Re: [PATCH v2 2/3] drm/vkms: Add a macro for write_line functions

["Maíra Canal" <mairacanal@riseup.net>]

Hi Louis,

On 14/08/24 05:42, Louis Chauvet wrote:
> As stated in [2], the write_line functions are very similar and force code

Where is [2]?

> duplication. This patch add a macro to avoid code repetition.
> 
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>   drivers/gpu/drm/vkms/vkms_formats.c | 107 ++++++++++--------------------------
>   1 file changed, 30 insertions(+), 77 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
> index d1309f6d307f..a25cdf656d8a 100644
> --- a/drivers/gpu/drm/vkms/vkms_formats.c
> +++ b/drivers/gpu/drm/vkms/vkms_formats.c
> @@ -654,6 +654,31 @@ static void argb_u16_to_RGB565(u8 *out_pixel, const struct pixel_argb_u16 *in_pi
>   	*pixel = cpu_to_le16(r << 11 | g << 5 | b);
>   }
>   
> +/**
> + * WRITE_LINE() - Generic generator for write_line functions
> + *
> + * This generator can only be used for format with only one plane and block_w == block_h == 1
> + *
> + * @function_name: Name to use for the generated function
> + * @conversion_function: Fonction to use for the conversion from argb_u16 to the required format.

s/Fonction/Function

> + */
> +#define WRITE_LINE(function_name, conversion_function)					\
> +static void function_name(struct vkms_writeback_job *wb,				\
> +			  struct pixel_argb_u16 *src_pixels, int count, int x_start,	\
> +			  int y_start)							\
> +{											\
> +	u8 *dst_pixels;									\
> +											\
> +	packed_pixels_addr_1x1(&wb->wb_frame_info, x_start, y_start, 0, &dst_pixels);	\
> +											\
> +	while (count) {									\
> +		(conversion_function)(dst_pixels, src_pixels);				\
> +		dst_pixels += wb->wb_frame_info.fb->format->char_per_block[0];		\
> +		src_pixels += 1;							\
> +		count--;								\

Just a nit: What do you think about this loop?

for (; count > 0; src_pixels++, count--)

It doesn't really matter what option you pick.

Best Regards,
- Maíra

> +	}										\
> +}
> +
>   /*
>    * The following functions are write_line function for each pixel format supported by VKMS.
>    *
> @@ -667,85 +692,13 @@ static void argb_u16_to_RGB565(u8 *out_pixel, const struct pixel_argb_u16 *in_pi
>    * [1]: https://lore.kernel.org/dri-devel/d258c8dc-78e9-4509-9037-a98f7f33b3a3@riseup.net/
>    */
>   
> -static void ARGB8888_write_line(struct vkms_writeback_job *wb,
> -				struct pixel_argb_u16 *src_pixels, int count, int x_start,
> -				int y_start)
> -{
> -	u8 *dst_pixels;
> +WRITE_LINE(ARGB8888_write_line, argb_u16_to_ARGB8888)
> +WRITE_LINE(XRGB8888_write_line, argb_u16_to_XRGB8888)
>   
> -	packed_pixels_addr_1x1(&wb->wb_frame_info, x_start, y_start, 0, &dst_pixels);
> +WRITE_LINE(ARGB16161616_write_line, argb_u16_to_ARGB16161616)
> +WRITE_LINE(XRGB16161616_write_line, argb_u16_to_XRGB16161616)
>   
> -	while (count) {
> -		argb_u16_to_ARGB8888(dst_pixels, src_pixels);
> -		dst_pixels += wb->wb_frame_info.fb->format->char_per_block[0];
> -		src_pixels += 1;
> -		count--;
> -	}
> -}
> -
> -static void XRGB8888_write_line(struct vkms_writeback_job *wb,
> -				struct pixel_argb_u16 *src_pixels, int count, int x_start,
> -				int y_start)
> -{
> -	u8 *dst_pixels;
> -
> -	packed_pixels_addr_1x1(&wb->wb_frame_info, x_start, y_start, 0, &dst_pixels);
> -
> -	while (count) {
> -		argb_u16_to_XRGB8888(dst_pixels, src_pixels);
> -		dst_pixels += wb->wb_frame_info.fb->format->char_per_block[0];
> -		src_pixels += 1;
> -		count--;
> -	}
> -}
> -
> -static void ARGB16161616_write_line(struct vkms_writeback_job *wb,
> -				    struct pixel_argb_u16 *src_pixels, int count, int x_start,
> -				    int y_start)
> -{
> -	u8 *dst_pixels;
> -
> -	packed_pixels_addr_1x1(&wb->wb_frame_info, x_start, y_start, 0, &dst_pixels);
> -
> -	while (count) {
> -		argb_u16_to_ARGB16161616(dst_pixels, src_pixels);
> -		dst_pixels += wb->wb_frame_info.fb->format->char_per_block[0];
> -		src_pixels += 1;
> -		count--;
> -	}
> -}
> -
> -static void XRGB16161616_write_line(struct vkms_writeback_job *wb,
> -				    struct pixel_argb_u16 *src_pixels, int count, int x_start,
> -				    int y_start)
> -{
> -	u8 *dst_pixels;
> -
> -	packed_pixels_addr_1x1(&wb->wb_frame_info, x_start, y_start, 0, &dst_pixels);
> -
> -	while (count) {
> -		argb_u16_to_XRGB16161616(dst_pixels, src_pixels);
> -		dst_pixels += wb->wb_frame_info.fb->format->char_per_block[0];
> -		src_pixels += 1;
> -		count--;
> -	}
> -}
> -
> -static void RGB565_write_line(struct vkms_writeback_job *wb,
> -			      struct pixel_argb_u16 *src_pixels, int count, int x_start,
> -			      int y_start)
> -{
> -	u8 *dst_pixels;
> -
> -	packed_pixels_addr_1x1(&wb->wb_frame_info, x_start, y_start, 0, &dst_pixels);
> -
> -	while (count) {
> -		argb_u16_to_RGB565(dst_pixels, src_pixels);
> -		dst_pixels += wb->wb_frame_info.fb->format->char_per_block[0];
> -		src_pixels += 1;
> -		count--;
> -	}
> -}
> +WRITE_LINE(RGB565_write_line, argb_u16_to_RGB565)
>   
>   /**
>    * get_pixel_read_function() - Retrieve the correct read_line function for a specific
>