VFIO: platform: add reset callback

A new reset callback is introduced. If this callback is populated,
the reset is invoked on device first open/last close or upon userspace
ioctl.  The modality is exposed on VFIO_DEVICE_GET_INFO.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Acked-by: Baptiste Reynal <b.reynal@virtualopensystems.com>
Tested-by: Baptiste Reynal <b.reynal@virtualopensystems.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

2 files changed, 14 insertions, 2 deletions

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index 611597e65f44..63935811cbd9 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -103,6 +103,8 @@ static void vfio_platform_release(void *device_data)
         mutex_lock(&driver_lock);
 
         if (!(--vdev->refcnt)) {
+                if (vdev->reset)
+                        vdev->reset(vdev);
                 vfio_platform_regions_cleanup(vdev);
                 vfio_platform_irq_cleanup(vdev);
         }
@@ -130,6 +132,9 @@ static int vfio_platform_open(void *device_data)
                 ret = vfio_platform_irq_init(vdev);
                 if (ret)
                         goto err_irq;
+
+                if (vdev->reset)
+                        vdev->reset(vdev);
         }
 
         vdev->refcnt++;
@@ -162,6 +167,8 @@ static long vfio_platform_ioctl(void *device_data,
                 if (info.argsz < minsz)
                         return -EINVAL;
 
+                if (vdev->reset)
+                        vdev->flags |= VFIO_DEVICE_FLAGS_RESET;
                 info.flags = vdev->flags;
                 info.num_regions = vdev->num_regions;
                 info.num_irqs = vdev->num_irqs;
@@ -255,8 +262,12 @@ static long vfio_platform_ioctl(void *device_data,
 
                 return ret;
 
-        } else if (cmd == VFIO_DEVICE_RESET)
-                return -EINVAL;
+        } else if (cmd == VFIO_DEVICE_RESET) {
+                if (vdev->reset)
+                        return vdev->reset(vdev);
+                else
+                        return -EINVAL;
+        }
 
         return -ENOTTY;
 }
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index 9e37b9fda483..1c9b3d59543c 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -67,6 +67,7 @@ struct vfio_platform_device {
         struct resource*
                 (*get_resource)(struct vfio_platform_device *vdev, int i);
         int     (*get_irq)(struct vfio_platform_device *vdev, int i);
+        int     (*reset)(struct vfio_platform_device *vdev);
 };
 
 struct vfio_platform_reset_combo {