hw/display/ramfb.c

   1 /*
   2  * early boot framebuffer in guest ram
   3  * configured using fw_cfg
   4  *
   5  * Copyright Red Hat, Inc. 2017
   6  *
   7  * Author:
   8  *     Gerd Hoffmann <kraxel@redhat.com>
   9  *
  10  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  11  * See the COPYING file in the top-level directory.
  12  */
  13
  14 #include "qemu/osdep.h"
  15 #include "qapi/error.h"
  16 #include "hw/loader.h"
  17 #include "hw/display/ramfb.h"
  18 #include "hw/display/bochs-vbe.h" /* for limits */
  19 #include "ui/console.h"
  20 #include "sysemu/reset.h"
  21
  22 struct QEMU_PACKED RAMFBCfg {
  23     uint64_t addr;
  24     uint32_t fourcc;
  25     uint32_t flags;
  26     uint32_t width;
  27     uint32_t height;
  28     uint32_t stride;
  29 };
  30
  31 struct RAMFBState {
  32     DisplaySurface *ds;
  33     uint32_t width, height;
  34     struct RAMFBCfg cfg;
  35 };
  36
  37 static void ramfb_unmap_display_surface(pixman_image_t *image, void *unused)
  38 {
  39     void *data = pixman_image_get_data(image);
  40     uint32_t size = pixman_image_get_stride(image) *
  41         pixman_image_get_height(image);
  42     cpu_physical_memory_unmap(data, size, 0, 0);
  43 }
  44
  45 static DisplaySurface *ramfb_create_display_surface(int width, int height,
  46                                                     pixman_format_code_t format,
  47                                                     hwaddr stride, hwaddr addr)
  48 {
  49     DisplaySurface *surface;
  50     hwaddr size, mapsize, linesize;
  51     void *data;
  52
  53     if (width < 16 || width > VBE_DISPI_MAX_XRES ||
  54         height < 16 || height > VBE_DISPI_MAX_YRES ||
  55         format == 0 /* unknown format */)
  56         return NULL;
  57
  58     linesize = width * PIXMAN_FORMAT_BPP(format) / 8;
  59     if (stride == 0) {
  60         stride = linesize;
  61     }
  62
  63     mapsize = size = stride * (height - 1) + linesize;
  64     data = cpu_physical_memory_map(addr, &mapsize, false);
  65     if (size != mapsize) {
  66         cpu_physical_memory_unmap(data, mapsize, 0, 0);
  67         return NULL;
  68     }
  69
  70     surface = qemu_create_displaysurface_from(width, height,
  71                                               format, stride, data);
  72     pixman_image_set_destroy_function(surface->image,
  73                                       ramfb_unmap_display_surface, NULL);
  74
  75     return surface;
  76 }
  77
  78 static void ramfb_fw_cfg_write(void *dev, off_t offset, size_t len)
  79 {
  80     RAMFBState *s = dev;
  81     DisplaySurface *surface;
  82     uint32_t fourcc, format, width, height;
  83     hwaddr stride, addr;
  84
  85     width  = be32_to_cpu(s->cfg.width);
  86     height = be32_to_cpu(s->cfg.height);
  87     stride = be32_to_cpu(s->cfg.stride);
  88     fourcc = be32_to_cpu(s->cfg.fourcc);
  89     addr   = be64_to_cpu(s->cfg.addr);
  90     format = qemu_drm_format_to_pixman(fourcc);
  91
  92     surface = ramfb_create_display_surface(width, height,
  93                                            format, stride, addr);
  94     if (!surface) {
  95         return;
  96     }
  97
  98     s->width = width;
  99     s->height = height;
 100     s->ds = surface;
 101 }
 102
 103 void ramfb_display_update(QemuConsole *con, RAMFBState *s)
 104 {
 105     if (!s->width || !s->height) {
 106         return;
 107     }
 108
 109     if (s->ds) {
 110         dpy_gfx_replace_surface(con, s->ds);
 111         s->ds = NULL;
 112     }
 113
 114     /* simple full screen update */
 115     dpy_gfx_update_full(con);
 116 }
 117
 118 RAMFBState *ramfb_setup(Error **errp)
 119 {
 120     FWCfgState *fw_cfg = fw_cfg_find();
 121     RAMFBState *s;
 122
 123     if (!fw_cfg || !fw_cfg->dma_enabled) {
 124         error_setg(errp, "ramfb device requires fw_cfg with DMA");
 125         return NULL;
 126     }
 127
 128     s = g_new0(RAMFBState, 1);
 129
 130     rom_add_vga("vgabios-ramfb.bin");
 131     fw_cfg_add_file_callback(fw_cfg, "etc/ramfb",
 132                              NULL, ramfb_fw_cfg_write, s,
 133                              &s->cfg, sizeof(s->cfg), false);
 134     return s;
 135 }