efi_loader: return binary from efi_dp_from_lo()

For finding distro supplied device-trees we need to know from which device
we are booting. This can be identified via the device-path of the binary.

Up to now efi_dp_from_lo() only could return the initrd or fdt device-path.
Allow returning the binary device-path, too.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
index 18be8a1b4f1a1f21e1560db866b2e9e2821050c8..0f684590f22a1c88758b968630bec2f4030ff747 100644 (file)
--- a/lib/efi_loader/efi_device_path.c
+++ b/lib/efi_loader/efi_device_path.c
@@ -1133,17 +1133,18 @@ ssize_t efi_dp_check_length(const struct efi_device_path *dp,
 }
 
 /**
- * efi_dp_from_lo() - Get the instance of a VenMedia node in a
- *                    multi-instance device path that matches
- *                    a specific GUID. This kind of device paths
- *                    is found in Boot#### options describing an
- *                    initrd location
+ * efi_dp_from_lo() - get device-path from load option
  *
- * @lo:                EFI_LOAD_OPTION containing a valid device path
- * @guid:      guid to search for
+ * The load options in U-Boot may contain multiple concatenated device-paths.
+ * The first device-path indicates the EFI binary to execute. Subsequent
+ * device-paths start with a VenMedia node where the GUID identifies the
+ * function (initrd or fdt).
+ *
+ * @lo:                EFI load option containing a valid device path
+ * @guid:      GUID identifying device-path or NULL for the EFI binary
  *
  * Return:
- * device path including the VenMedia node or NULL.
+ * device path excluding the matched VenMedia node or NULL.
  * Caller must free the returned value.
  */
 struct
@@ -1154,6 +1155,9 @@ efi_device_path *efi_dp_from_lo(struct efi_load_option *lo,
        struct efi_device_path_vendor *vendor;
        int lo_len = lo->file_path_length;
 
+       if (!guid)
+               return efi_dp_dup(fp);
+
        for (; lo_len >=  sizeof(struct efi_device_path);
             lo_len -= fp->length, fp = (void *)fp + fp->length) {
                if (lo_len < 0 || efi_dp_check_length(fp, lo_len) < 0)