bootstd: Add the concept of a bootdev hunter

Some bootdevs must be enumerated before they appear. For example, USB
bootdevs are not visible until USB is enumerated.

With standard boot this needs to happen automatically, since we only
want to enumerate a bus if it is needed.

Add a way to define bootdev 'hunters' which can be used to hunt for
bootdevs of a given type. Track which ones have been used and add a
command to list them.

Include a clang work-around which seems to be needed.

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

1 files changed, 31 insertions, 0 deletions

diff --git a/boot/bootdev-uclass.c b/boot/bootdev-uclass.c
index 0ef3daf24c..62eb0b617c 100644
--- a/boot/bootdev-uclass.c
+++ b/boot/bootdev-uclass.c
@@ -636,6 +636,37 @@ int bootdev_setup_iter_order(struct bootflow_iter *iter, struct udevice **devp)
 	return 0;
 }
 
+void bootdev_list_hunters(struct bootstd_priv *std)
+{
+	struct bootdev_hunter *orig, *start;
+	int n_ent, i;
+
+	orig = ll_entry_start(struct bootdev_hunter, bootdev_hunter);
+	n_ent = ll_entry_count(struct bootdev_hunter, bootdev_hunter);
+
+	/*
+	 * workaround for strange bug in clang-12 which sees all the below data
+	 * as zeroes. Any access of start seems to fix it, such as
+	 *
+	 *    printf("%p", start);
+	 *
+	 * Use memcpy() to force the correct behaviour.
+	 */
+	memcpy(&start, &orig, sizeof(orig));
+	printf("%4s  %4s  %-15s  %s\n", "Prio", "Used", "Uclass", "Hunter");
+	printf("%4s  %4s  %-15s  %s\n", "----", "----", "---------------", "---------------");
+	for (i = 0; i < n_ent; i++) {
+		struct bootdev_hunter *info = start + i;
+
+		printf("%4d  %4s  %-15s  %s\n", info->prio,
+		       std->hunters_used & BIT(i) ? "*" : "",
+		       uclass_get_name(info->uclass),
+		       info->drv ? info->drv->name : "(none)");
+	}
+
+	printf("(total hunters: %d)\n", n_ent);
+}
+
 static int bootdev_post_bind(struct udevice *dev)
 {
 	struct bootdev_uc_plat *ucp = dev_get_uclass_plat(dev);