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drm/sharp-memory: Do not access GEM-DMA vaddr directly

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Use DRM's shadow-plane helper to map and access the GEM object's buffer
within kernel address space. Encapsulates the vmap logic in the GEM-DMA
helpers.

The sharp-memory driver currently reads the vaddr field from the GME
buffer object directly. This only works because GEM code 'automagically'
sets vaddr.

Shadow-plane helpers perform the same steps, but with correct abstraction
behind drm_gem_vmap(). The shadow-plane state provides the buffer address
in kernel address space and the format-conversion state.

v2:
- fix typo in commit description

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20250627152327.8244-1-tzimmermann@suse.de
This commit is contained in:
Thomas Zimmermann 2025-06-27 17:23:09 +02:00
parent c585c1b29a
commit 136c374d8c
1 changed files with 13 additions and 14 deletions
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27
drivers/gpu/drm/tiny/sharp-memory.c
View File

@ -126,28 +126,28 @@ static inline void sharp_memory_set_tx_buffer_addresses(u8 *buffer,
static void sharp_memory_set_tx_buffer_data(u8 *buffer,
struct drm_framebuffer *fb,
const struct iosys_map *vmap,
struct drm_rect clip,
u32 pitch,
struct drm_format_conv_state *fmtcnv_state)
{
int ret;
struct iosys_map dst, vmap;
struct drm_gem_dma_object *dma_obj = drm_fb_dma_get_gem_obj(fb, 0);
struct iosys_map dst;
ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
if (ret)
return;
iosys_map_set_vaddr(&dst, buffer);
iosys_map_set_vaddr(&vmap, dma_obj->vaddr);
drm_fb_xrgb8888_to_mono(&dst, &pitch, &vmap, fb, &clip, fmtcnv_state);
drm_fb_xrgb8888_to_mono(&dst, &pitch, vmap, fb, &clip, fmtcnv_state);
drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
}
static int sharp_memory_update_display(struct sharp_memory_device *smd,
struct drm_framebuffer *fb,
const struct iosys_map *vmap,
struct drm_rect clip,
struct drm_format_conv_state *fmtcnv_state)
{
@ -163,7 +163,7 @@ static int sharp_memory_update_display(struct sharp_memory_device *smd,
sharp_memory_set_tx_buffer_mode(&tx_buffer[0],
SHARP_MEMORY_DISPLAY_UPDATE_MODE, vcom);
sharp_memory_set_tx_buffer_addresses(&tx_buffer[1], clip, pitch);
sharp_memory_set_tx_buffer_data(&tx_buffer[2], fb, clip, pitch, fmtcnv_state);
sharp_memory_set_tx_buffer_data(&tx_buffer[2], fb, vmap, clip, pitch, fmtcnv_state);
ret = sharp_memory_spi_write(smd->spi, tx_buffer, tx_buffer_size);
@ -206,7 +206,8 @@ static int sharp_memory_clear_display(struct sharp_memory_device *smd)
return ret;
}
static void sharp_memory_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect,
static void sharp_memory_fb_dirty(struct drm_framebuffer *fb, const struct iosys_map *vmap,
struct drm_rect *rect,
struct drm_format_conv_state *fmtconv_state)
{
struct drm_rect clip;
@ -218,7 +219,7 @@ static void sharp_memory_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *r
clip.y1 = rect->y1;
clip.y2 = rect->y2;
sharp_memory_update_display(smd, fb, clip, fmtconv_state);
sharp_memory_update_display(smd, fb, vmap, clip, fmtconv_state);
}
static int sharp_memory_plane_atomic_check(struct drm_plane *plane,
@ -242,7 +243,7 @@ static void sharp_memory_plane_atomic_update(struct drm_plane *plane,
{
struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state, plane);
struct drm_plane_state *plane_state = plane->state;
struct drm_format_conv_state fmtcnv_state = DRM_FORMAT_CONV_STATE_INIT;
struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
struct sharp_memory_device *smd;
struct drm_rect rect;
@ -251,15 +252,15 @@ static void sharp_memory_plane_atomic_update(struct drm_plane *plane,
return;
if (drm_atomic_helper_damage_merged(old_state, plane_state, &rect))
sharp_memory_fb_dirty(plane_state->fb, &rect, &fmtcnv_state);
drm_format_conv_state_release(&fmtcnv_state);
sharp_memory_fb_dirty(plane_state->fb, shadow_plane_state->data,
&rect, &shadow_plane_state->fmtcnv_state);
}
static const struct drm_plane_helper_funcs sharp_memory_plane_helper_funcs = {
.prepare_fb = drm_gem_plane_helper_prepare_fb,
.atomic_check = sharp_memory_plane_atomic_check,
.atomic_update = sharp_memory_plane_atomic_update,
DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
};
static bool sharp_memory_format_mod_supported(struct drm_plane *plane,
@ -273,9 +274,7 @@ static const struct drm_plane_funcs sharp_memory_plane_funcs = {
.update_plane = drm_atomic_helper_update_plane,
.disable_plane = drm_atomic_helper_disable_plane,
.destroy = drm_plane_cleanup,
.reset = drm_atomic_helper_plane_reset,
.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
.atomic_destroy_state = drm_atomic_helper_plane_destroy_state,
DRM_GEM_SHADOW_PLANE_FUNCS,
.format_mod_supported = sharp_memory_format_mod_supported,
};