Re: [PATCH v1 3/6] drm/panfrost: Unify panfrost_mmu_enable/disable common code

[Boris Brezillon]

On Mon, 10 Mar 2025 16:59:18 -0300
Ariel D'Alessandro <ariel.dalessandro@xxxxxxxxxxxxx> wrote:

> Both these functions write to MMU_AS_CONTROL register in the same way.
> Define a common _panfrost_mmu_as_control_write function with the shared
> code.
> 
> Signed-off-by: Ariel D'Alessandro <ariel.dalessandro@xxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/panfrost/panfrost_mmu.c | 33 ++++++++++++-------------
>  1 file changed, 16 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> index 294f86b3c25e7..31df3a96f89bd 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> @@ -121,38 +121,37 @@ static int mmu_hw_do_operation(struct panfrost_device *pfdev,
>  	return ret;
>  }
>  
> -static void panfrost_mmu_enable(struct panfrost_device *pfdev, struct panfrost_mmu *mmu)
> +static void
> +_panfrost_mmu_as_control_write(struct panfrost_device *pfdev, u32 as_nr,
> +			       u64 transtab, u64 memattr)

I'm honestly not convinced this is needed. Let's just stick to
panfrost_mmu_enable/disable().

>  {
> -	int as_nr = mmu->as;
> -	struct io_pgtable_cfg *cfg = &mmu->pgtbl_cfg;
> -	u64 transtab = cfg->arm_mali_lpae_cfg.transtab;
> -	u64 memattr = cfg->arm_mali_lpae_cfg.memattr;
> -
>  	mmu_hw_do_operation_locked(pfdev, as_nr, 0, ~0ULL, AS_COMMAND_FLUSH_MEM);
>  
>  	mmu_write(pfdev, AS_TRANSTAB_LO(as_nr), lower_32_bits(transtab));
>  	mmu_write(pfdev, AS_TRANSTAB_HI(as_nr), upper_32_bits(transtab));
>  
> -	/* Need to revisit mem attrs.
> -	 * NC is the default, Mali driver is inner WT.
> -	 */
>  	mmu_write(pfdev, AS_MEMATTR_LO(as_nr), lower_32_bits(memattr));
>  	mmu_write(pfdev, AS_MEMATTR_HI(as_nr), upper_32_bits(memattr));
>  
>  	write_cmd(pfdev, as_nr, AS_COMMAND_UPDATE);
>  }
>  
> -static void panfrost_mmu_disable(struct panfrost_device *pfdev, u32 as_nr)
> +static void panfrost_mmu_enable(struct panfrost_device *pfdev, struct panfrost_mmu *mmu)
>  {
> -	mmu_hw_do_operation_locked(pfdev, as_nr, 0, ~0ULL, AS_COMMAND_FLUSH_MEM);
> -
> -	mmu_write(pfdev, AS_TRANSTAB_LO(as_nr), 0);
> -	mmu_write(pfdev, AS_TRANSTAB_HI(as_nr), 0);
> +	int as_nr = mmu->as;
> +	struct io_pgtable_cfg *cfg = &mmu->pgtbl_cfg;
> +	u64 transtab = cfg->arm_mali_lpae_cfg.transtab;
> +	u64 memattr = cfg->arm_mali_lpae_cfg.memattr;
>  
> -	mmu_write(pfdev, AS_MEMATTR_LO(as_nr), 0);
> -	mmu_write(pfdev, AS_MEMATTR_HI(as_nr), 0);
> +	/* Need to revisit mem attrs.
> +	 * NC is the default, Mali driver is inner WT.
> +	 */
> +	_panfrost_mmu_as_control_write(pfdev, as_nr, transtab, memattr);
> +}
>  
> -	write_cmd(pfdev, as_nr, AS_COMMAND_UPDATE);
> +static void panfrost_mmu_disable(struct panfrost_device *pfdev, u32 as_nr)
> +{
> +	_panfrost_mmu_as_control_write(pfdev, as_nr, 0, 0);
>  }
>  
>  u32 panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu *mmu)