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authorSinan Kaya <okaya@codeaurora.org>2016-07-19 16:01:46 +0300
committerAlex Williamson <alex.williamson@redhat.com>2016-07-19 19:26:44 +0300
commitd30daa33ec1d035acfdfc7662d7a5360592af44c (patch)
tree1ce71778d5c55adade4c911258d797028359d35b /drivers/vfio
parent5afec27474fdc52e9d80b359ce10fab59c85d131 (diff)
downloadlinux-d30daa33ec1d035acfdfc7662d7a5360592af44c.tar.xz
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>
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/platform/vfio_platform_common.c50
1 files changed, 49 insertions, 1 deletions
diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index a9760c2e68ad..a15a69b52080 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -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);
}