[PATCH 1/2] drm/vkms: Create a type to check a function pointer validity

Louis Chauvet
2024-02-01T17:32:19Z

Add the pixel_read_t type to check function prototype in structures
and functions.
It avoids casting to (void *) and at the same occasion allows the
compiler to check the type properly.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
drivers/gpu/drm/vkms/vkms_drv.h | 17 +++++++++++++++--
drivers/gpu/drm/vkms/vkms_formats.c | 4 ++--
drivers/gpu/drm/vkms/vkms_formats.h | 2 +-
3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index 51349a0c32d8..cb20bab26cae 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -48,6 +48,20 @@ struct vkms_writeback_job {
void (*pixel_write)(u8 *dst_pixels, struct pixel_argb_u16 *in_pixel);
};

+/**
+ * typedef pixel_read_t - These functions are used to read the pixels in the source frame, convert
+ * them to argb16 and write them to out_pixel.
+ * It assumes that src_pixels point to a valid pixel (not a block, or a block of 1x1 pixel)
+ *
+ * @src_pixels: Source pointer to a pixel
+ * @out_pixel: Pointer where to write the pixel value
+ * @encoding: Color encoding to use (mainly used for YUV formats)
+ * @range: Color range to use (mainly used for YUV formats)
+ */
+typedef void (*pixel_read_t)(u8 **src_pixels, int y,
+ struct pixel_argb_u16 *out_pixel, enum drm_color_encoding enconding,
+ enum drm_color_range range);
+
/**
* vkms_plane_state - Driver specific plane state
* @base: base plane state
@@ -56,8 +70,7 @@ struct vkms_writeback_job {
struct vkms_plane_state {
struct drm_shadow_plane_state base;
struct vkms_frame_info *frame_info;
- void (*pixel_read)(u8 **src_buffer, struct pixel_argb_u16 *out_pixel,
- enum drm_color_encoding enconding, enum drm_color_range range);
+ pixel_read_t pixel_read;
};

struct vkms_plane {
diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
index e06bbd7c0a67..c6376db58d38 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.c
+++ b/drivers/gpu/drm/vkms/vkms_formats.c
@@ -390,7 +390,7 @@ void vkms_writeback_row(struct vkms_writeback_job *wb,
wb->pixel_write(dst_pixels, &in_pixels[x]);
}

-void *get_pixel_conversion_function(u32 format)
+pixel_read_t get_pixel_conversion_function(u32 format)
{
switch (format) {
case DRM_FORMAT_ARGB8888:
@@ -420,7 +420,7 @@ void *get_pixel_conversion_function(u32 format)
case DRM_FORMAT_YVU444:
return &planar_yvu_to_argb_u16;
default:
- return NULL;
+ return (pixel_read_t)NULL;
}
}

diff --git a/drivers/gpu/drm/vkms/vkms_formats.h b/drivers/gpu/drm/vkms/vkms_formats.h
index 0cf835292cec..04e31e126ab1 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.h
+++ b/drivers/gpu/drm/vkms/vkms_formats.h
@@ -5,7 +5,7 @@

#include "vkms_drv.h"

-void *get_pixel_conversion_function(u32 format);
+pixel_read_t get_pixel_conversion_function(u32 format);

void *get_pixel_write_function(u32 format);

--
2.43.0