[PATCH -next v6 03/10] arm: armv8: mmu: export mmu_setup

[Ilias Apalodimas]

On Fri, 5 Sept 2025 at 11:19, Anshul Dalal <anshuld at ti.com> wrote:
>
> The mmu_setup function configures the page tables based on the board
> supplied mem_map struct array. It is called implicitly as part of
> dcache_enable but this limits us to only be able to use APIs such as
> mmu_change_region_attr only after caches are enabled.
>
> This might lead to speculative accesses before we can unmap a region
> that is marked as cacheable in the static memory map.
>
> Therefore this patch exports the mmu_setup function in mmu.h allowing
> users to have more control over when the mmu is configured.
>
> For K3 specifically this allows for the following configuration sequence
> as part of enable_caches:
>
> static mem_map fixups (TODO) -> mmu_setup -> carveouts using
> mmu_change_region_attr (TODO) -> icache/dcache enable
>
> Signed-off-by: Anshul Dalal <anshuld at ti.com>
> ---
>  arch/arm/include/asm/armv8/mmu.h | 5 +++++
>  arch/arm/mach-k3/common.c        | 3 +++
>  2 files changed, 8 insertions(+)
>
> diff --git a/arch/arm/include/asm/armv8/mmu.h b/arch/arm/include/asm/armv8/mmu.h
> index 6af8cd111a4..3807c702fb6 100644
> --- a/arch/arm/include/asm/armv8/mmu.h
> +++ b/arch/arm/include/asm/armv8/mmu.h
> @@ -197,6 +197,11 @@ struct mm_region {
>  extern struct mm_region *mem_map;
>  void setup_pgtables(void);
>  u64 get_tcr(u64 *pips, u64 *pva_bits);
> +
> +/**
> + * mmu_setup() - Sets up the mmu page tables as per mem_map
> + */
> +void mmu_setup(void);
>  #endif
>
>  #endif /* _ASM_ARMV8_MMU_H_ */
> diff --git a/arch/arm/mach-k3/common.c b/arch/arm/mach-k3/common.c
> index 9d6c6fea451..e9b48b528d6 100644
> --- a/arch/arm/mach-k3/common.c
> +++ b/arch/arm/mach-k3/common.c
> @@ -30,6 +30,7 @@
>  #include <soc.h>
>  #include <dm/uclass-internal.h>
>  #include <dm/device-internal.h>
> +#include <asm/armv8/mmu.h>
>
>  #define PROC_BOOT_CTRL_FLAG_R5_CORE_HALT       0x00000001
>  #define PROC_BOOT_STATUS_FLAG_R5_WFI           0x00000002
> @@ -261,6 +262,8 @@ void board_prep_linux(struct bootm_headers *images)
>
>  void enable_caches(void)
>  {
> +       mmu_setup();
> +

mmu_setup() will run twice here. I assume that's ok ?

Thanks
/Ilias
>         icache_enable();
>         dcache_enable();
>  }
> --
> 2.50.1
>