[U-Boot] [PATCH 2/2] ARM: qemu-arm: define fdt_addr_r

[Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>]

Hi Takahiro,

On Fri, 12 Oct 2018 14:07:57 +0900
AKASHI Takahiro <takahiro.akashi@linaro.org> wrote:

> This variable, fdt_addr_t, is missing in the current qemu-arm.h while
> it seems to be mandatory, at least, to run distro_bootcmd as expected.
> So just add its definition. A size of 1MB would be enough.
> 

In what way is this required for distro_bootcmd to work? At least in the
past I've tested qemu_arm64_defconfig and EFI boot with the Fedora
netinst image and it has worked fine in stock U-Boot.

Note that these '-machine virt' based targets are slightly different
from real hardware in the sense that instead of loading a .dtb file
provided by the OS, the device tree is provided by QEMU. In the hunk
below you can see "fdt_addr=0x40000000\0" providing the address of
the QEMU-provided device tree which the distro scripts should be
using.

I guess in principle having ${fdt_addr_r} set as well shouldn't hurt and
might be used for testing/unusual purposes. Glancing at cmd/pxe.c,
there is a problem though, in that if ${fdt_addr_r} were defined, a PXE
file using the FDTDIR directive would attempt loading a dtb file named
"<NULL>-qemu-arm.dtb" instead of falling back to using ${fdt_addr}.
That bug would need to be fixed first before applying this patch.

> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> ---
>  include/configs/qemu-arm.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/include/configs/qemu-arm.h b/include/configs/qemu-arm.h
> index 91fb8d47edf8..0e66f946dde5 100644
> --- a/include/configs/qemu-arm.h
> +++ b/include/configs/qemu-arm.h
> @@ -55,6 +55,7 @@
>  	"fdt_high=0xffffffff\0" \
>  	"initrd_high=0xffffffff\0" \
>  	"fdt_addr=0x40000000\0" \
> +	"fdt_addr_r=0x40100000\0" \
>  	"scriptaddr=0x40200000\0" \
>  	"pxefile_addr_r=0x40300000\0" \
>  	"kernel_addr_r=0x40400000\0" \