BIT(28)  /* RW */
 
-#define EMMC50_CFG3_OUTS_WR       GENMASK(4, 0)  /* RW */
+/* EMMC50_CFG2 mask */
+#define EMMC50_CFG2_AXI_SET_LEN   GENMASK(27, 24) /* RW */
+
+#define EMMC50_CFG3_OUTS_WR       GENMASK(4, 0)   /* RW */
 
 #define SDC_FIFO_CFG_WRVALIDSEL   BIT(24)  /* RW */
 #define SDC_FIFO_CFG_RDVALIDSEL   BIT(25)  /* RW */
@@ -1917,9 +1921,13 @@ static void msdc_init_hw(struct msdc_host *host)
 	pb1_val |= FIELD_PREP(MSDC_PATCH_BIT1_CMDTA, 1);
 	pb1_val |= MSDC_PB1_DDR_CMD_FIX_SEL;
 
-	/* Set single burst mode, auto sync state clear, block gap stop clk */
-	pb1_val |= MSDC_PB1_SINGLE_BURST | MSDC_PB1_RSVD20 |
-		   MSDC_PB1_AUTO_SYNCST_CLR | MSDC_PB1_MARK_POP_WATER;
+	/* Support 'single' burst type only when AXI_LEN is 0 */
+	sdr_get_field(host->base + EMMC50_CFG2, EMMC50_CFG2_AXI_SET_LEN, &val);
+	if (!val)
+		pb1_val |= MSDC_PB1_SINGLE_BURST;
+
+	/* Set auto sync state clear, block gap stop clk */
+	pb1_val |= MSDC_PB1_RSVD20 | MSDC_PB1_AUTO_SYNCST_CLR | MSDC_PB1_MARK_POP_WATER;
 
 	/* Set low power DCM, use HCLK for GDMA, use MSDC CLK for everything else */
 	pb1_val |= MSDC_PB1_LP_DCM_EN | MSDC_PB1_RSVD3 |