linux-kernel - Re: [PATCH v1 3/6] drm/panfrost: Unify panfrost_mmu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250311085158.37329b0c@collabora.com>
Date: Tue, 11 Mar 2025 08:51:58 +0100
From: Boris Brezillon <boris.brezillon@...labora.com>
To: Ariel D'Alessandro <ariel.dalessandro@...labora.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
 robh@...nel.org, steven.price@....com, maarten.lankhorst@...ux.intel.com,
 mripard@...nel.org, tzimmermann@...e.de, airlied@...il.com,
 simona@...ll.ch, kernel@...labora.com, linux-mediatek@...ts.infradead.org,
 linux-arm-kernel@...ts.infradead.org, sjoerd@...labora.com
Subject: Re: [PATCH v1 3/6] drm/panfrost: Unify panfrost_mmu_enable/disable
 common code

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