qemu/hw/display/ramfb.c
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   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 "qemu/option.h"
  17#include "hw/loader.h"
  18#include "hw/display/ramfb.h"
  19#include "ui/console.h"
  20#include "sysemu/reset.h"
  21
  22struct 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
  31struct RAMFBState {
  32    DisplaySurface *ds;
  33    uint32_t width, height;
  34    uint32_t starting_width, starting_height;
  35    struct RAMFBCfg cfg;
  36    bool locked;
  37};
  38
  39static void ramfb_unmap_display_surface(pixman_image_t *image, void *unused)
  40{
  41    void *data = pixman_image_get_data(image);
  42    uint32_t size = pixman_image_get_stride(image) *
  43        pixman_image_get_height(image);
  44    cpu_physical_memory_unmap(data, size, 0, 0);
  45}
  46
  47static DisplaySurface *ramfb_create_display_surface(int width, int height,
  48                                                    pixman_format_code_t format,
  49                                                    int linesize, uint64_t addr)
  50{
  51    DisplaySurface *surface;
  52    hwaddr size;
  53    void *data;
  54
  55    if (linesize == 0) {
  56        linesize = width * PIXMAN_FORMAT_BPP(format) / 8;
  57    }
  58
  59    size = (hwaddr)linesize * height;
  60    data = cpu_physical_memory_map(addr, &size, 0);
  61    if (size != (hwaddr)linesize * height) {
  62        cpu_physical_memory_unmap(data, size, 0, 0);
  63        return NULL;
  64    }
  65
  66    surface = qemu_create_displaysurface_from(width, height,
  67                                              format, linesize, data);
  68    pixman_image_set_destroy_function(surface->image,
  69                                      ramfb_unmap_display_surface, NULL);
  70
  71    return surface;
  72}
  73
  74static void ramfb_fw_cfg_write(void *dev, off_t offset, size_t len)
  75{
  76    RAMFBState *s = dev;
  77    uint32_t fourcc, format, width, height;
  78    hwaddr stride, addr;
  79
  80    width     = be32_to_cpu(s->cfg.width);
  81    height    = be32_to_cpu(s->cfg.height);
  82    stride    = be32_to_cpu(s->cfg.stride);
  83    fourcc    = be32_to_cpu(s->cfg.fourcc);
  84    addr      = be64_to_cpu(s->cfg.addr);
  85    format    = qemu_drm_format_to_pixman(fourcc);
  86
  87    fprintf(stderr, "%s: %dx%d @ 0x%" PRIx64 "\n", __func__,
  88            width, height, addr);
  89    if (s->locked) {
  90        fprintf(stderr, "%s: resolution locked, change rejected\n", __func__);
  91        return;
  92    }
  93    s->locked = true;
  94    s->width = width;
  95    s->height = height;
  96    s->ds = ramfb_create_display_surface(s->width, s->height,
  97                                         format, stride, addr);
  98}
  99
 100void ramfb_display_update(QemuConsole *con, RAMFBState *s)
 101{
 102    if (!s->width || !s->height) {
 103        return;
 104    }
 105
 106    if (s->ds) {
 107        dpy_gfx_replace_surface(con, s->ds);
 108        s->ds = NULL;
 109    }
 110
 111    /* simple full screen update */
 112    dpy_gfx_update_full(con);
 113}
 114
 115static void ramfb_reset(void *opaque)
 116{
 117    RAMFBState *s = (RAMFBState *)opaque;
 118    s->locked = false;
 119    memset(&s->cfg, 0, sizeof(s->cfg));
 120    s->cfg.width = s->starting_width;
 121    s->cfg.height = s->starting_height;
 122}
 123
 124RAMFBState *ramfb_setup(DeviceState* dev, Error **errp)
 125{
 126    FWCfgState *fw_cfg = fw_cfg_find();
 127    RAMFBState *s;
 128
 129    if (!fw_cfg || !fw_cfg->dma_enabled) {
 130        error_setg(errp, "ramfb device requires fw_cfg with DMA");
 131        return NULL;
 132    }
 133
 134    s = g_new0(RAMFBState, 1);
 135
 136    const char *s_fb_width = qemu_opt_get(dev->opts, "xres");
 137    const char *s_fb_height = qemu_opt_get(dev->opts, "yres");
 138    if (s_fb_width) {
 139        s->cfg.width = atoi(s_fb_width);
 140        s->starting_width = s->cfg.width;
 141    }
 142    if (s_fb_height) {
 143        s->cfg.height = atoi(s_fb_height);
 144        s->starting_height = s->cfg.height;
 145    }
 146    s->locked = false;
 147
 148    rom_add_vga("vgabios-ramfb.bin");
 149    fw_cfg_add_file_callback(fw_cfg, "etc/ramfb",
 150                             NULL, ramfb_fw_cfg_write, s,
 151                             &s->cfg, sizeof(s->cfg), false);
 152    qemu_register_reset(ramfb_reset, s);
 153    return s;
 154}
 155