Re: [PATCH v2 1/8] media: platform: amd: Introduce amd isp4 capture driver

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

Many thanks Askari Alius for your careful review.

On 7/28/2025 1:54 PM, Sakari Ailus wrote:
> Hi Bin,
> 
> On Wed, Jun 18, 2025 at 05:19:52PM +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 MAINAINERS file
> 
> You could rewrap the text and use the full lines here -- up to 75
> characters per line.
> 
Sure, will do in the next patch>>
>> Signed-off-by: Bin Du <Bin.Du@amd.com>
>> Signed-off-by: Svetoslav Stoilov <Svetoslav.Stoilov@amd.com>
>> ---
>>   MAINTAINERS                              |  10 ++
>>   drivers/media/platform/Kconfig           |   1 +
>>   drivers/media/platform/Makefile          |   1 +
>>   drivers/media/platform/amd/Kconfig       |  17 +++
>>   drivers/media/platform/amd/Makefile      |   5 +
>>   drivers/media/platform/amd/isp4/Makefile |  21 ++++
>>   drivers/media/platform/amd/isp4/isp4.c   | 139 +++++++++++++++++++++++
>>   drivers/media/platform/amd/isp4/isp4.h   |  35 ++++++
>>   8 files changed, 229 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/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 10893c91b1c1..15070afb14b5 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -1107,6 +1107,16 @@ 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/*
>> +
>>   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 85d2627776b6..d525c2262a7d 100644
>> --- a/drivers/media/platform/Kconfig
>> +++ b/drivers/media/platform/Kconfig
>> @@ -89,5 +89,6 @@ source "drivers/media/platform/ti/Kconfig"
>>   source "drivers/media/platform/verisilicon/Kconfig"
>>   source "drivers/media/platform/via/Kconfig"
>>   source "drivers/media/platform/xilinx/Kconfig"
>> +source "drivers/media/platform/amd/Kconfig"
>>   
>>   endif # MEDIA_PLATFORM_DRIVERS
>> diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
>> index ace4e34483dd..9f3d1693868d 100644
>> --- a/drivers/media/platform/Makefile
>> +++ b/drivers/media/platform/Makefile
>> @@ -32,6 +32,7 @@ obj-y += ti/
>>   obj-y += verisilicon/
>>   obj-y += via/
>>   obj-y += xilinx/
>> +obj-y += amd/
>>   
>>   # Please place here only ancillary drivers that aren't SoC-specific
>>   # Please keep it alphabetically sorted by Kconfig name
>> diff --git a/drivers/media/platform/amd/Kconfig b/drivers/media/platform/amd/Kconfig
>> new file mode 100644
>> index 000000000000..3b1dba0400a0
>> --- /dev/null
>> +++ b/drivers/media/platform/amd/Kconfig
>> @@ -0,0 +1,17 @@
>> +# SPDX-License-Identifier: MIT
>> +
>> +config AMD_ISP4
>> +	tristate "AMD ISP4 and camera driver"
>> +	default y
>> +	depends on VIDEO_DEV && VIDEO_V4L2_SUBDEV_API
>> +	select VIDEOBUF2_CORE
>> +	select VIDEOBUF2_V4L2
>> +	select VIDEOBUF2_MEMOPS
>> +	select VIDEOBUF2_VMALLOC
>> +	select VIDEOBUF2_DMA_CONTIG
>> +	select VIDEOBUF2_DMA_SG
> 
> Do you need all these three? Most drivers need only one.
> 
After double check, yes, none of theam are used in our code, will remove 
them and also the header files included>> +	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.
>> diff --git a/drivers/media/platform/amd/Makefile b/drivers/media/platform/amd/Makefile
>> new file mode 100644
>> index 000000000000..76146efcd2bf
>> --- /dev/null
>> +++ b/drivers/media/platform/amd/Makefile
>> @@ -0,0 +1,5 @@
>> +# Copyright 2024 Advanced Micro Devices, Inc.
>> +# add isp block
>> +ifneq ($(CONFIG_AMD_ISP4),)
>> +obj-y += isp4/
>> +endif
>> diff --git a/drivers/media/platform/amd/isp4/Makefile b/drivers/media/platform/amd/isp4/Makefile
>> new file mode 100644
>> index 000000000000..e9e84160517d
>> --- /dev/null
>> +++ b/drivers/media/platform/amd/isp4/Makefile
>> @@ -0,0 +1,21 @@
>> +# SPDX-License-Identifier: GPL-2.0+
>> +#
>> +# Copyright (C) 2025 Advanced Micro Devices, Inc.
>> +
>> +obj-$(CONFIG_AMD_ISP4) += amd_capture.o
>> +amd_capture-objs := isp4.o
>> +
>> +ccflags-y += -I$(srctree)/drivers/media/platform/amd/isp4
>> +ccflags-y += -I$(srctree)/include
>> +
>> +ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
>> +	cc_stack_align := -mpreferred-stack-boundary=4
>> +endif
> 
> Uh... does the driver actually depend on this?
> 
Yes, other comments also mentioned this, will update in the next patch>> +
>> +ccflags-y += $(cc_stack_align)
>> +ccflags-y += -DCONFIG_COMPAT
>> +ccflags-y += -Wunused-but-set-variable
>> +ccflags-y += -Wmissing-include-dirs
>> +ccflags-y += -Wunused-const-variable
>> +ccflags-y += -Wmaybe-uninitialized
>> +ccflags-y += -Wunused-value
>> diff --git a/drivers/media/platform/amd/isp4/isp4.c b/drivers/media/platform/amd/isp4/isp4.c
>> new file mode 100644
>> index 000000000000..d0be90c5ec3b
>> --- /dev/null
>> +++ b/drivers/media/platform/amd/isp4/isp4.c
>> @@ -0,0 +1,139 @@
>> +// 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>
> 
> Alphabetic order, please.
> 
Sorry, seems it's already in alphabetic order, an example in 
drivers/media/v4l2-core/v4l2-ioctl.c is like
#include <linux/v4l2-subdev.h>
#include <linux/videodev2.h>

#include <media/media-device.h> /* for media_set_bus_info() */
#include <media/v4l2-common.h>
Suppose i can add an empty line before #include <media/v4l2-ioctl.h>>> +
>> +#include "isp4.h"
>> +
>> +#define VIDEO_BUF_NUM 5
> 
> Unused.
> 
Yes, other comments also mentioned this, will remove it in the next 
patch>> +
>> +#define ISP4_DRV_NAME "amd_isp_capture"
>> +
>> +/* interrupt num */
>> +static const u32 isp4_ringbuf_interrupt_num[] = {
>> +	0, /* ISP_4_1__SRCID__ISP_RINGBUFFER_WPT9 */
>> +	1, /* ISP_4_1__SRCID__ISP_RINGBUFFER_WPT10 */
>> +	3, /* ISP_4_1__SRCID__ISP_RINGBUFFER_WPT11 */
>> +	4, /* ISP_4_1__SRCID__ISP_RINGBUFFER_WPT12 */
>> +};
>> +
>> +#define to_isp4_device(dev) \
>> +	((struct isp4_device *)container_of(dev, struct isp4_device, v4l2_dev))
> 
> No need for the cast.
> 
Sure, will remove the cast in the next patch>> +
>> +static irqreturn_t isp4_irq_handler(int irq, void *arg)
>> +{
>> +	struct isp4_device *isp_dev = dev_get_drvdata((struct device *)arg);
>> +
>> +	if (!isp_dev)
>> +		goto error_drv_data;
>> +
>> +error_drv_data:
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +/*
>> + * amd capture module
>> + */
>> +static int isp4_capture_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct isp4_device *isp_dev;
>> +
> 
> Extra newline.
> 
Yes, other comments also mentioned this, will remove it in the next 
patch>> +	int i, irq, ret;
> 
> unsigned int i?
> 
Weired, no compile warning about this, will change it to size_t i in the 
next patch.>> +
>> +	isp_dev = devm_kzalloc(&pdev->dev, sizeof(*isp_dev), GFP_KERNEL);
>> +	if (!isp_dev)
>> +		return -ENOMEM;
>> +
>> +	isp_dev->pdev = pdev;
>> +	dev->init_name = ISP4_DRV_NAME;
>> +
>> +	for (i = 0; i < ARRAY_SIZE(isp4_ringbuf_interrupt_num); i++) {
>> +		irq = platform_get_irq(pdev, isp4_ringbuf_interrupt_num[i]);
>> +		if (irq < 0)
>> +			return dev_err_probe(dev, -ENODEV,
>> +					     "fail to get irq %d\n",
>> +					     isp4_ringbuf_interrupt_num[i]);
>> +		ret = devm_request_irq(&pdev->dev, irq, isp4_irq_handler, 0,
>> +				       "ISP_IRQ", &pdev->dev);
>> +		if (ret)
>> +			return dev_err_probe(dev, ret, "fail to req irq %d\n",
>> +					     irq);
>> +	}
>> +
>> +	isp_dev->pltf_data = pdev->dev.platform_data;
>> +
>> +	dev_dbg(dev, "isp irq registration successful\n");
> 
> Please leave this out.
> 
Yes, other comments also mentioned this, will remove it in the next 
patch>> +
>> +	/* 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);
>> +	isp_dev->mdev.dev = &pdev->dev;
>> +	media_device_init(&isp_dev->mdev);
>> +
>> +	/* register v4l2 device */
>> +	snprintf(isp_dev->v4l2_dev.name, sizeof(isp_dev->v4l2_dev.name),
>> +		 "AMD-V4L2-ROOT");
>> +	ret = v4l2_device_register(&pdev->dev, &isp_dev->v4l2_dev);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret,
>> +				     "fail register v4l2 device\n");
>> +
>> +	dev_dbg(dev, "AMD ISP v4l2 device registered\n");
> 
> This doesn't seem useful.
> 
Yes, other comments also mentioned this, will remove it in the next 
patch>> +
>> +	ret = media_device_register(&isp_dev->mdev);
>> +	if (ret) {
>> +		dev_err(dev, "fail to register media device %d\n", ret);
>> +		goto err_unreg_v4l2;
>> +	}
>> +
>> +	platform_set_drvdata(pdev, isp_dev);
>> +
>> +	pm_runtime_set_suspended(dev);
>> +	pm_runtime_enable(dev);
> 
> You'll need to enable runtime PM before registering any interfaces on UAPI.
> Same goes for setting driver data for the device.
> 
Sure, will modify in the next patch>> +
>> +	return 0;
>> +
>> +err_unreg_v4l2:
>> +	v4l2_device_unregister(&isp_dev->v4l2_dev);
>> +
>> +	return dev_err_probe(dev, ret, "isp probe fail\n");
>> +}
>> +
>> +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);
>> +	v4l2_device_unregister(&isp_dev->v4l2_dev);
>> +	dev_dbg(dev, "AMD ISP v4l2 device unregistered\n");
> 
> I'd say this is redundant.
> 
Yes, other comments also mentioned this, will remove it in the next 
patch>> +}
>> +
>> +static struct platform_driver isp4_capture_drv = {
>> +	.probe = isp4_capture_probe,
>> +	.remove = isp4_capture_remove,
>> +	.driver = {
>> +		.name = ISP4_DRV_NAME,
>> +		.owner = THIS_MODULE,
>> +	}
>> +};
>> +
>> +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..27a7362ce6f9
>> --- /dev/null
>> +++ b/drivers/media/platform/amd/isp4/isp4.h
>> @@ -0,0 +1,35 @@
>> +/* SPDX-License-Identifier: GPL-2.0+ */
>> +/*
>> + * Copyright (C) 2025 Advanced Micro Devices, Inc.
>> + */
>> +
>> +#ifndef _ISP4_H_
>> +#define _ISP4_H_
>> +
>> +#include <linux/mutex.h>
>> +#include <media/v4l2-device.h>
>> +#include <media/videobuf2-memops.h>
>> +#include <media/videobuf2-vmalloc.h>
>> +
>> +#define ISP4_GET_ISP_REG_BASE(isp4sd) (((isp4sd))->mmio)
>> +
>> +struct isp4_platform_data {
>> +	void *adev;
>> +	void *bo;
>> +	void *cpu_ptr;
>> +	u64 gpu_addr;
>> +	u32 size;
>> +	u32 asic_type;
>> +	resource_size_t base_rmmio_size;
>> +};
>> +
>> +struct isp4_device {
>> +	struct v4l2_device v4l2_dev;
>> +	struct media_device mdev;
>> +
>> +	struct isp4_platform_data *pltf_data;
>> +	struct platform_device *pdev;
>> +	struct notifier_block i2c_nb;
>> +};
>> +
>> +#endif /* isp4.h */
> 
> Use the same name as for the macro here, please.
> 
Yes, other comments also mentioned this, will modify in the next patch