From: Stephen Warren swarren@nvidia.com

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 --- arch/arm/mach-tegra/tegra186/nvtboot_board.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)

diff --git a/arch/arm/mach-tegra/tegra186/nvtboot_board.c b/arch/arm/mach-tegra/tegra186/nvtboot_board.c index 1d78346f9843..feb935f0d908 100644 --- 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();