Re: [PATCH v5 01/14] media: iris: Add iris vpu bus support

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

On 5/9/2026 12:46 AM, Dmitry Baryshkov wrote:
> On Sat, May 09, 2026 at 12:29:50AM +0530, Vishnu Reddy wrote:
>> 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.
>>
>> Reviewed-by: Vishnu Reddy <busanna.reddy@oss.qualcomm.com>
>> 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/Kconfig        |  4 ++
>>  drivers/media/platform/qcom/iris/Makefile       |  1 +
>>  drivers/media/platform/qcom/iris/iris_vpu_bus.c | 69 +++++++++++++++++++++++++
>>  include/linux/iris_vpu_bus.h                    | 25 +++++++++
>>  4 files changed, 99 insertions(+)
>>
>> diff --git a/drivers/media/platform/qcom/iris/Kconfig b/drivers/media/platform/qcom/iris/Kconfig
>> index 5498f48362d1..025280ef1221 100644
>> --- a/drivers/media/platform/qcom/iris/Kconfig
>> +++ b/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
>> @@ -6,6 +9,7 @@ config VIDEO_QCOM_IRIS
>>          select QCOM_MDT_LOADER
>>          select QCOM_SCM
>>          select VIDEOBUF2_DMA_CONTIG
>> +        select QCOM_IRIS_VPU_BUS
>>          help
>>            This is a V4L2 driver for Qualcomm iris video accelerator
>>            hardware. It accelerates decoding operations on various
>> diff --git a/drivers/media/platform/qcom/iris/Makefile b/drivers/media/platform/qcom/iris/Makefile
>> index 2abbd3aeb4af..79bc67980339 100644
>> --- a/drivers/media/platform/qcom/iris/Makefile
>> +++ b/drivers/media/platform/qcom/iris/Makefile
>> @@ -31,3 +31,4 @@ qcom-iris-objs += iris_platform_gen1.o
>>  endif
>>  
>>  obj-$(CONFIG_VIDEO_QCOM_IRIS) += qcom-iris.o
>> +obj-$(CONFIG_QCOM_IRIS_VPU_BUS) += iris_vpu_bus.o
>> 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);
> This should be drm_get_platdata() rather than _drvdata().

Ack, will use dev_get_platdata().

>> +
>> +	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);
> Just 'return bus_register();'

Ack.

>> +		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..7437a2ba411c
>> --- /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>
>> +
>> +#ifdef CONFIG_QCOM_IRIS_VPU_BUS
>> +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,
> You are adding globally visible API without _any_ sensible prefix. It
> should be named other way: iris_vpu_bus_create_device().

Ack.

>> +							const char *name, u64 dma_mask,
>> +							const u32 *iommu_fid)
>> +{
>> +	return ERR_PTR(-ENODEV);
>> +}
>> +#endif
>> +
>> +#endif /* _LINUX_IRIS_VPU_BUS_H */
>>
>> -- 
>> 2.34.1
>>