[PATCH v3 08/11] remoteproc: mediatek: Control SCP core 1 boot by rproc subdevice

[Tinghan Shen]

Register SCP core 1 as a subdevice of core 0 to control the boot sequence
and watchdog handling. The core 1 has to boot after core 0 because the
SCP clock and SRAM power is controlled by SCP core 0.
When SCP core 0 reports a watchdog timeout event, the SRAM is emptied
before rebooting the SCP core 0, forcing the reload of the SCP core 1 image.

Signed-off-by: Tinghan Shen <tinghan.shen at mediatek.com>
---
 drivers/remoteproc/mtk_common.h |  8 ++++
 drivers/remoteproc/mtk_scp.c    | 71 +++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+)

diff --git a/drivers/remoteproc/mtk_common.h b/drivers/remoteproc/mtk_common.h
index 54265c515315..dcde25f8bbf9 100644
--- a/drivers/remoteproc/mtk_common.h
+++ b/drivers/remoteproc/mtk_common.h
@@ -95,6 +95,13 @@ struct scp_ipi_desc {
 	void *priv;
 };
 
+struct scp_subdev_core {
+	struct rproc_subdev subdev;
+	struct mtk_scp *scp;
+};
+
+#define to_subdev_core(d) container_of(d, struct scp_subdev_core, subdev)
+
 struct mtk_scp;
 
 struct mtk_scp_of_data {
@@ -142,6 +149,7 @@ struct mtk_scp {
 	struct rproc_subdev *rpmsg_subdev;
 
 	struct mtk_scp *main_scp;
+	struct rproc_subdev *core_subdev;
 };
 
 /**
diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
index f7b738743ba9..2d43338b96da 100644
--- a/drivers/remoteproc/mtk_scp.c
+++ b/drivers/remoteproc/mtk_scp.c
@@ -871,6 +871,54 @@ static void scp_remove_rpmsg_subdev(struct mtk_scp *scp)
 	}
 }
 
+static int scp_core_subdev_start(struct rproc_subdev *subdev)
+{
+	struct scp_subdev_core *subdev_core = to_subdev_core(subdev);
+	struct mtk_scp *scp = subdev_core->scp;
+
+	rproc_boot(scp->rproc);
+
+	return 0;
+}
+
+static void scp_core_subdev_stop(struct rproc_subdev *subdev, bool crashed)
+{
+	struct scp_subdev_core *subdev_core = to_subdev_core(subdev);
+	struct mtk_scp *scp = subdev_core->scp;
+
+	rproc_shutdown(scp->rproc);
+}
+
+static int scp_core_subdev_register(struct mtk_scp *scp)
+{
+	struct device *dev = scp->dev;
+	struct scp_subdev_core *subdev_core;
+
+	subdev_core = devm_kzalloc(dev, sizeof(*subdev_core), GFP_KERNEL);
+	if (!subdev_core) {
+		scp->core_subdev = NULL;
+		return -ENOMEM;
+	}
+
+	subdev_core->scp = scp;
+	subdev_core->subdev.start = scp_core_subdev_start;
+	subdev_core->subdev.stop = scp_core_subdev_stop;
+
+	scp->core_subdev = &subdev_core->subdev;
+	rproc_add_subdev(scp->main_scp->rproc, scp->core_subdev);
+
+	return 0;
+}
+
+static void scp_core_subdev_unregister(struct mtk_scp *scp)
+{
+	if (scp->core_subdev) {
+		rproc_remove_subdev(scp->main_scp->rproc, scp->core_subdev);
+		devm_kfree(scp->dev, to_subdev_core(scp->core_subdev));
+		scp->core_subdev = NULL;
+	}
+}
+
 static int scp_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -974,6 +1022,23 @@ static int scp_probe(struct platform_device *pdev)
 		goto remove_subdev;
 	}
 
+	if (of_device_is_compatible(np, "mediatek,mt8195-scp-core")) {
+		ret = scp_core_subdev_register(scp);
+		if (ret) {
+			dev_err_probe(dev, ret, "Failed to register subdev\n");
+			goto remove_subdev;
+		}
+
+		/* sub cores are booted as subdevices of main core. */
+		rproc->auto_boot = false;
+	} else {
+		ret = devm_of_platform_populate(dev);
+		if (ret) {
+			dev_err_probe(dev, ret, "Failed to probe sub cores\n");
+			goto remove_subdev;
+		}
+	}
+
 	ret = rproc_add(rproc);
 	if (ret)
 		goto remove_subdev;
@@ -981,6 +1046,7 @@ static int scp_probe(struct platform_device *pdev)
 	return 0;
 
 remove_subdev:
+	scp_core_subdev_unregister(scp);
 	scp_remove_rpmsg_subdev(scp);
 	scp_ipi_unregister(scp, SCP_IPI_INIT);
 release_dev_mem:
@@ -997,6 +1063,11 @@ static int scp_remove(struct platform_device *pdev)
 	struct mtk_scp *scp = platform_get_drvdata(pdev);
 	int i;
 
+	if (of_device_is_compatible(scp->dev->of_node, "mediatek,mt8195-scp-core"))
+		scp_core_subdev_unregister(scp);
+	else
+		devm_of_platform_depopulate(scp->dev);
+
 	rproc_del(scp->rproc);
 	scp_remove_rpmsg_subdev(scp);
 	scp_ipi_unregister(scp, SCP_IPI_INIT);
-- 
2.18.0