Re: [PATCH v8 02/18] vfio: platform: probe to devices on the platform bus

[Eric Auger <eric.auger-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>]

On 10/21/2014 06:17 PM, Alex Williamson wrote:
> On Mon, 2014-10-13 at 15:10 +0200, Antonios Motakis wrote:
>> Driver to bind to Linux platform devices, and callbacks to discover their
>> resources to be used by the main VFIO PLATFORM code.
>>
>> Signed-off-by: Antonios Motakis <a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>
>> ---
>>  drivers/vfio/platform/vfio_platform.c | 107 ++++++++++++++++++++++++++++++++++
>>  include/uapi/linux/vfio.h             |   1 +
>>  2 files changed, 108 insertions(+)
>>  create mode 100644 drivers/vfio/platform/vfio_platform.c
>>
>> diff --git a/drivers/vfio/platform/vfio_platform.c b/drivers/vfio/platform/vfio_platform.c
>> new file mode 100644
>> index 0000000..baeb7da
>> --- /dev/null
>> +++ b/drivers/vfio/platform/vfio_platform.c
>> @@ -0,0 +1,107 @@
>> +/*
>> + * Copyright (C) 2013 - Virtual Open Systems
>> + * Author: Antonios Motakis <a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License, version 2, as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + */
>> +
>> +#include <linux/device.h>
>> +#include <linux/eventfd.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/iommu.h>
>> +#include <linux/module.h>
>> +#include <linux/mutex.h>
>> +#include <linux/notifier.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/slab.h>
>> +#include <linux/types.h>
>> +#include <linux/uaccess.h>
>> +#include <linux/vfio.h>
>> +#include <linux/io.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/irq.h>
>> +
>> +#include "vfio_platform_private.h"
>> +
>> +#define DRIVER_VERSION  "0.8"
>> +#define DRIVER_AUTHOR   "Antonios Motakis <a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>"
>> +#define DRIVER_DESC     "VFIO for platform devices - User Level meta-driver"
>> +
>> +/* probing devices from the linux platform bus */
>> +
>> +static struct resource *get_platform_resource(struct vfio_platform_device *vdev,
>> +						int num)
>> +{
>> +	struct platform_device *dev = (struct platform_device *) vdev->opaque;
>> +	int i;
>> +
>> +	for (i = 0; i < dev->num_resources; i++) {
>> +		struct resource *r = &dev->resource[i];
>> +
>> +		if (resource_type(r) & (IORESOURCE_MEM|IORESOURCE_IO)) {
>> +			num--;
>> +
>> +			if (!num)
>> +				return r;
> 
> Has this been tested?  What happens when we call this with num = 0?
Yep. I confirm I enter that case with my xgmac where the IORESOURCE_MEM
is the 1st resource. I Just ended to the same cause ;-)

Best Regards

Eric
> 
>> +		}
>> +	}
>> +	return NULL;
>> +}
>> +
>> +static int get_platform_irq(struct vfio_platform_device *vdev, int i)
>> +{
>> +	struct platform_device *pdev = (struct platform_device *) vdev->opaque;
>> +
>> +	return platform_get_irq(pdev, i);
>> +}
>> +
>> +
>> +static int vfio_platform_probe(struct platform_device *pdev)
>> +{
>> +	struct vfio_platform_device *vdev;
>> +	int ret;
>> +
>> +	vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
>> +	if (!vdev)
>> +		return -ENOMEM;
>> +
>> +	vdev->opaque = (void *) pdev;
>> +	vdev->name = pdev->name;
>> +	vdev->flags = VFIO_DEVICE_FLAGS_PLATFORM;
>> +	vdev->get_resource = get_platform_resource;
>> +	vdev->get_irq = get_platform_irq;
>> +
>> +	ret = vfio_platform_probe_common(vdev, &pdev->dev);
>> +	if (ret)
>> +		kfree(vdev);
>> +
>> +	return ret;
>> +}
>> +
>> +static int vfio_platform_remove(struct platform_device *pdev)
>> +{
>> +	return vfio_platform_remove_common(&pdev->dev);
>> +}
>> +
>> +static struct platform_driver vfio_platform_driver = {
>> +	.probe		= vfio_platform_probe,
>> +	.remove		= vfio_platform_remove,
>> +	.driver	= {
>> +		.name	= "vfio-platform",
>> +		.owner	= THIS_MODULE,
>> +	},
>> +};
>> +
>> +module_platform_driver(vfio_platform_driver);
>> +
>> +MODULE_VERSION(DRIVER_VERSION);
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_AUTHOR(DRIVER_AUTHOR);
>> +MODULE_DESCRIPTION(DRIVER_DESC);
>> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
>> index 111b5e8..aca6d3e 100644
>> --- a/include/uapi/linux/vfio.h
>> +++ b/include/uapi/linux/vfio.h
>> @@ -158,6 +158,7 @@ struct vfio_device_info {
>>  	__u32	flags;
>>  #define VFIO_DEVICE_FLAGS_RESET	(1 << 0)	/* Device supports reset */
>>  #define VFIO_DEVICE_FLAGS_PCI	(1 << 1)	/* vfio-pci device */
>> +#define VFIO_DEVICE_FLAGS_PLATFORM (1 << 2)	/* vfio-platform device */
>>  	__u32	num_regions;	/* Max region index + 1 */
>>  	__u32	num_irqs;	/* Max IRQ index + 1 */
>>  };
> 
> 
>