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