Merge tag 'mediatek-drm-fixes-20231211' of...

Merge tag 'mediatek-drm-fixes-20231211' of https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux into drm-fixes

Mediatek DRM Fixes - 20231211

1. mtk_disp_gamma: Fix breakage due to merge issue
2. fix kernel oops if no crtc is found
3. Add spinlock for setting vblank event in atomic_begin
4. Fix access violation in mtk_drm_crtc_dma_dev_get
Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231211151510.6749-1-chunkuang.hu@kernel.org

drivers/gpu/drm/mediatek/mtk_disp_gamma.c

@@ -203,7 +203,7 @@ void mtk_gamma_set(struct device *dev, struct drm_crtc_state *state)
 	/* Disable RELAY mode to pass the processed image */
 	cfg_val &= ~GAMMA_RELAY_MODE;
 
-	cfg_val = readl(gamma->regs + DISP_GAMMA_CFG);
+	writel(cfg_val, gamma->regs + DISP_GAMMA_CFG);
 }
 
 void mtk_gamma_config(struct device *dev, unsigned int w,

drivers/gpu/drm/mediatek/mtk_drm_crtc.c

@@ -788,6 +788,7 @@ static void mtk_drm_crtc_atomic_begin(struct drm_crtc *crtc,
 									  crtc);
 	struct mtk_crtc_state *mtk_crtc_state = to_mtk_crtc_state(crtc_state);
 	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
+	unsigned long flags;
 
 	if (mtk_crtc->event && mtk_crtc_state->base.event)
 		DRM_ERROR("new event while there is still a pending event\n");
@@ -795,7 +796,11 @@ static void mtk_drm_crtc_atomic_begin(struct drm_crtc *crtc,
 	if (mtk_crtc_state->base.event) {
 		mtk_crtc_state->base.event->pipe = drm_crtc_index(crtc);
 		WARN_ON(drm_crtc_vblank_get(crtc) != 0);
+
+		spin_lock_irqsave(&crtc->dev->event_lock, flags);
 		mtk_crtc->event = mtk_crtc_state->base.event;
+		spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
+
 		mtk_crtc_state->base.event = NULL;
 	}
 }
@@ -921,7 +926,14 @@ static int mtk_drm_crtc_init_comp_planes(struct drm_device *drm_dev,
 
 struct device *mtk_drm_crtc_dma_dev_get(struct drm_crtc *crtc)
 {
-	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
+	struct mtk_drm_crtc *mtk_crtc = NULL;
+
+	if (!crtc)
+		return NULL;
+
+	mtk_crtc = to_mtk_crtc(crtc);
+	if (!mtk_crtc)
+		return NULL;
 
 	return mtk_crtc->dma_dev;
 }

drivers/gpu/drm/mediatek/mtk_drm_drv.c

@@ -443,6 +443,7 @@ static int mtk_drm_kms_init(struct drm_device *drm)
 	struct mtk_drm_private *private = drm->dev_private;
 	struct mtk_drm_private *priv_n;
 	struct device *dma_dev = NULL;
+	struct drm_crtc *crtc;
 	int ret, i, j;
 
 	if (drm_firmware_drivers_only())
@@ -519,7 +520,9 @@ static int mtk_drm_kms_init(struct drm_device *drm)
 	}
 
 	/* Use OVL device for all DMA memory allocations */
-	dma_dev = mtk_drm_crtc_dma_dev_get(drm_crtc_from_index(drm, 0));
+	crtc = drm_crtc_from_index(drm, 0);
+	if (crtc)
+		dma_dev = mtk_drm_crtc_dma_dev_get(crtc);
 	if (!dma_dev) {
 		ret = -ENODEV;
 		dev_err(drm->dev, "Need at least one OVL device\n");