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: Sinan Kaya <okaya@codeaurora.org> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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@ -28,6 +28,8 @@
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#define DRIVER_AUTHOR "Antonios Motakis <a.motakis@virtualopensystems.com>"
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#define DRIVER_DESC "VFIO platform base module"
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#define VFIO_PLATFORM_IS_ACPI(vdev) ((vdev)->acpihid != NULL)
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static LIST_HEAD(reset_list);
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static DEFINE_MUTEX(driver_lock);
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@ -71,13 +73,53 @@ static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
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return WARN_ON(!vdev->acpihid) ? -EINVAL : 0;
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}
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int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
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const char **extra_dbg)
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{
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#ifdef CONFIG_ACPI
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struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
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struct device *dev = vdev->device;
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acpi_handle handle = ACPI_HANDLE(dev);
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acpi_status acpi_ret;
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acpi_ret = acpi_evaluate_object(handle, "_RST", NULL, &buffer);
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if (ACPI_FAILURE(acpi_ret)) {
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if (extra_dbg)
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*extra_dbg = acpi_format_exception(acpi_ret);
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return -EINVAL;
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}
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return 0;
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#else
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return -ENOENT;
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#endif
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}
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bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
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{
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#ifdef CONFIG_ACPI
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struct device *dev = vdev->device;
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acpi_handle handle = ACPI_HANDLE(dev);
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return acpi_has_method(handle, "_RST");
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#else
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return false;
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#endif
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}
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static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
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{
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if (VFIO_PLATFORM_IS_ACPI(vdev))
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return vfio_platform_acpi_has_reset(vdev);
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return vdev->of_reset ? true : false;
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}
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static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
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{
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if (VFIO_PLATFORM_IS_ACPI(vdev))
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return;
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vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
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&vdev->reset_module);
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if (!vdev->of_reset) {
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@ -89,6 +131,9 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
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static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
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{
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if (VFIO_PLATFORM_IS_ACPI(vdev))
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return;
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if (vdev->of_reset)
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module_put(vdev->reset_module);
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}
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@ -164,7 +209,10 @@ static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev)
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static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
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const char **extra_dbg)
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{
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if (vdev->of_reset) {
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if (VFIO_PLATFORM_IS_ACPI(vdev)) {
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dev_info(vdev->device, "reset\n");
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return vfio_platform_acpi_call_reset(vdev, extra_dbg);
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} else if (vdev->of_reset) {
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dev_info(vdev->device, "reset\n");
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return vdev->of_reset(vdev);
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}
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