1/* SPDX-License-Identifier: GPL-2.0 OR MIT */
  2
  3/*
  4 *  Xen para-virtual DRM device
  5 *
  6 * Copyright (C) 2016-2018 EPAM Systems Inc.
  7 *
  8 * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
  9 */
 10
 11#ifndef __XEN_DRM_FRONT_H_
 12#define __XEN_DRM_FRONT_H_
 13
 14#include <linux/scatterlist.h>
 15
 16#include <drm/drm_connector.h>
 17#include <drm/drm_simple_kms_helper.h>
 18
 19#include "xen_drm_front_cfg.h"
 20
 21struct drm_device;
 22struct drm_framebuffer;
 23struct drm_gem_object;
 24struct drm_pending_vblank_event;
 25
 26/**
 27 * DOC: Driver modes of operation in terms of display buffers used
 28 *
 29 * Depending on the requirements for the para-virtualized environment, namely
 30 * requirements dictated by the accompanying DRM/(v)GPU drivers running in both
 31 * host and guest environments, display buffers can be allocated by either
 32 * frontend driver or backend.
 33 */
 34
 35/**
 36 * DOC: Buffers allocated by the frontend driver
 37 *
 38 * In this mode of operation driver allocates buffers from system memory.
 39 *
 40 * Note! If used with accompanying DRM/(v)GPU drivers this mode of operation
 41 * may require IOMMU support on the platform, so accompanying DRM/vGPU
 42 * hardware can still reach display buffer memory while importing PRIME
 43 * buffers from the frontend driver.
 44 */
 45
 46/**
 47 * DOC: Buffers allocated by the backend
 48 *
 49 * This mode of operation is run-time configured via guest domain configuration
 50 * through XenStore entries.
 51 *
 52 * For systems which do not provide IOMMU support, but having specific
 53 * requirements for display buffers it is possible to allocate such buffers
 54 * at backend side and share those with the frontend.
 55 * For example, if host domain is 1:1 mapped and has DRM/GPU hardware expecting
 56 * physically contiguous memory, this allows implementing zero-copying
 57 * use-cases.
 58 *
 59 * Note, while using this scenario the following should be considered:
 60 *
 61 * #. If guest domain dies then pages/grants received from the backend
 62 *    cannot be claimed back
 63 *
 64 * #. Misbehaving guest may send too many requests to the
 65 *    backend exhausting its grant references and memory
 66 *    (consider this from security POV)
 67 */
 68
 69/**
 70 * DOC: Driver limitations
 71 *
 72 * #. Only primary plane without additional properties is supported.
 73 *
 74 * #. Only one video mode per connector supported which is configured
 75 *    via XenStore.
 76 *
 77 * #. All CRTCs operate at fixed frequency of 60Hz.
 78 */
 79
 80/* timeout in ms to wait for backend to respond */
 81#define XEN_DRM_FRONT_WAIT_BACK_MS	3000
 82
 83#ifndef GRANT_INVALID_REF
 84/*
 85 * Note on usage of grant reference 0 as invalid grant reference:
 86 * grant reference 0 is valid, but never exposed to a PV driver,
 87 * because of the fact it is already in use/reserved by the PV console.
 88 */
 89#define GRANT_INVALID_REF	0
 90#endif
 91
 92struct xen_drm_front_info {
 93	struct xenbus_device *xb_dev;
 94	struct xen_drm_front_drm_info *drm_info;
 95
 96	/* to protect data between backend IO code and interrupt handler */
 97	spinlock_t io_lock;
 98
 99	int num_evt_pairs;
100	struct xen_drm_front_evtchnl_pair *evt_pairs;
101	struct xen_drm_front_cfg cfg;
102
103	/* display buffers */
104	struct list_head dbuf_list;
105};
106
107struct xen_drm_front_drm_pipeline {
108	struct xen_drm_front_drm_info *drm_info;
109
110	int index;
111
112	struct drm_simple_display_pipe pipe;
113
114	struct drm_connector conn;
115	/* These are only for connector mode checking */
116	int width, height;
117
118	struct drm_pending_vblank_event *pending_event;
119
120	struct delayed_work pflip_to_worker;
121
122	bool conn_connected;
123};
124
125struct xen_drm_front_drm_info {
126	struct xen_drm_front_info *front_info;
127	struct drm_device *drm_dev;
128
129	struct xen_drm_front_drm_pipeline pipeline[XEN_DRM_FRONT_MAX_CRTCS];
130};
131
132static inline u64 xen_drm_front_fb_to_cookie(struct drm_framebuffer *fb)
133{
134	return (uintptr_t)fb;
135}
136
137static inline u64 xen_drm_front_dbuf_to_cookie(struct drm_gem_object *gem_obj)
138{
139	return (uintptr_t)gem_obj;
140}
141
142int xen_drm_front_mode_set(struct xen_drm_front_drm_pipeline *pipeline,
143			   u32 x, u32 y, u32 width, u32 height,
144			   u32 bpp, u64 fb_cookie);
145
146int xen_drm_front_dbuf_create(struct xen_drm_front_info *front_info,
147			      u64 dbuf_cookie, u32 width, u32 height,
148			      u32 bpp, u64 size, u32 offset, struct page **pages);
149
150int xen_drm_front_fb_attach(struct xen_drm_front_info *front_info,
151			    u64 dbuf_cookie, u64 fb_cookie, u32 width,
152			    u32 height, u32 pixel_format);
153
154int xen_drm_front_fb_detach(struct xen_drm_front_info *front_info,
155			    u64 fb_cookie);
156
157int xen_drm_front_page_flip(struct xen_drm_front_info *front_info,
158			    int conn_idx, u64 fb_cookie);
159
160void xen_drm_front_on_frame_done(struct xen_drm_front_info *front_info,
161				 int conn_idx, u64 fb_cookie);
162
163#endif /* __XEN_DRM_FRONT_H_ */