media: mtk-vpu: VPU should be in idle state before system is suspended

VPU should be in idle state before system is suspended
or it will work abnormally like VPU program counter not
in a correct address or VPU reset
Signed-off-by: Irui Wang <irui.wang@mediatek.com>
Reviewed-by: Alexandre Courbot <acourbot@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/platform/mtk-vpu/mtk_vpu.c

@@ -27,6 +27,7 @@
 
 #define INIT_TIMEOUT_MS		2000U
 #define IPI_TIMEOUT_MS		2000U
+#define VPU_IDLE_TIMEOUT_MS	1000U
 #define VPU_FW_VER_LEN		16
 
 /* maximum program/data TCM (Tightly-Coupled Memory) size */
@@ -57,11 +58,15 @@
 #define VPU_DMEM_EXT0_ADDR	0x0014
 #define VPU_DMEM_EXT1_ADDR	0x0018
 #define HOST_TO_VPU		0x0024
+#define VPU_IDLE_REG		0x002C
+#define VPU_INT_STATUS		0x0034
 #define VPU_PC_REG		0x0060
 #define VPU_WDT_REG		0x0084
 
 /* vpu inter-processor communication interrupt */
 #define VPU_IPC_INT		BIT(8)
+/* vpu idle state */
+#define VPU_IDLE_STATE		BIT(23)
 
 /**
  * enum vpu_fw_type - VPU firmware type
@@ -945,11 +950,74 @@ static int mtk_vpu_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static int mtk_vpu_suspend(struct device *dev)
+{
+	struct mtk_vpu *vpu = dev_get_drvdata(dev);
+	unsigned long timeout;
+	int ret;
+
+	ret = vpu_clock_enable(vpu);
+	if (ret) {
+		dev_err(dev, "failed to enable vpu clock\n");
+		return ret;
+	}
+
+	mutex_lock(&vpu->vpu_mutex);
+	/* disable vpu timer interrupt */
+	vpu_cfg_writel(vpu, vpu_cfg_readl(vpu, VPU_INT_STATUS) | VPU_IDLE_STATE,
+		       VPU_INT_STATUS);
+	/* check if vpu is idle for system suspend */
+	timeout = jiffies + msecs_to_jiffies(VPU_IDLE_TIMEOUT_MS);
+	do {
+		if (time_after(jiffies, timeout)) {
+			dev_err(dev, "vpu idle timeout\n");
+			mutex_unlock(&vpu->vpu_mutex);
+			vpu_clock_disable(vpu);
+			return -EIO;
+		}
+	} while (!vpu_cfg_readl(vpu, VPU_IDLE_REG));
+
+	mutex_unlock(&vpu->vpu_mutex);
+	vpu_clock_disable(vpu);
+	clk_unprepare(vpu->clk);
+
+	return 0;
+}
+
+static int mtk_vpu_resume(struct device *dev)
+{
+	struct mtk_vpu *vpu = dev_get_drvdata(dev);
+	int ret;
+
+	clk_prepare(vpu->clk);
+	ret = vpu_clock_enable(vpu);
+	if (ret) {
+		dev_err(dev, "failed to enable vpu clock\n");
+		return ret;
+	}
+
+	mutex_lock(&vpu->vpu_mutex);
+	/* enable vpu timer interrupt */
+	vpu_cfg_writel(vpu,
+		       vpu_cfg_readl(vpu, VPU_INT_STATUS) & ~(VPU_IDLE_STATE),
+		       VPU_INT_STATUS);
+	mutex_unlock(&vpu->vpu_mutex);
+	vpu_clock_disable(vpu);
+
+	return 0;
+}
+
+static const struct dev_pm_ops mtk_vpu_pm = {
+	.suspend = mtk_vpu_suspend,
+	.resume = mtk_vpu_resume,
+};
+
 static struct platform_driver mtk_vpu_driver = {
 	.probe	= mtk_vpu_probe,
 	.remove	= mtk_vpu_remove,
 	.driver	= {
 		.name	= "mtk_vpu",
+		.pm = &mtk_vpu_pm,
 		.of_match_table = mtk_vpu_match,
 	},
 };