Re: [PATCH v4 9/9] drm: vkms: Add support to the RGB565 format

On 01/21, Igor Torrente wrote:

Adds this common format to vkms.

This commit also adds new helper macros to deal with fixed-point arithmetic.

It was done to improve the precision of the conversion to ARGB16161616 since the "conversion ratio" is not an integer.

Signed-off-by: Igor Torrente igormtorrente@gmail.com

V3: Adapt the handlers to the new format introduced in patch 7 V3.

drivers/gpu/drm/vkms/vkms_formats.c | 74 +++++++++++++++++++++++++++ drivers/gpu/drm/vkms/vkms_formats.h | 6 +++ drivers/gpu/drm/vkms/vkms_plane.c | 6 ++- drivers/gpu/drm/vkms/vkms_writeback.c | 3 +- 4 files changed, 86 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c index 661da39d1276..dc612882dd8c 100644 --- a/drivers/gpu/drm/vkms/vkms_formats.c +++ b/drivers/gpu/drm/vkms/vkms_formats.c @@ -11,6 +11,8 @@ format_transform_func get_fmt_transform_function(u32 format) return &get_ARGB16161616; else if (format == DRM_FORMAT_XRGB16161616) return &XRGB16161616_to_ARGB16161616;

• else if (format == DRM_FORMAT_RGB565)

• return &RGB565_to_ARGB16161616;
  

  else return &XRGB8888_to_ARGB16161616;

} @@ -23,6 +25,8 @@ format_transform_func get_wb_fmt_transform_function(u32 format) return &convert_to_ARGB16161616; else if (format == DRM_FORMAT_XRGB16161616) return &convert_to_XRGB16161616;

• else if (format == DRM_FORMAT_RGB565)

• return &convert_to_RGB565;
  

  else return &convert_to_XRGB8888;

} @@ -33,6 +37,26 @@ static int pixel_offset(struct vkms_frame_info *frame_info, int x, int y) + (x * frame_info->cpp); }

+/*

• • FP stands for _Fixed Point_ and **not** _Float Point_
• • LF stands for Long Float (i.e. double)
• • The following macros help doing fixed point arithmetic.
• */

+/*

• • With FP scale 15 we have 17 and 15 bits of integer and fractional parts
• • respectively.
• • | 0000 0000 0000 0000 0.000 0000 0000 0000 |
• • 31 0
• */

+#define FP_SCALE 15

+#define LF_TO_FP(a) ((a) * (u64)(1 << FP_SCALE)) +#define INT_TO_FP(a) ((a) << FP_SCALE) +#define FP_MUL(a, b) ((s32)(((s64)(a) * (b)) >> FP_SCALE)) +#define FP_DIV(a, b) ((s32)(((s64)(a) << FP_SCALE) / (b))) +/* This macro converts a fixed point number to int, and round half up it */ +#define FP_TO_INT_ROUND_UP(a) (((a) + (1 << (FP_SCALE - 1))) >> FP_SCALE)

/*

• packed_pixels_addr - Get the pointer to pixel of a given pair of coordinates

@@ -125,6 +149,33 @@ void XRGB16161616_to_ARGB16161616(struct vkms_frame_info *frame_info, int y, } }

+void RGB565_to_ARGB16161616(struct vkms_frame_info *frame_info, int y,

• 	    struct line_buffer *stage_buffer)
  

+{

• u16 *src_pixels = get_packed_src_addr(frame_info, y);
• int x, x_limit = drm_rect_width(&frame_info->dst);
• for (x = 0; x < x_limit; x++, src_pixels++) {

• u16 rgb_565 = le16_to_cpu(*src_pixels);
  

• int fp_r = INT_TO_FP((rgb_565 >> 11) & 0x1f);
  

• int fp_g = INT_TO_FP((rgb_565 >> 5) & 0x3f);
  

• int fp_b = INT_TO_FP(rgb_565 & 0x1f);
  

• /*
  

•  * The magic constants is the "conversion ratio" and is calculated
  

•  * dividing 65535(2^16 - 1) by 31(2^5 -1) and 63(2^6 - 1)
  

•  * respectively.
  

•  */
  

• int fp_rb_ratio = LF_TO_FP(2114.032258065);
  

• int fp_g_ratio = LF_TO_FP(1040.238095238);
  

• stage_buffer[x].a = (u16)0xffff;
  

• stage_buffer[x].r = FP_TO_INT_ROUND_UP(FP_MUL(fp_r, fp_rb_ratio));
  

• stage_buffer[x].g = FP_TO_INT_ROUND_UP(FP_MUL(fp_g, fp_g_ratio));
  

• stage_buffer[x].b = FP_TO_INT_ROUND_UP(FP_MUL(fp_b, fp_rb_ratio));
  

• }

+}

I don't know if there is a testcase in IGT check this conversion, did you use anyone here? Does it enables any other testcase?

Thanks,

Melissa

/*

• The following functions take an line of ARGB16161616 pixels from the

@@ -203,3 +254,26 @@ void convert_to_XRGB16161616(struct vkms_frame_info *frame_info, int y, dst_pixels[0] = src_buffer[x].b; } }

+void convert_to_RGB565(struct vkms_frame_info *frame_info, int y,

•        struct line_buffer *src_buffer)
  

+{

• int x, x_dst = frame_info->dst.x1;
• u16 *dst_pixels = packed_pixels_addr(frame_info, x_dst, y);
• int x_limit = drm_rect_width(&frame_info->dst);
• for (x = 0; x < x_limit; x++, dst_pixels++) {

• int fp_r = INT_TO_FP(src_buffer[x].r);
  

• int fp_g = INT_TO_FP(src_buffer[x].g);
  

• int fp_b = INT_TO_FP(src_buffer[x].b);
  

• int fp_rb_ratio = LF_TO_FP(2114.032258065);
  

• int fp_g_ratio = LF_TO_FP(1040.238095238);
  

• u16 r = FP_TO_INT_ROUND_UP(FP_DIV(fp_r, fp_rb_ratio));
  

• u16 g = FP_TO_INT_ROUND_UP(FP_DIV(fp_g, fp_g_ratio));
  

• u16 b = FP_TO_INT_ROUND_UP(FP_DIV(fp_b, fp_rb_ratio));
  

• *dst_pixels = cpu_to_le16(r << 11 | g << 5 | b);
  

• }

+} diff --git a/drivers/gpu/drm/vkms/vkms_formats.h b/drivers/gpu/drm/vkms/vkms_formats.h index 22358f3a33ab..836d6e43ea90 100644 --- a/drivers/gpu/drm/vkms/vkms_formats.h +++ b/drivers/gpu/drm/vkms/vkms_formats.h @@ -21,6 +21,9 @@ void get_ARGB16161616(struct vkms_frame_info *frame_info, int y, void XRGB16161616_to_ARGB16161616(struct vkms_frame_info *frame_info, int y, struct line_buffer *stage_buffer);

+void RGB565_to_ARGB16161616(struct vkms_frame_info *frame_info, int y,

• 	    struct line_buffer *stage_buffer);
  

void convert_to_ARGB8888(struct vkms_frame_info *frame_info, int y, struct line_buffer *src_buffer);

@@ -33,6 +36,9 @@ void convert_to_ARGB16161616(struct vkms_frame_info *frame_info, int y, void convert_to_XRGB16161616(struct vkms_frame_info *frame_info, int y, struct line_buffer *src_buffer);

+void convert_to_RGB565(struct vkms_frame_info *frame_info, int y,

•        struct line_buffer *src_buffer);
  

typedef void (*format_transform_func)(struct vkms_frame_info *frame_info, int y, struct line_buffer *buffer);

diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c index 1d70c9e8f109..4643eefcdf29 100644 --- a/drivers/gpu/drm/vkms/vkms_plane.c +++ b/drivers/gpu/drm/vkms/vkms_plane.c @@ -13,14 +13,16 @@

static const u32 vkms_formats[] = { DRM_FORMAT_XRGB8888,

• DRM_FORMAT_XRGB16161616

• DRM_FORMAT_XRGB16161616,
• DRM_FORMAT_RGB565

};

static const u32 vkms_plane_formats[] = { DRM_FORMAT_ARGB8888, DRM_FORMAT_XRGB8888, DRM_FORMAT_XRGB16161616,

• DRM_FORMAT_ARGB16161616

• DRM_FORMAT_ARGB16161616,
• DRM_FORMAT_RGB565

};

static struct drm_plane_state * diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c b/drivers/gpu/drm/vkms/vkms_writeback.c index 393d3fc7966f..1aaa630090d3 100644 --- a/drivers/gpu/drm/vkms/vkms_writeback.c +++ b/drivers/gpu/drm/vkms/vkms_writeback.c @@ -15,7 +15,8 @@ static const u32 vkms_wb_formats[] = { DRM_FORMAT_XRGB8888, DRM_FORMAT_XRGB16161616,

• DRM_FORMAT_ARGB16161616

• DRM_FORMAT_ARGB16161616,
• DRM_FORMAT_RGB565

};

static const struct drm_connector_funcs vkms_wb_connector_funcs = {

2.30.2