mmc: use the generic timeout for cmd6 (SWITCH) provided in the ext_csd

Starting with rev 4.5, the eMMC can define a generic timeout for the
SWITCH command.

Following Linux Kernel code, the timeout also changed from 1000 -> 500

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index a61e311..ff56c3dd 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -21,6 +21,8 @@
 #include <div64.h>
 #include "mmc_private.h"
 
+#define DEFAULT_CMD6_TIMEOUT_MS  500
+
 static int mmc_set_signal_voltage(struct mmc *mmc, uint signal_voltage);
 static int mmc_power_cycle(struct mmc *mmc);
 #if !CONFIG_IS_ENABLED(MMC_TINY)
@@ -745,10 +747,13 @@
 			bool send_status)
 {
 	struct mmc_cmd cmd;
-	int timeout = 1000;
+	int timeout = DEFAULT_CMD6_TIMEOUT_MS;
 	int retries = 3;
 	int ret;
 
+	if (mmc->gen_cmd6_time)
+		timeout = mmc->gen_cmd6_time * 10;
+
 	cmd.cmdidx = MMC_CMD_SWITCH;
 	cmd.resp_type = MMC_RSP_R1b;
 	cmd.cmdarg = (MMC_SWITCH_MODE_WRITE_BYTE << 24) |
@@ -2135,6 +2140,9 @@
 			mmc->capacity_user = capacity;
 	}
 
+	if (mmc->version >= MMC_VERSION_4_5)
+		mmc->gen_cmd6_time = ext_csd[EXT_CSD_GENERIC_CMD6_TIME];
+
 	/* The partition data may be non-zero but it is only
 	 * effective if PARTITION_SETTING_COMPLETED is set in
 	 * EXT_CSD, so ignore any data if this bit is not set,
diff --git a/include/mmc.h b/include/mmc.h
index cf83b74..711cb5d1 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -230,6 +230,7 @@
 #define EXT_CSD_HC_WP_GRP_SIZE		221	/* RO */
 #define EXT_CSD_HC_ERASE_GRP_SIZE	224	/* RO */
 #define EXT_CSD_BOOT_MULT		226	/* RO */
+#define EXT_CSD_GENERIC_CMD6_TIME       248     /* RO */
 #define EXT_CSD_BKOPS_SUPPORT		502	/* RO */
 
 /*
@@ -585,6 +586,7 @@
 	u8 part_attr;
 	u8 wr_rel_set;
 	u8 part_config;
+	u8 gen_cmd6_time;
 	uint tran_speed;
 	uint legacy_speed; /* speed for the legacy mode provided by the card */
 	uint read_bl_len;