1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <stdbool.h>
18#include <stdlib.h>
19#include <unistd.h>
20
21#include <fcntl.h>
22#include <stdio.h>
23
24#include <sys/cdefs.h>
25#include <sys/ioctl.h>
26#include <sys/mman.h>
27#include <sys/types.h>
28
29#include <linux/fb.h>
30#include <linux/kd.h>
31
32#include "minui.h"
33#include "graphics.h"
34
35static gr_surface fbdev_init(minui_backend*);
36static gr_surface fbdev_flip(minui_backend*);
37static void fbdev_blank(minui_backend*, bool);
38static void fbdev_exit(minui_backend*);
39
40static GRSurface gr_framebuffer[2];
41static bool double_buffered;
42static GRSurface* gr_draw = NULL;
43static int displayed_buffer;
44
45static struct fb_var_screeninfo vi;
46static int fb_fd = -1;
47
48static minui_backend my_backend = {
49    .init = fbdev_init,
50    .flip = fbdev_flip,
51    .blank = fbdev_blank,
52    .exit = fbdev_exit,
53};
54
55minui_backend* open_fbdev() {
56    return &my_backend;
57}
58
59static void fbdev_blank(minui_backend* backend __unused, bool blank)
60{
61    int ret;
62
63    ret = ioctl(fb_fd, FBIOBLANK, blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
64    if (ret < 0)
65        perror("ioctl(): blank");
66}
67
68static void set_displayed_framebuffer(unsigned n)
69{
70    if (n > 1 || !double_buffered) return;
71
72    vi.yres_virtual = gr_framebuffer[0].height * 2;
73    vi.yoffset = n * gr_framebuffer[0].height;
74    vi.bits_per_pixel = gr_framebuffer[0].pixel_bytes * 8;
75    if (ioctl(fb_fd, FBIOPUT_VSCREENINFO, &vi) < 0) {
76        perror("active fb swap failed");
77    }
78    displayed_buffer = n;
79}
80
81static gr_surface fbdev_init(minui_backend* backend) {
82    int fd;
83    void *bits;
84
85    struct fb_fix_screeninfo fi;
86
87    fd = open("/dev/graphics/fb0", O_RDWR);
88    if (fd < 0) {
89        perror("cannot open fb0");
90        return NULL;
91    }
92
93    if (ioctl(fd, FBIOGET_FSCREENINFO, &fi) < 0) {
94        perror("failed to get fb0 info");
95        close(fd);
96        return NULL;
97    }
98
99    if (ioctl(fd, FBIOGET_VSCREENINFO, &vi) < 0) {
100        perror("failed to get fb0 info");
101        close(fd);
102        return NULL;
103    }
104
105    // We print this out for informational purposes only, but
106    // throughout we assume that the framebuffer device uses an RGBX
107    // pixel format.  This is the case for every development device I
108    // have access to.  For some of those devices (eg, hammerhead aka
109    // Nexus 5), FBIOGET_VSCREENINFO *reports* that it wants a
110    // different format (XBGR) but actually produces the correct
111    // results on the display when you write RGBX.
112    //
113    // If you have a device that actually *needs* another pixel format
114    // (ie, BGRX, or 565), patches welcome...
115
116    printf("fb0 reports (possibly inaccurate):\n"
117           "  vi.bits_per_pixel = %d\n"
118           "  vi.red.offset   = %3d   .length = %3d\n"
119           "  vi.green.offset = %3d   .length = %3d\n"
120           "  vi.blue.offset  = %3d   .length = %3d\n",
121           vi.bits_per_pixel,
122           vi.red.offset, vi.red.length,
123           vi.green.offset, vi.green.length,
124           vi.blue.offset, vi.blue.length);
125
126    bits = mmap(0, fi.smem_len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
127    if (bits == MAP_FAILED) {
128        perror("failed to mmap framebuffer");
129        close(fd);
130        return NULL;
131    }
132
133    memset(bits, 0, fi.smem_len);
134
135    gr_framebuffer[0].width = vi.xres;
136    gr_framebuffer[0].height = vi.yres;
137    gr_framebuffer[0].row_bytes = fi.line_length;
138    gr_framebuffer[0].pixel_bytes = vi.bits_per_pixel / 8;
139    gr_framebuffer[0].data = bits;
140    memset(gr_framebuffer[0].data, 0, gr_framebuffer[0].height * gr_framebuffer[0].row_bytes);
141
142    /* check if we can use double buffering */
143    if (vi.yres * fi.line_length * 2 <= fi.smem_len) {
144        double_buffered = true;
145
146        memcpy(gr_framebuffer+1, gr_framebuffer, sizeof(GRSurface));
147        gr_framebuffer[1].data = gr_framebuffer[0].data +
148            gr_framebuffer[0].height * gr_framebuffer[0].row_bytes;
149
150        gr_draw = gr_framebuffer+1;
151
152    } else {
153        double_buffered = false;
154
155        // Without double-buffering, we allocate RAM for a buffer to
156        // draw in, and then "flipping" the buffer consists of a
157        // memcpy from the buffer we allocated to the framebuffer.
158
159        gr_draw = (GRSurface*) malloc(sizeof(GRSurface));
160        memcpy(gr_draw, gr_framebuffer, sizeof(GRSurface));
161        gr_draw->data = (unsigned char*) malloc(gr_draw->height * gr_draw->row_bytes);
162        if (!gr_draw->data) {
163            perror("failed to allocate in-memory surface");
164            return NULL;
165        }
166    }
167
168    memset(gr_draw->data, 0, gr_draw->height * gr_draw->row_bytes);
169    fb_fd = fd;
170    set_displayed_framebuffer(0);
171
172    printf("framebuffer: %d (%d x %d)\n", fb_fd, gr_draw->width, gr_draw->height);
173
174    fbdev_blank(backend, true);
175    fbdev_blank(backend, false);
176
177    return gr_draw;
178}
179
180static gr_surface fbdev_flip(minui_backend* backend __unused) {
181    if (double_buffered) {
182#if defined(RECOVERY_BGRA)
183        // In case of BGRA, do some byte swapping
184        unsigned int idx;
185        unsigned char tmp;
186        unsigned char* ucfb_vaddr = (unsigned char*)gr_draw->data;
187        for (idx = 0 ; idx < (gr_draw->height * gr_draw->row_bytes);
188                idx += 4) {
189            tmp = ucfb_vaddr[idx];
190            ucfb_vaddr[idx    ] = ucfb_vaddr[idx + 2];
191            ucfb_vaddr[idx + 2] = tmp;
192        }
193#endif
194        // Change gr_draw to point to the buffer currently displayed,
195        // then flip the driver so we're displaying the other buffer
196        // instead.
197        gr_draw = gr_framebuffer + displayed_buffer;
198        set_displayed_framebuffer(1-displayed_buffer);
199    } else {
200        // Copy from the in-memory surface to the framebuffer.
201
202#if defined(RECOVERY_BGRA)
203        unsigned int idx;
204        unsigned char* ucfb_vaddr = (unsigned char*)gr_framebuffer[0].data;
205        unsigned char* ucbuffer_vaddr = (unsigned char*)gr_draw->data;
206        for (idx = 0 ; idx < (gr_draw->height * gr_draw->row_bytes); idx += 4) {
207            ucfb_vaddr[idx    ] = ucbuffer_vaddr[idx + 2];
208            ucfb_vaddr[idx + 1] = ucbuffer_vaddr[idx + 1];
209            ucfb_vaddr[idx + 2] = ucbuffer_vaddr[idx    ];
210            ucfb_vaddr[idx + 3] = ucbuffer_vaddr[idx + 3];
211        }
212#else
213        memcpy(gr_framebuffer[0].data, gr_draw->data,
214               gr_draw->height * gr_draw->row_bytes);
215#endif
216    }
217    return gr_draw;
218}
219
220static void fbdev_exit(minui_backend* backend __unused) {
221    close(fb_fd);
222    fb_fd = -1;
223
224    if (!double_buffered && gr_draw) {
225        free(gr_draw->data);
226        free(gr_draw);
227    }
228    gr_draw = NULL;
229}
230