[PATCH 5/8] drm/mipi-dbi: Prepare framebuffer copy operation in pipe-update helpers

Noralf Trønnes noralf at tronnes.org
Fri Nov 25 17:39:07 UTC 2022



Den 21.11.2022 11.45, skrev Thomas Zimmermann:
> Move the vmap/vunmap blocks from the inner fb_dirty helpers into the
> MIPI DBI update helpers. The function calls can result in waiting and/or
> processing overhead. Reduce the penalties by executing the functions once
> in the outer-most function of the pipe update.
> 
> This change also prepares for MIPI DBI for shadow-plane helpers. With
> shadow-plane helpers, transfer source buffers are mapped into kernel
> address space automatically.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> ---
>  drivers/gpu/drm/drm_mipi_dbi.c | 60 +++++++++++++++++++---------------
>  drivers/gpu/drm/tiny/ili9225.c | 31 ++++++++++++++----
>  drivers/gpu/drm/tiny/st7586.c  | 28 +++++++++++-----
>  include/drm/drm_mipi_dbi.h     |  6 ++--
>  4 files changed, 81 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
> index a6ac565808765..40e59a3a6481e 100644
> --- a/drivers/gpu/drm/drm_mipi_dbi.c
> +++ b/drivers/gpu/drm/drm_mipi_dbi.c
> @@ -192,6 +192,7 @@ EXPORT_SYMBOL(mipi_dbi_command_stackbuf);
>  /**
>   * mipi_dbi_buf_copy - Copy a framebuffer, transforming it if necessary
>   * @dst: The destination buffer
> + * @src: The source buffer
>   * @fb: The source framebuffer
>   * @clip: Clipping rectangle of the area to be copied
>   * @swap: When true, swap MSB/LSB of 16-bit values
> @@ -199,12 +200,13 @@ EXPORT_SYMBOL(mipi_dbi_command_stackbuf);
>   * Returns:
>   * Zero on success, negative error code on failure.
>   */
> -int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
> +int mipi_dbi_buf_copy(void *dst, struct iosys_map *src, struct drm_framebuffer *fb,
>  		      struct drm_rect *clip, bool swap)
>  {
>  	struct drm_gem_object *gem = drm_gem_fb_get_obj(fb, 0);
> -	struct iosys_map map[DRM_FORMAT_MAX_PLANES];
> -	struct iosys_map data[DRM_FORMAT_MAX_PLANES];
> +	struct iosys_map data[DRM_FORMAT_MAX_PLANES] = {
> +		*src,
> +	};

I would prefer that you used src directly when calling the drm_fb_*
functions, data can be anything and to me it isn't clear what that
contains when I see it (ofc now I know, but next year I've forgotten).
And is the array necessary, this helper will only ever support one color
plane after all?

>  	struct iosys_map dst_map = IOSYS_MAP_INIT_VADDR(dst);
>  	int ret;
>  
> @@ -212,10 +214,6 @@ int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
>  	if (ret)
>  		return ret;
>  
> -	ret = drm_gem_fb_vmap(fb, map, data);
> -	if (ret)
> -		goto out_drm_gem_fb_end_cpu_access;
> -
>  	switch (fb->format->format) {
>  	case DRM_FORMAT_RGB565:
>  		if (swap)
> @@ -232,8 +230,6 @@ int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
>  		ret = -EINVAL;
>  	}
>  
> -	drm_gem_fb_vunmap(fb, map);
> -out_drm_gem_fb_end_cpu_access:
>  	drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
>  
>  	return ret;
> @@ -257,10 +253,9 @@ static void mipi_dbi_set_window_address(struct mipi_dbi_dev *dbidev,
>  			 ys & 0xff, (ye >> 8) & 0xff, ye & 0xff);
>  }
>  
> -static void mipi_dbi_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
> +static void mipi_dbi_fb_dirty(struct iosys_map *src, struct drm_framebuffer *fb,
> +			      struct drm_rect *rect)
>  {
> -	struct iosys_map map[DRM_FORMAT_MAX_PLANES];
> -	struct iosys_map data[DRM_FORMAT_MAX_PLANES];
>  	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
>  	unsigned int height = rect->y2 - rect->y1;
>  	unsigned int width = rect->x2 - rect->x1;
> @@ -270,16 +265,9 @@ static void mipi_dbi_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
>  	bool full;
>  	void *tr;
>  
> -	if (WARN_ON(!fb))
> -		return;
> -
>  	if (!drm_dev_enter(fb->dev, &idx))
>  		return;
>  
> -	ret = drm_gem_fb_vmap(fb, map, data);
> -	if (ret)
> -		goto err_drm_dev_exit;
> -
>  	full = width == fb->width && height == fb->height;
>  
>  	DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
> @@ -287,11 +275,11 @@ static void mipi_dbi_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
>  	if (!dbi->dc || !full || swap ||
>  	    fb->format->format == DRM_FORMAT_XRGB8888) {
>  		tr = dbidev->tx_buf;
> -		ret = mipi_dbi_buf_copy(dbidev->tx_buf, fb, rect, swap);
> +		ret = mipi_dbi_buf_copy(tr, src, fb, rect, swap);
>  		if (ret)
>  			goto err_msg;
>  	} else {
> -		tr = data[0].vaddr; /* TODO: Use mapping abstraction properly */
> +		tr = src->vaddr; /* TODO: Use mapping abstraction properly */
>  	}
>  
>  	mipi_dbi_set_window_address(dbidev, rect->x1, rect->x2 - 1, rect->y1,
> @@ -303,9 +291,6 @@ static void mipi_dbi_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
>  	if (ret)
>  		drm_err_once(fb->dev, "Failed to update display %d\n", ret);
>  
> -	drm_gem_fb_vunmap(fb, map);
> -
> -err_drm_dev_exit:
>  	drm_dev_exit(idx);
>  }
>  
> @@ -338,14 +323,27 @@ EXPORT_SYMBOL(mipi_dbi_pipe_mode_valid);
>  void mipi_dbi_pipe_update(struct drm_simple_display_pipe *pipe,
>  			  struct drm_plane_state *old_state)
>  {
> +	struct iosys_map map[DRM_FORMAT_MAX_PLANES];
> +	struct iosys_map data[DRM_FORMAT_MAX_PLANES];

These should have been zeroed to avoid UBSAN complaint, but you'll
remove these later so not so important.

>  	struct drm_plane_state *state = pipe->plane.state;
> +	struct drm_framebuffer *fb = state->fb;
>  	struct drm_rect rect;
> +	int ret;
>  
>  	if (!pipe->crtc.state->active)
>  		return;
>  
> +	if (WARN_ON(!fb))
> +		return;
> +
> +	ret = drm_gem_fb_vmap(fb, map, data);
> +	if (ret)
> +		return;
> +
>  	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
> -		mipi_dbi_fb_dirty(state->fb, &rect);
> +		mipi_dbi_fb_dirty(&data[0], fb, &rect);
> +
> +	drm_gem_fb_vunmap(fb, map);
>  }
>  EXPORT_SYMBOL(mipi_dbi_pipe_update);
>  
> @@ -373,14 +371,22 @@ void mipi_dbi_enable_flush(struct mipi_dbi_dev *dbidev,
>  		.y1 = 0,
>  		.y2 = fb->height,
>  	};
> -	int idx;
> +	struct iosys_map map[DRM_FORMAT_MAX_PLANES];
> +	struct iosys_map data[DRM_FORMAT_MAX_PLANES];
> +	int idx, ret;
>  
>  	if (!drm_dev_enter(&dbidev->drm, &idx))
>  		return;
>  
> -	mipi_dbi_fb_dirty(fb, &rect);
> +	ret = drm_gem_fb_vmap(fb, map, data);
> +	if (ret)
> +		goto err_drm_dev_exit;
> +
> +	mipi_dbi_fb_dirty(&data[0], fb, &rect);
>  	backlight_enable(dbidev->backlight);
>  
> +	drm_gem_fb_vunmap(fb, map);
> +err_drm_dev_exit:
>  	drm_dev_exit(idx);
>  }
>  EXPORT_SYMBOL(mipi_dbi_enable_flush);
> diff --git a/drivers/gpu/drm/tiny/ili9225.c b/drivers/gpu/drm/tiny/ili9225.c
> index f05a2d25866c1..0115c4090f9e7 100644
> --- a/drivers/gpu/drm/tiny/ili9225.c
> +++ b/drivers/gpu/drm/tiny/ili9225.c
> @@ -25,6 +25,7 @@
>  #include <drm/drm_framebuffer.h>
>  #include <drm/drm_gem_atomic_helper.h>
>  #include <drm/drm_gem_dma_helper.h>
> +#include <drm/drm_gem_framebuffer_helper.h>
>  #include <drm/drm_managed.h>
>  #include <drm/drm_mipi_dbi.h>
>  #include <drm/drm_rect.h>
> @@ -76,9 +77,9 @@ static inline int ili9225_command(struct mipi_dbi *dbi, u8 cmd, u16 data)
>  	return mipi_dbi_command_buf(dbi, cmd, par, 2);
>  }
>  
> -static void ili9225_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
> +static void ili9225_fb_dirty(struct iosys_map *src, struct drm_framebuffer *fb,
> +			     struct drm_rect *rect)
>  {
> -	struct drm_gem_dma_object *dma_obj = drm_fb_dma_get_gem_obj(fb, 0);
>  	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
>  	unsigned int height = rect->y2 - rect->y1;
>  	unsigned int width = rect->x2 - rect->x1;
> @@ -100,11 +101,11 @@ static void ili9225_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
>  	if (!dbi->dc || !full || swap ||
>  	    fb->format->format == DRM_FORMAT_XRGB8888) {
>  		tr = dbidev->tx_buf;
> -		ret = mipi_dbi_buf_copy(dbidev->tx_buf, fb, rect, swap);
> +		ret = mipi_dbi_buf_copy(tr, src, fb, rect, swap);
>  		if (ret)
>  			goto err_msg;
>  	} else {
> -		tr = dma_obj->vaddr;
> +		tr = src->vaddr; /* TODO: Use mapping abstraction properly */
>  	}
>  
>  	switch (dbidev->rotation) {
> @@ -162,14 +163,24 @@ static void ili9225_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
>  static void ili9225_pipe_update(struct drm_simple_display_pipe *pipe,
>  				struct drm_plane_state *old_state)
>  {
> +	struct iosys_map map[DRM_FORMAT_MAX_PLANES];
> +	struct iosys_map data[DRM_FORMAT_MAX_PLANES];
>  	struct drm_plane_state *state = pipe->plane.state;
> +	struct drm_framebuffer *fb = state->fb;
>  	struct drm_rect rect;
> +	int ret;
>  
>  	if (!pipe->crtc.state->active)
>  		return;
>  
> +	ret = drm_gem_fb_vmap(fb, map, data);
> +	if (ret)
> +		return;
> +
>  	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
> -		ili9225_fb_dirty(state->fb, &rect);
> +		ili9225_fb_dirty(&data[0], fb, &rect);
> +
> +	drm_gem_fb_vunmap(fb, map);
>  }
>  
>  static void ili9225_pipe_enable(struct drm_simple_display_pipe *pipe,
> @@ -186,6 +197,8 @@ static void ili9225_pipe_enable(struct drm_simple_display_pipe *pipe,
>  		.y1 = 0,
>  		.y2 = fb->height,
>  	};
> +	struct iosys_map map[DRM_FORMAT_MAX_PLANES];
> +	struct iosys_map data[DRM_FORMAT_MAX_PLANES];
>  	int ret, idx;
>  	u8 am_id;
>  
> @@ -276,7 +289,13 @@ static void ili9225_pipe_enable(struct drm_simple_display_pipe *pipe,
>  
>  	ili9225_command(dbi, ILI9225_DISPLAY_CONTROL_1, 0x1017);
>  
> -	ili9225_fb_dirty(fb, &rect);
> +	ret = drm_gem_fb_vmap(fb, map, data);
> +	if (ret)
> +		goto out_exit;
> +
> +	ili9225_fb_dirty(&data[0], fb, &rect);
> +
> +	drm_gem_fb_vunmap(fb, map);
>  out_exit:
>  	drm_dev_exit(idx);
>  }
> diff --git a/drivers/gpu/drm/tiny/st7586.c b/drivers/gpu/drm/tiny/st7586.c
> index 6bdd23e2a47c7..e773b1f2fd5f3 100644
> --- a/drivers/gpu/drm/tiny/st7586.c
> +++ b/drivers/gpu/drm/tiny/st7586.c
> @@ -92,25 +92,24 @@ static void st7586_xrgb8888_to_gray332(u8 *dst, void *vaddr,
>  	kfree(buf);
>  }
>  
> -static int st7586_buf_copy(void *dst, struct drm_framebuffer *fb,
> +static int st7586_buf_copy(void *dst, struct iosys_map *src, struct drm_framebuffer *fb,
>  			   struct drm_rect *clip)
>  {
> -	struct drm_gem_dma_object *dma_obj = drm_fb_dma_get_gem_obj(fb, 0);
> -	void *src = dma_obj->vaddr;
> -	int ret = 0;
> +	int ret;
>  
>  	ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
>  	if (ret)
>  		return ret;
>  
> -	st7586_xrgb8888_to_gray332(dst, src, fb, clip);
> +	st7586_xrgb8888_to_gray332(dst, src->vaddr, fb, clip);
>  
>  	drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
>  
>  	return 0;
>  }
>  
> -static void st7586_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
> +static void st7586_fb_dirty(struct iosys_map *src, struct drm_framebuffer *fb,
> +			    struct drm_rect *rect)
>  {
>  	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
>  	struct mipi_dbi *dbi = &dbidev->dbi;
> @@ -125,7 +124,7 @@ static void st7586_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
>  
>  	DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
>  
> -	ret = st7586_buf_copy(dbidev->tx_buf, fb, rect);
> +	ret = st7586_buf_copy(dbidev->tx_buf, src, fb, rect);
>  	if (ret)
>  		goto err_msg;
>  
> @@ -154,13 +153,19 @@ static void st7586_pipe_update(struct drm_simple_display_pipe *pipe,
>  			       struct drm_plane_state *old_state)
>  {
>  	struct drm_plane_state *state = pipe->plane.state;
> +	struct drm_framebuffer *fb = state->fb;
> +	struct drm_gem_dma_object *dma_obj;
> +	struct iosys_map src;
>  	struct drm_rect rect;
>  
>  	if (!pipe->crtc.state->active)
>  		return;
>  
> +	dma_obj = drm_fb_dma_get_gem_obj(fb, 0);
> +	iosys_map_set_vaddr(&src, dma_obj->vaddr);
> +

You use drm_gem_fb_vmap() in the other places but here you access the
object directly (and in the next hunk), but again not so important since
it goes away in a later patch.

With the comments considered:

Reviewed-by: Noralf Trønnes <noralf at tronnes.org>

>  	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
> -		st7586_fb_dirty(state->fb, &rect);
> +		st7586_fb_dirty(&src, fb, &rect);
>  }
>  
>  static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
> @@ -176,6 +181,8 @@ static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
>  		.y1 = 0,
>  		.y2 = fb->height,
>  	};
> +	struct drm_gem_dma_object *dma_obj;
> +	struct iosys_map src;
>  	int idx, ret;
>  	u8 addr_mode;
>  
> @@ -235,7 +242,10 @@ static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
>  
>  	msleep(100);
>  
> -	st7586_fb_dirty(fb, &rect);
> +	dma_obj = drm_fb_dma_get_gem_obj(fb, 0);
> +	iosys_map_set_vaddr(&src, dma_obj->vaddr);
> +
> +	st7586_fb_dirty(&src, fb, &rect);
>  
>  	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
>  out_exit:
> diff --git a/include/drm/drm_mipi_dbi.h b/include/drm/drm_mipi_dbi.h
> index 8c4ea7956d61d..36ac8495566b0 100644
> --- a/include/drm/drm_mipi_dbi.h
> +++ b/include/drm/drm_mipi_dbi.h
> @@ -13,9 +13,10 @@
>  #include <drm/drm_simple_kms_helper.h>
>  
>  struct drm_rect;
> -struct spi_device;
>  struct gpio_desc;
> +struct iosys_map;
>  struct regulator;
> +struct spi_device;
>  
>  /**
>   * struct mipi_dbi - MIPI DBI interface
> @@ -176,8 +177,9 @@ int mipi_dbi_command_read(struct mipi_dbi *dbi, u8 cmd, u8 *val);
>  int mipi_dbi_command_buf(struct mipi_dbi *dbi, u8 cmd, u8 *data, size_t len);
>  int mipi_dbi_command_stackbuf(struct mipi_dbi *dbi, u8 cmd, const u8 *data,
>  			      size_t len);
> -int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
> +int mipi_dbi_buf_copy(void *dst, struct iosys_map *src, struct drm_framebuffer *fb,
>  		      struct drm_rect *clip, bool swap);
> +
>  /**
>   * mipi_dbi_command - MIPI DCS command with optional parameter(s)
>   * @dbi: MIPI DBI structure


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