Introduce the usage of block_h/block_w to compute the offset and the
pointer of a pixel. The previous implementation was specialized for
planes with block_h == block_w == 1. To avoid confusion and allow easier
implementation of tiled formats. It also remove the usage of the
deprecated format field `cpp`.

Introduce the plane_index parameter to get an offset/pointer on a
different plane.

Acked-by: Maíra Canal <mairacanal@riseup.net>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_formats.c | 114 ++++++++++++++++++++++++++++--------
 1 file changed, 91 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
index 06aef5162529..7f932d42394d 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.c
+++ b/drivers/gpu/drm/vkms/vkms_formats.c
@@ -10,22 +10,46 @@
 #include "vkms_formats.h"
 
 /**
- * pixel_offset() - Get the offset of the pixel at coordinates x/y in the first plane
+ * packed_pixels_offset() - Get the offset of the block containing the pixel at coordinates x/y
  *
  * @frame_info: Buffer metadata
  * @x: The x coordinate of the wanted pixel in the buffer
  * @y: The y coordinate of the wanted pixel in the buffer
+ * @plane_index: The index of the plane to use
+ * @offset: The returned offset inside the buffer of the block
+ * @rem_x: The returned X coordinate of the requested pixel in the block
+ * @rem_y: The returned Y coordinate of the requested pixel in the block
  *
- * The caller must ensure that the framebuffer associated with this request uses a pixel format
- * where block_h == block_w == 1.
- * If this requirement is not fulfilled, the resulting offset can point to an other pixel or
- * outside of the buffer.
+ * As some pixel formats store multiple pixels in a block (DRM_FORMAT_R* for example), some
+ * pixels are not individually addressable. This function return 3 values: the offset of the
+ * whole block, and the coordinate of the requested pixel inside this block.
+ * For example, if the format is DRM_FORMAT_R1 and the requested coordinate is 13,5, the offset
+ * will point to the byte 5*pitches + 13/8 (second byte of the 5th line), and the rem_x/rem_y
+ * coordinates will be (13 % 8, 5 % 1) = (5, 0)
+ *
+ * With this function, the caller just have to extract the correct pixel from the block.
  */
-static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int y)
+static void packed_pixels_offset(const struct vkms_frame_info *frame_info, int x, int y,
+				 int plane_index, int *offset, int *rem_x, int *rem_y)
 {
 	struct drm_framebuffer *fb = frame_info->fb;
+	const struct drm_format_info *format = frame_info->fb->format;
+	/* Directly using x and y to multiply pitches and format->ccp is not sufficient because
+	 * in some formats a block can represent multiple pixels.
+	 *
+	 * Dividing x and y by the block size allows to extract the correct offset of the block
+	 * containing the pixel.
+	 */
 
-	return fb->offsets[0] + (y * fb->pitches[0]) + (x * fb->format->cpp[0]);
+	int block_x = x / drm_format_info_block_width(format, plane_index);
+	int block_y = y / drm_format_info_block_height(format, plane_index);
+	int block_pitch = fb->pitches[plane_index] * drm_format_info_block_height(format,
+										  plane_index);
+	*rem_x = x % drm_format_info_block_width(format, plane_index);
+	*rem_y = y % drm_format_info_block_height(format, plane_index);
+	*offset = fb->offsets[plane_index] +
+		  block_y * block_pitch +
+		  block_x * format->char_per_block[plane_index];
 }
 
 /**
@@ -35,30 +59,71 @@ static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int
  * @frame_info: Buffer metadata
  * @x: The x (width) coordinate inside the plane
  * @y: The y (height) coordinate inside the plane
+ * @plane_index: The index of the plane
+ * @addr: The returned pointer
+ * @rem_x: The returned X coordinate of the requested pixel in the block
+ * @rem_y: The returned Y coordinate of the requested pixel in the block
  *
- * Takes the information stored in the frame_info, a pair of coordinates, and
- * returns the address of the first color channel.
- * This function assumes the channels are packed together, i.e. a color channel
- * comes immediately after another in the memory. And therefore, this function
- * doesn't work for YUV with chroma subsampling (e.g. YUV420 and NV21).
+ * Takes the information stored in the frame_info, a pair of coordinates, and returns the address
+ * of the block containing this pixel and the pixel position inside this block.
  *
- * The caller must ensure that the framebuffer associated with this request uses a pixel format
- * where block_h == block_w == 1, otherwise the returned pointer can be outside the buffer.
+ * See @packed_pixel_offset for details about rem_x/rem_y behavior.
  */
-static void *packed_pixels_addr(const struct vkms_frame_info *frame_info,
-				int x, int y)
+static void packed_pixels_addr(const struct vkms_frame_info *frame_info,
+			       int x, int y, int plane_index, u8 **addr, int *rem_x,
+			       int *rem_y)
 {
-	size_t offset = pixel_offset(frame_info, x, y);
+	int offset;
 
-	return (u8 *)frame_info->map[0].vaddr + offset;
+	packed_pixels_offset(frame_info, x, y, plane_index, &offset, rem_x, rem_y);
+	*addr = (u8 *)frame_info->map[0].vaddr + offset;
 }
 
-static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y)
+/**
+ * packed_pixels_addr_1x1() - Get the pointer to the block containing the pixel at the given
+ * coordinates
+ *
+ * @frame_info: Buffer metadata
+ * @x: The x (width) coordinate inside the plane
+ * @y: The y (height) coordinate inside the plane
+ * @plane_index: The index of the plane
+ * @addr: The returned pointer
+ *
+ * This function can only be used with format where block_h == block_w == 1.
+ */
+static void packed_pixels_addr_1x1(const struct vkms_frame_info *frame_info,
+				   int x, int y, int plane_index, u8 **addr)
+{
+	int offset, rem_x, rem_y;
+
+	WARN_ONCE(drm_format_info_block_width(frame_info->fb->format,
+					      plane_index) != 1,
+		"%s() only support formats with block_w == 1", __func__);
+	WARN_ONCE(drm_format_info_block_height(frame_info->fb->format,
+					       plane_index) != 1,
+		"%s() only support formats with block_h == 1", __func__);
+
+	packed_pixels_offset(frame_info, x, y, plane_index, &offset, &rem_x,
+			     &rem_y);
+	*addr = (u8 *)frame_info->map[0].vaddr + offset;
+}
+
+static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y,
+				 int plane_index)
 {
 	int x_src = frame_info->src.x1 >> 16;
 	int y_src = y - frame_info->rotated.y1 + (frame_info->src.y1 >> 16);
+	u8 *addr;
+	int rem_x, rem_y;
+
+	WARN_ONCE(drm_format_info_block_width(frame_info->fb->format, plane_index) != 1,
+		  "%s() only support formats with block_w == 1", __func__);
+	WARN_ONCE(drm_format_info_block_height(frame_info->fb->format, plane_index) != 1,
+		  "%s() only support formats with block_h == 1", __func__);
 
-	return packed_pixels_addr(frame_info, x_src, y_src);
+	packed_pixels_addr(frame_info, x_src, y_src, plane_index, &addr, &rem_x, &rem_y);
+
+	return addr;
 }
 
 static int get_x_position(const struct vkms_frame_info *frame_info, int limit, int x)
@@ -152,14 +217,14 @@ void vkms_compose_row(struct line_buffer *stage_buffer, struct vkms_plane_state
 {
 	struct pixel_argb_u16 *out_pixels = stage_buffer->pixels;
 	struct vkms_frame_info *frame_info = plane->frame_info;
-	u8 *src_pixels = get_packed_src_addr(frame_info, y);
+	u8 *src_pixels = get_packed_src_addr(frame_info, y, 0);
 	int limit = min_t(size_t, drm_rect_width(&frame_info->dst), stage_buffer->n_pixels);
 
 	for (size_t x = 0; x < limit; x++, src_pixels += frame_info->fb->format->cpp[0]) {
 		int x_pos = get_x_position(frame_info, limit, x);
 
 		if (drm_rotation_90_or_270(frame_info->rotation))
-			src_pixels = get_packed_src_addr(frame_info, x + frame_info->rotated.y1)
+			src_pixels = get_packed_src_addr(frame_info, x + frame_info->rotated.y1, 0)
 				+ frame_info->fb->format->cpp[0] * y;
 
 		plane->pixel_read(src_pixels, &out_pixels[x_pos]);
@@ -250,7 +315,10 @@ void vkms_writeback_row(struct vkms_writeback_job *wb,
 {
 	struct vkms_frame_info *frame_info = &wb->wb_frame_info;
 	int x_dst = frame_info->dst.x1;
-	u8 *dst_pixels = packed_pixels_addr(frame_info, x_dst, y);
+	u8 *dst_pixels;
+	int rem_x, rem_y;
+
+	packed_pixels_addr(frame_info, x_dst, y, 0, &dst_pixels, &rem_x, &rem_y);
 	struct pixel_argb_u16 *in_pixels = src_buffer->pixels;
 	int x_limit = min_t(size_t, drm_rect_width(&frame_info->dst), src_buffer->n_pixels);
 

-- 
2.46.2

> Introduce the usage of block_h/block_w to compute the offset and the
> pointer of a pixel. The previous implementation was specialized for
> planes with block_h == block_w == 1. To avoid confusion and allow easier
> implementation of tiled formats. It also remove the usage of the
> deprecated format field `cpp`.
> 
> Introduce the plane_index parameter to get an offset/pointer on a
> different plane.
> 
> Acked-by: Maíra Canal <mairacanal@riseup.net>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>  drivers/gpu/drm/vkms/vkms_formats.c | 114 ++++++++++++++++++++++++++++--------
>  1 file changed, 91 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
> index 06aef5162529..7f932d42394d 100644
> --- a/drivers/gpu/drm/vkms/vkms_formats.c
> +++ b/drivers/gpu/drm/vkms/vkms_formats.c
> @@ -10,22 +10,46 @@
>  #include "vkms_formats.h"
>  
>  /**
> - * pixel_offset() - Get the offset of the pixel at coordinates x/y in the first plane
> + * packed_pixels_offset() - Get the offset of the block containing the pixel at coordinates x/y
>   *
>   * @frame_info: Buffer metadata
>   * @x: The x coordinate of the wanted pixel in the buffer
>   * @y: The y coordinate of the wanted pixel in the buffer
> + * @plane_index: The index of the plane to use
> + * @offset: The returned offset inside the buffer of the block

The previous function (pixel_offset) returned a size_t for the offset rather
than an int. Do you know if we are safe using an int in this case?

> + * @rem_x: The returned X coordinate of the requested pixel in the block
> + * @rem_y: The returned Y coordinate of the requested pixel in the block
>   *
> - * The caller must ensure that the framebuffer associated with this request uses a pixel format
> - * where block_h == block_w == 1.
> - * If this requirement is not fulfilled, the resulting offset can point to an other pixel or
> - * outside of the buffer.
> + * As some pixel formats store multiple pixels in a block (DRM_FORMAT_R* for example), some
> + * pixels are not individually addressable. This function return 3 values: the offset of the
> + * whole block, and the coordinate of the requested pixel inside this block.
> + * For example, if the format is DRM_FORMAT_R1 and the requested coordinate is 13,5, the offset
> + * will point to the byte 5*pitches + 13/8 (second byte of the 5th line), and the rem_x/rem_y
> + * coordinates will be (13 % 8, 5 % 1) = (5, 0)
> + *
> + * With this function, the caller just have to extract the correct pixel from the block.
>   */
> -static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int y)
> +static void packed_pixels_offset(const struct vkms_frame_info *frame_info, int x, int y,
> +				 int plane_index, int *offset, int *rem_x, int *rem_y)
>  {
>  	struct drm_framebuffer *fb = frame_info->fb;
> +	const struct drm_format_info *format = frame_info->fb->format;
> +	/* Directly using x and y to multiply pitches and format->ccp is not sufficient because
> +	 * in some formats a block can represent multiple pixels.
> +	 *
> +	 * Dividing x and y by the block size allows to extract the correct offset of the block
> +	 * containing the pixel.
> +	 */
>  
> -	return fb->offsets[0] + (y * fb->pitches[0]) + (x * fb->format->cpp[0]);
> +	int block_x = x / drm_format_info_block_width(format, plane_index);
> +	int block_y = y / drm_format_info_block_height(format, plane_index);
> +	int block_pitch = fb->pitches[plane_index] * drm_format_info_block_height(format,
> +										  plane_index);
> +	*rem_x = x % drm_format_info_block_width(format, plane_index);
> +	*rem_y = y % drm_format_info_block_height(format, plane_index);
> +	*offset = fb->offsets[plane_index] +
> +		  block_y * block_pitch +
> +		  block_x * format->char_per_block[plane_index];
>  }
>  
>  /**
> @@ -35,30 +59,71 @@ static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int
>   * @frame_info: Buffer metadata
>   * @x: The x (width) coordinate inside the plane
>   * @y: The y (height) coordinate inside the plane
> + * @plane_index: The index of the plane
> + * @addr: The returned pointer
> + * @rem_x: The returned X coordinate of the requested pixel in the block
> + * @rem_y: The returned Y coordinate of the requested pixel in the block
>   *
> - * Takes the information stored in the frame_info, a pair of coordinates, and
> - * returns the address of the first color channel.
> - * This function assumes the channels are packed together, i.e. a color channel
> - * comes immediately after another in the memory. And therefore, this function
> - * doesn't work for YUV with chroma subsampling (e.g. YUV420 and NV21).
> + * Takes the information stored in the frame_info, a pair of coordinates, and returns the address
> + * of the block containing this pixel and the pixel position inside this block.
>   *
> - * The caller must ensure that the framebuffer associated with this request uses a pixel format
> - * where block_h == block_w == 1, otherwise the returned pointer can be outside the buffer.
> + * See @packed_pixel_offset for details about rem_x/rem_y behavior.

Missing "s" in the name of the function. Should read "@packed_pixels_offset".

>   */
> -static void *packed_pixels_addr(const struct vkms_frame_info *frame_info,
> -				int x, int y)
> +static void packed_pixels_addr(const struct vkms_frame_info *frame_info,
> +			       int x, int y, int plane_index, u8 **addr, int *rem_x,
> +			       int *rem_y)
>  {
> -	size_t offset = pixel_offset(frame_info, x, y);
> +	int offset;
>  
> -	return (u8 *)frame_info->map[0].vaddr + offset;
> +	packed_pixels_offset(frame_info, x, y, plane_index, &offset, rem_x, rem_y);
> +	*addr = (u8 *)frame_info->map[0].vaddr + offset;
>  }
>  
> -static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y)
> +/**
> + * packed_pixels_addr_1x1() - Get the pointer to the block containing the pixel at the given
> + * coordinates
> + *
> + * @frame_info: Buffer metadata
> + * @x: The x (width) coordinate inside the plane
> + * @y: The y (height) coordinate inside the plane
> + * @plane_index: The index of the plane
> + * @addr: The returned pointer
> + *
> + * This function can only be used with format where block_h == block_w == 1.
> + */
> +static void packed_pixels_addr_1x1(const struct vkms_frame_info *frame_info,
> +				   int x, int y, int plane_index, u8 **addr)
> +{
> +	int offset, rem_x, rem_y;

Nitpick, but it'd be nice if packed_pixels_offset() could take NULLs in
the output values so we avoid declaring unused variables here and when
calling packed_pixels_addr().

> +
> +	WARN_ONCE(drm_format_info_block_width(frame_info->fb->format,
> +					      plane_index) != 1,
> +		"%s() only support formats with block_w == 1", __func__);
> +	WARN_ONCE(drm_format_info_block_height(frame_info->fb->format,
> +					       plane_index) != 1,
> +		"%s() only support formats with block_h == 1", __func__);
> +
> +	packed_pixels_offset(frame_info, x, y, plane_index, &offset, &rem_x,
> +			     &rem_y);
> +	*addr = (u8 *)frame_info->map[0].vaddr + offset;
> +}
> +
> +static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y,
> +				 int plane_index)
>  {
>  	int x_src = frame_info->src.x1 >> 16;
>  	int y_src = y - frame_info->rotated.y1 + (frame_info->src.y1 >> 16);
> +	u8 *addr;
> +	int rem_x, rem_y;
> +
> +	WARN_ONCE(drm_format_info_block_width(frame_info->fb->format, plane_index) != 1,
> +		  "%s() only support formats with block_w == 1", __func__);
> +	WARN_ONCE(drm_format_info_block_height(frame_info->fb->format, plane_index) != 1,
> +		  "%s() only support formats with block_h == 1", __func__);
>  
> -	return packed_pixels_addr(frame_info, x_src, y_src);
> +	packed_pixels_addr(frame_info, x_src, y_src, plane_index, &addr, &rem_x, &rem_y);
> +
> +	return addr;
>  }
>  
>  static int get_x_position(const struct vkms_frame_info *frame_info, int limit, int x)
> @@ -152,14 +217,14 @@ void vkms_compose_row(struct line_buffer *stage_buffer, struct vkms_plane_state
>  {
>  	struct pixel_argb_u16 *out_pixels = stage_buffer->pixels;
>  	struct vkms_frame_info *frame_info = plane->frame_info;
> -	u8 *src_pixels = get_packed_src_addr(frame_info, y);
> +	u8 *src_pixels = get_packed_src_addr(frame_info, y, 0);
>  	int limit = min_t(size_t, drm_rect_width(&frame_info->dst), stage_buffer->n_pixels);
>  
>  	for (size_t x = 0; x < limit; x++, src_pixels += frame_info->fb->format->cpp[0]) {
>  		int x_pos = get_x_position(frame_info, limit, x);
>  
>  		if (drm_rotation_90_or_270(frame_info->rotation))
> -			src_pixels = get_packed_src_addr(frame_info, x + frame_info->rotated.y1)
> +			src_pixels = get_packed_src_addr(frame_info, x + frame_info->rotated.y1, 0)
>  				+ frame_info->fb->format->cpp[0] * y;
>  
>  		plane->pixel_read(src_pixels, &out_pixels[x_pos]);
> @@ -250,7 +315,10 @@ void vkms_writeback_row(struct vkms_writeback_job *wb,
>  {
>  	struct vkms_frame_info *frame_info = &wb->wb_frame_info;
>  	int x_dst = frame_info->dst.x1;
> -	u8 *dst_pixels = packed_pixels_addr(frame_info, x_dst, y);
> +	u8 *dst_pixels;
> +	int rem_x, rem_y;
> +
> +	packed_pixels_addr(frame_info, x_dst, y, 0, &dst_pixels, &rem_x, &rem_y);
>  	struct pixel_argb_u16 *in_pixels = src_buffer->pixels;
>  	int x_limit = min_t(size_t, drm_rect_width(&frame_info->dst), src_buffer->n_pixels);
>  
> 

On 18/11/24 - 18:10, José Expósito wrote:
> > Introduce the usage of block_h/block_w to compute the offset and the
> > pointer of a pixel. The previous implementation was specialized for
> > planes with block_h == block_w == 1. To avoid confusion and allow easier
> > implementation of tiled formats. It also remove the usage of the
> > deprecated format field `cpp`.
> > 
> > Introduce the plane_index parameter to get an offset/pointer on a
> > different plane.
> > 
> > Acked-by: Maíra Canal <mairacanal@riseup.net>
> > Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> > ---
> >  drivers/gpu/drm/vkms/vkms_formats.c | 114 ++++++++++++++++++++++++++++--------
> >  1 file changed, 91 insertions(+), 23 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
> > index 06aef5162529..7f932d42394d 100644
> > --- a/drivers/gpu/drm/vkms/vkms_formats.c
> > +++ b/drivers/gpu/drm/vkms/vkms_formats.c
> > @@ -10,22 +10,46 @@
> >  #include "vkms_formats.h"
> >  
> >  /**
> > - * pixel_offset() - Get the offset of the pixel at coordinates x/y in the first plane
> > + * packed_pixels_offset() - Get the offset of the block containing the pixel at coordinates x/y
> >   *
> >   * @frame_info: Buffer metadata
> >   * @x: The x coordinate of the wanted pixel in the buffer
> >   * @y: The y coordinate of the wanted pixel in the buffer
> > + * @plane_index: The index of the plane to use
> > + * @offset: The returned offset inside the buffer of the block
> 
> The previous function (pixel_offset) returned a size_t for the offset rather
> than an int. Do you know if we are safe using an int in this case?

I think I used int everywhere because it may avoid strange issues with 
implicit casting and negative number. I don't remember exactly where, but 
Pekka suggested it.
 
> > + * @rem_x: The returned X coordinate of the requested pixel in the block
> > + * @rem_y: The returned Y coordinate of the requested pixel in the block
> >   *
> > - * The caller must ensure that the framebuffer associated with this request uses a pixel format
> > - * where block_h == block_w == 1.
> > - * If this requirement is not fulfilled, the resulting offset can point to an other pixel or
> > - * outside of the buffer.
> > + * As some pixel formats store multiple pixels in a block (DRM_FORMAT_R* for example), some
> > + * pixels are not individually addressable. This function return 3 values: the offset of the
> > + * whole block, and the coordinate of the requested pixel inside this block.
> > + * For example, if the format is DRM_FORMAT_R1 and the requested coordinate is 13,5, the offset
> > + * will point to the byte 5*pitches + 13/8 (second byte of the 5th line), and the rem_x/rem_y
> > + * coordinates will be (13 % 8, 5 % 1) = (5, 0)
> > + *
> > + * With this function, the caller just have to extract the correct pixel from the block.
> >   */
> > -static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int y)
> > +static void packed_pixels_offset(const struct vkms_frame_info *frame_info, int x, int y,
> > +				 int plane_index, int *offset, int *rem_x, int *rem_y)
> >  {
> >  	struct drm_framebuffer *fb = frame_info->fb;
> > +	const struct drm_format_info *format = frame_info->fb->format;
> > +	/* Directly using x and y to multiply pitches and format->ccp is not sufficient because
> > +	 * in some formats a block can represent multiple pixels.
> > +	 *
> > +	 * Dividing x and y by the block size allows to extract the correct offset of the block
> > +	 * containing the pixel.
> > +	 */
> >  
> > -	return fb->offsets[0] + (y * fb->pitches[0]) + (x * fb->format->cpp[0]);
> > +	int block_x = x / drm_format_info_block_width(format, plane_index);
> > +	int block_y = y / drm_format_info_block_height(format, plane_index);
> > +	int block_pitch = fb->pitches[plane_index] * drm_format_info_block_height(format,
> > +										  plane_index);
> > +	*rem_x = x % drm_format_info_block_width(format, plane_index);
> > +	*rem_y = y % drm_format_info_block_height(format, plane_index);
> > +	*offset = fb->offsets[plane_index] +
> > +		  block_y * block_pitch +
> > +		  block_x * format->char_per_block[plane_index];
> >  }
> >  
> >  /**
> > @@ -35,30 +59,71 @@ static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int
> >   * @frame_info: Buffer metadata
> >   * @x: The x (width) coordinate inside the plane
> >   * @y: The y (height) coordinate inside the plane
> > + * @plane_index: The index of the plane
> > + * @addr: The returned pointer
> > + * @rem_x: The returned X coordinate of the requested pixel in the block
> > + * @rem_y: The returned Y coordinate of the requested pixel in the block
> >   *
> > - * Takes the information stored in the frame_info, a pair of coordinates, and
> > - * returns the address of the first color channel.
> > - * This function assumes the channels are packed together, i.e. a color channel
> > - * comes immediately after another in the memory. And therefore, this function
> > - * doesn't work for YUV with chroma subsampling (e.g. YUV420 and NV21).
> > + * Takes the information stored in the frame_info, a pair of coordinates, and returns the address
> > + * of the block containing this pixel and the pixel position inside this block.
> >   *
> > - * The caller must ensure that the framebuffer associated with this request uses a pixel format
> > - * where block_h == block_w == 1, otherwise the returned pointer can be outside the buffer.
> > + * See @packed_pixel_offset for details about rem_x/rem_y behavior.
> 
> Missing "s" in the name of the function. Should read "@packed_pixels_offset".

Thanks!

> >   */
> > -static void *packed_pixels_addr(const struct vkms_frame_info *frame_info,
> > -				int x, int y)
> > +static void packed_pixels_addr(const struct vkms_frame_info *frame_info,
> > +			       int x, int y, int plane_index, u8 **addr, int *rem_x,
> > +			       int *rem_y)
> >  {
> > -	size_t offset = pixel_offset(frame_info, x, y);
> > +	int offset;
> >  
> > -	return (u8 *)frame_info->map[0].vaddr + offset;
> > +	packed_pixels_offset(frame_info, x, y, plane_index, &offset, rem_x, rem_y);
> > +	*addr = (u8 *)frame_info->map[0].vaddr + offset;
> >  }
> >  
> > -static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y)
> > +/**
> > + * packed_pixels_addr_1x1() - Get the pointer to the block containing the pixel at the given
> > + * coordinates
> > + *
> > + * @frame_info: Buffer metadata
> > + * @x: The x (width) coordinate inside the plane
> > + * @y: The y (height) coordinate inside the plane
> > + * @plane_index: The index of the plane
> > + * @addr: The returned pointer
> > + *
> > + * This function can only be used with format where block_h == block_w == 1.
> > + */
> > +static void packed_pixels_addr_1x1(const struct vkms_frame_info *frame_info,
> > +				   int x, int y, int plane_index, u8 **addr)
> > +{
> > +	int offset, rem_x, rem_y;
> 
> Nitpick, but it'd be nice if packed_pixels_offset() could take NULLs in
> the output values so we avoid declaring unused variables here and when
> calling packed_pixels_addr().

It is not a trivial change, and as I want this series to be merged I will 
send the v14 without it. But if I have the time I will send a new 
patch/series with this cleanup, thanks for the suggestion.

> > +
> > +	WARN_ONCE(drm_format_info_block_width(frame_info->fb->format,
> > +					      plane_index) != 1,
> > +		"%s() only support formats with block_w == 1", __func__);
> > +	WARN_ONCE(drm_format_info_block_height(frame_info->fb->format,
> > +					       plane_index) != 1,
> > +		"%s() only support formats with block_h == 1", __func__);
> > +
> > +	packed_pixels_offset(frame_info, x, y, plane_index, &offset, &rem_x,
> > +			     &rem_y);
> > +	*addr = (u8 *)frame_info->map[0].vaddr + offset;
> > +}
> > +
> > +static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y,
> > +				 int plane_index)
> >  {
> >  	int x_src = frame_info->src.x1 >> 16;
> >  	int y_src = y - frame_info->rotated.y1 + (frame_info->src.y1 >> 16);
> > +	u8 *addr;
> > +	int rem_x, rem_y;
> > +
> > +	WARN_ONCE(drm_format_info_block_width(frame_info->fb->format, plane_index) != 1,
> > +		  "%s() only support formats with block_w == 1", __func__);
> > +	WARN_ONCE(drm_format_info_block_height(frame_info->fb->format, plane_index) != 1,
> > +		  "%s() only support formats with block_h == 1", __func__);
> >  
> > -	return packed_pixels_addr(frame_info, x_src, y_src);
> > +	packed_pixels_addr(frame_info, x_src, y_src, plane_index, &addr, &rem_x, &rem_y);
> > +
> > +	return addr;
> >  }
> >  
> >  static int get_x_position(const struct vkms_frame_info *frame_info, int limit, int x)
> > @@ -152,14 +217,14 @@ void vkms_compose_row(struct line_buffer *stage_buffer, struct vkms_plane_state
> >  {
> >  	struct pixel_argb_u16 *out_pixels = stage_buffer->pixels;
> >  	struct vkms_frame_info *frame_info = plane->frame_info;
> > -	u8 *src_pixels = get_packed_src_addr(frame_info, y);
> > +	u8 *src_pixels = get_packed_src_addr(frame_info, y, 0);
> >  	int limit = min_t(size_t, drm_rect_width(&frame_info->dst), stage_buffer->n_pixels);
> >  
> >  	for (size_t x = 0; x < limit; x++, src_pixels += frame_info->fb->format->cpp[0]) {
> >  		int x_pos = get_x_position(frame_info, limit, x);
> >  
> >  		if (drm_rotation_90_or_270(frame_info->rotation))
> > -			src_pixels = get_packed_src_addr(frame_info, x + frame_info->rotated.y1)
> > +			src_pixels = get_packed_src_addr(frame_info, x + frame_info->rotated.y1, 0)
> >  				+ frame_info->fb->format->cpp[0] * y;
> >  
> >  		plane->pixel_read(src_pixels, &out_pixels[x_pos]);
> > @@ -250,7 +315,10 @@ void vkms_writeback_row(struct vkms_writeback_job *wb,
> >  {
> >  	struct vkms_frame_info *frame_info = &wb->wb_frame_info;
> >  	int x_dst = frame_info->dst.x1;
> > -	u8 *dst_pixels = packed_pixels_addr(frame_info, x_dst, y);
> > +	u8 *dst_pixels;
> > +	int rem_x, rem_y;
> > +
> > +	packed_pixels_addr(frame_info, x_dst, y, 0, &dst_pixels, &rem_x, &rem_y);
> >  	struct pixel_argb_u16 *in_pixels = src_buffer->pixels;
> >  	int x_limit = min_t(size_t, drm_rect_width(&frame_info->dst), src_buffer->n_pixels);
> >  
> > 

On Mon, Nov 18, 2024 at 06:17:11PM +0100, Louis Chauvet wrote:
> On 18/11/24 - 18:10, José Expósito wrote:
> > > Introduce the usage of block_h/block_w to compute the offset and the
> > > pointer of a pixel. The previous implementation was specialized for
> > > planes with block_h == block_w == 1. To avoid confusion and allow easier
> > > implementation of tiled formats. It also remove the usage of the
> > > deprecated format field `cpp`.
> > > 
> > > Introduce the plane_index parameter to get an offset/pointer on a
> > > different plane.
> > > 
> > > Acked-by: Maíra Canal <mairacanal@riseup.net>
> > > Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> > > ---
> > >  drivers/gpu/drm/vkms/vkms_formats.c | 114 ++++++++++++++++++++++++++++--------
> > >  1 file changed, 91 insertions(+), 23 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
> > > index 06aef5162529..7f932d42394d 100644
> > > --- a/drivers/gpu/drm/vkms/vkms_formats.c
> > > +++ b/drivers/gpu/drm/vkms/vkms_formats.c
> > > @@ -10,22 +10,46 @@
> > >  #include "vkms_formats.h"
> > >  
> > >  /**
> > > - * pixel_offset() - Get the offset of the pixel at coordinates x/y in the first plane
> > > + * packed_pixels_offset() - Get the offset of the block containing the pixel at coordinates x/y
> > >   *
> > >   * @frame_info: Buffer metadata
> > >   * @x: The x coordinate of the wanted pixel in the buffer
> > >   * @y: The y coordinate of the wanted pixel in the buffer
> > > + * @plane_index: The index of the plane to use
> > > + * @offset: The returned offset inside the buffer of the block
> > 
> > The previous function (pixel_offset) returned a size_t for the offset rather
> > than an int. Do you know if we are safe using an int in this case?
> 
> I think I used int everywhere because it may avoid strange issues with 
> implicit casting and negative number. I don't remember exactly where, but 
> Pekka suggested it.

Ah! Good to know. For the record, I ran locally the IGT tests and
perform some manual testing and I found no issues.

> > > + * @rem_x: The returned X coordinate of the requested pixel in the block
> > > + * @rem_y: The returned Y coordinate of the requested pixel in the block
> > >   *
> > > - * The caller must ensure that the framebuffer associated with this request uses a pixel format
> > > - * where block_h == block_w == 1.
> > > - * If this requirement is not fulfilled, the resulting offset can point to an other pixel or
> > > - * outside of the buffer.
> > > + * As some pixel formats store multiple pixels in a block (DRM_FORMAT_R* for example), some
> > > + * pixels are not individually addressable. This function return 3 values: the offset of the
> > > + * whole block, and the coordinate of the requested pixel inside this block.
> > > + * For example, if the format is DRM_FORMAT_R1 and the requested coordinate is 13,5, the offset
> > > + * will point to the byte 5*pitches + 13/8 (second byte of the 5th line), and the rem_x/rem_y
> > > + * coordinates will be (13 % 8, 5 % 1) = (5, 0)
> > > + *
> > > + * With this function, the caller just have to extract the correct pixel from the block.
> > >   */
> > > -static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int y)
> > > +static void packed_pixels_offset(const struct vkms_frame_info *frame_info, int x, int y,
> > > +				 int plane_index, int *offset, int *rem_x, int *rem_y)
> > >  {
> > >  	struct drm_framebuffer *fb = frame_info->fb;
> > > +	const struct drm_format_info *format = frame_info->fb->format;
> > > +	/* Directly using x and y to multiply pitches and format->ccp is not sufficient because
> > > +	 * in some formats a block can represent multiple pixels.
> > > +	 *
> > > +	 * Dividing x and y by the block size allows to extract the correct offset of the block
> > > +	 * containing the pixel.
> > > +	 */
> > >  
> > > -	return fb->offsets[0] + (y * fb->pitches[0]) + (x * fb->format->cpp[0]);
> > > +	int block_x = x / drm_format_info_block_width(format, plane_index);
> > > +	int block_y = y / drm_format_info_block_height(format, plane_index);
> > > +	int block_pitch = fb->pitches[plane_index] * drm_format_info_block_height(format,
> > > +										  plane_index);
> > > +	*rem_x = x % drm_format_info_block_width(format, plane_index);
> > > +	*rem_y = y % drm_format_info_block_height(format, plane_index);
> > > +	*offset = fb->offsets[plane_index] +
> > > +		  block_y * block_pitch +
> > > +		  block_x * format->char_per_block[plane_index];
> > >  }
> > >  
> > >  /**
> > > @@ -35,30 +59,71 @@ static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int
> > >   * @frame_info: Buffer metadata
> > >   * @x: The x (width) coordinate inside the plane
> > >   * @y: The y (height) coordinate inside the plane
> > > + * @plane_index: The index of the plane
> > > + * @addr: The returned pointer
> > > + * @rem_x: The returned X coordinate of the requested pixel in the block
> > > + * @rem_y: The returned Y coordinate of the requested pixel in the block
> > >   *
> > > - * Takes the information stored in the frame_info, a pair of coordinates, and
> > > - * returns the address of the first color channel.
> > > - * This function assumes the channels are packed together, i.e. a color channel
> > > - * comes immediately after another in the memory. And therefore, this function
> > > - * doesn't work for YUV with chroma subsampling (e.g. YUV420 and NV21).
> > > + * Takes the information stored in the frame_info, a pair of coordinates, and returns the address
> > > + * of the block containing this pixel and the pixel position inside this block.
> > >   *
> > > - * The caller must ensure that the framebuffer associated with this request uses a pixel format
> > > - * where block_h == block_w == 1, otherwise the returned pointer can be outside the buffer.
> > > + * See @packed_pixel_offset for details about rem_x/rem_y behavior.
> > 
> > Missing "s" in the name of the function. Should read "@packed_pixels_offset".
> 
> Thanks!
> 
> > >   */
> > > -static void *packed_pixels_addr(const struct vkms_frame_info *frame_info,
> > > -				int x, int y)
> > > +static void packed_pixels_addr(const struct vkms_frame_info *frame_info,
> > > +			       int x, int y, int plane_index, u8 **addr, int *rem_x,
> > > +			       int *rem_y)
> > >  {
> > > -	size_t offset = pixel_offset(frame_info, x, y);
> > > +	int offset;
> > >  
> > > -	return (u8 *)frame_info->map[0].vaddr + offset;
> > > +	packed_pixels_offset(frame_info, x, y, plane_index, &offset, rem_x, rem_y);
> > > +	*addr = (u8 *)frame_info->map[0].vaddr + offset;
> > >  }
> > >  
> > > -static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y)
> > > +/**
> > > + * packed_pixels_addr_1x1() - Get the pointer to the block containing the pixel at the given
> > > + * coordinates
> > > + *
> > > + * @frame_info: Buffer metadata
> > > + * @x: The x (width) coordinate inside the plane
> > > + * @y: The y (height) coordinate inside the plane
> > > + * @plane_index: The index of the plane
> > > + * @addr: The returned pointer
> > > + *
> > > + * This function can only be used with format where block_h == block_w == 1.
> > > + */
> > > +static void packed_pixels_addr_1x1(const struct vkms_frame_info *frame_info,
> > > +				   int x, int y, int plane_index, u8 **addr)
> > > +{
> > > +	int offset, rem_x, rem_y;
> > 
> > Nitpick, but it'd be nice if packed_pixels_offset() could take NULLs in
> > the output values so we avoid declaring unused variables here and when
> > calling packed_pixels_addr().
> 
> It is not a trivial change, and as I want this series to be merged I will 
> send the v14 without it. But if I have the time I will send a new 
> patch/series with this cleanup, thanks for the suggestion.

That works for me, we can always fix it in a follow up... Specially since
2 other series depend on this one :)

Jose
 
> > > +
> > > +	WARN_ONCE(drm_format_info_block_width(frame_info->fb->format,
> > > +					      plane_index) != 1,
> > > +		"%s() only support formats with block_w == 1", __func__);
> > > +	WARN_ONCE(drm_format_info_block_height(frame_info->fb->format,
> > > +					       plane_index) != 1,
> > > +		"%s() only support formats with block_h == 1", __func__);
> > > +
> > > +	packed_pixels_offset(frame_info, x, y, plane_index, &offset, &rem_x,
> > > +			     &rem_y);
> > > +	*addr = (u8 *)frame_info->map[0].vaddr + offset;
> > > +}
> > > +
> > > +static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y,
> > > +				 int plane_index)
> > >  {
> > >  	int x_src = frame_info->src.x1 >> 16;
> > >  	int y_src = y - frame_info->rotated.y1 + (frame_info->src.y1 >> 16);
> > > +	u8 *addr;
> > > +	int rem_x, rem_y;
> > > +
> > > +	WARN_ONCE(drm_format_info_block_width(frame_info->fb->format, plane_index) != 1,
> > > +		  "%s() only support formats with block_w == 1", __func__);
> > > +	WARN_ONCE(drm_format_info_block_height(frame_info->fb->format, plane_index) != 1,
> > > +		  "%s() only support formats with block_h == 1", __func__);
> > >  
> > > -	return packed_pixels_addr(frame_info, x_src, y_src);
> > > +	packed_pixels_addr(frame_info, x_src, y_src, plane_index, &addr, &rem_x, &rem_y);
> > > +
> > > +	return addr;
> > >  }
> > >  
> > >  static int get_x_position(const struct vkms_frame_info *frame_info, int limit, int x)
> > > @@ -152,14 +217,14 @@ void vkms_compose_row(struct line_buffer *stage_buffer, struct vkms_plane_state
> > >  {
> > >  	struct pixel_argb_u16 *out_pixels = stage_buffer->pixels;
> > >  	struct vkms_frame_info *frame_info = plane->frame_info;
> > > -	u8 *src_pixels = get_packed_src_addr(frame_info, y);
> > > +	u8 *src_pixels = get_packed_src_addr(frame_info, y, 0);
> > >  	int limit = min_t(size_t, drm_rect_width(&frame_info->dst), stage_buffer->n_pixels);
> > >  
> > >  	for (size_t x = 0; x < limit; x++, src_pixels += frame_info->fb->format->cpp[0]) {
> > >  		int x_pos = get_x_position(frame_info, limit, x);
> > >  
> > >  		if (drm_rotation_90_or_270(frame_info->rotation))
> > > -			src_pixels = get_packed_src_addr(frame_info, x + frame_info->rotated.y1)
> > > +			src_pixels = get_packed_src_addr(frame_info, x + frame_info->rotated.y1, 0)
> > >  				+ frame_info->fb->format->cpp[0] * y;
> > >  
> > >  		plane->pixel_read(src_pixels, &out_pixels[x_pos]);
> > > @@ -250,7 +315,10 @@ void vkms_writeback_row(struct vkms_writeback_job *wb,
> > >  {
> > >  	struct vkms_frame_info *frame_info = &wb->wb_frame_info;
> > >  	int x_dst = frame_info->dst.x1;
> > > -	u8 *dst_pixels = packed_pixels_addr(frame_info, x_dst, y);
> > > +	u8 *dst_pixels;
> > > +	int rem_x, rem_y;
> > > +
> > > +	packed_pixels_addr(frame_info, x_dst, y, 0, &dst_pixels, &rem_x, &rem_y);
> > >  	struct pixel_argb_u16 *in_pixels = src_buffer->pixels;
> > >  	int x_limit = min_t(size_t, drm_rect_width(&frame_info->dst), src_buffer->n_pixels);
> > >  
> > > 

On 18/11/24 - 18:24, José Expósito wrote:
> On Mon, Nov 18, 2024 at 06:17:11PM +0100, Louis Chauvet wrote:
> > On 18/11/24 - 18:10, José Expósito wrote:
> > > > Introduce the usage of block_h/block_w to compute the offset and the
> > > > pointer of a pixel. The previous implementation was specialized for
> > > > planes with block_h == block_w == 1. To avoid confusion and allow easier
> > > > implementation of tiled formats. It also remove the usage of the
> > > > deprecated format field `cpp`.
> > > > 
> > > > Introduce the plane_index parameter to get an offset/pointer on a
> > > > different plane.
> > > > 
> > > > Acked-by: Maíra Canal <mairacanal@riseup.net>
> > > > Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> > > > ---
> > > >  drivers/gpu/drm/vkms/vkms_formats.c | 114 ++++++++++++++++++++++++++++--------
> > > >  1 file changed, 91 insertions(+), 23 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
> > > > index 06aef5162529..7f932d42394d 100644
> > > > --- a/drivers/gpu/drm/vkms/vkms_formats.c
> > > > +++ b/drivers/gpu/drm/vkms/vkms_formats.c
> > > > @@ -10,22 +10,46 @@
> > > >  #include "vkms_formats.h"
> > > >  
> > > >  /**
> > > > - * pixel_offset() - Get the offset of the pixel at coordinates x/y in the first plane
> > > > + * packed_pixels_offset() - Get the offset of the block containing the pixel at coordinates x/y
> > > >   *
> > > >   * @frame_info: Buffer metadata
> > > >   * @x: The x coordinate of the wanted pixel in the buffer
> > > >   * @y: The y coordinate of the wanted pixel in the buffer
> > > > + * @plane_index: The index of the plane to use
> > > > + * @offset: The returned offset inside the buffer of the block
> > > 
> > > The previous function (pixel_offset) returned a size_t for the offset rather
> > > than an int. Do you know if we are safe using an int in this case?
> > 
> > I think I used int everywhere because it may avoid strange issues with 
> > implicit casting and negative number. I don't remember exactly where, but 
> > Pekka suggested it.
> 
> Ah! Good to know. For the record, I ran locally the IGT tests and
> perform some manual testing and I found no issues.
> 
> > > > + * @rem_x: The returned X coordinate of the requested pixel in the block
> > > > + * @rem_y: The returned Y coordinate of the requested pixel in the block
> > > >   *
> > > > - * The caller must ensure that the framebuffer associated with this request uses a pixel format
> > > > - * where block_h == block_w == 1.
> > > > - * If this requirement is not fulfilled, the resulting offset can point to an other pixel or
> > > > - * outside of the buffer.
> > > > + * As some pixel formats store multiple pixels in a block (DRM_FORMAT_R* for example), some
> > > > + * pixels are not individually addressable. This function return 3 values: the offset of the
> > > > + * whole block, and the coordinate of the requested pixel inside this block.
> > > > + * For example, if the format is DRM_FORMAT_R1 and the requested coordinate is 13,5, the offset
> > > > + * will point to the byte 5*pitches + 13/8 (second byte of the 5th line), and the rem_x/rem_y
> > > > + * coordinates will be (13 % 8, 5 % 1) = (5, 0)
> > > > + *
> > > > + * With this function, the caller just have to extract the correct pixel from the block.
> > > >   */
> > > > -static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int y)
> > > > +static void packed_pixels_offset(const struct vkms_frame_info *frame_info, int x, int y,
> > > > +				 int plane_index, int *offset, int *rem_x, int *rem_y)
> > > >  {
> > > >  	struct drm_framebuffer *fb = frame_info->fb;
> > > > +	const struct drm_format_info *format = frame_info->fb->format;
> > > > +	/* Directly using x and y to multiply pitches and format->ccp is not sufficient because
> > > > +	 * in some formats a block can represent multiple pixels.
> > > > +	 *
> > > > +	 * Dividing x and y by the block size allows to extract the correct offset of the block
> > > > +	 * containing the pixel.
> > > > +	 */
> > > >  
> > > > -	return fb->offsets[0] + (y * fb->pitches[0]) + (x * fb->format->cpp[0]);
> > > > +	int block_x = x / drm_format_info_block_width(format, plane_index);
> > > > +	int block_y = y / drm_format_info_block_height(format, plane_index);
> > > > +	int block_pitch = fb->pitches[plane_index] * drm_format_info_block_height(format,
> > > > +										  plane_index);
> > > > +	*rem_x = x % drm_format_info_block_width(format, plane_index);
> > > > +	*rem_y = y % drm_format_info_block_height(format, plane_index);
> > > > +	*offset = fb->offsets[plane_index] +
> > > > +		  block_y * block_pitch +
> > > > +		  block_x * format->char_per_block[plane_index];
> > > >  }
> > > >  
> > > >  /**
> > > > @@ -35,30 +59,71 @@ static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int
> > > >   * @frame_info: Buffer metadata
> > > >   * @x: The x (width) coordinate inside the plane
> > > >   * @y: The y (height) coordinate inside the plane
> > > > + * @plane_index: The index of the plane
> > > > + * @addr: The returned pointer
> > > > + * @rem_x: The returned X coordinate of the requested pixel in the block
> > > > + * @rem_y: The returned Y coordinate of the requested pixel in the block
> > > >   *
> > > > - * Takes the information stored in the frame_info, a pair of coordinates, and
> > > > - * returns the address of the first color channel.
> > > > - * This function assumes the channels are packed together, i.e. a color channel
> > > > - * comes immediately after another in the memory. And therefore, this function
> > > > - * doesn't work for YUV with chroma subsampling (e.g. YUV420 and NV21).
> > > > + * Takes the information stored in the frame_info, a pair of coordinates, and returns the address
> > > > + * of the block containing this pixel and the pixel position inside this block.
> > > >   *
> > > > - * The caller must ensure that the framebuffer associated with this request uses a pixel format
> > > > - * where block_h == block_w == 1, otherwise the returned pointer can be outside the buffer.
> > > > + * See @packed_pixel_offset for details about rem_x/rem_y behavior.
> > > 
> > > Missing "s" in the name of the function. Should read "@packed_pixels_offset".
> > 
> > Thanks!
> > 
> > > >   */
> > > > -static void *packed_pixels_addr(const struct vkms_frame_info *frame_info,
> > > > -				int x, int y)
> > > > +static void packed_pixels_addr(const struct vkms_frame_info *frame_info,
> > > > +			       int x, int y, int plane_index, u8 **addr, int *rem_x,
> > > > +			       int *rem_y)
> > > >  {
> > > > -	size_t offset = pixel_offset(frame_info, x, y);
> > > > +	int offset;
> > > >  
> > > > -	return (u8 *)frame_info->map[0].vaddr + offset;
> > > > +	packed_pixels_offset(frame_info, x, y, plane_index, &offset, rem_x, rem_y);
> > > > +	*addr = (u8 *)frame_info->map[0].vaddr + offset;
> > > >  }
> > > >  
> > > > -static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y)
> > > > +/**
> > > > + * packed_pixels_addr_1x1() - Get the pointer to the block containing the pixel at the given
> > > > + * coordinates
> > > > + *
> > > > + * @frame_info: Buffer metadata
> > > > + * @x: The x (width) coordinate inside the plane
> > > > + * @y: The y (height) coordinate inside the plane
> > > > + * @plane_index: The index of the plane
> > > > + * @addr: The returned pointer
> > > > + *
> > > > + * This function can only be used with format where block_h == block_w == 1.
> > > > + */
> > > > +static void packed_pixels_addr_1x1(const struct vkms_frame_info *frame_info,
> > > > +				   int x, int y, int plane_index, u8 **addr)
> > > > +{
> > > > +	int offset, rem_x, rem_y;
> > > 
> > > Nitpick, but it'd be nice if packed_pixels_offset() could take NULLs in
> > > the output values so we avoid declaring unused variables here and when
> > > calling packed_pixels_addr().
> > 
> > It is not a trivial change, and as I want this series to be merged I will 
> > send the v14 without it. But if I have the time I will send a new 
> > patch/series with this cleanup, thanks for the suggestion.
> 
> That works for me, we can always fix it in a follow up... Specially since
> 2 other series depend on this one :)

As the series is completly reviewed/acked, how long do I need to 
wait after the v14 before commiting on drm-misc-next? I plan to send the 
v14 today/tomorrow morning with your changes.

Thanks,
Louis Chauvet
 
> Jose
>  
> > > > +
> > > > +	WARN_ONCE(drm_format_info_block_width(frame_info->fb->format,
> > > > +					      plane_index) != 1,
> > > > +		"%s() only support formats with block_w == 1", __func__);
> > > > +	WARN_ONCE(drm_format_info_block_height(frame_info->fb->format,
> > > > +					       plane_index) != 1,
> > > > +		"%s() only support formats with block_h == 1", __func__);
> > > > +
> > > > +	packed_pixels_offset(frame_info, x, y, plane_index, &offset, &rem_x,
> > > > +			     &rem_y);
> > > > +	*addr = (u8 *)frame_info->map[0].vaddr + offset;
> > > > +}
> > > > +
> > > > +static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y,
> > > > +				 int plane_index)
> > > >  {
> > > >  	int x_src = frame_info->src.x1 >> 16;
> > > >  	int y_src = y - frame_info->rotated.y1 + (frame_info->src.y1 >> 16);
> > > > +	u8 *addr;
> > > > +	int rem_x, rem_y;
> > > > +
> > > > +	WARN_ONCE(drm_format_info_block_width(frame_info->fb->format, plane_index) != 1,
> > > > +		  "%s() only support formats with block_w == 1", __func__);
> > > > +	WARN_ONCE(drm_format_info_block_height(frame_info->fb->format, plane_index) != 1,
> > > > +		  "%s() only support formats with block_h == 1", __func__);
> > > >  
> > > > -	return packed_pixels_addr(frame_info, x_src, y_src);
> > > > +	packed_pixels_addr(frame_info, x_src, y_src, plane_index, &addr, &rem_x, &rem_y);
> > > > +
> > > > +	return addr;
> > > >  }
> > > >  
> > > >  static int get_x_position(const struct vkms_frame_info *frame_info, int limit, int x)
> > > > @@ -152,14 +217,14 @@ void vkms_compose_row(struct line_buffer *stage_buffer, struct vkms_plane_state
> > > >  {
> > > >  	struct pixel_argb_u16 *out_pixels = stage_buffer->pixels;
> > > >  	struct vkms_frame_info *frame_info = plane->frame_info;
> > > > -	u8 *src_pixels = get_packed_src_addr(frame_info, y);
> > > > +	u8 *src_pixels = get_packed_src_addr(frame_info, y, 0);
> > > >  	int limit = min_t(size_t, drm_rect_width(&frame_info->dst), stage_buffer->n_pixels);
> > > >  
> > > >  	for (size_t x = 0; x < limit; x++, src_pixels += frame_info->fb->format->cpp[0]) {
> > > >  		int x_pos = get_x_position(frame_info, limit, x);
> > > >  
> > > >  		if (drm_rotation_90_or_270(frame_info->rotation))
> > > > -			src_pixels = get_packed_src_addr(frame_info, x + frame_info->rotated.y1)
> > > > +			src_pixels = get_packed_src_addr(frame_info, x + frame_info->rotated.y1, 0)
> > > >  				+ frame_info->fb->format->cpp[0] * y;
> > > >  
> > > >  		plane->pixel_read(src_pixels, &out_pixels[x_pos]);
> > > > @@ -250,7 +315,10 @@ void vkms_writeback_row(struct vkms_writeback_job *wb,
> > > >  {
> > > >  	struct vkms_frame_info *frame_info = &wb->wb_frame_info;
> > > >  	int x_dst = frame_info->dst.x1;
> > > > -	u8 *dst_pixels = packed_pixels_addr(frame_info, x_dst, y);
> > > > +	u8 *dst_pixels;
> > > > +	int rem_x, rem_y;
> > > > +
> > > > +	packed_pixels_addr(frame_info, x_dst, y, 0, &dst_pixels, &rem_x, &rem_y);
> > > >  	struct pixel_argb_u16 *in_pixels = src_buffer->pixels;
> > > >  	int x_limit = min_t(size_t, drm_rect_width(&frame_info->dst), src_buffer->n_pixels);
> > > >  
> > > > 

On Mon, Nov 18, 2024 at 06:35:30PM +0100, Louis Chauvet wrote:
> On 18/11/24 - 18:24, José Expósito wrote:
> > On Mon, Nov 18, 2024 at 06:17:11PM +0100, Louis Chauvet wrote:
> > > On 18/11/24 - 18:10, José Expósito wrote:
> > > > > Introduce the usage of block_h/block_w to compute the offset and the
> > > > > pointer of a pixel. The previous implementation was specialized for
> > > > > planes with block_h == block_w == 1. To avoid confusion and allow easier
> > > > > implementation of tiled formats. It also remove the usage of the
> > > > > deprecated format field `cpp`.
> > > > > 
> > > > > Introduce the plane_index parameter to get an offset/pointer on a
> > > > > different plane.
> > > > > 
> > > > > Acked-by: Maíra Canal <mairacanal@riseup.net>
> > > > > Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> > > > > ---
> > > > >  drivers/gpu/drm/vkms/vkms_formats.c | 114 ++++++++++++++++++++++++++++--------
> > > > >  1 file changed, 91 insertions(+), 23 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
> > > > > index 06aef5162529..7f932d42394d 100644
> > > > > --- a/drivers/gpu/drm/vkms/vkms_formats.c
> > > > > +++ b/drivers/gpu/drm/vkms/vkms_formats.c
> > > > > @@ -10,22 +10,46 @@
> > > > >  #include "vkms_formats.h"
> > > > >  
> > > > >  /**
> > > > > - * pixel_offset() - Get the offset of the pixel at coordinates x/y in the first plane
> > > > > + * packed_pixels_offset() - Get the offset of the block containing the pixel at coordinates x/y
> > > > >   *
> > > > >   * @frame_info: Buffer metadata
> > > > >   * @x: The x coordinate of the wanted pixel in the buffer
> > > > >   * @y: The y coordinate of the wanted pixel in the buffer
> > > > > + * @plane_index: The index of the plane to use
> > > > > + * @offset: The returned offset inside the buffer of the block
> > > > 
> > > > The previous function (pixel_offset) returned a size_t for the offset rather
> > > > than an int. Do you know if we are safe using an int in this case?
> > > 
> > > I think I used int everywhere because it may avoid strange issues with 
> > > implicit casting and negative number. I don't remember exactly where, but 
> > > Pekka suggested it.
> > 
> > Ah! Good to know. For the record, I ran locally the IGT tests and
> > perform some manual testing and I found no issues.
> > 
> > > > > + * @rem_x: The returned X coordinate of the requested pixel in the block
> > > > > + * @rem_y: The returned Y coordinate of the requested pixel in the block
> > > > >   *
> > > > > - * The caller must ensure that the framebuffer associated with this request uses a pixel format
> > > > > - * where block_h == block_w == 1.
> > > > > - * If this requirement is not fulfilled, the resulting offset can point to an other pixel or
> > > > > - * outside of the buffer.
> > > > > + * As some pixel formats store multiple pixels in a block (DRM_FORMAT_R* for example), some
> > > > > + * pixels are not individually addressable. This function return 3 values: the offset of the
> > > > > + * whole block, and the coordinate of the requested pixel inside this block.
> > > > > + * For example, if the format is DRM_FORMAT_R1 and the requested coordinate is 13,5, the offset
> > > > > + * will point to the byte 5*pitches + 13/8 (second byte of the 5th line), and the rem_x/rem_y
> > > > > + * coordinates will be (13 % 8, 5 % 1) = (5, 0)
> > > > > + *
> > > > > + * With this function, the caller just have to extract the correct pixel from the block.
> > > > >   */
> > > > > -static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int y)
> > > > > +static void packed_pixels_offset(const struct vkms_frame_info *frame_info, int x, int y,
> > > > > +				 int plane_index, int *offset, int *rem_x, int *rem_y)
> > > > >  {
> > > > >  	struct drm_framebuffer *fb = frame_info->fb;
> > > > > +	const struct drm_format_info *format = frame_info->fb->format;
> > > > > +	/* Directly using x and y to multiply pitches and format->ccp is not sufficient because
> > > > > +	 * in some formats a block can represent multiple pixels.
> > > > > +	 *
> > > > > +	 * Dividing x and y by the block size allows to extract the correct offset of the block
> > > > > +	 * containing the pixel.
> > > > > +	 */
> > > > >  
> > > > > -	return fb->offsets[0] + (y * fb->pitches[0]) + (x * fb->format->cpp[0]);
> > > > > +	int block_x = x / drm_format_info_block_width(format, plane_index);
> > > > > +	int block_y = y / drm_format_info_block_height(format, plane_index);
> > > > > +	int block_pitch = fb->pitches[plane_index] * drm_format_info_block_height(format,
> > > > > +										  plane_index);
> > > > > +	*rem_x = x % drm_format_info_block_width(format, plane_index);
> > > > > +	*rem_y = y % drm_format_info_block_height(format, plane_index);
> > > > > +	*offset = fb->offsets[plane_index] +
> > > > > +		  block_y * block_pitch +
> > > > > +		  block_x * format->char_per_block[plane_index];
> > > > >  }
> > > > >  
> > > > >  /**
> > > > > @@ -35,30 +59,71 @@ static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int
> > > > >   * @frame_info: Buffer metadata
> > > > >   * @x: The x (width) coordinate inside the plane
> > > > >   * @y: The y (height) coordinate inside the plane
> > > > > + * @plane_index: The index of the plane
> > > > > + * @addr: The returned pointer
> > > > > + * @rem_x: The returned X coordinate of the requested pixel in the block
> > > > > + * @rem_y: The returned Y coordinate of the requested pixel in the block
> > > > >   *
> > > > > - * Takes the information stored in the frame_info, a pair of coordinates, and
> > > > > - * returns the address of the first color channel.
> > > > > - * This function assumes the channels are packed together, i.e. a color channel
> > > > > - * comes immediately after another in the memory. And therefore, this function
> > > > > - * doesn't work for YUV with chroma subsampling (e.g. YUV420 and NV21).
> > > > > + * Takes the information stored in the frame_info, a pair of coordinates, and returns the address
> > > > > + * of the block containing this pixel and the pixel position inside this block.
> > > > >   *
> > > > > - * The caller must ensure that the framebuffer associated with this request uses a pixel format
> > > > > - * where block_h == block_w == 1, otherwise the returned pointer can be outside the buffer.
> > > > > + * See @packed_pixel_offset for details about rem_x/rem_y behavior.
> > > > 
> > > > Missing "s" in the name of the function. Should read "@packed_pixels_offset".
> > > 
> > > Thanks!
> > > 
> > > > >   */
> > > > > -static void *packed_pixels_addr(const struct vkms_frame_info *frame_info,
> > > > > -				int x, int y)
> > > > > +static void packed_pixels_addr(const struct vkms_frame_info *frame_info,
> > > > > +			       int x, int y, int plane_index, u8 **addr, int *rem_x,
> > > > > +			       int *rem_y)
> > > > >  {
> > > > > -	size_t offset = pixel_offset(frame_info, x, y);
> > > > > +	int offset;
> > > > >  
> > > > > -	return (u8 *)frame_info->map[0].vaddr + offset;
> > > > > +	packed_pixels_offset(frame_info, x, y, plane_index, &offset, rem_x, rem_y);
> > > > > +	*addr = (u8 *)frame_info->map[0].vaddr + offset;
> > > > >  }
> > > > >  
> > > > > -static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y)
> > > > > +/**
> > > > > + * packed_pixels_addr_1x1() - Get the pointer to the block containing the pixel at the given
> > > > > + * coordinates
> > > > > + *
> > > > > + * @frame_info: Buffer metadata
> > > > > + * @x: The x (width) coordinate inside the plane
> > > > > + * @y: The y (height) coordinate inside the plane
> > > > > + * @plane_index: The index of the plane
> > > > > + * @addr: The returned pointer
> > > > > + *
> > > > > + * This function can only be used with format where block_h == block_w == 1.
> > > > > + */
> > > > > +static void packed_pixels_addr_1x1(const struct vkms_frame_info *frame_info,
> > > > > +				   int x, int y, int plane_index, u8 **addr)
> > > > > +{
> > > > > +	int offset, rem_x, rem_y;
> > > > 
> > > > Nitpick, but it'd be nice if packed_pixels_offset() could take NULLs in
> > > > the output values so we avoid declaring unused variables here and when
> > > > calling packed_pixels_addr().
> > > 
> > > It is not a trivial change, and as I want this series to be merged I will 
> > > send the v14 without it. But if I have the time I will send a new 
> > > patch/series with this cleanup, thanks for the suggestion.
> > 
> > That works for me, we can always fix it in a follow up... Specially since
> > 2 other series depend on this one :)
> 
> As the series is completly reviewed/acked, how long do I need to 
> wait after the v14 before commiting on drm-misc-next? I plan to send the 
> v14 today/tomorrow morning with your changes.

Thanks for sending v14, I checked very quickly the patches and my sugestions
were fixed.

I can't answer this question, but all patches have been reviewed/tested by at
least 2 people, plus you are the only maintainer of the driver now.
I think that, if in a few days there are no complains, this series should be
ready to be merged.

Maybe Maíra, as the previous maintainer, can give you some advice. I have
never maintained a driver, so I'm not sure what are the best practices.

Jose

> Thanks,
> Louis Chauvet
>  
> > Jose
> >  
> > > > > +
> > > > > +	WARN_ONCE(drm_format_info_block_width(frame_info->fb->format,
> > > > > +					      plane_index) != 1,
> > > > > +		"%s() only support formats with block_w == 1", __func__);
> > > > > +	WARN_ONCE(drm_format_info_block_height(frame_info->fb->format,
> > > > > +					       plane_index) != 1,
> > > > > +		"%s() only support formats with block_h == 1", __func__);
> > > > > +
> > > > > +	packed_pixels_offset(frame_info, x, y, plane_index, &offset, &rem_x,
> > > > > +			     &rem_y);
> > > > > +	*addr = (u8 *)frame_info->map[0].vaddr + offset;
> > > > > +}
> > > > > +
> > > > > +static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y,
> > > > > +				 int plane_index)
> > > > >  {
> > > > >  	int x_src = frame_info->src.x1 >> 16;
> > > > >  	int y_src = y - frame_info->rotated.y1 + (frame_info->src.y1 >> 16);
> > > > > +	u8 *addr;
> > > > > +	int rem_x, rem_y;
> > > > > +
> > > > > +	WARN_ONCE(drm_format_info_block_width(frame_info->fb->format, plane_index) != 1,
> > > > > +		  "%s() only support formats with block_w == 1", __func__);
> > > > > +	WARN_ONCE(drm_format_info_block_height(frame_info->fb->format, plane_index) != 1,
> > > > > +		  "%s() only support formats with block_h == 1", __func__);
> > > > >  
> > > > > -	return packed_pixels_addr(frame_info, x_src, y_src);
> > > > > +	packed_pixels_addr(frame_info, x_src, y_src, plane_index, &addr, &rem_x, &rem_y);
> > > > > +
> > > > > +	return addr;
> > > > >  }
> > > > >  
> > > > >  static int get_x_position(const struct vkms_frame_info *frame_info, int limit, int x)
> > > > > @@ -152,14 +217,14 @@ void vkms_compose_row(struct line_buffer *stage_buffer, struct vkms_plane_state
> > > > >  {
> > > > >  	struct pixel_argb_u16 *out_pixels = stage_buffer->pixels;
> > > > >  	struct vkms_frame_info *frame_info = plane->frame_info;
> > > > > -	u8 *src_pixels = get_packed_src_addr(frame_info, y);
> > > > > +	u8 *src_pixels = get_packed_src_addr(frame_info, y, 0);
> > > > >  	int limit = min_t(size_t, drm_rect_width(&frame_info->dst), stage_buffer->n_pixels);
> > > > >  
> > > > >  	for (size_t x = 0; x < limit; x++, src_pixels += frame_info->fb->format->cpp[0]) {
> > > > >  		int x_pos = get_x_position(frame_info, limit, x);
> > > > >  
> > > > >  		if (drm_rotation_90_or_270(frame_info->rotation))
> > > > > -			src_pixels = get_packed_src_addr(frame_info, x + frame_info->rotated.y1)
> > > > > +			src_pixels = get_packed_src_addr(frame_info, x + frame_info->rotated.y1, 0)
> > > > >  				+ frame_info->fb->format->cpp[0] * y;
> > > > >  
> > > > >  		plane->pixel_read(src_pixels, &out_pixels[x_pos]);
> > > > > @@ -250,7 +315,10 @@ void vkms_writeback_row(struct vkms_writeback_job *wb,
> > > > >  {
> > > > >  	struct vkms_frame_info *frame_info = &wb->wb_frame_info;
> > > > >  	int x_dst = frame_info->dst.x1;
> > > > > -	u8 *dst_pixels = packed_pixels_addr(frame_info, x_dst, y);
> > > > > +	u8 *dst_pixels;
> > > > > +	int rem_x, rem_y;
> > > > > +
> > > > > +	packed_pixels_addr(frame_info, x_dst, y, 0, &dst_pixels, &rem_x, &rem_y);
> > > > >  	struct pixel_argb_u16 *in_pixels = src_buffer->pixels;
> > > > >  	int x_limit = min_t(size_t, drm_rect_width(&frame_info->dst), src_buffer->n_pixels);
> > > > >  
> > > > >