The boot framebuffer is expected to be configured by the firmware, so it uses fw_cfg as interface. Initialization goes as follows: (1) Check whenever etc/ramfb is present. (2) Allocate framebuffer from RAM. (3) Fill struct RAMFBCfg, write it to etc/ramfb. Done. You can write stuff to the framebuffer now, and it should appear automagically on the screen. Note that this isn't very efficient because it does a full display update on each refresh. No dirty tracking. Dirty tracking would have to be active for the whole ram slot, so that wouldn't be very efficient either. For a boot display which is active for a short time only this isn't a big deal. As permanent guest display something better should be used (if possible). This is the ramfb core code. Some windup is needed for display devices which want have a ramfb boot display. Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Tested-by: Laszlo Ersek <lersek@redhat.com> Message-id: 20180613122948.18149-2-kraxel@redhat.com Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
96 lines
2.4 KiB
C
96 lines
2.4 KiB
C
/*
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* early boot framebuffer in guest ram
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* configured using fw_cfg
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*
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* Copyright Red Hat, Inc. 2017
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*
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* Author:
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* Gerd Hoffmann <kraxel@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "hw/loader.h"
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#include "hw/display/ramfb.h"
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#include "ui/console.h"
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#include "sysemu/sysemu.h"
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struct QEMU_PACKED RAMFBCfg {
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uint64_t addr;
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uint32_t fourcc;
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uint32_t flags;
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uint32_t width;
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uint32_t height;
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uint32_t stride;
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};
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struct RAMFBState {
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DisplaySurface *ds;
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uint32_t width, height;
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struct RAMFBCfg cfg;
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};
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static void ramfb_fw_cfg_write(void *dev, off_t offset, size_t len)
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{
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RAMFBState *s = dev;
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void *framebuffer;
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uint32_t stride, fourcc, format;
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hwaddr addr, length;
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s->width = be32_to_cpu(s->cfg.width);
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s->height = be32_to_cpu(s->cfg.height);
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stride = be32_to_cpu(s->cfg.stride);
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fourcc = be32_to_cpu(s->cfg.fourcc);
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addr = be64_to_cpu(s->cfg.addr);
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length = stride * s->height;
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format = qemu_drm_format_to_pixman(fourcc);
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fprintf(stderr, "%s: %dx%d @ 0x%" PRIx64 "\n", __func__,
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s->width, s->height, addr);
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framebuffer = address_space_map(&address_space_memory,
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addr, &length, false,
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MEMTXATTRS_UNSPECIFIED);
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if (!framebuffer || length < stride * s->height) {
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s->width = 0;
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s->height = 0;
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return;
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}
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s->ds = qemu_create_displaysurface_from(s->width, s->height,
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format, stride, framebuffer);
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}
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void ramfb_display_update(QemuConsole *con, RAMFBState *s)
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{
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if (!s->width || !s->height) {
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return;
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}
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if (s->ds) {
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dpy_gfx_replace_surface(con, s->ds);
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s->ds = NULL;
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}
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/* simple full screen update */
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dpy_gfx_update_full(con);
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}
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RAMFBState *ramfb_setup(Error **errp)
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{
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FWCfgState *fw_cfg = fw_cfg_find();
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RAMFBState *s;
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if (!fw_cfg || !fw_cfg->dma_enabled) {
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error_setg(errp, "ramfb device requires fw_cfg with DMA");
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return NULL;
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}
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s = g_new0(RAMFBState, 1);
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fw_cfg_add_file_callback(fw_cfg, "etc/ramfb",
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NULL, ramfb_fw_cfg_write, s,
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&s->cfg, sizeof(s->cfg), false);
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return s;
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}
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