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Commit d30daa33 authored by Sinan Kaya's avatar Sinan Kaya Committed by Alex Williamson
Browse files

vfio: platform: call _RST method when using ACPI 



The device tree code checks for the presence of a reset driver and calls
the of_reset function pointer by looking up the reset driver as a module.

ACPI defines _RST method to perform device level reset. After the _RST
method is executed, the OS can resume using the device. _RST method is
expected to stop DMA transfers and IRQs.

This patch introduces two functions as vfio_platform_acpi_has_reset and
vfio_platform_acpi_call_reset. The has reset method is used to declare
reset capability via the ioctl flag VFIO_DEVICE_FLAGS_RESET. The call
reset function is used to execute the _RST ACPI method.

Signed-off-by: default avatarSinan Kaya <okaya@codeaurora.org>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 5afec274

drivers/vfio/platform/vfio_platform_common.c

+49 −1
Original line number Diff line number Diff line
@@ -28,6 +28,8 @@ 
#define DRIVER_AUTHOR   "Antonios Motakis <a.motakis@virtualopensystems.com>"

#define DRIVER_DESC     "VFIO platform base module"



#define VFIO_PLATFORM_IS_ACPI(vdev) ((vdev)->acpihid != NULL)



static LIST_HEAD(reset_list);

static DEFINE_MUTEX(driver_lock);
@@ -71,13 +73,53 @@ static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev, 
	return WARN_ON(!vdev->acpihid) ? -EINVAL : 0;

}



int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,

				  const char **extra_dbg)

{

#ifdef CONFIG_ACPI

	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

	struct device *dev = vdev->device;

	acpi_handle handle = ACPI_HANDLE(dev);

	acpi_status acpi_ret;



	acpi_ret = acpi_evaluate_object(handle, "_RST", NULL, &buffer);

	if (ACPI_FAILURE(acpi_ret)) {

		if (extra_dbg)

			*extra_dbg = acpi_format_exception(acpi_ret);

		return -EINVAL;

	}



	return 0;

#else

	return -ENOENT;

#endif

}



bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)

{

#ifdef CONFIG_ACPI

	struct device *dev = vdev->device;

	acpi_handle handle = ACPI_HANDLE(dev);



	return acpi_has_method(handle, "_RST");

#else

	return false;

#endif

}



static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)

{

	if (VFIO_PLATFORM_IS_ACPI(vdev))

		return vfio_platform_acpi_has_reset(vdev);



	return vdev->of_reset ? true : false;

}



static void vfio_platform_get_reset(struct vfio_platform_device *vdev)

{

	if (VFIO_PLATFORM_IS_ACPI(vdev))

		return;



	vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,

						    &vdev->reset_module);

	if (!vdev->of_reset) {
@@ -89,6 +131,9 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev) 


static void vfio_platform_put_reset(struct vfio_platform_device *vdev)

{

	if (VFIO_PLATFORM_IS_ACPI(vdev))

		return;



	if (vdev->of_reset)

		module_put(vdev->reset_module);

}
@@ -164,7 +209,10 @@ static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev) 
static int vfio_platform_call_reset(struct vfio_platform_device *vdev,

				    const char **extra_dbg)

{

	if (vdev->of_reset) {

	if (VFIO_PLATFORM_IS_ACPI(vdev)) {

		dev_info(vdev->device, "reset\n");

		return vfio_platform_acpi_call_reset(vdev, extra_dbg);

	} else if (vdev->of_reset) {

		dev_info(vdev->device, "reset\n");

		return vdev->of_reset(vdev);

	}