drm/armada: implement primary plane update

Implement primary plane update without having to go through a modeset
to achieve that; the hardware does not require such complexity.  This
means we treat the primary plane as any other, allowing the format,
size, position and scaling to be updated via the normal plane ioctls.

This also allows us to seemlessly disable and re-enable the primary
plane when (eg) displaying full-frame video without any graphic
clipping the overlaid video - which saves wasting memory bandwidth
needlessly verifying that the colorkey is indeed filling the entire
primary plane.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

drivers/gpu/drm/armada/armada_crtc.c

@@ -1138,6 +1138,122 @@ static const struct drm_crtc_funcs armada_crtc_funcs = {
 	.disable_vblank	= armada_drm_crtc_disable_vblank,
 };
 
+static void armada_drm_primary_update_state(struct drm_plane_state *state,
+	struct armada_regs *regs)
+{
+	struct armada_plane *dplane = drm_to_armada_plane(state->plane);
+	struct armada_crtc *dcrtc = drm_to_armada_crtc(state->crtc);
+	struct armada_framebuffer *dfb = drm_fb_to_armada_fb(state->fb);
+	bool was_disabled;
+	unsigned int idx = 0;
+	u32 val;
+
+	val = CFG_GRA_FMT(dfb->fmt) | CFG_GRA_MOD(dfb->mod);
+	if (dfb->fmt > CFG_420)
+		val |= CFG_PALETTE_ENA;
+	if (state->visible)
+		val |= CFG_GRA_ENA;
+	if (drm_rect_width(&state->src) >> 16 != drm_rect_width(&state->dst))
+		val |= CFG_GRA_HSMOOTH;
+
+	was_disabled = !(dplane->state.ctrl0 & CFG_GRA_ENA);
+	if (was_disabled)
+		armada_reg_queue_mod(regs, idx,
+				     0, CFG_PDWN64x66, LCD_SPU_SRAM_PARA1);
+
+	dplane->state.ctrl0 = val;
+	dplane->state.src_hw = (drm_rect_height(&state->src) & 0xffff0000) |
+				drm_rect_width(&state->src) >> 16;
+	dplane->state.dst_hw = drm_rect_height(&state->dst) << 16 |
+			       drm_rect_width(&state->dst);
+	dplane->state.dst_yx = state->dst.y1 << 16 | state->dst.x1;
+
+	armada_drm_gra_plane_regs(regs + idx, &dfb->fb, &dplane->state,
+				  state->src.x1 >> 16, state->src.y1 >> 16,
+				  dcrtc->interlaced);
+
+	dplane->state.vsync_update = !was_disabled;
+	dplane->state.changed = true;
+}
+
+static int armada_drm_primary_update(struct drm_plane *plane,
+	struct drm_crtc *crtc, struct drm_framebuffer *fb,
+	int crtc_x, int crtc_y, unsigned int crtc_w, unsigned int crtc_h,
+	uint32_t src_x, uint32_t src_y, uint32_t src_w, uint32_t src_h,
+	struct drm_modeset_acquire_ctx *ctx)
+{
+	struct armada_plane *dplane = drm_to_armada_plane(plane);
+	struct armada_crtc *dcrtc = drm_to_armada_crtc(crtc);
+	struct armada_plane_work *work;
+	struct drm_plane_state state = {
+		.plane = plane,
+		.crtc = crtc,
+		.fb = fb,
+		.src_x = src_x,
+		.src_y = src_y,
+		.src_w = src_w,
+		.src_h = src_h,
+		.crtc_x = crtc_x,
+		.crtc_y = crtc_y,
+		.crtc_w = crtc_w,
+		.crtc_h = crtc_h,
+		.rotation = DRM_MODE_ROTATE_0,
+	};
+	const struct drm_rect clip = {
+		.x2 = crtc->mode.hdisplay,
+		.y2 = crtc->mode.vdisplay,
+	};
+	int ret;
+
+	ret = drm_plane_helper_check_state(&state, &clip, 0, INT_MAX, true,
+					    false);
+	if (ret)
+		return ret;
+
+	work = &dplane->works[dplane->next_work];
+	work->fn = armada_drm_crtc_complete_frame_work;
+
+	if (plane->fb != fb) {
+		/*
+		 * Take a reference on the new framebuffer - we want to
+		 * hold on to it while the hardware is displaying it.
+		 */
+		drm_framebuffer_reference(fb);
+
+		work->old_fb = plane->fb;
+	} else {
+		work->old_fb = NULL;
+	}
+
+	armada_drm_primary_update_state(&state, work->regs);
+
+	if (!dplane->state.changed)
+		return 0;
+
+	/* Wait for pending work to complete */
+	if (armada_drm_plane_work_wait(dplane, HZ / 10) == 0)
+		armada_drm_plane_work_cancel(dcrtc, dplane);
+
+	if (!dplane->state.vsync_update) {
+		work->fn(dcrtc, work);
+		if (work->old_fb)
+			drm_framebuffer_unreference(work->old_fb);
+		return 0;
+	}
+
+	/* Queue it for update on the next interrupt if we are enabled */
+	ret = armada_drm_plane_work_queue(dcrtc, work);
+	if (ret) {
+		work->fn(dcrtc, work);
+		if (work->old_fb)
+			drm_framebuffer_unreference(work->old_fb);
+	}
+
+	dplane->next_work = !dplane->next_work;
+
+	return 0;
+}
+
 int armada_drm_plane_disable(struct drm_plane *plane,
 			     struct drm_modeset_acquire_ctx *ctx)
 {
@@ -1199,7 +1315,7 @@ int armada_drm_plane_disable(struct drm_plane *plane,
 }
 
 static const struct drm_plane_funcs armada_primary_plane_funcs = {
-	.update_plane	= drm_primary_helper_update,
+	.update_plane	= armada_drm_primary_update,
 	.disable_plane	= armada_drm_plane_disable,
 	.destroy	= drm_primary_helper_destroy,
 };