doc: document the fdtdir PXE command

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>

diff --git a/doc/README.pxe b/doc/README.pxe
index 8363383c53cef10fb9710d411792d397069971d2..bd175eb22dffd45cb0bfa9e5379932c9322ad13e 100644 (file)
--- a/doc/README.pxe
+++ b/doc/README.pxe
@@ -155,6 +155,13 @@ fdt <path>     - if this label is chosen, use tftp to retrieve the fdt blob
                      the fdt_addr_r environment variable, and that address will
                      be passed to bootm.
 
+fdtdir <path>      - if this label is chosen, use tftp to retrieve a fdt blob
+                     relative to <path>. If the fdtfile environment variable
+                     is set, <path>/<fdtfile> is retrieved. Otherwise, the
+                     filename is generated from the soc and board environment
+                     variables, i.e. <path>/<soc>-<board>.dtb is retrieved.
+                     If the fdt command is specified, fdtdir is ignored.
+
 localboot <flag>    - Run the command defined by "localcmd" in the environment.
                      <flag> is ignored and is only here to match the syntax of
                      PXELINUX config files.