mmc: Add a new callback function to perform the 74 clocks cycle sequence

Add a new callback function *send_init_stream* which start a sequence of
at least 74 clock cycles.
The mmc core uses *mmc_send_init_stream* in order to invoke the callback
function. This will be used during power cycle where the specification
requires such a sequence after power up.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>

drivers/mmc/mmc-uclass.c

@@ -51,6 +51,19 @@ int mmc_set_ios(struct mmc *mmc)
 	return dm_mmc_set_ios(mmc->dev);
 }
 
+void dm_mmc_send_init_stream(struct udevice *dev)
+{
+	struct dm_mmc_ops *ops = mmc_get_ops(dev);
+
+	if (ops->send_init_stream)
+		ops->send_init_stream(dev);
+}
+
+void mmc_send_init_stream(struct mmc *mmc)
+{
+	dm_mmc_send_init_stream(mmc->dev);
+}
+
 int dm_mmc_get_wp(struct udevice *dev)
 {
 	struct dm_mmc_ops *ops = mmc_get_ops(dev);

drivers/mmc/mmc.c

@@ -1198,6 +1198,10 @@ static inline int bus_width(uint cap)
 }
 
 #if !CONFIG_IS_ENABLED(DM_MMC)
+static void mmc_send_init_stream(struct mmc *mmc)
+{
+}
+
 static int mmc_set_ios(struct mmc *mmc)
 {
 	int ret = 0;
@@ -1983,6 +1987,8 @@ int mmc_start_init(struct mmc *mmc)
 	mmc_set_bus_width(mmc, 1);
 	mmc_set_clock(mmc, 1);
 
+	mmc_send_init_stream(mmc);
+
 	/* Reset the Card */
 	err = mmc_go_idle(mmc);
 

include/mmc.h

@@ -360,6 +360,14 @@ struct dm_mmc_ops {
 	 */
 	int (*set_ios)(struct udevice *dev);
 
+	/**
+	 * send_init_stream() - send the initialization stream: 74 clock cycles
+	 * This is used after power up before sending the first command
+	 *
+	 * @dev:	Device to update
+	 */
+	void (*send_init_stream)(struct udevice *dev);
+
 	/**
 	 * get_cd() - See whether a card is present
 	 *
@@ -382,11 +390,13 @@ struct dm_mmc_ops {
 int dm_mmc_send_cmd(struct udevice *dev, struct mmc_cmd *cmd,
 		    struct mmc_data *data);
 int dm_mmc_set_ios(struct udevice *dev);
+void dm_mmc_send_init_stream(struct udevice *dev);
 int dm_mmc_get_cd(struct udevice *dev);
 int dm_mmc_get_wp(struct udevice *dev);
 
 /* Transition functions for compatibility */
 int mmc_set_ios(struct mmc *mmc);
+void mmc_send_init_stream(struct mmc *mmc);
 int mmc_getcd(struct mmc *mmc);
 int mmc_getwp(struct mmc *mmc);