ARM: tegra: allow passing cboot DTB to the kernel

Some users may wish to pass the cboot-supplied DTB to the booted kernel
rather than having U-Boot load the DTB itself. To allow this, expose the
address of the cboot-supplied DTB in environment variable $fdt_addr. At
least when using extlinux.conf, if the user doesn't explicitly specify
which DTB to pass to the kernel, U-Boot passes the DTB referred to by
this variable.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>

diff --git a/arch/arm/mach-tegra/tegra186/nvtboot_board.c b/arch/arm/mach-tegra/tegra186/nvtboot_board.c
index 1d78346..feb935f 100644 (file)
--- a/arch/arm/mach-tegra/tegra186/nvtboot_board.c
+++ b/arch/arm/mach-tegra/tegra186/nvtboot_board.c
@@ -11,6 +11,19 @@
 
 extern unsigned long nvtboot_boot_x0;
 
+static int set_fdt_addr(void)
+{
+       int ret;
+
+       ret = setenv_hex("fdt_addr", nvtboot_boot_x0);
+       if (ret) {
+               printf("Failed to set fdt_addr to point at DTB: %d\n", ret);
+               return ret;
+       }
+
+       return 0;
+}
+
 /*
  * Attempt to use /chosen/nvidia,ether-mac in the nvtboot DTB to U-Boot's
  * ethaddr environment variable if possible.
@@ -47,6 +60,11 @@ static int set_ethaddr_from_nvtboot(void)
 
 int tegra_soc_board_init_late(void)
 {
+       /*
+        * Ignore errors here; the value may not be used depending on
+        * extlinux.conf or boot script content.
+        */
+       set_fdt_addr();
        /* Ignore errors here; not all cases care about Ethernet addresses */
        set_ethaddr_from_nvtboot();