[PATCH] rpi: always set fdt_addr to the correct value

[Jim Posen]

Another related issue that I was confused by is that I expected the FDT address
to be in the variable fdt_addr_r but it is in fdt_addr. In the U-Boot
documentation here
https://u-boot.readthedocs.io/en/latest/usage/environment.html#image-locations,
*_r variables indicate addresses in RAM whereas fdt_addr refers to a flash
location. This may provide a solution to the backwards compatibility problem
with this patch. I propose setting both fdt_addr and fdt_addr_r to the
firmware-provided FDT in fw_dtb_pointer, and you can make it so that fdt_addr_r
will be overwritten even if there is a pre-existing value for it in the
environment. Thoughts?


On Mon, Feb 14, 2022 at 6:25 AM Marek Szyprowski
<m.szyprowski at samsung.com> wrote:
>
> The fdt_addr env have meaning only for the current runtime and it depends
> on the dtb size or firmware version. If one save the environment to disk
> and the loads it on the latter boot, the fdt_addr might change, what
> result in passing incorrect dtb address to the kernel. Fix this by always
> setting the fdt_addr env. This fixes system operation after saving the
> env to disk and updating i.e. dtb files or firmware.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
> Reviewed-by: Jaehoon Chung <jh80.chung at samsung.com>
> ---
>  board/raspberrypi/rpi/rpi.c | 3 ---
>  1 file changed, 3 deletions(-)
>
> diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
> index bc3cc597adb..6d6d2e69234 100644
> --- a/board/raspberrypi/rpi/rpi.c
> +++ b/board/raspberrypi/rpi/rpi.c
> @@ -347,9 +347,6 @@ static void set_fdtfile(void)
>   */
>  static void set_fdt_addr(void)
>  {
> -       if (env_get("fdt_addr"))
> -               return;
> -
>         if (fdt_magic(fw_dtb_pointer) != FDT_MAGIC)
>                 return;
>