[RFC PATCH 22/29] drm/xe/uapi: Add uAPI to convert user semaphore to / from drm syncobj

[Matthew Brost]

Simple interface to allow user space to share user syncs with kernel
syncs (dma-fences). The idea also is when user syncs are converted to
kernel syncs, preemption is guarded against until the kernel sync
signals. This is required to adhere to dma-fencing rules (no memory
allocates done in path of dma-fence, resume after preemption requires
memory allocations).

FIXME: uAPI likely to change, perhaps in drm generic way. Currently
enough for a PoC and enable initial Mesa development.

Signed-off-by: Matthew Brost <matthew.brost at intel.com>
---
 include/uapi/drm/xe_drm.h | 62 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h
index 9356a714a2e0..0cd473d2d91b 100644
--- a/include/uapi/drm/xe_drm.h
+++ b/include/uapi/drm/xe_drm.h
@@ -102,6 +102,7 @@ extern "C" {
 #define DRM_XE_EXEC			0x09
 #define DRM_XE_WAIT_USER_FENCE		0x0a
 #define DRM_XE_OBSERVATION		0x0b
+#define DRM_XE_VM_CONVERT_FENCE		0x0c
 
 /* Must be kept compact -- no holes */
 
@@ -117,6 +118,7 @@ extern "C" {
 #define DRM_IOCTL_XE_EXEC			DRM_IOW(DRM_COMMAND_BASE + DRM_XE_EXEC, struct drm_xe_exec)
 #define DRM_IOCTL_XE_WAIT_USER_FENCE		DRM_IOWR(DRM_COMMAND_BASE + DRM_XE_WAIT_USER_FENCE, struct drm_xe_wait_user_fence)
 #define DRM_IOCTL_XE_OBSERVATION		DRM_IOW(DRM_COMMAND_BASE + DRM_XE_OBSERVATION, struct drm_xe_observation_param)
+#define DRM_IOCTL_XE_VM_CONVERT_FENCE		DRM_IOW(DRM_COMMAND_BASE + DRM_XE_VM_CONVERT_FENCE, struct drm_xe_vm_convert_fence)
 
 /**
  * DOC: Xe IOCTL Extensions
@@ -1796,6 +1798,66 @@ struct drm_xe_oa_stream_info {
 	__u64 reserved[3];
 };
 
+/**
+ * struct drm_xe_semaphore - Semaphore
+ */
+struct drm_xe_semaphore {
+	/**
+	 * @handle: Handle for the semaphore. Must be bound to the VM when
+	 * passed into drm_xe_vm_convert_fence.
+	 */
+	__u32 handle;
+
+	/** @offset: Offset in BO for semaphore, must QW aligned */
+	__u32 offset;
+
+	/** @seqno: Sequence number of semaphore */
+	__u64 seqno;
+
+	/** @token: Semaphore token - MBZ as not supported yet */
+	__u64 token;
+
+	/** @reserved: reserved for future use */
+	__u64 reserved[2];
+};
+
+/**
+ * struct drm_xe_vm_convert_fence - Convert semaphore to / from syncobj
+ *
+ * DRM_XE_SYNC_FLAG_SIGNAL set indicates semaphore -> syncobj
+ * DRM_XE_SYNC_FLAG_SIGNAL clear indicates syncobj -> semaphore
+ */
+struct drm_xe_vm_convert_fence {
+	/**
+	 * @extensions: Pointer to the first extension struct, if any
+	 */
+	__u64 extensions;
+
+	/** @vm_id: VM ID */
+	__u32 vm_id;
+
+	/** @flags: Flags - MBZ */
+	__u32 flags;
+
+	/** @pad: MBZ */
+	__u32 pad;
+
+	/**
+	 * @num_syncs: Number of struct drm_xe_sync and struct drm_xe_semaphore
+	 * in arrays.
+	 */
+	__u32 num_syncs;
+
+	/** @syncs: Pointer to struct drm_xe_sync array. */
+	__u64 syncs;
+
+	/** @semaphores: Pointer to struct drm_xe_semaphore array. */
+	__u64 semaphores;
+
+	/** @reserved: reserved for future use */
+	__u64 reserved[2];
+};
+
 #if defined(__cplusplus)
 }
 #endif
-- 
2.34.1