cmd: pxe: support INITRD and FDT selection with FIT

Since the commit d5ba6188dfbf ("cmd: pxe_utils: Check fdtcontroladdr
in label_boot") the FDT or the FDTDIR label is required in extlinux.conf
and the fallback done by bootm command when only the device tree present
in this command parameters is no more performed when FIT is used for
kernel.

When the label FDT or FDTDIR are absent or if the device tree file is
absent, the PXE command in U-Boot uses the default U-Boot device tree
selected by fdtcontroladdr = gd->fdt_blob, it is the "Scenario 3".

With this scenario the bootm FIP fallback is no more possible with
the extlinux.conf when only "kernel" label is present and is a FIP:

  kernel <path>#<conf>[#<extra-conf[#...]]

As the U-Boot FDT is always provided in the third bootm argument,
the device tree found in FIP is not used as fallback, it was done
previously in boot_get_fdt().

This patch adds a new field kernel_label to save the full kernel label.
The FDT bootm parameters use the kernel address (to avoid to load a
second time the same FIP) and the config when this full label is reused
for "fdt" or "initrd" label.

This FIP support in extlinux.conf is restored when the "FDT" label
can be found and select the same FIP (identical file and configuration):

  kernel <path>#<conf>[#<extra-conf[#...]]
  fdt <path>#<conf>[#<extra-conf[#...]]

The patch add also this possibility for initrd.

  initrd <path>#<conf>[#<extra-conf[#...]]

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/doc/README.pxe b/doc/README.pxe
index d14d2bdcc9b..172201093d0 100644
--- a/doc/README.pxe
+++ b/doc/README.pxe
@@ -179,11 +179,19 @@ initrd <path>	    - if this label is chosen, use tftp to retrieve the initrd
 		      at <path>. it will be stored at the address indicated in
 		      the initrd_addr_r environment variable, and that address
 		      will be passed to bootm.
+		      For FIT image, the initrd can be provided with the same value than
+		      kernel, including configuration:
+		        <path>#<conf>[#<extra-conf[#...]]
+		      In this case, kernel_addr_r is passed to bootm.
 
 fdt <path>	    - if this label is chosen, use tftp to retrieve the fdt blob
 		      at <path>. it will be stored at the address indicated in
 		      the fdt_addr_r environment variable, and that address will
 		      be passed to bootm.
+		      For FIT image, the device tree can be provided with the same value
+		      than kernel, including configuration:
+		        <path>#<conf>[#<extra-conf[#...]]
+		      In this case, kernel_addr_r is passed to bootm.
 
 devicetree <path>   - if this label is chosen, use tftp to retrieve the fdt blob
 		      at <path>. it will be stored at the address indicated in