drivers/gpu/drm/xen/xen_drm_front.h

   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, u32 offset, 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 void xen_drm_front_gem_object_free(struct drm_gem_object *obj);
 164
 165 #endif /* __XEN_DRM_FRONT_H_ */