// SPDX-License-Identifier: GPL-2.0+
#include <linux/crc32.h>
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_blend.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_fixed.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_vblank.h>
#include <linux/minmax.h>
#include "vkms_drv.h"
static u16 pre_mul_blend_channel(u16 src, u16 dst, u16 alpha)
{
u32 new_color;
new_color = (src * 0xffff + dst * (0xffff - alpha));
return DIV_ROUND_CLOSEST(new_color, 0xffff);
}
/**
* pre_mul_alpha_blend - alpha blending equation
* @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
*
* 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.
*
* 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 pre_mul_alpha_blend(struct vkms_frame_info *frame_info,
struct line_buffer *stage_buffer,
struct line_buffer *output_buffer)
{
int x_dst = frame_info->dst.x1;
struct pixel_argb_u16 *out = output_buffer->pixels + x_dst;
struct pixel_argb_u16 *in = stage_buffer->pixels;
int x_limit = min_t(size_t, drm_rect_width(&frame_info->dst),
stage_buffer->n_pixels);
for (int 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);
}
}
static int get_y_pos(struct vkms_frame_info *frame_info, int y)
{
if (frame_info->rotation & DRM_MODE_REFLECT_Y)
return drm_rect_height(&frame_info->rotated) - y - 1;
switch (frame_info->rotation & DRM_MODE_ROTATE_MASK) {
case DRM_MODE_ROTATE_90:
return frame_info->rotated.x2 - y - 1;
case DRM_MODE_ROTATE_270:
return y + frame_info->rotated.x1;
default:
return y;
}
}
static bool check_limit(struct vkms_frame_info *frame_info, int pos)
{
if (drm_rotation_90_or_270(frame_info->rotation)) {
if (pos >= 0 && pos < drm_rect_width(&frame_info->rotated))
return true;
} else {
if (pos >= frame_info->rotated.y1 && pos < frame_info->rotated.y2)
return true;
}
return false;
}
static void fill_background(const struct pixel_argb_u16 *background_color,
struct line_buffer *output_buffer)
{
for (size_t i = 0; i < output_buffer->n_pixels; i++)
output_buffer->pixels[i] = *background_color;
}
// lerp(a, b, t) = a + (b - a) * t
static u16 lerp_u16(u16 a, u16 b, s64 t)
{
s64 a_fp = drm_int2fixp(a);
s64 b_fp = drm_int2fixp(b);
s64 delta = drm_fixp_mul(b_fp - a_fp, t);
return drm_fixp2int(a_fp + delta);
}
static s64 get_lut_index(const struct vkms_color_lut *lut, u16 channel_value)
{
s64 color_channel_fp = drm_int2fixp(channel_value);
return drm_fixp_mul(color_channel_fp, lut->channel_value2index_ratio);
}
/*
* This enum is related to the positions of the variables inside
* `struct drm_color_lut`, so the order of both needs to be the same.
*/
enum lut_channel {
LUT_RED = 0,
LUT_GREEN,
LUT_BLUE,
LUT_RESERVED
};
static u16 apply_lut_to_channel_value(const struct vkms_color_lut *lut, u16 channel_value,
enum lut_channel channel)
{
s64 lut_index = get_lut_index(lut, channel_value);
u16 *floor_lut_value, *ceil_lut_value;
u16 floor_channel_value, ceil_channel_value;
/*
* This checks if `struct drm_color_lut` has any gap added by the compiler
* between the struct fields.
*/
static_assert(sizeof(struct drm_color_lut) == sizeof(__u16) * 4);
floor_lut_value = (__u16 *)&lut->base[drm_fixp2int(lut_index)];
if (drm_fixp2int(lut_index) == (lut->lut_length - 1))
/* We're at the end of the LUT array, use same value for ceil and floor */
ceil_lut_value = floor_lut_value;
else
ceil_lut_value = (__u16 *)&lut->base[drm_fixp2int_ceil(lut_index)];
floor_channel_value = floor_lut_value[channel];
ceil_channel_value = ceil_lut_value[channel];
return lerp_u16(floor_channel_value, ceil_channel_value,
lut_index & DRM_FIXED_DECIMAL_MASK);
}
static void apply_lut(const struct vkms_crtc_state *crtc_state, struct line_buffer *output_buffer)
{
if (!crtc_state->gamma_lut.base)
return;
if (!crtc_state->gamma_lut.lut_length)
return;
for (size_t x = 0; x < output_buffer->n_pixels; x++) {
struct pixel_argb_u16 *pixel = &output_buffer->pixels[x];
pixel->r = apply_lut_to_channel_value(&crtc_state->gamma_lut, pixel->r, LUT_RED);
pixel->g = apply_lut_to_channel_value(&crtc_state->gamma_lut, pixel->g, LUT_GREEN);
pixel->b = apply_lut_to_channel_value(&crtc_state->gamma_lut, pixel->b, LUT_BLUE);
}
}
/**
* blend - blend the pixels from all planes and compute crc
* @wb: The writeback frame buffer metadata
* @crtc_state: The crtc state
* @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 plane being blend to the output
* @row_size: The size, in bytes, of a single row
*
* 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.
*/
static void blend(struct vkms_writeback_job *wb,
struct vkms_crtc_state *crtc_state,
u32 *crc32, struct line_buffer *stage_buffer,
struct line_buffer *output_buffer, size_t row_size)
{
struct vkms_plane_state **plane = crtc_state->active_planes;
u32 n_active_planes = crtc_state->num_active_planes;
int y_pos;
const struct pixel_argb_u16 background_color = { .a = 0xffff };
size_t crtc_y_limit = crtc_state->base.crtc->mode.vdisplay;
for (size_t y = 0; y < crtc_y_limit; y++) {
fill_background(&background_color, output_buffer);
/* The active planes are composed associatively in z-order. */
for (size_t i = 0; i < n_active_planes; i++) {
y_pos = get_y_pos(plane[i]->frame_info, y);
if (!check_limit(plane[i]->frame_info, y_pos))
continue;
vkms_compose_row(stage_buffer, plane[i], y_pos);
pre_mul_alpha_blend(plane[i]->frame_info, stage_buffer,
output_buffer);
}
apply_lut(crtc_state, output_buffer);
*crc32 = crc32_le(*crc32, (void *)output_buffer->pixels, row_size);
if (wb)
vkms_writeback_row(wb, output_buffer, y_pos);
}
}
static int check_format_funcs(struct vkms_crtc_state *crtc_state,
struct vkms_writeback_job *active_wb)
{
struct vkms_plane_state **planes = crtc_state->active_planes;
u32 n_active_planes = crtc_state->num_active_planes;
for (size_t i = 0; i < n_active_planes; i++)
if (!planes[i]->pixel_read)
return -1;
if (active_wb && !active_wb->pixel_write)
return -1;
return 0;
}
static int check_iosys_map(struct vkms_crtc_state *crtc_state)
{
struct vkms_plane_state **plane_state = crtc_state->active_planes;
u32 n_active_planes = crtc_state->num_active_planes;
for (size_t i = 0; i < n_active_planes; i++)
if (iosys_map_is_null(&plane_state[i]->frame_info->map[0]))
return -1;
return 0;
}
static int compose_active_planes(struct vkms_writeback_job *active_wb,
struct vkms_crtc_state *crtc_state,
u32 *crc32)
{
size_t line_width, pixel_size = sizeof(struct pixel_argb_u16);
struct line_buffer output_buffer, stage_buffer;
int ret = 0;
/*
* This check exists so we can call `crc32_le` for the entire line
* instead doing it for each channel of each pixel in case
* `struct `pixel_argb_u16` had any gap added by the compiler
* between the struct fields.
*/
static_assert(sizeof(struct pixel_argb_u16) == 8);
if (WARN_ON(check_iosys_map(crtc_state)))
return -EINVAL;
if (WARN_ON(check_format_funcs(crtc_state, active_wb)))
return -EINVAL;
line_width = crtc_state->base.crtc->mode.hdisplay;
stage_buffer.n_pixels = line_width;
output_buffer.n_pixels = line_width;
stage_buffer.pixels = kvmalloc(line_width * pixel_size, GFP_KERNEL);
if (!stage_buffer.pixels) {
DRM_ERROR("Cannot allocate memory for the output line buffer");
return -ENOMEM;
}
output_buffer.pixels = kvmalloc(line_width * pixel_size, GFP_KERNEL);
if (!output_buffer.pixels) {
DRM_ERROR("Cannot allocate memory for intermediate line buffer");
ret = -ENOMEM;
goto free_stage_buffer;
}
blend(active_wb, crtc_state, crc32, &stage_buffer,
&output_buffer, line_width * pixel_size);
kvfree(output_buffer.pixels);
free_stage_buffer:
kvfree(stage_buffer.pixels);
return ret;
}
/**
* vkms_composer_worker - ordered work_struct to compute CRC
*
* @work: work_struct
*
* Work handler for composing and computing CRCs. work_struct scheduled in
* an ordered workqueue that's periodically scheduled to run by
* vkms_vblank_simulate() and flushed at vkms_atomic_commit_tail().
*/
void vkms_composer_worker(struct work_struct *work)
{
struct vkms_crtc_state *crtc_state = container_of(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_output *out = drm_crtc_to_vkms_output(crtc);
bool crc_pending, wb_pending;
u64 frame_start, frame_end;
u32 crc32 = 0;
int ret;
spin_lock_irq(&out->composer_lock);
frame_start = crtc_state->frame_start;
frame_end = crtc_state->frame_end;
crc_pending = crtc_state->crc_pending;
wb_pending = crtc_state->wb_pending;
crtc_state->frame_start = 0;
crtc_state->frame_end = 0;
crtc_state->crc_pending = false;
if (crtc->state->gamma_lut) {
s64 max_lut_index_fp;
s64 u16_max_fp = drm_int2fixp(0xffff);
crtc_state->gamma_lut.base = (struct drm_color_lut *)crtc->state->gamma_lut->data;
crtc_state->gamma_lut.lut_length =
crtc->state->gamma_lut->length / sizeof(struct drm_color_lut);
max_lut_index_fp = drm_int2fixp(crtc_state->gamma_lut.lut_length - 1);
crtc_state->gamma_lut.channel_value2index_ratio = drm_fixp_div(max_lut_index_fp,
u16_max_fp);
} else {
crtc_state->gamma_lut.base = NULL;
}
spin_unlock_irq(&out->composer_lock);
/*
* We raced with the vblank hrtimer and previous work already computed
* the crc, nothing to do.
*/
if (!crc_pending)
return;
if (wb_pending)
ret = compose_active_planes(active_wb, crtc_state, &crc32);
else
ret = compose_active_planes(NULL, crtc_state, &crc32);
if (ret)
return;
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);
}
/*
* The worker can fall behind the vblank hrtimer, make sure we catch up.
*/
while (frame_start <= frame_end)
drm_crtc_add_crc_entry(crtc, true, frame_start++, &crc32);
}
static const char * const pipe_crc_sources[] = {"auto"};
const char *const *vkms_get_crc_sources(struct drm_crtc *crtc,
size_t *count)
{
*count = ARRAY_SIZE(pipe_crc_sources);
return pipe_crc_sources;
}
static int vkms_crc_parse_source(const char *src_name, bool *enabled)
{
int ret = 0;
if (!src_name) {
*enabled = false;
} else if (strcmp(src_name, "auto") == 0) {
*enabled = true;
} else {
*enabled = false;
ret = -EINVAL;
}
return ret;
}
int vkms_verify_crc_source(struct drm_crtc *crtc, const char *src_name,
size_t *values_cnt)
{
bool enabled;
if (vkms_crc_parse_source(src_name, &enabled) < 0) {
DRM_DEBUG_DRIVER("unknown source %s\n", src_name);
return -EINVAL;
}
*values_cnt = 1;
return 0;
}
void vkms_set_composer(struct vkms_output *out, bool enabled)
{
bool old_enabled;
if (enabled)
drm_crtc_vblank_get(&out->crtc);
spin_lock_irq(&out->lock);
old_enabled = out->composer_enabled;
out->composer_enabled = enabled;
spin_unlock_irq(&out->lock);
if (old_enabled)
drm_crtc_vblank_put(&out->crtc);
}
int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name)
{
struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
bool enabled = false;
int ret = 0;
ret = vkms_crc_parse_source(src_name, &enabled);
vkms_set_composer(out, enabled);
return ret;
}
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