pxe: Allow calling the pxe_get logic directly

Refactor this code so that we can call the 'pxe get' command without going
through the command-line interpreter. This makes it easier to get the
information we need, without going through environment variables.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Artem Lapkin <email2tema@gmail.com>
Tested-by: Artem Lapkin <email2tema@gmail.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
diff --git a/include/pxe_utils.h b/include/pxe_utils.h
index 194a5ed..b7037f8 100644
--- a/include/pxe_utils.h
+++ b/include/pxe_utils.h
@@ -236,4 +236,18 @@
  */
 int pxe_get_file_size(ulong *sizep);
 
+/**
+ * pxe_get() - Get the PXE file from the server
+ *
+ * This tries various filenames to obtain a PXE file
+ *
+ * @pxefile_addr_r: Address to put file
+ * @bootdirp: Returns the boot filename, or NULL if none. This is the 'bootfile'
+ *	option provided by the DHCP server. If none, returns NULL. For example,
+ *	"rpi/info", which indicates that all files should be fetched from the
+ *	"rpi/" subdirectory
+ * @sizep: Size of the PXE file (not bootfile)
+ */
+int pxe_get(ulong pxefile_addr_r, char **bootdirp, ulong *sizep);
+
 #endif /* __PXE_UTILS_H */