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>

1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
index 8030769daab7..b77d4560f414 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
+++ b/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;