~lkcamp/patches

Add new formats support to vkms v4 PROPOSED

Summary
=======
This series of patches refactor some vkms components in order to introduce
new formats to the planes and writeback connector.

Now in the blend function, the plane's pixels are converted to ARGB16161616
and then blended together.

The CRC is calculated based on the ARGB1616161616 buffer. And if required,
this buffer is copied/converted to the writeback buffer format.

And to handle the pixel conversion, new functions were added to convert
from a specific format to ARGB16161616 (the reciprocal is also true).

Tests
=====
This patch series was tested using the following igt tests:
-t ".*kms_plane.*"
-t ".*kms_writeback.*"
-t ".*kms_cursor_crc*"
-t ".*kms_flip.*"

New tests passing
-------------------
- pipe-A-cursor-size-change
- pipe-A-cursor-alpha-transparent

Performance
-----------
Further optimizing the code, now it's running slightly faster than the V2.
And it consumes less memory than the current implementation in the common case
(more detail in the commit message).

Results running the IGT tests `kms_cursor_crc`:

|                             Frametime                                 |
|:---------------:|:---------:|:--------------:|:------------:|:-------:|
|  implmentation  |  Current  |  Per-pixel(V1) | Per-line(V2) |   V3    |
| frametime range |  8~22 ms  |    32~56 ms    |    6~19 ms   | 5~18 ms |
|     Average     |  10.0 ms  |     35.8 ms    |    8.6 ms    |  7.3 ms |

| Memory consumption (output dimensions) |
|:--------------------------------------:|
|       Current      |     This patch    |
|:------------------:|:-----------------:|
|   Width * Heigth   |     2 * Width     |

XRGB to ARGB behavior
=====================
During the development, I decided to always fill the alpha channel of
the output pixel whenever the conversion from a format without an alpha
channel to ARGB16161616 is necessary. Therefore, I ignore the value
received from the XRGB and overwrite the value with 0xFFFF.

---
Igor Torrente (9):
  drm: vkms: Replace the deprecated drm_mode_config_init
  drm: vkms: Alloc the compose frame using vzalloc
  drm: vkms: Replace hardcoded value of `vkms_composer.map` to
    DRM_FORMAT_MAX_PLANES
  drm: vkms: Rename `vkms_composer` to `vkms_frame_info`
  drm: vkms: Add fb information to `vkms_writeback_job`
  drm: drm_atomic_helper: Add a new helper to deal with the writeback
    connector validation
  drm: vkms: Refactor the plane composer to accept new formats
  drm: vkms: Adds XRGB_16161616 and ARGB_1616161616 formats
  drm: vkms: Add support to the RGB565 format

 drivers/gpu/drm/drm_atomic_helper.c   |  39 +++
 drivers/gpu/drm/vkms/Makefile         |   1 +
 drivers/gpu/drm/vkms/vkms_composer.c  | 336 +++++++++++++-------------
 drivers/gpu/drm/vkms/vkms_drv.c       |   6 +-
 drivers/gpu/drm/vkms/vkms_drv.h       |  20 +-
 drivers/gpu/drm/vkms/vkms_formats.c   | 279 +++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_formats.h   |  49 ++++
 drivers/gpu/drm/vkms/vkms_plane.c     |  47 ++--
 drivers/gpu/drm/vkms/vkms_writeback.c |  32 ++-
 include/drm/drm_atomic_helper.h       |   3 +
 10 files changed, 600 insertions(+), 212 deletions(-)
 create mode 100644 drivers/gpu/drm/vkms/vkms_formats.c
 create mode 100644 drivers/gpu/drm/vkms/vkms_formats.h

-- 
2.30.2
On Fri, 21 Jan 2022 18:38:29 -0300
Igor Torrente <igormtorrente@gmail.com> wrote:
Next
Why round-up rather than the usual mathematical rounding?
Next
Here you would check that you don't overrun any of the arrays. At this
point, I believe an overrun would indicate a bug in VKMS, so handle it
according to the kernel conventions. I have suggestion further below
how to make that check possible. In other places, I'll just say "check
for overruns" for short.
Next
Is it not *from* each plane?

Each plane... does this mean that all planes must have the same pixel
format?

Oh wait, it's a pointer, so an array, isn't it? You're passing in an
array without passing in the array size. That seems quite risky to me.
Think of someone else needing to patch something here without fully
understanding how this all works, they'd easily introduce a subtle bug.

Looks like the array must be number of "active planes" long. So it's
not even a constant, and the size of the array is not documented here.

What if the fmt_func was a field in struct vkms_frame_info? So you
could set it when creating a vkms_frame_info. Wouldn't that simplify
the code in blend() and its callers?
Next
Mm, you only need to clear output_buffer, not the whole writeback FB.
output_buffer will unconditionally and totally overwrite the writeback
FB, right?
Next
Using "wb" as short for writeback is... well, it's hard for the me
remember at least. Could this not be named simply "writeback"?
Next
Shouldn't this be called y_dst instead?
Next
It took me a while to understand that all these y-coordinates are CRTC
coordinates. Maybe call them crtc_y, crtc_y_begin, crtc_y_end,
crtc_y_height, etc.
Next
That's interesting. Looks like you reject everything if any plane is
not fully inside the primary plane destination rectangle. But that's
not the right check, is it? If you want to check this, you would check
against the CRTC dimensions.

Then again, I think some hardware do allow planes to reach outside of
the CRTC dimensions. Cursor plane is probably the best example. The
cursor can be partly off-screen. So this is something that would need
to be supported both ways I suppose, but going with the "all plane
destination rectangles must be strictly inside the CRTC dimensions" is
a good start.

But why only x-coordinate check? y should have the same rules, right?
Next
This needs to be CRTC width, not primary plane width.
Next
In functions like this you should prepare for caller errors. Use a
switch, and fail any attempt to use a pixel format it doesn't support.
Failing is much better than silently producing garbage or worse: buffer
overruns when bytes-per-pixel is not what you expected.

What to do on failure depends on whether the failure here is never
supposed to happen (follow the kernel style) e.g. malicious userspace
cannot trigger it, or if you actually use this function to define the
supported for pixel formats.

The latter means you'd have a list of all DRM pixel formats and then
you'd ask for each one if this function knows it, and if yes, you add
the format to the list of supported formats advertised to userspace. I
don't know if that would be fine by DRM coding style.
Next
Good work!


Thanks,
pq
Next
On Fri, 21 Jan 2022 18:38:31 -0300
Igor Torrente <igormtorrente@gmail.com> wrote:
Next
Hi Melissa,
Next
hmm.. is it happening when running kms_cursor_crc? Is the results
variation random or is it possible to follow a set of steps to reproduce
it? When failing, what is the reason displayed by the log?

From my side, only the first two subtest of kms_cursor_crc is passing
before this patch. And after your changes here, all subtests are
successful again, except those related to 32x10 cursor size (that needs
futher investigation). I didn't check how the recent changes in
kms_cursor_crc affect VKMS performance on it, but I bet that clearing
the alpha channel is the reason to have the performance back.


Ok, previously checkpatch was complaining only for `vkms_format.c` but
not for the header. I got it wrong when I pointed to the .h file too,
sorry. I had two points in mind, but the second issue is not here, it is
`multiple blank lines` in the next patch.

btw, you find more details about the comment style for SPDX here:
https://www.kernel.org/doc/html/latest/process/license-rules.html#license-identifier-syntax
Hi Melissa,
Next
I investigated it a little bit and discovered that the KMS
cursor(".*kms_cursor_crc*" ) are failing after the execution of
writeback tests(".*kms_writeback.*").

I don't know what is causing it, but they are failing while trying to 
commit the KMS changes.

out.txt:
IGT-Version: 1.26-NO-GIT (x86_64) (Linux: 5.17.0-rc2 x86_64)
Stack trace:
   #0 ../lib/igt_core.c:1754 __igt_fail_assert()
   #1 ../lib/igt_kms.c:3795 do_display_commit()
   #2 ../lib/igt_kms.c:3901 igt_display_commit2()
   #3 ../tests/kms_cursor_crc.c:820 __igt_unique____real_main814()
   #4 ../tests/kms_cursor_crc.c:814 main()
   #5 ../csu/libc-start.c:308 __libc_start_main()
   #6 [_start+0x2a]
Subtest pipe-A-cursor-size-change: FAIL

err.txt:
(kms_cursor_crc:1936) igt_kms-CRITICAL: Test assertion failure function 
do_display_commit, file ../lib/igt_kms.c:3795:
(kms_cursor_crc:1936) igt_kms-CRITICAL: Failed assertion: ret == 0
(kms_cursor_crc:1936) igt_kms-CRITICAL: Last errno: 22, Invalid argument
(kms_cursor_crc:1936) igt_kms-CRITICAL: error: -22 != 0
Next
Hi Pekka,
Next
I didn't think about it. But it makes a lot of sense to me.
Next
On Sun, 20 Feb 2022 22:02:12 -0300
Igor Torrente <igormtorrente@gmail.com> wrote:
Next
Hi Pekka,
Next
I don't know the answer to all these questions.

I did try to find the commit that introduces this issue, and I found
that it's happening since the writeback was introduced in Aug
2020(dbd9d80c).

And the failure related to the 32x10 cursor was happening before my
changes.
Next
On Mon, 21 Feb 2022 22:13:21 -0300
Igor Torrente <igormtorrente@gmail.com> wrote:
Next
On Thu, 24 Feb 2022 21:43:01 -0300
Igor Torrente <igormtorrente@gmail.com> wrote:
Next
Oops, I think the format already exists.
Next
Hi Pekka,
Next
Actually, I wasn't trying to argue about anything. Sorry if it sounded
that way.

Also, I had some confusion and I have to correct what I said. The
DIV_ROUND_UP isn't the usual mathematical rounding, it's more
like a round and ceiling.

I don't know why I thought that was the usual rounding.
Next
Apparently, yes.

rcar_du_writeback.c:24:struct rcar_du_wb_conn_state {
rcar_du_writeback.c:29:#define to_rcar_wb_conn_state
rcar_du_writeback.c:219:        struct rcar_du_wb_job *rjob; q1
komeda_wb_connector.c:111:komeda_wb_connector_detect(...)
komeda_wb_connector.c:78:static const struct drm_encoder_helper_funcs
komeda_wb_encoder_helper_funcs = {qq
amdgpu_device.c:1095:static void amdgpu_device_wb_fini(...)
Next
Ok, makes sense.
Next
Ok, got it. I will change it.
Next
Right. I will do it later, As this patch series is already big enough.

Best Regards,
---
Igor Torrente
Next
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[PATCH v4 1/9] drm: vkms: Replace the deprecated drm_mode_config_init Export this patch

`drm_mode_config_init` is deprecated since commit c3b790ea07a1 ("drm: Manage
drm_mode_config_init with drmm_") in favor of `drmm_mode_config_init`. Update
the former to the latter.

Signed-off-by: Igor Torrente <igormtorrente@gmail.com>
---
V2: Change the code style(Thomas Zimmermann).

V4: Update the commit message(Nícolas F. R. A. Prado)
---
 drivers/gpu/drm/vkms/vkms_drv.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index 0ffe5f0e33f7..ee4d96dabe19 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -140,8 +140,12 @@ static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = {
static int vkms_modeset_init(struct vkms_device *vkmsdev)
{
	struct drm_device *dev = &vkmsdev->drm;
	int ret;

	ret = drmm_mode_config_init(dev);
	if (ret < 0)
		return ret;

	drm_mode_config_init(dev);
	dev->mode_config.funcs = &vkms_mode_funcs;
	dev->mode_config.min_width = XRES_MIN;
	dev->mode_config.min_height = YRES_MIN;
-- 
2.30.2

[PATCH v4 2/9] drm: vkms: Alloc the compose frame using vzalloc Export this patch

Currently, the memory to the composition frame is being allocated using
the kzmalloc. This comes with the limitation of maximum size of one
page size(which in the x86_64 is 4Kb and 4MB for default and hugepage
respectively).

Somes test of igt (e.g. kms_plane@pixel-format) uses more than 4MB when
testing some pixel formats like ARGB16161616.
This problem is addessed by allocating the memory using kvzalloc that
circunvents this limitation.
Signed-off-by: Igor Torrente <igormtorrente@gmail.com>
---
 drivers/gpu/drm/vkms/vkms_composer.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
index 9e8204be9a14..82f79e508f81 100644
--- a/drivers/gpu/drm/vkms/vkms_composer.c
+++ b/drivers/gpu/drm/vkms/vkms_composer.c
@@ -180,7 +180,7 @@ static int compose_active_planes(void **vaddr_out,
	int i;

	if (!*vaddr_out) {
		*vaddr_out = kzalloc(gem_obj->size, GFP_KERNEL);
		*vaddr_out = kvzalloc(gem_obj->size, GFP_KERNEL);
		if (!*vaddr_out) {
			DRM_ERROR("Cannot allocate memory for output frame.");
			return -ENOMEM;
@@ -263,7 +263,7 @@ void vkms_composer_worker(struct work_struct *work)
				    crtc_state);
	if (ret) {
		if (ret == -EINVAL && !wb_pending)
			kfree(vaddr_out);
			kvfree(vaddr_out);
		return;
	}

@@ -275,7 +275,7 @@ void vkms_composer_worker(struct work_struct *work)
		crtc_state->wb_pending = false;
		spin_unlock_irq(&out->composer_lock);
	} else {
		kfree(vaddr_out);
		kvfree(vaddr_out);
	}

	/*
-- 
2.30.2

[PATCH v4 3/9] drm: vkms: Replace hardcoded value of `vkms_composer.map` to DRM_FORMAT_MAX_PLANES Export this patch

The `map` vector at `vkms_composer` uses a hardcoded value to define its
size.

If someday the maximum number of planes increases, this hardcoded value
can be a problem.

This value is being replaced with the DRM_FORMAT_MAX_PLANES macro.

Signed-off-by: Igor Torrente <igormtorrente@gmail.com>
---
 drivers/gpu/drm/vkms/vkms_drv.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index 9496fdc900b8..0eeea6f93733 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -30,7 +30,7 @@ struct vkms_writeback_job {
struct vkms_composer {
	struct drm_framebuffer fb;
	struct drm_rect src, dst;
	struct dma_buf_map map[4];
	struct dma_buf_map map[DRM_FORMAT_MAX_PLANES];
	unsigned int offset;
	unsigned int pitch;
	unsigned int cpp;
-- 
2.30.2

[PATCH v4 4/9] drm: vkms: Rename `vkms_composer` to `vkms_frame_info` Export this patch

Changes the name of this struct to a more meaningful name.
A name that represents better what this struct is about.

Composer is the code that do the compositing of the planes.
This struct is contains information of the frame that is
being used in the output composition. Thus, vkms_frame_info
is a better name to represent this.
Signed-off-by: Igor Torrente <igormtorrente@gmail.com>
---
 drivers/gpu/drm/vkms/vkms_composer.c | 87 ++++++++++++++--------------
 drivers/gpu/drm/vkms/vkms_drv.h      |  6 +-
 drivers/gpu/drm/vkms/vkms_plane.c    | 38 ++++++------
 3 files changed, 66 insertions(+), 65 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
index 82f79e508f81..2d946368a561 100644
--- a/drivers/gpu/drm/vkms/vkms_composer.c
+++ b/drivers/gpu/drm/vkms/vkms_composer.c
@@ -11,11 +11,11 @@
#include "vkms_drv.h"

static u32 get_pixel_from_buffer(int x, int y, const u8 *buffer,
				 const struct vkms_composer *composer)
				 const struct vkms_frame_info *frame_info)
{
	u32 pixel;
	int src_offset = composer->offset + (y * composer->pitch)
				      + (x * composer->cpp);
	int src_offset = frame_info->offset + (y * frame_info->pitch)
					    + (x * frame_info->cpp);

	pixel = *(u32 *)&buffer[src_offset];

@@ -26,24 +26,24 @@ static u32 get_pixel_from_buffer(int x, int y, const u8 *buffer,
 * compute_crc - Compute CRC value on output frame
 *
 * @vaddr: address to final framebuffer
 * @composer: framebuffer's metadata
 * @frame_info: framebuffer's metadata
 *
 * returns CRC value computed using crc32 on the visible portion of
 * the final framebuffer at vaddr_out
 */
static uint32_t compute_crc(const u8 *vaddr,
			    const struct vkms_composer *composer)
			    const struct vkms_frame_info *frame_info)
{
	int x, y;
	u32 crc = 0, pixel = 0;
	int x_src = composer->src.x1 >> 16;
	int y_src = composer->src.y1 >> 16;
	int h_src = drm_rect_height(&composer->src) >> 16;
	int w_src = drm_rect_width(&composer->src) >> 16;
	int x_src = frame_info->src.x1 >> 16;
	int y_src = frame_info->src.y1 >> 16;
	int h_src = drm_rect_height(&frame_info->src) >> 16;
	int w_src = drm_rect_width(&frame_info->src) >> 16;

	for (y = y_src; y < y_src + h_src; ++y) {
		for (x = x_src; x < x_src + w_src; ++x) {
			pixel = get_pixel_from_buffer(x, y, vaddr, composer);
			pixel = get_pixel_from_buffer(x, y, vaddr, frame_info);
			crc = crc32_le(crc, (void *)&pixel, sizeof(u32));
		}
	}
@@ -98,8 +98,8 @@ static void x_blend(const u8 *xrgb_src, u8 *xrgb_dst)
 * blend - blend value at vaddr_src with value at vaddr_dst
 * @vaddr_dst: destination address
 * @vaddr_src: source address
 * @dst_composer: destination framebuffer's metadata
 * @src_composer: source framebuffer's metadata
 * @dst_frame_info: destination framebuffer's metadata
 * @src_frame_info: source framebuffer's metadata
 * @pixel_blend: blending equation based on plane format
 *
 * Blend the vaddr_src value with the vaddr_dst value using a pixel blend
@@ -111,33 +111,33 @@ static void x_blend(const u8 *xrgb_src, u8 *xrgb_dst)
 * pixel color values
 */
static void blend(void *vaddr_dst, void *vaddr_src,
		  struct vkms_composer *dst_composer,
		  struct vkms_composer *src_composer,
		  struct vkms_frame_info *dst_frame_info,
		  struct vkms_frame_info *src_frame_info,
		  void (*pixel_blend)(const u8 *, u8 *))
{
	int i, j, j_dst, i_dst;
	int offset_src, offset_dst;
	u8 *pixel_dst, *pixel_src;

	int x_src = src_composer->src.x1 >> 16;
	int y_src = src_composer->src.y1 >> 16;
	int x_src = src_frame_info->src.x1 >> 16;
	int y_src = src_frame_info->src.y1 >> 16;

	int x_dst = src_composer->dst.x1;
	int y_dst = src_composer->dst.y1;
	int h_dst = drm_rect_height(&src_composer->dst);
	int w_dst = drm_rect_width(&src_composer->dst);
	int x_dst = src_frame_info->dst.x1;
	int y_dst = src_frame_info->dst.y1;
	int h_dst = drm_rect_height(&src_frame_info->dst);
	int w_dst = drm_rect_width(&src_frame_info->dst);

	int y_limit = y_src + h_dst;
	int x_limit = x_src + w_dst;

	for (i = y_src, i_dst = y_dst; i < y_limit; ++i) {
		for (j = x_src, j_dst = x_dst; j < x_limit; ++j) {
			offset_dst = dst_composer->offset
				     + (i_dst * dst_composer->pitch)
				     + (j_dst++ * dst_composer->cpp);
			offset_src = src_composer->offset
				     + (i * src_composer->pitch)
				     + (j * src_composer->cpp);
			offset_dst = dst_frame_info->offset
				     + (i_dst * dst_frame_info->pitch)
				     + (j_dst++ * dst_frame_info->cpp);
			offset_src = src_frame_info->offset
				     + (i * src_frame_info->pitch)
				     + (j * src_frame_info->cpp);

			pixel_src = (u8 *)(vaddr_src + offset_src);
			pixel_dst = (u8 *)(vaddr_dst + offset_dst);
@@ -149,32 +149,33 @@ static void blend(void *vaddr_dst, void *vaddr_src,
	}
}

static void compose_plane(struct vkms_composer *primary_composer,
			  struct vkms_composer *plane_composer,
static void compose_plane(struct vkms_frame_info *primary_plane_info,
			  struct vkms_frame_info *plane_frame_info,
			  void *vaddr_out)
{
	struct drm_framebuffer *fb = &plane_composer->fb;
	struct drm_framebuffer *fb = &plane_frame_info->fb;
	void *vaddr;
	void (*pixel_blend)(const u8 *p_src, u8 *p_dst);

	if (WARN_ON(dma_buf_map_is_null(&primary_composer->map[0])))
	if (WARN_ON(dma_buf_map_is_null(&primary_plane_info->map[0])))
		return;

	vaddr = plane_composer->map[0].vaddr;
	vaddr = plane_frame_info->map[0].vaddr;

	if (fb->format->format == DRM_FORMAT_ARGB8888)
		pixel_blend = &alpha_blend;
	else
		pixel_blend = &x_blend;

	blend(vaddr_out, vaddr, primary_composer, plane_composer, pixel_blend);
	blend(vaddr_out, vaddr, primary_plane_info,
	      plane_frame_info, pixel_blend);
}

static int compose_active_planes(void **vaddr_out,
				 struct vkms_composer *primary_composer,
				 struct vkms_frame_info *primary_plane_info,
				 struct vkms_crtc_state *crtc_state)
{
	struct drm_framebuffer *fb = &primary_composer->fb;
	struct drm_framebuffer *fb = &primary_plane_info->fb;
	struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
	const void *vaddr;
	int i;
@@ -187,10 +188,10 @@ static int compose_active_planes(void **vaddr_out,
		}
	}

	if (WARN_ON(dma_buf_map_is_null(&primary_composer->map[0])))
	if (WARN_ON(dma_buf_map_is_null(&primary_plane_info->map[0])))
		return -EINVAL;

	vaddr = primary_composer->map[0].vaddr;
	vaddr = primary_plane_info->map[0].vaddr;

	memcpy(*vaddr_out, vaddr, gem_obj->size);

@@ -199,8 +200,8 @@ static int compose_active_planes(void **vaddr_out,
	 * ((primary <- overlay) <- cursor)
	 */
	for (i = 1; i < crtc_state->num_active_planes; i++)
		compose_plane(primary_composer,
			      crtc_state->active_planes[i]->composer,
		compose_plane(primary_plane_info,
			      crtc_state->active_planes[i]->frame_info,
			      *vaddr_out);

	return 0;
@@ -222,7 +223,7 @@ void vkms_composer_worker(struct work_struct *work)
						composer_work);
	struct drm_crtc *crtc = crtc_state->base.crtc;
	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
	struct vkms_composer *primary_composer = NULL;
	struct vkms_frame_info *primary_plane_info = NULL;
	struct vkms_plane_state *act_plane = NULL;
	bool crc_pending, wb_pending;
	void *vaddr_out = NULL;
@@ -250,16 +251,16 @@ void vkms_composer_worker(struct work_struct *work)
	if (crtc_state->num_active_planes >= 1) {
		act_plane = crtc_state->active_planes[0];
		if (act_plane->base.base.plane->type == DRM_PLANE_TYPE_PRIMARY)
			primary_composer = act_plane->composer;
			primary_plane_info = act_plane->frame_info;
	}

	if (!primary_composer)
	if (!primary_plane_info)
		return;

	if (wb_pending)
		vaddr_out = crtc_state->active_writeback->data[0].vaddr;

	ret = compose_active_planes(&vaddr_out, primary_composer,
	ret = compose_active_planes(&vaddr_out, primary_plane_info,
				    crtc_state);
	if (ret) {
		if (ret == -EINVAL && !wb_pending)
@@ -267,7 +268,7 @@ void vkms_composer_worker(struct work_struct *work)
		return;
	}

	crc32 = compute_crc(vaddr_out, primary_composer);
	crc32 = compute_crc(vaddr_out, primary_plane_info);

	if (wb_pending) {
		drm_writeback_signal_completion(&out->wb_connector, 0);
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index 0eeea6f93733..2e6342164bef 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -27,7 +27,7 @@ struct vkms_writeback_job {
	struct dma_buf_map data[DRM_FORMAT_MAX_PLANES];
};

struct vkms_composer {
struct vkms_frame_info {
	struct drm_framebuffer fb;
	struct drm_rect src, dst;
	struct dma_buf_map map[DRM_FORMAT_MAX_PLANES];
@@ -39,11 +39,11 @@ struct vkms_composer {
/**
 * vkms_plane_state - Driver specific plane state
 * @base: base plane state
 * @composer: data required for composing computation
 * @frame_info: data required for composing computation
 */
struct vkms_plane_state {
	struct drm_shadow_plane_state base;
	struct vkms_composer *composer;
	struct vkms_frame_info *frame_info;
};

struct vkms_plane {
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index 32409e15244b..a56b0f76eddd 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -24,20 +24,20 @@ static struct drm_plane_state *
vkms_plane_duplicate_state(struct drm_plane *plane)
{
	struct vkms_plane_state *vkms_state;
	struct vkms_composer *composer;
	struct vkms_frame_info *frame_info;

	vkms_state = kzalloc(sizeof(*vkms_state), GFP_KERNEL);
	if (!vkms_state)
		return NULL;

	composer = kzalloc(sizeof(*composer), GFP_KERNEL);
	if (!composer) {
		DRM_DEBUG_KMS("Couldn't allocate composer\n");
	frame_info = kzalloc(sizeof(*frame_info), GFP_KERNEL);
	if (!frame_info) {
		DRM_DEBUG_KMS("Couldn't allocate frame_info\n");
		kfree(vkms_state);
		return NULL;
	}

	vkms_state->composer = composer;
	vkms_state->frame_info = frame_info;

	__drm_gem_duplicate_shadow_plane_state(plane, &vkms_state->base);

@@ -54,12 +54,12 @@ static void vkms_plane_destroy_state(struct drm_plane *plane,
		/* dropping the reference we acquired in
		 * vkms_primary_plane_update()
		 */
		if (drm_framebuffer_read_refcount(&vkms_state->composer->fb))
			drm_framebuffer_put(&vkms_state->composer->fb);
		if (drm_framebuffer_read_refcount(&vkms_state->frame_info->fb))
			drm_framebuffer_put(&vkms_state->frame_info->fb);
	}

	kfree(vkms_state->composer);
	vkms_state->composer = NULL;
	kfree(vkms_state->frame_info);
	vkms_state->frame_info = NULL;

	__drm_gem_destroy_shadow_plane_state(&vkms_state->base);
	kfree(vkms_state);
@@ -99,7 +99,7 @@ static void vkms_plane_atomic_update(struct drm_plane *plane,
	struct vkms_plane_state *vkms_plane_state;
	struct drm_shadow_plane_state *shadow_plane_state;
	struct drm_framebuffer *fb = new_state->fb;
	struct vkms_composer *composer;
	struct vkms_frame_info *frame_info;

	if (!new_state->crtc || !fb)
		return;
@@ -107,15 +107,15 @@ static void vkms_plane_atomic_update(struct drm_plane *plane,
	vkms_plane_state = to_vkms_plane_state(new_state);
	shadow_plane_state = &vkms_plane_state->base;

	composer = vkms_plane_state->composer;
	memcpy(&composer->src, &new_state->src, sizeof(struct drm_rect));
	memcpy(&composer->dst, &new_state->dst, sizeof(struct drm_rect));
	memcpy(&composer->fb, fb, sizeof(struct drm_framebuffer));
	memcpy(&composer->map, &shadow_plane_state->data, sizeof(composer->map));
	drm_framebuffer_get(&composer->fb);
	composer->offset = fb->offsets[0];
	composer->pitch = fb->pitches[0];
	composer->cpp = fb->format->cpp[0];
	frame_info = vkms_plane_state->frame_info;
	memcpy(&frame_info->src, &new_state->src, sizeof(struct drm_rect));
	memcpy(&frame_info->dst, &new_state->dst, sizeof(struct drm_rect));
	memcpy(&frame_info->fb, fb, sizeof(struct drm_framebuffer));
	memcpy(&frame_info->map, &shadow_plane_state->data, sizeof(frame_info->map));
	drm_framebuffer_get(&frame_info->fb);
	frame_info->offset = fb->offsets[0];
	frame_info->pitch = fb->pitches[0];
	frame_info->cpp = fb->format->cpp[0];
}

static int vkms_plane_atomic_check(struct drm_plane *plane,
-- 
2.30.2

[PATCH v4 5/9] drm: vkms: Add fb information to `vkms_writeback_job` Export this patch

This commit is the groundwork to introduce new formats to the planes and
writeback buffer. As part of it, a new buffer metadata field is added to
`vkms_writeback_job`, this metadata is represented by the `vkms_composer`
struct.

This will allow us, in the future, to have different compositing and wb
format types.
Signed-off-by: Igor Torrente <igormtorrente@gmail.com>
---
V2: Change the code to get the drm_framebuffer reference and not copy its
    contents(Thomas Zimmermann).

V3: Drop the refcount in the wb code(Thomas Zimmermann).
---
 drivers/gpu/drm/vkms/vkms_composer.c  |  4 ++--
 drivers/gpu/drm/vkms/vkms_drv.h       | 12 ++++++------
 drivers/gpu/drm/vkms/vkms_plane.c     | 10 +++++-----
 drivers/gpu/drm/vkms/vkms_writeback.c | 20 +++++++++++++++++---
 4 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
index 2d946368a561..95029d2ebcac 100644
--- a/drivers/gpu/drm/vkms/vkms_composer.c
+++ b/drivers/gpu/drm/vkms/vkms_composer.c
@@ -153,7 +153,7 @@ static void compose_plane(struct vkms_frame_info *primary_plane_info,
			  struct vkms_frame_info *plane_frame_info,
			  void *vaddr_out)
{
	struct drm_framebuffer *fb = &plane_frame_info->fb;
	struct drm_framebuffer *fb = plane_frame_info->fb;
	void *vaddr;
	void (*pixel_blend)(const u8 *p_src, u8 *p_dst);

@@ -175,7 +175,7 @@ static int compose_active_planes(void **vaddr_out,
				 struct vkms_frame_info *primary_plane_info,
				 struct vkms_crtc_state *crtc_state)
{
	struct drm_framebuffer *fb = &primary_plane_info->fb;
	struct drm_framebuffer *fb = primary_plane_info->fb;
	struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
	const void *vaddr;
	int i;
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index 2e6342164bef..c850d755247c 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -22,13 +22,8 @@

#define NUM_OVERLAY_PLANES 8

struct vkms_writeback_job {
	struct dma_buf_map map[DRM_FORMAT_MAX_PLANES];
	struct dma_buf_map data[DRM_FORMAT_MAX_PLANES];
};

struct vkms_frame_info {
	struct drm_framebuffer fb;
	struct drm_framebuffer *fb;
	struct drm_rect src, dst;
	struct dma_buf_map map[DRM_FORMAT_MAX_PLANES];
	unsigned int offset;
@@ -36,6 +31,11 @@ struct vkms_frame_info {
	unsigned int cpp;
};

struct vkms_writeback_job {
	struct dma_buf_map data[DRM_FORMAT_MAX_PLANES];
	struct vkms_frame_info frame_info;
};

/**
 * vkms_plane_state - Driver specific plane state
 * @base: base plane state
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index a56b0f76eddd..28752af0118c 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -50,12 +50,12 @@ static void vkms_plane_destroy_state(struct drm_plane *plane,
	struct vkms_plane_state *vkms_state = to_vkms_plane_state(old_state);
	struct drm_crtc *crtc = vkms_state->base.base.crtc;

	if (crtc) {
	if (crtc && vkms_state->frame_info->fb) {
		/* dropping the reference we acquired in
		 * vkms_primary_plane_update()
		 */
		if (drm_framebuffer_read_refcount(&vkms_state->frame_info->fb))
			drm_framebuffer_put(&vkms_state->frame_info->fb);
		if (drm_framebuffer_read_refcount(vkms_state->frame_info->fb))
			drm_framebuffer_put(vkms_state->frame_info->fb);
	}

	kfree(vkms_state->frame_info);
@@ -110,9 +110,9 @@ static void vkms_plane_atomic_update(struct drm_plane *plane,
	frame_info = vkms_plane_state->frame_info;
	memcpy(&frame_info->src, &new_state->src, sizeof(struct drm_rect));
	memcpy(&frame_info->dst, &new_state->dst, sizeof(struct drm_rect));
	memcpy(&frame_info->fb, fb, sizeof(struct drm_framebuffer));
	frame_info->fb = fb;
	memcpy(&frame_info->map, &shadow_plane_state->data, sizeof(frame_info->map));
	drm_framebuffer_get(&frame_info->fb);
	drm_framebuffer_get(frame_info->fb);
	frame_info->offset = fb->offsets[0];
	frame_info->pitch = fb->pitches[0];
	frame_info->cpp = fb->format->cpp[0];
diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c b/drivers/gpu/drm/vkms/vkms_writeback.c
index 8694227f555f..de379331b236 100644
--- a/drivers/gpu/drm/vkms/vkms_writeback.c
+++ b/drivers/gpu/drm/vkms/vkms_writeback.c
@@ -75,12 +75,15 @@ static int vkms_wb_prepare_job(struct drm_writeback_connector *wb_connector,
	if (!vkmsjob)
		return -ENOMEM;

	ret = drm_gem_fb_vmap(job->fb, vkmsjob->map, vkmsjob->data);
	ret = drm_gem_fb_vmap(job->fb, vkmsjob->frame_info.map, vkmsjob->data);
	if (ret) {
		DRM_ERROR("vmap failed: %d\n", ret);
		goto err_kfree;
	}

	vkmsjob->frame_info.fb = job->fb;
	drm_framebuffer_get(vkmsjob->frame_info.fb);

	job->priv = vkmsjob;

	return 0;
@@ -99,7 +102,9 @@ static void vkms_wb_cleanup_job(struct drm_writeback_connector *connector,
	if (!job->fb)
		return;

	drm_gem_fb_vunmap(job->fb, vkmsjob->map);
	drm_gem_fb_vunmap(job->fb, vkmsjob->frame_info.map);

	drm_framebuffer_put(vkmsjob->frame_info.fb);

	vkmsdev = drm_device_to_vkms_device(job->fb->dev);
	vkms_set_composer(&vkmsdev->output, false);
@@ -116,14 +121,23 @@ static void vkms_wb_atomic_commit(struct drm_connector *conn,
	struct drm_writeback_connector *wb_conn = &output->wb_connector;
	struct drm_connector_state *conn_state = wb_conn->base.state;
	struct vkms_crtc_state *crtc_state = output->composer_state;
	struct drm_framebuffer *fb = connector_state->writeback_job->fb;
	struct vkms_writeback_job *active_wb;
	struct vkms_frame_info *wb_frame_info;

	if (!conn_state)
		return;

	vkms_set_composer(&vkmsdev->output, true);

	active_wb = conn_state->writeback_job->priv;
	wb_frame_info = &active_wb->frame_info;

	spin_lock_irq(&output->composer_lock);
	crtc_state->active_writeback = conn_state->writeback_job->priv;
	crtc_state->active_writeback = active_wb;
	wb_frame_info->offset = fb->offsets[0];
	wb_frame_info->pitch = fb->pitches[0];
	wb_frame_info->cpp = fb->format->cpp[0];
	crtc_state->wb_pending = true;
	spin_unlock_irq(&output->composer_lock);
	drm_writeback_queue_job(wb_conn, connector_state);
-- 
2.30.2

[PATCH v4 6/9] drm: drm_atomic_helper: Add a new helper to deal with the writeback connector validation Export this patch

Add a helper function to validate the connector configuration receive in
the encoder atomic_check by the drivers.

So the drivers don't need do these common validations themselves.

Signed-off-by: Igor Torrente <igormtorrente@gmail.com>
---
V2: Move the format verification to a new helper at the drm_atomic_helper.c
    (Thomas Zimmermann).

V3: Format check improvements (Leandro Ribeiro).
    Minor improvements(Thomas Zimmermann).
---
 drivers/gpu/drm/drm_atomic_helper.c   | 39 +++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_writeback.c |  9 +++----
 include/drm/drm_atomic_helper.h       |  3 +++
 3 files changed, 46 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index a7a05e1e26bb..ccb6e62bf80a 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -776,6 +776,45 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
}
EXPORT_SYMBOL(drm_atomic_helper_check_modeset);

/**
 * drm_atomic_helper_check_wb_connector_state() - Check writeback encoder state
 * @encoder: encoder state to check
 * @conn_state: connector state to check
 *
 * Checks if the writeback connector state is valid, and returns an error if it
 * isn't.
 *
 * RETURNS:
 * Zero for success or -errno
 */
int
drm_atomic_helper_check_wb_encoder_state(struct drm_encoder *encoder,
					 struct drm_connector_state *conn_state)
{
	struct drm_writeback_job *wb_job = conn_state->writeback_job;
	struct drm_property_blob *pixel_format_blob;
	struct drm_framebuffer *fb;
	size_t i, nformats;
	u32 *formats;

	if (!wb_job || !wb_job->fb)
		return 0;

	pixel_format_blob = wb_job->connector->pixel_formats_blob_ptr;
	nformats = pixel_format_blob->length / sizeof(u32);
	formats = pixel_format_blob->data;
	fb = wb_job->fb;

	for (i = 0; i < nformats; i++)
		if (fb->format->format == formats[i])
			return 0;

	drm_dbg_kms(encoder->dev, "Invalid pixel format %p4cc\n", &fb->format->format);

	return -EINVAL;
}
EXPORT_SYMBOL(drm_atomic_helper_check_wb_encoder_state);

/**
 * drm_atomic_helper_check_plane_state() - Check plane state for validity
 * @plane_state: plane state to check
diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c b/drivers/gpu/drm/vkms/vkms_writeback.c
index de379331b236..ad4bb1fb37ca 100644
--- a/drivers/gpu/drm/vkms/vkms_writeback.c
+++ b/drivers/gpu/drm/vkms/vkms_writeback.c
@@ -30,6 +30,7 @@ static int vkms_wb_encoder_atomic_check(struct drm_encoder *encoder,
{
	struct drm_framebuffer *fb;
	const struct drm_display_mode *mode = &crtc_state->mode;
	int ret;

	if (!conn_state->writeback_job || !conn_state->writeback_job->fb)
		return 0;
@@ -41,11 +42,9 @@ static int vkms_wb_encoder_atomic_check(struct drm_encoder *encoder,
		return -EINVAL;
	}

	if (fb->format->format != vkms_wb_formats[0]) {
		DRM_DEBUG_KMS("Invalid pixel format %p4cc\n",
			      &fb->format->format);
		return -EINVAL;
	}
	ret = drm_atomic_helper_check_wb_encoder_state(encoder, conn_state);
	if (ret < 0)
		return ret;

	return 0;
}
diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
index 4045e2507e11..3fbf695da60f 100644
--- a/include/drm/drm_atomic_helper.h
+++ b/include/drm/drm_atomic_helper.h
@@ -40,6 +40,9 @@ struct drm_private_state;

int drm_atomic_helper_check_modeset(struct drm_device *dev,
				struct drm_atomic_state *state);
int
drm_atomic_helper_check_wb_encoder_state(struct drm_encoder *encoder,
					 struct drm_connector_state *conn_state);
int drm_atomic_helper_check_plane_state(struct drm_plane_state *plane_state,
					const struct drm_crtc_state *crtc_state,
					int min_scale,
-- 
2.30.2

[PATCH v4 7/9] drm: vkms: Refactor the plane composer to accept new formats Export this patch

Currently the blend function only accepts XRGB_8888 and ARGB_8888
as a color input.

This patch refactors all the functions related to the plane composition
to overcome this limitation.

A new internal format(`struct pixel`) is introduced to deal with all
possible inputs. It consists of 16 bits fields that represent each of
the channels.

The pixels blend is done using this internal format. And new handlers
are being added to convert a specific format to/from this internal format.

So the blend operation depends on these handlers to convert to this common
format. The blended result, if necessary, is converted to the writeback
buffer format.

This patch introduces three major differences to the blend function.
1 - All the planes are blended at once.
2 - The blend calculus is done as per line instead of per pixel.
3 - It is responsible to calculates the CRC and writing the writeback
    buffer(if necessary).

These changes allow us to allocate way less memory in the intermediate
buffer to compute these operations. Because now we don't need to
have the entire intermediate image lines at once, just one line is
enough.

| Memory consumption (output dimensions) |
|:--------------------------------------:|
|       Current      |     This patch    |
|:------------------:|:-----------------:|
|   Width * Heigth   |     2 * Width     |

Beyond memory, we also have a minor performance benefit from all
these changes. Results running the IGT tests `*kms_cursor_crc*`:
|                 Frametime                  |
|:------------------------------------------:|
|  Implementation |  Current  |  This commit |
|:---------------:|:---------:|:------------:|
| frametime range |  8~22 ms  |    5~18 ms   |
|     Average     |  10.0 ms  |    7.3 ms    |

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Igor Torrente <igormtorrente@gmail.com>
---
V2: Improves the performance drastically, by perfoming the operations
    per-line and not per-pixel(Pekka Paalanen).
    Minor improvements(Pekka Paalanen).

V3: Changes the code to blend the planes all at once. This improves
    performance, memory consumption, and removes much of the weirdness
    of the V2(Pekka Paalanen and me).
    Minor improvements(Pekka Paalanen and me).

V4: Rebase the code and adapt it to the new NUM_OVERLAY_PLANES constant.
---
 drivers/gpu/drm/vkms/Makefile        |   1 +
 drivers/gpu/drm/vkms/vkms_composer.c | 335 +++++++++++++--------------
 drivers/gpu/drm/vkms/vkms_formats.c  | 138 +++++++++++
 drivers/gpu/drm/vkms/vkms_formats.h  |  31 +++
 4 files changed, 333 insertions(+), 172 deletions(-)
 create mode 100644 drivers/gpu/drm/vkms/vkms_formats.c
 create mode 100644 drivers/gpu/drm/vkms/vkms_formats.h
diff --git a/drivers/gpu/drm/vkms/Makefile b/drivers/gpu/drm/vkms/Makefile
index 72f779cbfedd..1b28a6a32948 100644
--- a/drivers/gpu/drm/vkms/Makefile
+++ b/drivers/gpu/drm/vkms/Makefile
@@ -3,6 +3,7 @@ vkms-y := \
	vkms_drv.o \
	vkms_plane.o \
	vkms_output.o \
	vkms_formats.o \
	vkms_crtc.o \
	vkms_composer.o \
	vkms_writeback.o
diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
index 95029d2ebcac..9f70fcf84fb9 100644
--- a/drivers/gpu/drm/vkms/vkms_composer.c
+++ b/drivers/gpu/drm/vkms/vkms_composer.c
@@ -9,202 +9,210 @@
#include <drm/drm_vblank.h>

#include "vkms_drv.h"
#include "vkms_formats.h"

static u32 get_pixel_from_buffer(int x, int y, const u8 *buffer,
				 const struct vkms_frame_info *frame_info)
static u16 pre_mul_blend_channel(u16 src, u16 dst, u16 alpha)
{
	u32 pixel;
	int src_offset = frame_info->offset + (y * frame_info->pitch)
					    + (x * frame_info->cpp);
	u32 new_color;

	pixel = *(u32 *)&buffer[src_offset];
	new_color = (src * 0xffff + dst * (0xffff - alpha));

	return pixel;
	return DIV_ROUND_UP(new_color, 0xffff);
}

/**
 * compute_crc - Compute CRC value on output frame
 * pre_mul_alpha_blend - alpha blending equation
 * @src_frame_info: source framebuffer's metadata
 * @stage_buffer: The line with the pixels from src_plane
 * @output_buffer: A line buffer that receives all the blends output
 *
 * @vaddr: address to final framebuffer
 * @frame_info: framebuffer's metadata
 * Using the information from the `frame_info`, this blends only the
 * necessary pixels from the `stage_buffer` to the `output_buffer`
 * using premultiplied blend formula.
 *
 * returns CRC value computed using crc32 on the visible portion of
 * the final framebuffer at vaddr_out
 * The current DRM assumption is that pixel color values have been already
 * pre-multiplied with the alpha channel values. See more
 * drm_plane_create_blend_mode_property(). Also, this formula assumes a
 * completely opaque background.
 */
static uint32_t compute_crc(const u8 *vaddr,
			    const struct vkms_frame_info *frame_info)
static void pre_mul_alpha_blend(struct vkms_frame_info *frame_info,
				struct line_buffer *stage_buffer,
				struct line_buffer *output_buffer)
{
	int x, y;
	u32 crc = 0, pixel = 0;
	int x_src = frame_info->src.x1 >> 16;
	int y_src = frame_info->src.y1 >> 16;
	int h_src = drm_rect_height(&frame_info->src) >> 16;
	int w_src = drm_rect_width(&frame_info->src) >> 16;

	for (y = y_src; y < y_src + h_src; ++y) {
		for (x = x_src; x < x_src + w_src; ++x) {
			pixel = get_pixel_from_buffer(x, y, vaddr, frame_info);
			crc = crc32_le(crc, (void *)&pixel, sizeof(u32));
		}
	int x, x_dst = frame_info->dst.x1;
	int x_limit = drm_rect_width(&frame_info->dst);
	struct line_buffer *out = output_buffer + x_dst;
	struct line_buffer *in = stage_buffer;

	for (x = 0; x < x_limit; x++) {
		out[x].a = (u16)0xffff;
		out[x].r = pre_mul_blend_channel(in[x].r, out[x].r, in[x].a);
		out[x].g = pre_mul_blend_channel(in[x].g, out[x].g, in[x].a);
		out[x].b = pre_mul_blend_channel(in[x].b, out[x].b, in[x].a);
	}

	return crc;
}

static u8 blend_channel(u8 src, u8 dst, u8 alpha)
static bool check_y_limit(struct vkms_frame_info *frame_info, int y)
{
	u32 pre_blend;
	u8 new_color;

	pre_blend = (src * 255 + dst * (255 - alpha));

	/* Faster div by 255 */
	new_color = ((pre_blend + ((pre_blend + 257) >> 8)) >> 8);
	if (y >= frame_info->dst.y1 && y < frame_info->dst.y2)
		return true;

	return new_color;
	return false;
}

/**
 * alpha_blend - alpha blending equation
 * @argb_src: src pixel on premultiplied alpha mode
 * @argb_dst: dst pixel completely opaque
 *
 * blend pixels using premultiplied blend formula. The current DRM assumption
 * is that pixel color values have been already pre-multiplied with the alpha
 * channel values. See more drm_plane_create_blend_mode_property(). Also, this
 * formula assumes a completely opaque background.
 */
static void alpha_blend(const u8 *argb_src, u8 *argb_dst)
{
	u8 alpha;

	alpha = argb_src[3];
	argb_dst[0] = blend_channel(argb_src[0], argb_dst[0], alpha);
	argb_dst[1] = blend_channel(argb_src[1], argb_dst[1], alpha);
	argb_dst[2] = blend_channel(argb_src[2], argb_dst[2], alpha);
}

/**
 * x_blend - blending equation that ignores the pixel alpha
 *
 * overwrites RGB color value from src pixel to dst pixel.
 */
static void x_blend(const u8 *xrgb_src, u8 *xrgb_dst)
{
	memcpy(xrgb_dst, xrgb_src, sizeof(u8) * 3);
}

/**
 * blend - blend value at vaddr_src with value at vaddr_dst
 * @vaddr_dst: destination address
 * @vaddr_src: source address
 * @dst_frame_info: destination framebuffer's metadata
 * @src_frame_info: source framebuffer's metadata
 * @pixel_blend: blending equation based on plane format
 * @wb_frame_info: The writeback frame buffer metadata
 * @wb_fmt_func: The format tranformatio function to the wb buffer
 * @crtc_state: The crtc state
 * @plane_fmt_func: A format tranformation function to each plane
 * @crc32: The crc output of the final frame
 * @output_buffer: A buffer of a row that will receive the result of the blend(s)
 * @stage_buffer: The line with the pixels from src_compositor
 *
 * Blend the vaddr_src value with the vaddr_dst value using a pixel blend
 * equation according to the supported plane formats DRM_FORMAT_(A/XRGB8888)
 * and clearing alpha channel to an completely opaque background. This function
 * uses buffer's metadata to locate the new composite values at vaddr_dst.
 * This function blends the pixels (Using the `pre_mul_alpha_blend`)
 * from all planes, calculates the crc32 of the output from the former step,
 * and, if necessary, convert and store the output to the writeback buffer.
 *
 * TODO: completely clear the primary plane (a = 0xff) before starting to blend
 * pixel color values
 */
static void blend(void *vaddr_dst, void *vaddr_src,
		  struct vkms_frame_info *dst_frame_info,
		  struct vkms_frame_info *src_frame_info,
		  void (*pixel_blend)(const u8 *, u8 *))
static void blend(struct vkms_frame_info *wb_frame_info,
		  format_transform_func wb_fmt_func,
		  struct vkms_crtc_state *crtc_state,
		  format_transform_func *plane_fmt_func,
		  u32 *crc32, struct line_buffer *stage_buffer,
		  struct line_buffer *output_buffer, s64 row_size)
{
	int i, j, j_dst, i_dst;
	int offset_src, offset_dst;
	u8 *pixel_dst, *pixel_src;

	int x_src = src_frame_info->src.x1 >> 16;
	int y_src = src_frame_info->src.y1 >> 16;

	int x_dst = src_frame_info->dst.x1;
	int y_dst = src_frame_info->dst.y1;
	int h_dst = drm_rect_height(&src_frame_info->dst);
	int w_dst = drm_rect_width(&src_frame_info->dst);
	struct vkms_plane_state **plane = crtc_state->active_planes;
	struct vkms_frame_info *primary_plane_info = plane[0]->frame_info;
	u32 n_active_planes = crtc_state->num_active_planes;

	int y_src = primary_plane_info->dst.y1;
	int h_dst = drm_rect_height(&primary_plane_info->dst);
	int y_limit = y_src + h_dst;
	int x_limit = x_src + w_dst;

	for (i = y_src, i_dst = y_dst; i < y_limit; ++i) {
		for (j = x_src, j_dst = x_dst; j < x_limit; ++j) {
			offset_dst = dst_frame_info->offset
				     + (i_dst * dst_frame_info->pitch)
				     + (j_dst++ * dst_frame_info->cpp);
			offset_src = src_frame_info->offset
				     + (i * src_frame_info->pitch)
				     + (j * src_frame_info->cpp);

			pixel_src = (u8 *)(vaddr_src + offset_src);
			pixel_dst = (u8 *)(vaddr_dst + offset_dst);
			pixel_blend(pixel_src, pixel_dst);
			/* clearing alpha channel (0xff)*/
			pixel_dst[3] = 0xff;
	int y, i;

	for (y = y_src; y < y_limit; y++) {
		plane_fmt_func[0](primary_plane_info, y, output_buffer);

		/* If there are other planes besides primary, we consider the active
		 * planes should be in z-order and compose them associatively:
		 * ((primary <- overlay) <- cursor)
		 */
		for (i = 1; i < n_active_planes; i++) {
			if (!check_y_limit(plane[i]->frame_info, y))
				continue;

			plane_fmt_func[i](plane[i]->frame_info, y, stage_buffer);
			pre_mul_alpha_blend(plane[i]->frame_info, stage_buffer,
					    output_buffer);
		}
		i_dst++;

		*crc32 = crc32_le(*crc32, (void *)output_buffer, row_size);

		if (wb_frame_info)
			wb_fmt_func(wb_frame_info, y, output_buffer);
	}
}

static void compose_plane(struct vkms_frame_info *primary_plane_info,
			  struct vkms_frame_info *plane_frame_info,
			  void *vaddr_out)
static void get_format_transform_functions(struct vkms_crtc_state *crtc_state,
					   format_transform_func plane_funcs[])
{
	struct drm_framebuffer *fb = plane_frame_info->fb;
	void *vaddr;
	void (*pixel_blend)(const u8 *p_src, u8 *p_dst);
	struct vkms_plane_state **active_planes = crtc_state->active_planes;
	u32 n_active_planes = crtc_state->num_active_planes, s_fmt;
	int i;

	if (WARN_ON(dma_buf_map_is_null(&primary_plane_info->map[0])))
		return;
	for (i = 0; i < n_active_planes; i++) {
		s_fmt = active_planes[i]->frame_info->fb->format->format;
		plane_funcs[i] = get_fmt_transform_function(s_fmt);
	}
}

	vaddr = plane_frame_info->map[0].vaddr;
static bool check_planes_x_bounds(struct vkms_crtc_state *crtc_state,
				  struct vkms_frame_info *wb_frame_info)
{
	struct vkms_plane_state **planes = crtc_state->active_planes;
	struct vkms_frame_info *primary_plane_info = planes[0]->frame_info;
	int line_width = drm_rect_width(&primary_plane_info->dst);
	u32 n_active_planes = crtc_state->num_active_planes;
	int i;

	if (fb->format->format == DRM_FORMAT_ARGB8888)
		pixel_blend = &alpha_blend;
	else
		pixel_blend = &x_blend;
	for (i = 0; i < n_active_planes; i++) {
		int x_dst = planes[i]->frame_info->dst.x1;
		int x_src = planes[i]->frame_info->src.x1 >> 16;
		int x2_src = planes[i]->frame_info->src.x2 >> 16;
		int x_limit = drm_rect_width(&planes[i]->frame_info->dst);

	blend(vaddr_out, vaddr, primary_plane_info,
	      plane_frame_info, pixel_blend);
		if (x_dst + x_limit > line_width)
			return false;
		if (x_src + x_limit > x2_src)
			return false;
	}

	return true;
}

static int compose_active_planes(void **vaddr_out,
				 struct vkms_frame_info *primary_plane_info,
				 struct vkms_crtc_state *crtc_state)
static int compose_active_planes(struct vkms_frame_info *wb_frame_info,
				 struct vkms_crtc_state *crtc_state,
				 u32 *crc32)
{
	struct drm_framebuffer *fb = primary_plane_info->fb;
	struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
	const void *vaddr;
	int i;
	format_transform_func plane_funcs[NUM_OVERLAY_PLANES], wb_func = NULL;
	int line_width, ret = 0, pixel_size = sizeof(struct line_buffer);
	struct vkms_frame_info *primary_plane_info = NULL;
	struct line_buffer *output_buffer, *stage_buffer;
	struct vkms_plane_state *act_plane = NULL;
	u32 wb_format;

	if (!*vaddr_out) {
		*vaddr_out = kvzalloc(gem_obj->size, GFP_KERNEL);
		if (!*vaddr_out) {
			DRM_ERROR("Cannot allocate memory for output frame.");
			return -ENOMEM;
		}
	if (WARN_ON(pixel_size != 8))
		return -EINVAL;

	if (crtc_state->num_active_planes >= 1) {
		act_plane = crtc_state->active_planes[0];
		if (act_plane->base.base.plane->type == DRM_PLANE_TYPE_PRIMARY)
			primary_plane_info = act_plane->frame_info;
	}

	if (!primary_plane_info)
		return -EINVAL;

	if (WARN_ON(dma_buf_map_is_null(&primary_plane_info->map[0])))
		return -EINVAL;

	vaddr = primary_plane_info->map[0].vaddr;
	if (WARN_ON(!check_planes_x_bounds(crtc_state, wb_frame_info)))
		return -EINVAL;

	memcpy(*vaddr_out, vaddr, gem_obj->size);
	line_width = drm_rect_width(&primary_plane_info->dst);

	/* If there are other planes besides primary, we consider the active
	 * planes should be in z-order and compose them associatively:
	 * ((primary <- overlay) <- cursor)
	 */
	for (i = 1; i < crtc_state->num_active_planes; i++)
		compose_plane(primary_plane_info,
			      crtc_state->active_planes[i]->frame_info,
			      *vaddr_out);
	stage_buffer = kvmalloc(line_width * pixel_size, GFP_KERNEL);
	if (!stage_buffer) {
		DRM_ERROR("Cannot allocate memory for the output line buffer");
		return -ENOMEM;
	}

	return 0;
	output_buffer = kvmalloc(line_width * pixel_size, GFP_KERNEL);
	if (!output_buffer) {
		DRM_ERROR("Cannot allocate memory for intermediate line buffer");
		ret = -ENOMEM;
		goto free_stage_buffer;
	}

	get_format_transform_functions(crtc_state, plane_funcs);

	if (wb_frame_info) {
		wb_format = wb_frame_info->fb->format->format;
		wb_func = get_wb_fmt_transform_function(wb_format);
		wb_frame_info->src = primary_plane_info->src;
		wb_frame_info->dst = primary_plane_info->dst;
	}

	blend(wb_frame_info, wb_func, crtc_state, plane_funcs, crc32,
	      stage_buffer, output_buffer, (s64)line_width * pixel_size);

	kvfree(output_buffer);
free_stage_buffer:
	kvfree(stage_buffer);

	return ret;
}

/**
@@ -222,13 +230,12 @@ void vkms_composer_worker(struct work_struct *work)
						struct vkms_crtc_state,
						composer_work);
	struct drm_crtc *crtc = crtc_state->base.crtc;
	struct vkms_writeback_job *active_wb = crtc_state->active_writeback;
	struct vkms_frame_info *wb_frame_info = &active_wb->frame_info;
	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
	struct vkms_frame_info *primary_plane_info = NULL;
	struct vkms_plane_state *act_plane = NULL;
	bool crc_pending, wb_pending;
	void *vaddr_out = NULL;
	u32 crc32 = 0;
	u64 frame_start, frame_end;
	u32 crc32 = 0;
	int ret;

	spin_lock_irq(&out->composer_lock);
@@ -248,35 +255,19 @@ void vkms_composer_worker(struct work_struct *work)
	if (!crc_pending)
		return;

	if (crtc_state->num_active_planes >= 1) {
		act_plane = crtc_state->active_planes[0];
		if (act_plane->base.base.plane->type == DRM_PLANE_TYPE_PRIMARY)
			primary_plane_info = act_plane->frame_info;
	}

	if (!primary_plane_info)
		return;

	if (wb_pending)
		vaddr_out = crtc_state->active_writeback->data[0].vaddr;
		ret = compose_active_planes(wb_frame_info, crtc_state, &crc32);
	else
		ret = compose_active_planes(NULL, crtc_state, &crc32);

	ret = compose_active_planes(&vaddr_out, primary_plane_info,
				    crtc_state);
	if (ret) {
		if (ret == -EINVAL && !wb_pending)
			kvfree(vaddr_out);
	if (ret)
		return;
	}

	crc32 = compute_crc(vaddr_out, primary_plane_info);

	if (wb_pending) {
		drm_writeback_signal_completion(&out->wb_connector, 0);
		spin_lock_irq(&out->composer_lock);
		crtc_state->wb_pending = false;
		spin_unlock_irq(&out->composer_lock);
	} else {
		kvfree(vaddr_out);
	}

	/*
diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
new file mode 100644
index 000000000000..0d1838d1b835
--- /dev/null
+++ b/drivers/gpu/drm/vkms/vkms_formats.c
@@ -0,0 +1,138 @@
/* SPDX-License-Identifier: GPL-2.0+ */

#include <drm/drm_rect.h>
#include "vkms_formats.h"

format_transform_func get_fmt_transform_function(u32 format)
{
	if (format == DRM_FORMAT_ARGB8888)
		return &ARGB8888_to_ARGB16161616;
	else
		return &XRGB8888_to_ARGB16161616;
}

format_transform_func get_wb_fmt_transform_function(u32 format)
{
	if (format == DRM_FORMAT_ARGB8888)
		return &convert_to_ARGB8888;
	else
		return &convert_to_XRGB8888;
}

static int pixel_offset(struct vkms_frame_info *frame_info, int x, int y)
{
	return frame_info->offset + (y * frame_info->pitch)
				  + (x * frame_info->cpp);
}

/*
 * packed_pixels_addr - Get the pointer to pixel of a given pair of coordinates
 *
 * @frame_info: Buffer metadata
 * @x: The x(width) coordinate of the 2D buffer
 * @y: The y(Heigth) coordinate of the 2D buffer
 *
 * 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).
 */
static void *packed_pixels_addr(struct vkms_frame_info *frame_info, int x, int y)
{
	int offset = pixel_offset(frame_info, x, y);

	return (u8 *)frame_info->map[0].vaddr + offset;
}

static void *get_packed_src_addr(struct vkms_frame_info *frame_info, int y)
{
	int x_src = frame_info->src.x1 >> 16;
	int y_src = y - frame_info->dst.y1 + (frame_info->src.y1 >> 16);

	return packed_pixels_addr(frame_info, x_src, y_src);
}

void ARGB8888_to_ARGB16161616(struct vkms_frame_info *frame_info, int y,
			      struct line_buffer *stage_buffer)
{
	u8 *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 += 4) {
		/*
		 * Organizes the channels in their respective positions and converts
		 * the 8 bits channel to 16.
		 * The 257 is the "conversion ratio". This number is obtained by the
		 * (2^16 - 1) / (2^8 - 1) division. Which, in this case, tries to get
		 * the best color value in a pixel format with more possibilities.
		 * And a similar idea applies to others RGB color conversions.
		 */
		stage_buffer[x].a = (u16)src_pixels[3] * 257;
		stage_buffer[x].r = (u16)src_pixels[2] * 257;
		stage_buffer[x].g = (u16)src_pixels[1] * 257;
		stage_buffer[x].b = (u16)src_pixels[0] * 257;
	}
}

void XRGB8888_to_ARGB16161616(struct vkms_frame_info *frame_info, int y,
			      struct line_buffer *stage_buffer)
{
	u8 *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 += 4) {
		stage_buffer[x].a = (u16)0xffff;
		stage_buffer[x].r = (u16)src_pixels[2] * 257;
		stage_buffer[x].g = (u16)src_pixels[1] * 257;
		stage_buffer[x].b = (u16)src_pixels[0] * 257;
	}
}

/*
 * The following  functions take an line of ARGB16161616 pixels from the
 * src_buffer, convert them to a specific format, and store them in the
 * destination.
 *
 * They are used in the `compose_active_planes` to convert and store a line
 * from the src_buffer to the writeback buffer.
 */
void convert_to_ARGB8888(struct vkms_frame_info *frame_info,
			 int y, struct line_buffer *src_buffer)
{
	int x, x_dst = frame_info->dst.x1;
	u8 *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 += 4) {
		/*
		 * This sequence below is important because the format's byte order is
		 * in little-endian. In the case of the ARGB8888 the memory is
		 * organized this way:
		 *
		 * | Addr     | = blue channel
		 * | Addr + 1 | = green channel
		 * | Addr + 2 | = Red channel
		 * | Addr + 3 | = Alpha channel
		 */
		dst_pixels[3] = DIV_ROUND_UP(src_buffer[x].a, 257);
		dst_pixels[2] = DIV_ROUND_UP(src_buffer[x].r, 257);
		dst_pixels[1] = DIV_ROUND_UP(src_buffer[x].g, 257);
		dst_pixels[0] = DIV_ROUND_UP(src_buffer[x].b, 257);
	}
}

void convert_to_XRGB8888(struct vkms_frame_info *frame_info,
			 int y, struct line_buffer *src_buffer)
{
	int x, x_dst = frame_info->dst.x1;
	u8 *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 += 4) {
		dst_pixels[3] = (u8)0xff;
		dst_pixels[2] = DIV_ROUND_UP(src_buffer[x].r, 257);
		dst_pixels[1] = DIV_ROUND_UP(src_buffer[x].g, 257);
		dst_pixels[0] = DIV_ROUND_UP(src_buffer[x].b, 257);
	}
}
diff --git a/drivers/gpu/drm/vkms/vkms_formats.h b/drivers/gpu/drm/vkms/vkms_formats.h
new file mode 100644
index 000000000000..817e8b2124ae
--- /dev/null
+++ b/drivers/gpu/drm/vkms/vkms_formats.h
@@ -0,0 +1,31 @@
/* SPDX-License-Identifier: GPL-2.0+ */

#ifndef _VKMS_FORMATS_H_
#define _VKMS_FORMATS_H_

#include "vkms_drv.h"

struct line_buffer {
	u16 a, r, g, b;
};

void ARGB8888_to_ARGB16161616(struct vkms_frame_info *frame_info, int y,
			      struct line_buffer *stage_buffer);

void XRGB8888_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);

void convert_to_XRGB8888(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);

format_transform_func get_fmt_transform_function(u32 format);

format_transform_func get_wb_fmt_transform_function(u32 format);

#endif /* _VKMS_FORMATS_H_ */
-- 
2.30.2
On Fri, 21 Jan 2022 18:38:29 -0300
Igor Torrente <igormtorrente@gmail.com> wrote:
Why round-up rather than the usual mathematical rounding?
Here you would check that you don't overrun any of the arrays. At this
point, I believe an overrun would indicate a bug in VKMS, so handle it
according to the kernel conventions. I have suggestion further below
how to make that check possible. In other places, I'll just say "check
for overruns" for short.
Is it not *from* each plane?

Each plane... does this mean that all planes must have the same pixel
format?

Oh wait, it's a pointer, so an array, isn't it? You're passing in an
array without passing in the array size. That seems quite risky to me.
Think of someone else needing to patch something here without fully
understanding how this all works, they'd easily introduce a subtle bug.

Looks like the array must be number of "active planes" long. So it's
not even a constant, and the size of the array is not documented here.

What if the fmt_func was a field in struct vkms_frame_info? So you
could set it when creating a vkms_frame_info. Wouldn't that simplify
the code in blend() and its callers?
Mm, you only need to clear output_buffer, not the whole writeback FB.
output_buffer will unconditionally and totally overwrite the writeback
FB, right?
Using "wb" as short for writeback is... well, it's hard for the me
remember at least. Could this not be named simply "writeback"?
Shouldn't this be called y_dst instead?
It took me a while to understand that all these y-coordinates are CRTC
coordinates. Maybe call them crtc_y, crtc_y_begin, crtc_y_end,
crtc_y_height, etc.
That's interesting. Looks like you reject everything if any plane is
not fully inside the primary plane destination rectangle. But that's
not the right check, is it? If you want to check this, you would check
against the CRTC dimensions.

Then again, I think some hardware do allow planes to reach outside of
the CRTC dimensions. Cursor plane is probably the best example. The
cursor can be partly off-screen. So this is something that would need
to be supported both ways I suppose, but going with the "all plane
destination rectangles must be strictly inside the CRTC dimensions" is
a good start.

But why only x-coordinate check? y should have the same rules, right?
This needs to be CRTC width, not primary plane width.
In functions like this you should prepare for caller errors. Use a
switch, and fail any attempt to use a pixel format it doesn't support.
Failing is much better than silently producing garbage or worse: buffer
overruns when bytes-per-pixel is not what you expected.

What to do on failure depends on whether the failure here is never
supposed to happen (follow the kernel style) e.g. malicious userspace
cannot trigger it, or if you actually use this function to define the
supported for pixel formats.

The latter means you'd have a list of all DRM pixel formats and then
you'd ask for each one if this function knows it, and if yes, you add
the format to the list of supported formats advertised to userspace. I
don't know if that would be fine by DRM coding style.
Good work!


Thanks,
pq

[PATCH v4 8/9] drm: vkms: Adds XRGB_16161616 and ARGB_1616161616 formats Export this patch

This will be useful to write tests that depends on these formats.

ARGB and XRGB follows the a similar implementation of the former formats.
Just adjusting for 16 bits per channel.

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   | 67 +++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_formats.h   | 12 +++++
 drivers/gpu/drm/vkms/vkms_plane.c     |  5 +-
 drivers/gpu/drm/vkms/vkms_writeback.c |  2 +
 4 files changed, 85 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
index 0d1838d1b835..661da39d1276 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.c
+++ b/drivers/gpu/drm/vkms/vkms_formats.c
@@ -7,6 +7,10 @@ format_transform_func get_fmt_transform_function(u32 format)
{
	if (format == DRM_FORMAT_ARGB8888)
		return &ARGB8888_to_ARGB16161616;
	else if (format == DRM_FORMAT_ARGB16161616)
		return &get_ARGB16161616;
	else if (format == DRM_FORMAT_XRGB16161616)
		return &XRGB16161616_to_ARGB16161616;
	else
		return &XRGB8888_to_ARGB16161616;
}
@@ -15,6 +19,10 @@ format_transform_func get_wb_fmt_transform_function(u32 format)
{
	if (format == DRM_FORMAT_ARGB8888)
		return &convert_to_ARGB8888;
	else if (format == DRM_FORMAT_ARGB16161616)
		return &convert_to_ARGB16161616;
	else if (format == DRM_FORMAT_XRGB16161616)
		return &convert_to_XRGB16161616;
	else
		return &convert_to_XRGB8888;
}
@@ -89,6 +97,35 @@ void XRGB8888_to_ARGB16161616(struct vkms_frame_info *frame_info, int y,
	}
}

void get_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 += 4) {
		stage_buffer[x].a = src_pixels[3];
		stage_buffer[x].r = src_pixels[2];
		stage_buffer[x].g = src_pixels[1];
		stage_buffer[x].b = src_pixels[0];
	}
}

void XRGB16161616_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 += 4) {
		stage_buffer[x].a = (u16)0xffff;
		stage_buffer[x].r = src_pixels[2];
		stage_buffer[x].g = src_pixels[1];
		stage_buffer[x].b = src_pixels[0];
	}
}


/*
 * The following  functions take an line of ARGB16161616 pixels from the
 * src_buffer, convert them to a specific format, and store them in the
@@ -136,3 +173,33 @@ void convert_to_XRGB8888(struct vkms_frame_info *frame_info,
		dst_pixels[0] = DIV_ROUND_UP(src_buffer[x].b, 257);
	}
}

void convert_to_ARGB16161616(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 += 4) {
		dst_pixels[3] = src_buffer[x].a;
		dst_pixels[2] = src_buffer[x].r;
		dst_pixels[1] = src_buffer[x].g;
		dst_pixels[0] = src_buffer[x].b;
	}
}

void convert_to_XRGB16161616(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 += 4) {
		dst_pixels[3] = src_buffer[x].a;
		dst_pixels[2] = src_buffer[x].r;
		dst_pixels[1] = src_buffer[x].g;
		dst_pixels[0] = src_buffer[x].b;
	}
}
diff --git a/drivers/gpu/drm/vkms/vkms_formats.h b/drivers/gpu/drm/vkms/vkms_formats.h
index 817e8b2124ae..22358f3a33ab 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.h
+++ b/drivers/gpu/drm/vkms/vkms_formats.h
@@ -15,12 +15,24 @@ void ARGB8888_to_ARGB16161616(struct vkms_frame_info *frame_info, int y,
void XRGB8888_to_ARGB16161616(struct vkms_frame_info *frame_info, int y,
			      struct line_buffer *stage_buffer);

void get_ARGB16161616(struct vkms_frame_info *frame_info, int y,
		      struct line_buffer *stage_buffer);

void XRGB16161616_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);

void convert_to_XRGB8888(struct vkms_frame_info *frame_info, int y,
			 struct line_buffer *src_buffer);

void convert_to_ARGB16161616(struct vkms_frame_info *frame_info, int y,
			     struct line_buffer *src_buffer);

void convert_to_XRGB16161616(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 28752af0118c..1d70c9e8f109 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -13,11 +13,14 @@

static const u32 vkms_formats[] = {
	DRM_FORMAT_XRGB8888,
	DRM_FORMAT_XRGB16161616
};

static const u32 vkms_plane_formats[] = {
	DRM_FORMAT_ARGB8888,
	DRM_FORMAT_XRGB8888
	DRM_FORMAT_XRGB8888,
	DRM_FORMAT_XRGB16161616,
	DRM_FORMAT_ARGB16161616
};

static struct drm_plane_state *
diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c b/drivers/gpu/drm/vkms/vkms_writeback.c
index ad4bb1fb37ca..393d3fc7966f 100644
--- a/drivers/gpu/drm/vkms/vkms_writeback.c
+++ b/drivers/gpu/drm/vkms/vkms_writeback.c
@@ -14,6 +14,8 @@

static const u32 vkms_wb_formats[] = {
	DRM_FORMAT_XRGB8888,
	DRM_FORMAT_XRGB16161616,
	DRM_FORMAT_ARGB16161616
};

static const struct drm_connector_funcs vkms_wb_connector_funcs = {
-- 
2.30.2

[PATCH v4 9/9] drm: vkms: Add support to the RGB565 format Export this patch

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));
	}
}


/*
 * 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
On Fri, 21 Jan 2022 18:38:31 -0300
Igor Torrente <igormtorrente@gmail.com> wrote: