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_ */ 164