drm/mediatek: add shadow register support

We need to acquire mutex before using the resources,
and need to release it after finished.
So we don't need to write registers in the blanking period.

Signed-off-by: YT Shen <yt.shen@mediatek.com>
Acked-by: CK Hu <ck.hu@mediatek.com>

drivers/gpu/drm/mediatek/mtk_drm_crtc.c

@@ -327,6 +327,42 @@ static void mtk_crtc_ddp_hw_fini(struct mtk_drm_crtc *mtk_crtc)
 	pm_runtime_put(drm->dev);
 }
 
+static void mtk_crtc_ddp_config(struct drm_crtc *crtc)
+{
+	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
+	struct mtk_crtc_state *state = to_mtk_crtc_state(mtk_crtc->base.state);
+	struct mtk_ddp_comp *ovl = mtk_crtc->ddp_comp[0];
+	unsigned int i;
+
+	/*
+	 * TODO: instead of updating the registers here, we should prepare
+	 * working registers in atomic_commit and let the hardware command
+	 * queue update module registers on vblank.
+	 */
+	if (state->pending_config) {
+		mtk_ddp_comp_config(ovl, state->pending_width,
+				    state->pending_height,
+				    state->pending_vrefresh, 0);
+
+		state->pending_config = false;
+	}
+
+	if (mtk_crtc->pending_planes) {
+		for (i = 0; i < OVL_LAYER_NR; i++) {
+			struct drm_plane *plane = &mtk_crtc->planes[i];
+			struct mtk_plane_state *plane_state;
+
+			plane_state = to_mtk_plane_state(plane->state);
+
+			if (plane_state->pending.config) {
+				mtk_ddp_comp_layer_config(ovl, i, plane_state);
+				plane_state->pending.config = false;
+			}
+		}
+		mtk_crtc->pending_planes = false;
+	}
+}
+
 static void mtk_drm_crtc_enable(struct drm_crtc *crtc)
 {
 	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
@@ -403,6 +439,7 @@ static void mtk_drm_crtc_atomic_flush(struct drm_crtc *crtc,
 				      struct drm_crtc_state *old_crtc_state)
 {
 	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
+	struct mtk_drm_private *priv = crtc->dev->dev_private;
 	unsigned int pending_planes = 0;
 	int i;
 
@@ -424,6 +461,12 @@ static void mtk_drm_crtc_atomic_flush(struct drm_crtc *crtc,
 	if (crtc->state->color_mgmt_changed)
 		for (i = 0; i < mtk_crtc->ddp_comp_nr; i++)
 			mtk_ddp_gamma_set(mtk_crtc->ddp_comp[i], crtc->state);
+
+	if (priv->data->shadow_register) {
+		mtk_disp_mutex_acquire(mtk_crtc->mutex);
+		mtk_crtc_ddp_config(crtc);
+		mtk_disp_mutex_release(mtk_crtc->mutex);
+	}
 }
 
 static const struct drm_crtc_funcs mtk_crtc_funcs = {
@@ -471,36 +514,10 @@ err_cleanup_crtc:
 void mtk_crtc_ddp_irq(struct drm_crtc *crtc, struct mtk_ddp_comp *ovl)
 {
 	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
-	struct mtk_crtc_state *state = to_mtk_crtc_state(mtk_crtc->base.state);
-	unsigned int i;
+	struct mtk_drm_private *priv = crtc->dev->dev_private;
 
-	/*
-	 * TODO: instead of updating the registers here, we should prepare
-	 * working registers in atomic_commit and let the hardware command
-	 * queue update module registers on vblank.
-	 */
-	if (state->pending_config) {
-		mtk_ddp_comp_config(ovl, state->pending_width,
-				    state->pending_height,
-				    state->pending_vrefresh, 0);
-
-		state->pending_config = false;
-	}
-
-	if (mtk_crtc->pending_planes) {
-		for (i = 0; i < OVL_LAYER_NR; i++) {
-			struct drm_plane *plane = &mtk_crtc->planes[i];
-			struct mtk_plane_state *plane_state;
-
-			plane_state = to_mtk_plane_state(plane->state);
-
-			if (plane_state->pending.config) {
-				mtk_ddp_comp_layer_config(ovl, i, plane_state);
-				plane_state->pending.config = false;
-			}
-		}
-		mtk_crtc->pending_planes = false;
-	}
+	if (!priv->data->shadow_register)
+		mtk_crtc_ddp_config(crtc);
 
 	mtk_drm_finish_page_flip(mtk_crtc);
 }

drivers/gpu/drm/mediatek/mtk_drm_ddp.c

@@ -12,6 +12,7 @@
  */
 
 #include <linux/clk.h>
+#include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
@@ -32,10 +33,13 @@
 #define DISP_REG_CONFIG_MMSYS_CG_CON0		0x100
 
 #define DISP_REG_MUTEX_EN(n)	(0x20 + 0x20 * (n))
+#define DISP_REG_MUTEX(n)	(0x24 + 0x20 * (n))
 #define DISP_REG_MUTEX_RST(n)	(0x28 + 0x20 * (n))
 #define DISP_REG_MUTEX_MOD(n)	(0x2c + 0x20 * (n))
 #define DISP_REG_MUTEX_SOF(n)	(0x30 + 0x20 * (n))
 
+#define INT_MUTEX				BIT(1)
+
 #define MT8173_MUTEX_MOD_DISP_OVL0		BIT(11)
 #define MT8173_MUTEX_MOD_DISP_OVL1		BIT(12)
 #define MT8173_MUTEX_MOD_DISP_RDMA0		BIT(13)
@@ -300,6 +304,27 @@ void mtk_disp_mutex_disable(struct mtk_disp_mutex *mutex)
 	writel(0, ddp->regs + DISP_REG_MUTEX_EN(mutex->id));
 }
 
+void mtk_disp_mutex_acquire(struct mtk_disp_mutex *mutex)
+{
+	struct mtk_ddp *ddp = container_of(mutex, struct mtk_ddp,
+					   mutex[mutex->id]);
+	u32 tmp;
+
+	writel(1, ddp->regs + DISP_REG_MUTEX_EN(mutex->id));
+	writel(1, ddp->regs + DISP_REG_MUTEX(mutex->id));
+	if (readl_poll_timeout_atomic(ddp->regs + DISP_REG_MUTEX(mutex->id),
+				      tmp, tmp & INT_MUTEX, 1, 10000))
+		pr_err("could not acquire mutex %d\n", mutex->id);
+}
+
+void mtk_disp_mutex_release(struct mtk_disp_mutex *mutex)
+{
+	struct mtk_ddp *ddp = container_of(mutex, struct mtk_ddp,
+					   mutex[mutex->id]);
+
+	writel(0, ddp->regs + DISP_REG_MUTEX(mutex->id));
+}
+
 static int mtk_ddp_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;

drivers/gpu/drm/mediatek/mtk_drm_ddp.h

@@ -37,5 +37,7 @@ void mtk_disp_mutex_remove_comp(struct mtk_disp_mutex *mutex,
 				enum mtk_ddp_comp_id id);
 void mtk_disp_mutex_unprepare(struct mtk_disp_mutex *mutex);
 void mtk_disp_mutex_put(struct mtk_disp_mutex *mutex);
+void mtk_disp_mutex_acquire(struct mtk_disp_mutex *mutex);
+void mtk_disp_mutex_release(struct mtk_disp_mutex *mutex);
 
 #endif /* MTK_DRM_DDP_H */

drivers/gpu/drm/mediatek/mtk_drm_drv.h

@@ -33,6 +33,7 @@ struct mtk_mmsys_driver_data {
 	unsigned int main_len;
 	const enum mtk_ddp_comp_id *ext_path;
 	unsigned int ext_len;
+	bool shadow_register;
 };
 
 struct mtk_drm_private {