[RFC PATCH v2 2/3] drm/rockchip: vop: add line flag function support

[Yakir Yang <ykk@rock-chips.com>]

VOP could use line flag interrupt to detect some target timing.
For example, eDP PSR is interesting in vact_end, then VOP could
configure the line number to vact_end, and wait for line flag
interrupt coming.

Signed-off-by: Yakir Yang <ykk@rock-chips.com>
---
Changes in v2:
- introduce in v2, split VOP line flag changes out

 drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 63 +++++++++++++++++++++++++++++
 drivers/gpu/drm/rockchip/rockchip_drm_vop.h |  3 ++
 drivers/gpu/drm/rockchip/rockchip_vop_reg.c |  2 +
 3 files changed, 68 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index 257501f..b2a36db 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -117,6 +117,8 @@ struct vop {
 	struct completion wait_update_complete;
 	struct drm_pending_vblank_event *event;
 
+	struct completion line_flag_completion;
+
 	const struct vop_data *data;
 
 	uint32_t *regsbak;
@@ -427,6 +429,59 @@ static void vop_dsp_hold_valid_irq_disable(struct vop *vop)
 	spin_unlock_irqrestore(&vop->irq_lock, flags);
 }
 
+/*
+ * (1) each frame starts at the start of the Vsync pulse which is signaled by
+ *     the "FRAME_SYNC" interrupt.
+ * (2) the active data region of each frame ends at dsp_vact_end
+ * (3) we should program this same number (dsp_vact_end) into dsp_line_frag_num,
+ *      to get "LINE_FLAG" interrupt at the end of the active on screen data.
+ *
+ * VOP_INTR_CTRL0.dsp_line_frag_num = VOP_DSP_VACT_ST_END.dsp_vact_end
+ * Interrupts
+ * LINE_FLAG -------------------------------+
+ * FRAME_SYNC ----+                         |
+ *                |                         |
+ *                v                         v
+ *                | Vsync | Vbp |  Vactive  | Vfp |
+ *                        ^     ^           ^     ^
+ *                        |     |           |     |
+ *                        |     |           |     |
+ * dsp_vs_end ------------+     |           |     |   VOP_DSP_VTOTAL_VS_END
+ * dsp_vact_start --------------+           |     |   VOP_DSP_VACT_ST_END
+ * dsp_vact_end ----------------------------+     |   VOP_DSP_VACT_ST_END
+ * dsp_total -------------------------------------+   VOP_DSP_VTOTAL_VS_END
+ */
+
+static void vop_line_flag_irq_enable(struct vop *vop, int line_num)
+{
+	unsigned long flags;
+
+	if (WARN_ON(!vop->is_enabled))
+		return;
+
+	spin_lock_irqsave(&vop->irq_lock, flags);
+
+	VOP_CTRL_SET(vop, line_flag_num_0, line_num);
+	VOP_INTR_SET_TYPE(vop, enable, LINE_FLAG_INTR, 1);
+	vop_cfg_done(vop);
+
+	spin_unlock_irqrestore(&vop->irq_lock, flags);
+}
+
+static void vop_line_flag_irq_disable(struct vop *vop)
+{
+	unsigned long flags;
+
+	if (WARN_ON(!vop->is_enabled))
+		return;
+
+	spin_lock_irqsave(&vop->irq_lock, flags);
+
+	VOP_INTR_SET_TYPE(vop, enable, LINE_FLAG_INTR, 0);
+
+	spin_unlock_irqrestore(&vop->irq_lock, flags);
+}
+
 static void vop_enable(struct drm_crtc *crtc)
 {
 	struct vop *vop = to_vop(crtc);
@@ -1154,6 +1209,13 @@ static irqreturn_t vop_isr(int irq, void *data)
 		ret = IRQ_HANDLED;
 	}
 
+	if (active_irqs & LINE_FLAG_INTR) {
+		if (!completion_done(&vop->line_flag_completion))
+			complete(&vop->line_flag_completion);
+		active_irqs &= ~LINE_FLAG_INTR;
+		ret = IRQ_HANDLED;
+	}
+
 	if (active_irqs & FS_INTR) {
 		drm_crtc_handle_vblank(crtc);
 		vop_handle_vblank(vop);
@@ -1252,6 +1314,7 @@ static int vop_create_crtc(struct vop *vop)
 
 	init_completion(&vop->dsp_hold_completion);
 	init_completion(&vop->wait_update_complete);
+	init_completion(&vop->line_flag_completion);
 	crtc->port = port;
 	rockchip_register_crtc_funcs(crtc, &private_crtc_funcs);
 
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.h b/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
index ff4f52e..34fcd03 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
@@ -61,6 +61,9 @@ struct vop_ctrl {
 	struct vop_reg hpost_st_end;
 	struct vop_reg vpost_st_end;
 
+	struct vop_reg line_flag_num_0;
+	struct vop_reg line_flag_num_1;
+
 	struct vop_reg cfg_done;
 };
 
diff --git a/drivers/gpu/drm/rockchip/rockchip_vop_reg.c b/drivers/gpu/drm/rockchip/rockchip_vop_reg.c
index 6f42e56..bf78892 100644
--- a/drivers/gpu/drm/rockchip/rockchip_vop_reg.c
+++ b/drivers/gpu/drm/rockchip/rockchip_vop_reg.c
@@ -299,6 +299,8 @@ static const struct vop_ctrl rk3399_ctrl_data = {
 	.vact_st_end = VOP_REG(RK3399_DSP_VACT_ST_END, 0x1fff1fff, 0),
 	.hpost_st_end = VOP_REG(RK3399_POST_DSP_HACT_INFO, 0x1fff1fff, 0),
 	.vpost_st_end = VOP_REG(RK3399_POST_DSP_VACT_INFO, 0x1fff1fff, 0),
+	.line_flag_num_0 = VOP_REG(RK3399_LINE_FLAG, 0xffff, 0),
+	.line_flag_num_1 = VOP_REG(RK3399_LINE_FLAG, 0xffff, 16),
 	.cfg_done = VOP_REG_MASK(RK3399_REG_CFG_DONE, 0x1, 0),
 };
 
-- 
1.9.1