mmc: sdhci-esdhc-imx: verify tuning control status after configuration

Enhance manual tuning configuration reliability by adding tuning control
status checks per the i.MX Reference Manual recommendations.

Signed-off-by: Luke Wang <[email protected]>
Acked-by: Adrian Hunter <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Ulf Hansson <[email protected]>

Author: Luke Wang

drivers/mmc/host/sdhci-esdhc-imx.c

@@ -83,6 +83,7 @@
 #define  ESDHC_TUNE_CTRL_STEP		1
 #define  ESDHC_TUNE_CTRL_MIN		0
 #define  ESDHC_TUNE_CTRL_MAX		((1 << 7) - 1)
+#define  ESDHC_TUNE_CTRL_STATUS_TAP_SEL_MASK		GENMASK(30, 16)
 #define  ESDHC_TUNE_CTRL_STATUS_TAP_SEL_PRE_MASK	GENMASK(30, 24)
 #define  ESDHC_TUNE_CTRL_STATUS_DLY_CELL_SET_PRE_MASK	GENMASK(14, 8)
 #define  ESDHC_TUNE_CTRL_STATUS_DLY_CELL_SET_OUT_MASK	GENMASK(7, 4)
@@ -1213,7 +1214,7 @@ static int esdhc_executing_tuning(struct sdhci_host *host, u32 opcode)
 {
 	int min, max, avg, ret;
 	int win_length, target_min, target_max, target_win_length;
-	u32 clk_tune_ctrl_status;
+	u32 clk_tune_ctrl_status, temp;
 
 	min = ESDHC_TUNE_CTRL_MIN;
 	max = ESDHC_TUNE_CTRL_MIN;
@@ -1269,6 +1270,13 @@ static int esdhc_executing_tuning(struct sdhci_host *host, u32 opcode)
 					  ESDHC_AUTO_TUNING_WINDOW);
 
 	writel(clk_tune_ctrl_status, host->ioaddr + ESDHC_TUNE_CTRL_STATUS);
+	ret = readl_poll_timeout(host->ioaddr + ESDHC_TUNE_CTRL_STATUS, temp,
+				 clk_tune_ctrl_status ==
+				 FIELD_GET(ESDHC_TUNE_CTRL_STATUS_TAP_SEL_MASK, temp),
+				 1, 10);
+	if (ret == -ETIMEDOUT)
+		dev_warn(mmc_dev(host->mmc),
+			 "clock tuning control status not set in 10us\n");
 
 	ret = mmc_send_tuning(host->mmc, opcode, NULL);
 	esdhc_post_tuning(host);