include/hw/xen/interface/io/fbif.h

   1 /* SPDX-License-Identifier: MIT */
   2 /*
   3  * fbif.h -- Xen virtual frame buffer device
   4  *
   5  * Copyright (C) 2005 Anthony Liguori <aliguori@us.ibm.com>
   6  * Copyright (C) 2006 Red Hat, Inc., Markus Armbruster <armbru@redhat.com>
   7  */
   8
   9 #ifndef __XEN_PUBLIC_IO_FBIF_H__
  10 #define __XEN_PUBLIC_IO_FBIF_H__
  11
  12 /* Out events (frontend -> backend) */
  13
  14 /*
  15  * Out events may be sent only when requested by backend, and receipt
  16  * of an unknown out event is an error.
  17  */
  18
  19 /* Event type 1 currently not used */
  20 /*
  21  * Framebuffer update notification event
  22  * Capable frontend sets feature-update in xenstore.
  23  * Backend requests it by setting request-update in xenstore.
  24  */
  25 #define XENFB_TYPE_UPDATE 2
  26
  27 struct xenfb_update
  28 {
  29     uint8_t type;    /* XENFB_TYPE_UPDATE */
  30     int32_t x;      /* source x */
  31     int32_t y;      /* source y */
  32     int32_t width;  /* rect width */
  33     int32_t height; /* rect height */
  34 };
  35
  36 /*
  37  * Framebuffer resize notification event
  38  * Capable backend sets feature-resize in xenstore.
  39  */
  40 #define XENFB_TYPE_RESIZE 3
  41
  42 struct xenfb_resize
  43 {
  44     uint8_t type;    /* XENFB_TYPE_RESIZE */
  45     int32_t width;   /* width in pixels */
  46     int32_t height;  /* height in pixels */
  47     int32_t stride;  /* stride in bytes */
  48     int32_t depth;   /* depth in bits */
  49     int32_t offset;  /* offset of the framebuffer in bytes */
  50 };
  51
  52 #define XENFB_OUT_EVENT_SIZE 40
  53
  54 union xenfb_out_event
  55 {
  56     uint8_t type;
  57     struct xenfb_update update;
  58     struct xenfb_resize resize;
  59     char pad[XENFB_OUT_EVENT_SIZE];
  60 };
  61
  62 /* In events (backend -> frontend) */
  63
  64 /*
  65  * Frontends should ignore unknown in events.
  66  */
  67
  68 /*
  69  * Framebuffer refresh period advice
  70  * Backend sends it to advise the frontend their preferred period of
  71  * refresh.  Frontends that keep the framebuffer constantly up-to-date
  72  * just ignore it.  Frontends that use the advice should immediately
  73  * refresh the framebuffer (and send an update notification event if
  74  * those have been requested), then use the update frequency to guide
  75  * their periodical refreshs.
  76  */
  77 #define XENFB_TYPE_REFRESH_PERIOD 1
  78 #define XENFB_NO_REFRESH 0
  79
  80 struct xenfb_refresh_period
  81 {
  82     uint8_t type;    /* XENFB_TYPE_UPDATE_PERIOD */
  83     uint32_t period; /* period of refresh, in ms,
  84                       * XENFB_NO_REFRESH if no refresh is needed */
  85 };
  86
  87 #define XENFB_IN_EVENT_SIZE 40
  88
  89 union xenfb_in_event
  90 {
  91     uint8_t type;
  92     struct xenfb_refresh_period refresh_period;
  93     char pad[XENFB_IN_EVENT_SIZE];
  94 };
  95
  96 /* shared page */
  97
  98 #define XENFB_IN_RING_SIZE 1024
  99 #define XENFB_IN_RING_LEN (XENFB_IN_RING_SIZE / XENFB_IN_EVENT_SIZE)
 100 #define XENFB_IN_RING_OFFS 1024
 101 #define XENFB_IN_RING(page) \
 102     ((union xenfb_in_event *)((char *)(page) + XENFB_IN_RING_OFFS))
 103 #define XENFB_IN_RING_REF(page, idx) \
 104     (XENFB_IN_RING((page))[(idx) % XENFB_IN_RING_LEN])
 105
 106 #define XENFB_OUT_RING_SIZE 2048
 107 #define XENFB_OUT_RING_LEN (XENFB_OUT_RING_SIZE / XENFB_OUT_EVENT_SIZE)
 108 #define XENFB_OUT_RING_OFFS (XENFB_IN_RING_OFFS + XENFB_IN_RING_SIZE)
 109 #define XENFB_OUT_RING(page) \
 110     ((union xenfb_out_event *)((char *)(page) + XENFB_OUT_RING_OFFS))
 111 #define XENFB_OUT_RING_REF(page, idx) \
 112     (XENFB_OUT_RING((page))[(idx) % XENFB_OUT_RING_LEN])
 113
 114 struct xenfb_page
 115 {
 116     uint32_t in_cons, in_prod;
 117     uint32_t out_cons, out_prod;
 118
 119     int32_t width;          /* the width of the framebuffer (in pixels) */
 120     int32_t height;         /* the height of the framebuffer (in pixels) */
 121     uint32_t line_length;   /* the length of a row of pixels (in bytes) */
 122     uint32_t mem_length;    /* the length of the framebuffer (in bytes) */
 123     uint8_t depth;          /* the depth of a pixel (in bits) */
 124
 125     /*
 126      * Framebuffer page directory
 127      *
 128      * Each directory page holds PAGE_SIZE / sizeof(*pd)
 129      * framebuffer pages, and can thus map up to PAGE_SIZE *
 130      * PAGE_SIZE / sizeof(*pd) bytes.  With PAGE_SIZE == 4096 and
 131      * sizeof(unsigned long) == 4/8, that's 4 Megs 32 bit and 2 Megs
 132      * 64 bit.  256 directories give enough room for a 512 Meg
 133      * framebuffer with a max resolution of 12,800x10,240.  Should
 134      * be enough for a while with room leftover for expansion.
 135      */
 136     unsigned long pd[256];
 137 };
 138
 139 /*
 140  * Wart: xenkbd needs to know default resolution.  Put it here until a
 141  * better solution is found, but don't leak it to the backend.
 142  */
 143 #ifdef __KERNEL__
 144 #define XENFB_WIDTH 800
 145 #define XENFB_HEIGHT 600
 146 #define XENFB_DEPTH 32
 147 #endif
 148
 149 #endif
 150
 151 /*
 152  * Local variables:
 153  * mode: C
 154  * c-file-style: "BSD"
 155  * c-basic-offset: 4
 156  * tab-width: 4
 157  * indent-tabs-mode: nil
 158  * End:
 159  */