xref: /openbmc/qemu/hw/display/ramfb.c (revision e3a99063)
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 
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     uint32_t starting_width, starting_height;
35     struct RAMFBCfg cfg;
36     bool locked;
37 };
38 
39 static 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 
47 static 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, false);
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 
74 static 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 
100 void 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 
115 static 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 
124 RAMFBState *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