[PATCH v3 03/12] media: iris: Add iris vpu bus support

[Vishnu Reddy <busanna.reddy@oss.qualcomm.com>]

From: Vikash Garodia <vikash.garodia@oss.qualcomm.com>

On glymur platform, firmware loading needs a separate IOMMU mapping with
its own stream ID. This stream ID is defined in the device tree with the
assosiated firmware function ID in the iommu-map property. To create this
mapping, a separate child device is needed so the firmware memory can be
isolated in its own IOMMU context.

Introduced a new bus called iris-vpu-bus. This creates a dynamic device,
and its dma_configure() callback calls of_dma_configure_id() with the
function ID provided by the client to map the corresponding stream ID.
This sets up a dedicated IOMMU context for the child device.

Signed-off-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
Signed-off-by: Vishnu Reddy <busanna.reddy@oss.qualcomm.com>
---
 drivers/media/platform/qcom/iris/Makefile       |  4 ++
 drivers/media/platform/qcom/iris/iris_vpu_bus.c | 69 +++++++++++++++++++++++++
 include/linux/iris_vpu_bus.h                    | 25 +++++++++
 3 files changed, 98 insertions(+)

diff --git a/drivers/media/platform/qcom/iris/Makefile b/drivers/media/platform/qcom/iris/Makefile
index 2abbd3aeb4af..6f4052b98491 100644
--- a/drivers/media/platform/qcom/iris/Makefile
+++ b/drivers/media/platform/qcom/iris/Makefile
@@ -31,3 +31,7 @@ qcom-iris-objs += iris_platform_gen1.o
 endif
 
 obj-$(CONFIG_VIDEO_QCOM_IRIS) += qcom-iris.o
+
+ifdef CONFIG_VIDEO_QCOM_IRIS
+obj-y += iris_vpu_bus.o
+endif
diff --git a/drivers/media/platform/qcom/iris/iris_vpu_bus.c b/drivers/media/platform/qcom/iris/iris_vpu_bus.c
new file mode 100644
index 000000000000..15ba4d9c563e
--- /dev/null
+++ b/drivers/media/platform/qcom/iris/iris_vpu_bus.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/device.h>
+#include <linux/iris_vpu_bus.h>
+#include <linux/of_device.h>
+
+static int iris_vpu_bus_dma_configure(struct device *dev)
+{
+	const u32 *iommu_fid = dev_get_drvdata(dev);
+
+	return of_dma_configure_id(dev, dev->parent->of_node, true, iommu_fid);
+}
+
+const struct bus_type iris_vpu_bus_type = {
+	.name = "iris-vpu-bus",
+	.dma_configure = iris_vpu_bus_dma_configure,
+};
+EXPORT_SYMBOL_GPL(iris_vpu_bus_type);
+
+static void release_iris_vpu_bus_device(struct device *dev)
+{
+	kfree(dev);
+}
+
+struct device *create_iris_vpu_bus_device(struct device *parent_device, const char *name,
+					  u64 dma_mask, const u32 *iommu_fid)
+{
+	struct device *dev;
+	int ret;
+
+	dev = kzalloc_obj(*dev);
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+
+	dev->release = release_iris_vpu_bus_device;
+	dev->bus = &iris_vpu_bus_type;
+	dev->parent = parent_device;
+	dev->coherent_dma_mask = dma_mask;
+	dev->dma_mask = &dev->coherent_dma_mask;
+
+	dev_set_name(dev, "%s", name);
+	dev_set_drvdata(dev, (void *)iommu_fid);
+
+	ret = device_register(dev);
+	if (ret) {
+		put_device(dev);
+		return ERR_PTR(ret);
+	}
+
+	return dev;
+}
+EXPORT_SYMBOL_GPL(create_iris_vpu_bus_device);
+
+static int __init iris_vpu_bus_init(void)
+{
+	int ret;
+
+	ret = bus_register(&iris_vpu_bus_type);
+	if (ret) {
+		pr_err("iris-vpu-bus registration failed: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+postcore_initcall(iris_vpu_bus_init);
diff --git a/include/linux/iris_vpu_bus.h b/include/linux/iris_vpu_bus.h
new file mode 100644
index 000000000000..750e878e489f
--- /dev/null
+++ b/include/linux/iris_vpu_bus.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _LINUX_IRIS_VPU_BUS_H
+#define _LINUX_IRIS_VPU_BUS_H
+
+#include <linux/device.h>
+
+#if IS_ENABLED(CONFIG_VIDEO_QCOM_IRIS)
+extern const struct bus_type iris_vpu_bus_type;
+
+struct device *create_iris_vpu_bus_device(struct device *parent_device, const char *name,
+					  u64 dma_mask, const u32 *iommu_fid);
+#else
+static inline struct device *create_iris_vpu_bus_device(struct device *parent_device,
+							const char *name, u64 dma_mask,
+							const u32 *iommu_fid)
+{
+	return NULL;
+}
+#endif
+
+#endif /* _LINUX_IRIS_VPU_BUS_H */

-- 
2.34.1