[PATCH 12/17] bootstd: Tweak scanning with labels

[Simon Glass]

The current implementation of labels uses the ordering of the media
devices to start its scan but then uses the ordering of the (child)
bootdev devices to iterate from then on. This is inconsistent and can
miss some bootdevs.

Update bootdev_next_label() so that it uses the ordering of the bootdev
devices to perform its scan. Check for running out of labels as well.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

 boot/bootdev-uclass.c | 70 +++++++++++++++++++++++--------------------
 1 file changed, 38 insertions(+), 32 deletions(-)

diff --git a/boot/bootdev-uclass.c b/boot/bootdev-uclass.c
index 3791ebfcb42..cfb298d5be5 100644
--- a/boot/bootdev-uclass.c
+++ b/boot/bootdev-uclass.c
@@ -421,7 +421,7 @@ int bootdev_find_by_label(const char *label, struct udevice **devp,
 			  int *method_flagsp)
 {
 	int seq, ret, method_flags = 0;
-	struct udevice *media;
+	struct udevice *bdev;
 	struct uclass *uc;
 	enum uclass_id id;
 
@@ -433,10 +433,27 @@ int bootdev_find_by_label(const char *label, struct udevice **devp,
 		return log_msg_ret("uc", ret);
 	id = ret;
 
-	/* Iterate through devices in the media uclass (e.g. UCLASS_MMC) */
-	uclass_id_foreach_dev(id, media, uc) {
-		struct udevice *bdev, *blk;
-		int ret;
+	/*
+	 * Iterate through all the bootdevs looking for the first one for the
+	 * correct media uclass (e.g. UCLASS_MMC). We do it this way so that
+	 * iter_incr() can continue iterating through others with the same media
+	 * uclass, thus making sure that every relevant bootdev is used.
+	 *
+	 * If instead we found the first media device of the correct uclass,
+	 * then started with its bootdev, that bootdev may be somewhere in the
+	 * middle of the UCLASS_BOOTDEV ordering, thus we would leave out quite
+	 * a few bootdevs as the iteration continues
+	 */
+	uclass_id_foreach_dev(UCLASS_BOOTDEV, bdev, uc) {
+		struct udevice *media;
+
+		media = dev_get_parent(bdev);
+		if (device_get_uclass_id(media) != id) {
+			log_debug("- skip, media '%s' want id '%s'\n",
+				  dev_get_uclass_name(media),
+				  uclass_get_name(id));
+			continue;
+		}
 
 		/* if there is no seq, match anything */
 		if (seq != -1 && dev_seq(media) != seq) {
@@ -444,33 +461,20 @@ int bootdev_find_by_label(const char *label, struct udevice **devp,
 			continue;
 		}
 
-		ret = device_find_first_child_by_uclass(media, UCLASS_BOOTDEV,
-							&bdev);
-		if (ret) {
-			log_debug("- looking via blk, seq=%d, id=%d\n", seq,
-				  id);
-			ret = blk_find_device(id, seq, &blk);
-			if (!ret) {
-				log_debug("- get from blk %s\n", blk->name);
-				ret = bootdev_get_from_blk(blk, &bdev);
-			}
-		}
-		if (!ret) {
-			log_debug("- found %s\n", bdev->name);
-			*devp = bdev;
-
-			/*
-			 * if no sequence number was provided, we must scan all
-			 * bootdevs for this media uclass
-			 */
-			if (seq == -1)
-				method_flags |= BOOTFLOW_METHF_SINGLE_UCLASS;
-			if (method_flagsp)
-				*method_flagsp = method_flags;
-			log_debug("method flags %x\n", method_flags);
-			return 0;
-		}
-		log_debug("- no device in %s\n", media->name);
+		log_debug("- found bdev, seq=%d id %s\n", dev_seq(bdev),
+			  uclass_get_name(id));
+		*devp = bdev;
+
+		/*
+		 * if no sequence number was provided, we must scan all
+		 * bootdevs for this media uclass
+		 */
+		if (seq == -1)
+			method_flags |= BOOTFLOW_METHF_SINGLE_UCLASS;
+		if (method_flagsp)
+			*method_flagsp = method_flags;
+		log_debug("method flags %x\n", method_flags);
+		return 0;
 	}
 
 	return -ENOENT;
@@ -586,6 +590,8 @@ int bootdev_next_label(struct bootflow_iter *iter, struct udevice **devp,
 		const char *label = iter->labels[iter->cur_label];
 		int ret;
 
+		if (!label)
+			break;
 		log_debug("Scanning: %s\n", label);
 		ret = bootdev_hunt_and_find_by_label(label, &dev,
 						     method_flagsp);
-- 
2.43.0