[RFC] efi_driver: fix a parent issue in efi-created block devices

[AKASHI Takahiro]

An EFI application may create an EFI block device (EFI_BLOCK_IO_PROTOCOL) in
EFI world, which in turn generates a corresponding U-Boot block device based on
U-Boot's Driver Model.
The latter device, however, doesn't work as U-Boot proper block device
due to an issue in efi_driver's implementation. We saw discussions in the past,
most recently in [1].

  [1] https://lists.denx.de/pipermail/u-boot/2023-July/522565.html

This RFC patch tries to address (part of) the issue.
If it is considered acceptable, I will create a formal patch.

Withtout this patch,
===8<===
=> env set efi_selftest 'block device'
=> bootefi selftest
 ...

Summary: 0 failures

=> dm tree
 Class     Index  Probed  Driver                Name
-----------------------------------------------------------
 root          0  [ + ]   root_driver           root_driver
 ...
 bootmeth      7  [   ]   vbe_simple            |   `-- vbe_simple
 blk           0  [ + ]   efi_blk               `-- efiblk#0
 partition     0  [ + ]   blk_partition             `-- efiblk#0:1
=> ls efiloader 0:1
** Bad device specification efiloader 0 **
Couldn't find partition efiloader 0:1
===>8===

With this patch applied, efiblk#0(:1) now gets accessible.

===8<===
=> env set efi_selftest 'block device'
=> bootefi selftest
 ...

Summary: 0 failures

=> dm tree
 Class     Index  Probed  Driver                Name
-----------------------------------------------------------
 root          0  [ + ]   root_driver           root_driver
 ...
 bootmeth      7  [   ]   vbe_simple            |   `-- vbe_simple
 efi           0  [ + ]   EFI block driver      `-- /VenHw(dbca4c98-6cb0-694d-0872-819c650cb7b8)
 blk           0  [ + ]   efi_blk                   `-- efiblk#0
 partition     0  [ + ]   blk_partition                 `-- efiblk#0:1
=> ls efiloader 0:1
       13   hello.txt
        7   u-boot.txt

2 file(s), 0 dir(s)
===>8===

Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
---
 include/efi_driver.h                         |  2 +-
 lib/efi_driver/efi_block_device.c            | 17 ++++++++++++-----
 lib/efi_driver/efi_uclass.c                  |  8 +++++++-
 lib/efi_selftest/efi_selftest_block_device.c |  2 ++
 4 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/include/efi_driver.h b/include/efi_driver.h
index 63a95e4cf800..ed66796f3519 100644
--- a/include/efi_driver.h
+++ b/include/efi_driver.h
@@ -42,7 +42,7 @@ struct efi_driver_ops {
 	const efi_guid_t *child_protocol;
 	efi_status_t (*init)(struct efi_driver_binding_extended_protocol *this);
 	efi_status_t (*bind)(struct efi_driver_binding_extended_protocol *this,
-			     efi_handle_t handle, void *interface);
+			     efi_handle_t handle, void *interface, char *name);
 };
 
 #endif /* _EFI_DRIVER_H */
diff --git a/lib/efi_driver/efi_block_device.c b/lib/efi_driver/efi_block_device.c
index add00eeebbea..43b7ed7c973c 100644
--- a/lib/efi_driver/efi_block_device.c
+++ b/lib/efi_driver/efi_block_device.c
@@ -115,9 +115,9 @@ static ulong efi_bl_write(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
  * Return:	status code
  */
 static efi_status_t
-efi_bl_create_block_device(efi_handle_t handle, void *interface)
+efi_bl_create_block_device(efi_handle_t handle, void *interface, struct udevice *parent)
 {
-	struct udevice *bdev = NULL, *parent = dm_root();
+	struct udevice *bdev = NULL;
 	efi_status_t ret;
 	int devnum;
 	char *name;
@@ -181,7 +181,7 @@ err:
  */
 static efi_status_t efi_bl_bind(
 			struct efi_driver_binding_extended_protocol *this,
-			efi_handle_t handle, void *interface)
+			efi_handle_t handle, void *interface, char *name)
 {
 	efi_status_t ret = EFI_SUCCESS;
 	struct efi_object *obj = efi_search_obj(handle);
@@ -191,8 +191,15 @@ static efi_status_t efi_bl_bind(
 	if (!obj || !interface)
 		return EFI_INVALID_PARAMETER;
 
-	if (!handle->dev)
-		ret = efi_bl_create_block_device(handle, interface);
+	if (!handle->dev) {
+		struct udevice *parent;
+
+		ret = device_bind_driver(dm_root(), "EFI block driver", name, &parent);
+		if (!ret)
+			ret = efi_bl_create_block_device(handle, interface, parent);
+		else
+			ret = EFI_DEVICE_ERROR;
+	}
 
 	return ret;
 }
diff --git a/lib/efi_driver/efi_uclass.c b/lib/efi_driver/efi_uclass.c
index 45f935198874..bf669742783e 100644
--- a/lib/efi_driver/efi_uclass.c
+++ b/lib/efi_driver/efi_uclass.c
@@ -145,7 +145,13 @@ static efi_status_t EFIAPI efi_uc_start(
 	ret = check_node_type(controller_handle);
 	if (ret != EFI_SUCCESS)
 		goto err;
-	ret = bp->ops->bind(bp, controller_handle, interface);
+
+	struct efi_handler *handler;
+	char tmpname[256] = "AppName";
+	ret = efi_search_protocol(controller_handle, &efi_guid_device_path,
+				  &handler);
+	snprintf(tmpname, 256, "%pD", handler->protocol_interface);
+	ret = bp->ops->bind(bp, controller_handle, interface, strdup(tmpname));
 	if (ret == EFI_SUCCESS)
 		goto out;
 
diff --git a/lib/efi_selftest/efi_selftest_block_device.c b/lib/efi_selftest/efi_selftest_block_device.c
index a367e8b89d17..0ab8e4590dfe 100644
--- a/lib/efi_selftest/efi_selftest_block_device.c
+++ b/lib/efi_selftest/efi_selftest_block_device.c
@@ -248,6 +248,7 @@ static int teardown(void)
 {
 	efi_status_t r = EFI_ST_SUCCESS;
 
+#if 0 /* Temporarily out for confirmation */
 	if (disk_handle) {
 		r = boottime->uninstall_protocol_interface(disk_handle,
 							   &guid_device_path,
@@ -273,6 +274,7 @@ static int teardown(void)
 			return EFI_ST_FAILURE;
 		}
 	}
+#endif
 	return r;
 }
 
-- 
2.41.0