Re: [PATCH 3/8] drm/panthor: De-duplicate FW memory section sync

Boris Brezillon
2026-05-05T15:47:54Z

On Tue, 5 May 2026 16:05:09 +0200
Ketil Johnsen <ketil.johnsen@arm.com> wrote:

> Handle the sync to device of FW memory sections inside
> panthor_fw_init_section_mem() so that the callers do not have to.
>
> This small improvement is also critical for protected FW sections,
> so we avoid issuing memory transactions to protected memory from
> CPU running in normal mode.
>
> Signed-off-by: Ketil Johnsen <ketil.johnsen@arm.com>

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

> ---
> drivers/gpu/drm/panthor/panthor_fw.c | 22 ++++++----------------
> 1 file changed, 6 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
> index be0da5b1f3abf..0d07a133dc3af 100644
> --- a/drivers/gpu/drm/panthor/panthor_fw.c
> +++ b/drivers/gpu/drm/panthor/panthor_fw.c
> @@ -446,6 +446,7 @@ static void panthor_fw_init_section_mem(struct panthor_device *ptdev,
> struct panthor_fw_section *section)
> {
> bool was_mapped = !!section->mem->kmap;
> + struct sg_table *sgt;
> int ret;
>
> if (!section->data.size &&
> @@ -464,6 +465,11 @@ static void panthor_fw_init_section_mem(struct panthor_device *ptdev,
>
> if (!was_mapped)
> panthor_kernel_bo_vunmap(section->mem);
> +
> + /* An sgt should have been requested when the kernel BO was GPU-mapped. */
> + sgt = to_panthor_bo(section->mem->obj)->dmap.sgt;
> + if (!drm_WARN_ON_ONCE(&ptdev->base, !sgt))
> + dma_sync_sgtable_for_device(ptdev->base.dev, sgt, DMA_TO_DEVICE);
> }
>
> /**
> @@ -626,7 +632,6 @@ static int panthor_fw_load_section_entry(struct panthor_device *ptdev,
> section_size = hdr.va.end - hdr.va.start;
> if (section_size) {
> u32 cache_mode = hdr.flags & CSF_FW_BINARY_IFACE_ENTRY_CACHE_MODE_MASK;
> - struct panthor_gem_object *bo;
> u32 vm_map_flags = 0;
> u64 va = hdr.va.start;
>
> @@ -663,14 +668,6 @@ static int panthor_fw_load_section_entry(struct panthor_device *ptdev,
> }
>
> panthor_fw_init_section_mem(ptdev, section);
> -
> - bo = to_panthor_bo(section->mem->obj);
> -
> - /* An sgt should have been requested when the kernel BO was GPU-mapped. */
> - if (drm_WARN_ON_ONCE(&ptdev->base, !bo->dmap.sgt))
> - return -EINVAL;
> -
> - dma_sync_sgtable_for_device(ptdev->base.dev, bo->dmap.sgt, DMA_TO_DEVICE);
> }
>
> if (hdr.va.start == CSF_MCU_SHARED_REGION_START)
> @@ -724,17 +721,10 @@ panthor_reload_fw_sections(struct panthor_device *ptdev, bool full_reload)
> struct panthor_fw_section *section;
>
> list_for_each_entry(section, &ptdev->fw->sections, node) {
> - struct sg_table *sgt;
> -
> if (!full_reload && !(section->flags & CSF_FW_BINARY_IFACE_ENTRY_WR))
> continue;
>
> panthor_fw_init_section_mem(ptdev, section);
> -
> - /* An sgt should have been requested when the kernel BO was GPU-mapped. */
> - sgt = to_panthor_bo(section->mem->obj)->dmap.sgt;
> - if (!drm_WARN_ON_ONCE(&ptdev->base, !sgt))
> - dma_sync_sgtable_for_device(ptdev->base.dev, sgt, DMA_TO_DEVICE);
> }
> }
>