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      1 /*	$NetBSD: xen_drm_front_evtchnl.h,v 1.2 2021/12/18 23:45:45 riastradh Exp $	*/
      2 
      3 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
      4 
      5 /*
      6  *  Xen para-virtual DRM device
      7  *
      8  * Copyright (C) 2016-2018 EPAM Systems Inc.
      9  *
     10  * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko (at) epam.com>
     11  */
     12 
     13 #ifndef __XEN_DRM_FRONT_EVTCHNL_H_
     14 #define __XEN_DRM_FRONT_EVTCHNL_H_
     15 
     16 #include <linux/completion.h>
     17 #include <linux/types.h>
     18 
     19 #include <xen/interface/io/ring.h>
     20 #include <xen/interface/io/displif.h>
     21 
     22 /*
     23  * All operations which are not connector oriented use this ctrl event channel,
     24  * e.g. fb_attach/destroy which belong to a DRM device, not to a CRTC.
     25  */
     26 #define GENERIC_OP_EVT_CHNL	0
     27 
     28 enum xen_drm_front_evtchnl_state {
     29 	EVTCHNL_STATE_DISCONNECTED,
     30 	EVTCHNL_STATE_CONNECTED,
     31 };
     32 
     33 enum xen_drm_front_evtchnl_type {
     34 	EVTCHNL_TYPE_REQ,
     35 	EVTCHNL_TYPE_EVT,
     36 };
     37 
     38 struct xen_drm_front_drm_info;
     39 
     40 struct xen_drm_front_evtchnl {
     41 	struct xen_drm_front_info *front_info;
     42 	int gref;
     43 	int port;
     44 	int irq;
     45 	int index;
     46 	enum xen_drm_front_evtchnl_state state;
     47 	enum xen_drm_front_evtchnl_type type;
     48 	/* either response id or incoming event id */
     49 	u16 evt_id;
     50 	/* next request id or next expected event id */
     51 	u16 evt_next_id;
     52 	union {
     53 		struct {
     54 			struct xen_displif_front_ring ring;
     55 			struct completion completion;
     56 			/* latest response status */
     57 			int resp_status;
     58 			/* serializer for backend IO: request/response */
     59 			struct mutex req_io_lock;
     60 		} req;
     61 		struct {
     62 			struct xendispl_event_page *page;
     63 		} evt;
     64 	} u;
     65 };
     66 
     67 struct xen_drm_front_evtchnl_pair {
     68 	struct xen_drm_front_evtchnl req;
     69 	struct xen_drm_front_evtchnl evt;
     70 };
     71 
     72 int xen_drm_front_evtchnl_create_all(struct xen_drm_front_info *front_info);
     73 
     74 int xen_drm_front_evtchnl_publish_all(struct xen_drm_front_info *front_info);
     75 
     76 void xen_drm_front_evtchnl_flush(struct xen_drm_front_evtchnl *evtchnl);
     77 
     78 void xen_drm_front_evtchnl_set_state(struct xen_drm_front_info *front_info,
     79 				     enum xen_drm_front_evtchnl_state state);
     80 
     81 void xen_drm_front_evtchnl_free_all(struct xen_drm_front_info *front_info);
     82 
     83 #endif /* __XEN_DRM_FRONT_EVTCHNL_H_ */
     84