drm/mediatek: Automatically search unclaimed mtk mutex in mtk_mutex_get()

Moving mutex resource management from client driver to  mutex driver
could prevent client drivers negotiating for resource management.
Signed-off-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

drivers/gpu/drm/mediatek/mtk_drm_crtc.c

@@ -773,7 +773,7 @@ int mtk_drm_crtc_create(struct drm_device *drm_dev,
 	if (!mtk_crtc->ddp_comp)
 		return -ENOMEM;
 
-	mtk_crtc->mutex = mtk_mutex_get(priv->mutex_dev, pipe);
+	mtk_crtc->mutex = mtk_mutex_get(priv->mutex_dev);
 	if (IS_ERR(mtk_crtc->mutex)) {
 		ret = PTR_ERR(mtk_crtc->mutex);
 		dev_err(dev, "Failed to get mutex: %d\n", ret);

drivers/gpu/drm/mediatek/mtk_mutex.c

@@ -228,18 +228,18 @@ static const struct mtk_mutex_data mt8173_mutex_driver_data = {
 	.mutex_sof_reg = MT2701_MUTEX0_SOF0,
 };
 
-struct mtk_mutex *mtk_mutex_get(struct device *dev, unsigned int id)
+struct mtk_mutex *mtk_mutex_get(struct device *dev)
 {
 	struct mtk_mutex_ctx *mtx = dev_get_drvdata(dev);
+	int i;
 
-	if (id >= 10)
-		return ERR_PTR(-EINVAL);
-	if (mtx->mutex[id].claimed)
-		return ERR_PTR(-EBUSY);
-
-	mtx->mutex[id].claimed = true;
+	for (i = 0; i < 10; i++)
+		if (!mtx->mutex[i].claimed) {
+			mtx->mutex[i].claimed = true;
+			return &mtx->mutex[i];
+		}
 
-	return &mtx->mutex[id];
+	return ERR_PTR(-EBUSY);
 }
 
 void mtk_mutex_put(struct mtk_mutex *mutex)

drivers/gpu/drm/mediatek/mtk_mutex.h

@@ -10,7 +10,7 @@ struct regmap;
 struct device;
 struct mtk_mutex;
 
-struct mtk_mutex *mtk_mutex_get(struct device *dev, unsigned int id);
+struct mtk_mutex *mtk_mutex_get(struct device *dev);
 int mtk_mutex_prepare(struct mtk_mutex *mutex);
 void mtk_mutex_add_comp(struct mtk_mutex *mutex,
 			enum mtk_ddp_comp_id id);