media: iris: Add iris vpu bus support

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
associated 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.

Introduce 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.

Reviewed-by: Vishnu Reddy <busanna.reddy@oss.qualcomm.com>
Signed-off-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Vishnu Reddy <busanna.reddy@oss.qualcomm.com>

MAINTAINERS

@@ -22306,6 +22306,7 @@ L:	linux-arm-msm@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/media/qcom,*-iris.yaml
 F:	drivers/media/platform/qcom/iris/
+F:	include/linux/iris_vpu_bus.h
 
 QUALCOMM MIPI CSI2 PHY DRIVER
 M:	Bryan O'Donoghue <bod@kernel.org>

drivers/media/platform/qcom/iris/Kconfig

@@ -1,3 +1,6 @@
+config QCOM_IRIS_VPU_BUS
+        bool
+
 config VIDEO_QCOM_IRIS
         tristate "Qualcomm iris V4L2 decoder driver"
         depends on VIDEO_DEV
@@ -5,6 +8,7 @@ config VIDEO_QCOM_IRIS
         select V4L2_MEM2MEM_DEV
         select QCOM_MDT_LOADER
         select QCOM_SCM
+        select QCOM_IRIS_VPU_BUS
         select QCOM_UBWC_CONFIG
         select VIDEOBUF2_DMA_CONTIG
         help

drivers/media/platform/qcom/iris/Makefile

@@ -31,3 +31,4 @@ qcom-iris-objs += iris_buffer.o \
              iris_vpu_common.o \
 
 obj-$(CONFIG_VIDEO_QCOM_IRIS) += qcom-iris.o
+obj-$(CONFIG_QCOM_IRIS_VPU_BUS) += iris_vpu_bus.o

drivers/media/platform/qcom/iris/iris_vpu_bus.c

@@ -0,0 +1,61 @@
+// 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>
+#include <linux/slab.h>
+
+static int iris_vpu_bus_dma_configure(struct device *dev)
+{
+	const u32 *iommu_fid = (const u32 *)dev_get_platdata(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 iris_vpu_bus_release_device(struct device *dev)
+{
+	kfree(dev);
+}
+
+struct device *iris_vpu_bus_create_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 = iris_vpu_bus_release_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->platform_data = (void *)iommu_fid;
+	dev_set_name(dev, "%s", name);
+
+	ret = device_register(dev);
+	if (ret) {
+		put_device(dev);
+		return ERR_PTR(ret);
+	}
+
+	return dev;
+}
+EXPORT_SYMBOL_GPL(iris_vpu_bus_create_device);
+
+static int __init iris_vpu_bus_init(void)
+{
+	return bus_register(&iris_vpu_bus_type);
+}
+postcore_initcall(iris_vpu_bus_init);

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>
+
+#ifdef CONFIG_QCOM_IRIS_VPU_BUS
+extern const struct bus_type iris_vpu_bus_type;
+
+struct device *iris_vpu_bus_create_device(struct device *parent_device, const char *name,
+					  u64 dma_mask, const u32 *iommu_fid);
+#else
+static inline struct device *iris_vpu_bus_create_device(struct device *parent_device,
+							const char *name, u64 dma_mask,
+							const u32 *iommu_fid)
+{
+	return ERR_PTR(-ENODEV);
+}
+#endif
+
+#endif /* _LINUX_IRIS_VPU_BUS_H */