Re: [PATCH v7 1/7] media: platform: amd: Introduce amd isp4 capture driver

["Du, Bin" <bin.du@amd.com>]

Thanks Sarkari for your review, apologies for my delayed response 
because I wanted to respect your holiday and avoid any interruption, I 
hope this excuse won't appear too lame :)

On 12/22/2025 5:23 PM, Sakari Ailus wrote:
> Hi Bin,
> 
> Thanks for the update. Please see my comments below.
> 
> On Tue, Dec 16, 2025 at 05:13:20PM +0800, Bin Du wrote:
>> AMD isp4 capture is a v4l2 media device which implements media controller
>> interface. It has one sub-device (AMD ISP4 sub-device) endpoint which can
>> be connected to a remote CSI2 TX endpoint. It supports only one physical
>> interface for now. Also add ISP4 driver related entry info into the
>> MAINTAINERS file
>>
>> Co-developed-by: Sultan Alsawaf <sultan@kerneltoast.com>
>> Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
>> Co-developed-by: Svetoslav Stoilov <Svetoslav.Stoilov@amd.com>
>> Signed-off-by: Svetoslav Stoilov <Svetoslav.Stoilov@amd.com>
>> Signed-off-by: Bin Du <Bin.Du@amd.com>
>> Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
>> Tested-by: Alexey Zagorodnikov <xglooom@gmail.com>
>> ---
>>   MAINTAINERS                              |  13 +++
>>   drivers/media/platform/Kconfig           |   1 +
>>   drivers/media/platform/Makefile          |   1 +
>>   drivers/media/platform/amd/Kconfig       |   3 +
>>   drivers/media/platform/amd/Makefile      |   3 +
>>   drivers/media/platform/amd/isp4/Kconfig  |  14 +++
>>   drivers/media/platform/amd/isp4/Makefile |   6 ++
>>   drivers/media/platform/amd/isp4/isp4.c   | 132 +++++++++++++++++++++++
>>   drivers/media/platform/amd/isp4/isp4.h   |  17 +++
>>   9 files changed, 190 insertions(+)
>>   create mode 100644 drivers/media/platform/amd/Kconfig
>>   create mode 100644 drivers/media/platform/amd/Makefile
>>   create mode 100644 drivers/media/platform/amd/isp4/Kconfig
>>   create mode 100644 drivers/media/platform/amd/isp4/Makefile
>>   create mode 100644 drivers/media/platform/amd/isp4/isp4.c
>>   create mode 100644 drivers/media/platform/amd/isp4/isp4.h
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index cd7ff55b5d32..3640a1e3262c 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -1133,6 +1133,19 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux.git
>>   F:	drivers/iommu/amd/
>>   F:	include/linux/amd-iommu.h
>>   
>> +AMD ISP4 DRIVER
>> +M:	Bin Du <bin.du@amd.com>
>> +M:	Nirujogi Pratap <pratap.nirujogi@amd.com>
>> +L:	linux-media@vger.kernel.org
>> +S:	Maintained
>> +T:	git git://linuxtv.org/media.git
>> +F:	drivers/media/platform/amd/Kconfig
>> +F:	drivers/media/platform/amd/Makefile
>> +F:	drivers/media/platform/amd/isp4/Kconfig
>> +F:	drivers/media/platform/amd/isp4/Makefile
>> +F:	drivers/media/platform/amd/isp4/isp4.c
>> +F:	drivers/media/platform/amd/isp4/isp4.h
>> +
>>   AMD KFD
>>   M:	Felix Kuehling <Felix.Kuehling@amd.com>
>>   L:	amd-gfx@lists.freedesktop.org
>> diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
>> index 9287faafdce5..772c70665510 100644
>> --- a/drivers/media/platform/Kconfig
>> +++ b/drivers/media/platform/Kconfig
>> @@ -63,6 +63,7 @@ config VIDEO_MUX
>>   
>>   # Platform drivers - Please keep it alphabetically sorted
>>   source "drivers/media/platform/allegro-dvt/Kconfig"
>> +source "drivers/media/platform/amd/Kconfig"
>>   source "drivers/media/platform/amlogic/Kconfig"
>>   source "drivers/media/platform/amphion/Kconfig"
>>   source "drivers/media/platform/aspeed/Kconfig"
>> diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
>> index 6fd7db0541c7..b207bd8d8022 100644
>> --- a/drivers/media/platform/Makefile
>> +++ b/drivers/media/platform/Makefile
>> @@ -6,6 +6,7 @@
>>   # Place here, alphabetically sorted by directory
>>   # (e. g. LC_ALL=C sort Makefile)
>>   obj-y += allegro-dvt/
>> +obj-y += amd/
>>   obj-y += amlogic/
>>   obj-y += amphion/
>>   obj-y += aspeed/
>> diff --git a/drivers/media/platform/amd/Kconfig b/drivers/media/platform/amd/Kconfig
>> new file mode 100644
>> index 000000000000..25af49f246b2
>> --- /dev/null
>> +++ b/drivers/media/platform/amd/Kconfig
>> @@ -0,0 +1,3 @@
>> +# SPDX-License-Identifier: GPL-2.0+
>> +
>> +source "drivers/media/platform/amd/isp4/Kconfig"
>> diff --git a/drivers/media/platform/amd/Makefile b/drivers/media/platform/amd/Makefile
>> new file mode 100644
>> index 000000000000..8bfc1955f22e
>> --- /dev/null
>> +++ b/drivers/media/platform/amd/Makefile
>> @@ -0,0 +1,3 @@
>> +# SPDX-License-Identifier: GPL-2.0+
>> +
>> +obj-y += isp4/
>> diff --git a/drivers/media/platform/amd/isp4/Kconfig b/drivers/media/platform/amd/isp4/Kconfig
>> new file mode 100644
>> index 000000000000..d4e4ad436600
>> --- /dev/null
>> +++ b/drivers/media/platform/amd/isp4/Kconfig
>> @@ -0,0 +1,14 @@
>> +# SPDX-License-Identifier: GPL-2.0+
>> +
>> +config AMD_ISP4
> 
> We've used "VIDEO_" prefix for V4L2 drivers.
> 

Yes, will change it to VIDEO_AMD_ISP4 to meet the convention.

>> +	tristate "AMD ISP4 and camera driver"
>> +	depends on DRM_AMD_ISP && VIDEO_DEV
>> +	select VIDEOBUF2_CORE
>> +	select VIDEOBUF2_MEMOPS
>> +	select VIDEOBUF2_V4L2
>> +	select VIDEO_V4L2_SUBDEV_API
>> +	help
>> +	  This is support for AMD ISP4 and camera subsystem driver.
>> +	  Say Y here to enable the ISP4 and camera device for video capture.
>> +	  To compile this driver as a module, choose M here. The module will
>> +	  be called amd_capture.
> 
> How about "amd_isp4"? That would be aligned with the file names as well as
> the Kconfig option.
> 

Yes, good suggestion. That makes more sense. Will modify the makefile as 
well.

>> diff --git a/drivers/media/platform/amd/isp4/Makefile b/drivers/media/platform/amd/isp4/Makefile
>> new file mode 100644
>> index 000000000000..de0092dad26f
>> --- /dev/null
>> +++ b/drivers/media/platform/amd/isp4/Makefile
>> @@ -0,0 +1,6 @@
>> +# SPDX-License-Identifier: GPL-2.0+
>> +#
>> +# Copyright (C) 2025 Advanced Micro Devices, Inc.
>> +
>> +obj-$(CONFIG_AMD_ISP4) += amd_capture.o
>> +amd_capture-objs := isp4.o
>> diff --git a/drivers/media/platform/amd/isp4/isp4.c b/drivers/media/platform/amd/isp4/isp4.c
>> new file mode 100644
>> index 000000000000..ad95e7f89189
>> --- /dev/null
>> +++ b/drivers/media/platform/amd/isp4/isp4.c
>> @@ -0,0 +1,132 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * Copyright (C) 2025 Advanced Micro Devices, Inc.
>> + */
>> +
>> +#include <linux/pm_runtime.h>
>> +#include <linux/vmalloc.h>
>> +#include <media/v4l2-ioctl.h>
>> +
>> +#include "isp4.h"
>> +
>> +#define VIDEO_BUF_NUM 5
>> +
>> +#define ISP4_DRV_NAME "amd_isp_capture"
>> +
>> +static const struct {
>> +	const char *name;
>> +	u32 status_mask;
>> +	u32 en_mask;
>> +	u32 ack_mask;
>> +	u32 rb_int_num;
>> +} isp4_irq[] = {
>> +	/* The IRQ order is aligned with the isp4_subdev.fw_resp_thread order */
>> +	{
>> +		.name = "isp_irq_global",
>> +		.rb_int_num = 4, /* ISP_4_1__SRCID__ISP_RINGBUFFER_WPT12 */
>> +	},
>> +	{
>> +		.name = "isp_irq_stream1",
>> +		.rb_int_num = 0, /* ISP_4_1__SRCID__ISP_RINGBUFFER_WPT9 */
>> +	},
>> +};
>> +
>> +static irqreturn_t isp4_irq_handler(int irq, void *arg)
>> +{
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static int isp4_capture_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	int irq[ARRAY_SIZE(isp4_irq)];
>> +	struct isp4_device *isp_dev;
>> +	size_t i;
>> +	int ret;
>> +
>> +	isp_dev = devm_kzalloc(dev, sizeof(*isp_dev), GFP_KERNEL);
>> +	if (!isp_dev)
>> +		return -ENOMEM;
>> +
>> +	dev->init_name = ISP4_DRV_NAME;
>> +
>> +	for (i = 0; i < ARRAY_SIZE(isp4_irq); i++) {
>> +		irq[i] = platform_get_irq(pdev, isp4_irq[i].rb_int_num);
>> +		if (irq[i] < 0)
>> +			return dev_err_probe(dev, irq[i], "fail to get irq %d\n",
>> +					     isp4_irq[i].rb_int_num);
>> +
>> +		ret = devm_request_irq(dev, irq[i], isp4_irq_handler,
>> +				       IRQF_NO_AUTOEN, isp4_irq[i].name, dev);
>> +		if (ret)
>> +			return dev_err_probe(dev, ret, "fail to req irq %d\n", irq[i]);
>> +	}
>> +
>> +	/* Link the media device within the v4l2_device */
>> +	isp_dev->v4l2_dev.mdev = &isp_dev->mdev;
>> +
>> +	/* Initialize media device */
>> +	strscpy(isp_dev->mdev.model, "amd_isp41_mdev", sizeof(isp_dev->mdev.model));
>> +	snprintf(isp_dev->mdev.bus_info, sizeof(isp_dev->mdev.bus_info),
>> +		 "platform:%s", ISP4_DRV_NAME);
> 
> No need to do this explicitly.
> 

Yes, it is done inside media_device_init, will remove the redundancy here.

>> +	isp_dev->mdev.dev = dev;
>> +	media_device_init(&isp_dev->mdev);
>> +
>> +	/* register v4l2 device */
> 
> Please drop this comment, it's not informational.
> 

Sure, will do that.

>> +	snprintf(isp_dev->v4l2_dev.name, sizeof(isp_dev->v4l2_dev.name),
>> +		 "AMD-V4L2-ROOT");
>> +	ret = v4l2_device_register(dev, &isp_dev->v4l2_dev);
>> +	if (ret) {
>> +		dev_err_probe(dev, ret, "fail register v4l2 device\n");
>> +		goto err_clean_media;
>> +	}
>> +
>> +	pm_runtime_set_suspended(dev);
>> +	pm_runtime_enable(dev);
>> +	ret = media_device_register(&isp_dev->mdev);
>> +	if (ret) {
>> +		dev_err_probe(dev, ret, "fail to register media device\n");
>> +		goto err_isp4_deinit;
>> +	}
>> +
>> +	platform_set_drvdata(pdev, isp_dev);
>> +
>> +	return 0;
>> +
>> +err_isp4_deinit:
>> +	pm_runtime_disable(dev);
>> +	v4l2_device_unregister(&isp_dev->v4l2_dev);
>> +err_clean_media:
>> +	media_device_cleanup(&isp_dev->mdev);
>> +
>> +	return ret;
>> +}
>> +
>> +static void isp4_capture_remove(struct platform_device *pdev)
>> +{
>> +	struct isp4_device *isp_dev = platform_get_drvdata(pdev);
>> +	struct device *dev = &pdev->dev;
>> +
>> +	media_device_unregister(&isp_dev->mdev);
>> +	pm_runtime_disable(dev);
>> +	v4l2_device_unregister(&isp_dev->v4l2_dev);
>> +	media_device_cleanup(&isp_dev->mdev);
>> +}
>> +
>> +static struct platform_driver isp4_capture_drv = {
>> +	.probe = isp4_capture_probe,
>> +	.remove = isp4_capture_remove,
>> +	.driver = {
>> +		.name = ISP4_DRV_NAME,
>> +	}
>> +};
>> +
>> +module_platform_driver(isp4_capture_drv);
>> +
>> +MODULE_ALIAS("platform:" ISP4_DRV_NAME);
>> +MODULE_IMPORT_NS("DMA_BUF");
>> +
>> +MODULE_DESCRIPTION("AMD ISP4 Driver");
>> +MODULE_AUTHOR("Bin Du <bin.du@amd.com>");
>> +MODULE_AUTHOR("Pratap Nirujogi <pratap.nirujogi@amd.com>");
>> +MODULE_LICENSE("GPL");
>> diff --git a/drivers/media/platform/amd/isp4/isp4.h b/drivers/media/platform/amd/isp4/isp4.h
>> new file mode 100644
>> index 000000000000..7f2db0dfa2d9
>> --- /dev/null
>> +++ b/drivers/media/platform/amd/isp4/isp4.h
>> @@ -0,0 +1,17 @@
>> +/* SPDX-License-Identifier: GPL-2.0+ */
>> +/*
>> + * Copyright (C) 2025 Advanced Micro Devices, Inc.
>> + */
>> +
>> +#ifndef _ISP4_H_
>> +#define _ISP4_H_
>> +
>> +#include <media/v4l2-device.h>
>> +#include <media/videobuf2-memops.h>
>> +
>> +struct isp4_device {
>> +	struct v4l2_device v4l2_dev;
>> +	struct media_device mdev;
>> +};
>> +
>> +#endif /* _ISP4_H_ */
> 

-- 
Regards,
Bin