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Commit a12a9368 authored by Sinan Kaya's avatar Sinan Kaya Committed by Alex Williamson
Browse files

vfio: platform: add support for ACPI probe 



The code is using the compatible DT string to associate a reset driver
with the actual device itself. The compatible string does not exist on
ACPI based systems. HID is the unique identifier for a device driver
instead.

Signed-off-by: default avatarSinan Kaya <okaya@codeaurora.org>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent dc5542fb

drivers/vfio/platform/vfio_platform_common.c

+59 −5
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
 */



#include <linux/device.h>

#include <linux/acpi.h>

#include <linux/iommu.h>

#include <linux/module.h>

#include <linux/mutex.h>
@@ -49,6 +50,27 @@ static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat, 
	return reset_fn;

}



static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,

				    struct device *dev)

{

	struct acpi_device *adev;



	if (acpi_disabled)

		return -ENOENT;



	adev = ACPI_COMPANION(dev);

	if (!adev) {

		pr_err("VFIO: ACPI companion device not found for %s\n",

			vdev->name);

		return -ENODEV;

	}



#ifdef CONFIG_ACPI

	vdev->acpihid = acpi_device_hid(adev);

#endif

	return WARN_ON(!vdev->acpihid) ? -EINVAL : 0;

}



static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)

{

	return vdev->of_reset ? true : false;
@@ -547,6 +569,37 @@ static const struct vfio_device_ops vfio_platform_ops = { 
	.mmap		= vfio_platform_mmap,

};



int vfio_platform_of_probe(struct vfio_platform_device *vdev,

			   struct device *dev)

{

	int ret;



	ret = device_property_read_string(dev, "compatible",

					  &vdev->compat);

	if (ret)

		pr_err("VFIO: cannot retrieve compat for %s\n",

			vdev->name);



	return ret;

}



/*

 * There can be two kernel build combinations. One build where

 * ACPI is not selected in Kconfig and another one with the ACPI Kconfig.

 *

 * In the first case, vfio_platform_acpi_probe will return since

 * acpi_disabled is 1. DT user will not see any kind of messages from

 * ACPI.

 *

 * In the second case, both DT and ACPI is compiled in but the system is

 * booting with any of these combinations.

 *

 * If the firmware is DT type, then acpi_disabled is 1. The ACPI probe routine

 * terminates immediately without any messages.

 *

 * If the firmware is ACPI type, then acpi_disabled is 0. All other checks are

 * valid checks. We cannot claim that this system is DT.

 */

int vfio_platform_probe_common(struct vfio_platform_device *vdev,

			       struct device *dev)

{
@@ -556,11 +609,12 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev, 
	if (!vdev)

		return -EINVAL;



	ret = device_property_read_string(dev, "compatible", &vdev->compat);

	if (ret) {

		pr_err("VFIO: cannot retrieve compat for %s\n", vdev->name);

		return -EINVAL;

	}

	ret = vfio_platform_acpi_probe(vdev, dev);

	if (ret)

		ret = vfio_platform_of_probe(vdev, dev);



	if (ret)

		return ret;



	vdev->device = dev;

drivers/vfio/platform/vfio_platform_private.h

+1 −0
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ struct vfio_platform_device { 
	struct mutex			igate;

	struct module			*parent_module;

	const char			*compat;

	const char			*acpihid;

	struct module			*reset_module;

	struct device			*device;