dm: core: Add DM_FLAG_OS_PREPARE flag

This new flag can be added to DM device drivers, which need to do some
final configuration before U-Boot exits and the OS (e.g. Linux) is
started. The remove functions of those drivers will get called at
this stage to do these last-stage configuration steps.

Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Cc: Bin Meng <bmeng.cn@gmail.com>

drivers/core/device-remove.c

@@ -152,6 +152,15 @@ void device_free(struct udevice *dev)
 	devres_release_probe(dev);
 }
 
+static bool flags_remove(uint flags, uint drv_flags)
+{
+	if ((flags & DM_REMOVE_NORMAL) ||
+	    (flags & (drv_flags & (DM_FLAG_ACTIVE_DMA | DM_FLAG_OS_PREPARE))))
+		return true;
+
+	return false;
+}
+
 int device_remove(struct udevice *dev, uint flags)
 {
 	const struct driver *drv;
@@ -178,9 +187,7 @@ int device_remove(struct udevice *dev, uint flags)
 	 * Remove the device if called with the "normal" remove flag set,
 	 * or if the remove flag matches any of the drivers remove flags
 	 */
-	if (drv->remove &&
-	    ((flags & DM_REMOVE_NORMAL) ||
-	     (flags & (drv->flags & DM_FLAG_ACTIVE_DMA)))) {
+	if (drv->remove && flags_remove(flags, drv->flags)) {
 		ret = drv->remove(dev);
 		if (ret)
 			goto err_remove;
@@ -194,8 +201,7 @@ int device_remove(struct udevice *dev, uint flags)
 		}
 	}
 
-	if ((flags & DM_REMOVE_NORMAL) ||
-	    (flags & (drv->flags & DM_FLAG_ACTIVE_DMA))) {
+	if (flags_remove(flags, drv->flags)) {
 		device_free(dev);
 
 		dev->seq = -1;

include/dm/device.h

@@ -54,6 +54,12 @@ struct driver_info;
  */
 #define DM_FLAG_ACTIVE_DMA		(1 << 9)
 
+/*
+ * Call driver remove function to do some final configuration, before
+ * U-Boot exits and the OS is started
+ */
+#define DM_FLAG_OS_PREPARE		(1 << 10)
+
 /*
  * One or multiple of these flags are passed to device_remove() so that
  * a selective device removal as specified by the remove-stage and the
@@ -66,10 +72,13 @@ enum {
 	/* Remove devices with active DMA */
 	DM_REMOVE_ACTIVE_DMA = DM_FLAG_ACTIVE_DMA,
 
+	/* Remove devices which need some final OS preparation steps */
+	DM_REMOVE_OS_PREPARE = DM_FLAG_OS_PREPARE,
+
 	/* Add more use cases here */
 
 	/* Remove devices with any active flag */
-	DM_REMOVE_ACTIVE_ALL = DM_REMOVE_ACTIVE_DMA,
+	DM_REMOVE_ACTIVE_ALL = DM_REMOVE_ACTIVE_DMA | DM_REMOVE_OS_PREPARE,
 };
 
 /**