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
21 struct drm_device;
22 struct drm_framebuffer;
23 struct drm_gem_object;
24 struct 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
92 struct 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
107 struct 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
125 struct 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
132 static inline u64 xen_drm_front_fb_to_cookie(struct drm_framebuffer *fb)
133 {
134 return (uintptr_t)fb;
135 }
136
137 static inline u64 xen_drm_front_dbuf_to_cookie(struct drm_gem_object *gem_obj)
138 {
139 return (uintptr_t)gem_obj;
140 }
141
142 int 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
146 int 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, struct page **pages);
149
150 int 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
154 int xen_drm_front_fb_detach(struct xen_drm_front_info *front_info,
155 u64 fb_cookie);
156
157 int xen_drm_front_page_flip(struct xen_drm_front_info *front_info,
158 int conn_idx, u64 fb_cookie);
159
160 void 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_ */