On 9/17/25 14:31, Patrick Delaunay wrote:
> Use the ARM64 kernel booting register settings, defined in Linux
> documentation Documentation/arch/arm64/booting.rst:
>
> x0 = physical address of device tree blob (dtb) in system RAM.
>
> so kernel can replace U-Boot in FIP without modification of BL31.
>
> Use x0 for future TF-A version and keep x2 as fallback to be compatible
> with previous version of TF-A BL31.
>
> Signed-off-by: Patrick Delaunay <[email protected]>
> ---
>
> arch/arm/mach-stm32mp/stm32mp2/cpu.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/mach-stm32mp/stm32mp2/cpu.c
> b/arch/arm/mach-stm32mp/stm32mp2/cpu.c
> index c3b87d7f9810..e081dc605b84 100644
> --- a/arch/arm/mach-stm32mp/stm32mp2/cpu.c
> +++ b/arch/arm/mach-stm32mp/stm32mp2/cpu.c
> @@ -92,13 +92,21 @@ uintptr_t get_stm32mp_bl2_dtb(void)
> }
>
> /*
> - * Save the FDT address provided by TF-A in r2 at boot time
> + * Save the FDT address provided by TF-A at boot time
> * This function is called from start.S
> */
> -void save_boot_params(unsigned long r0, unsigned long r1, unsigned long r2,
> - unsigned long r3)
> +void save_boot_params(unsigned long x0, unsigned long x1, unsigned long x2,
> + unsigned long x3)
> {
> - nt_fw_dtb = r2;
> + /* use the ARM64 kernel booting register settings:
> + * x0 = physical address of device tree blob (dtb) in system RAM.
> + * so kernel can replace U-Boot in FIP wihtout BL31 modification
> + * else falback to x2 used in previous TF-A version
> + */
> + if (x0)
> + nt_fw_dtb = x0;
> + else
> + nt_fw_dtb = x2;
>
> save_boot_params_ret();
> }
Reviewed-by: Patrice Chotard <[email protected]>
Thanks
Patrice
