/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <sys/cdefs.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <linux/fb.h>
#include <linux/kd.h>
#include "minui.h"
#include "graphics.h"
static GRSurface* fbdev_init(minui_backend*);
static GRSurface* fbdev_flip(minui_backend*);
static void fbdev_blank(minui_backend*, bool);
static void fbdev_exit(minui_backend*);
static GRSurface gr_framebuffer[2];
static bool double_buffered;
static GRSurface* gr_draw = NULL;
static int displayed_buffer;
static fb_var_screeninfo vi;
static int fb_fd = -1;
static minui_backend my_backend = {
.init = fbdev_init,
.flip = fbdev_flip,
.blank = fbdev_blank,
.exit = fbdev_exit,
};
minui_backend* open_fbdev() {
return &my_backend;
}
static void fbdev_blank(minui_backend* backend __unused, bool blank)
{
int ret;
ret = ioctl(fb_fd, FBIOBLANK, blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
if (ret < 0)
perror("ioctl(): blank");
}
static void set_displayed_framebuffer(unsigned n)
{
if (n > 1 || !double_buffered) return;
vi.yres_virtual = gr_framebuffer[0].height * 2;
vi.yoffset = n * gr_framebuffer[0].height;
vi.bits_per_pixel = gr_framebuffer[0].pixel_bytes * 8;
if (ioctl(fb_fd, FBIOPUT_VSCREENINFO, &vi) < 0) {
perror("active fb swap failed");
}
displayed_buffer = n;
}
static GRSurface* fbdev_init(minui_backend* backend) {
int fd = open("/dev/graphics/fb0", O_RDWR);
if (fd == -1) {
perror("cannot open fb0");
return NULL;
}
fb_fix_screeninfo fi;
if (ioctl(fd, FBIOGET_FSCREENINFO, &fi) < 0) {
perror("failed to get fb0 info");
close(fd);
return NULL;
}
if (ioctl(fd, FBIOGET_VSCREENINFO, &vi) < 0) {
perror("failed to get fb0 info");
close(fd);
return NULL;
}
// We print this out for informational purposes only, but
// throughout we assume that the framebuffer device uses an RGBX
// pixel format. This is the case for every development device I
// have access to. For some of those devices (eg, hammerhead aka
// Nexus 5), FBIOGET_VSCREENINFO *reports* that it wants a
// different format (XBGR) but actually produces the correct
// results on the display when you write RGBX.
//
// If you have a device that actually *needs* another pixel format
// (ie, BGRX, or 565), patches welcome...
printf("fb0 reports (possibly inaccurate):\n"
" vi.bits_per_pixel = %d\n"
" vi.red.offset = %3d .length = %3d\n"
" vi.green.offset = %3d .length = %3d\n"
" vi.blue.offset = %3d .length = %3d\n",
vi.bits_per_pixel,
vi.red.offset, vi.red.length,
vi.green.offset, vi.green.length,
vi.blue.offset, vi.blue.length);
void* bits = mmap(0, fi.smem_len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (bits == MAP_FAILED) {
perror("failed to mmap framebuffer");
close(fd);
return NULL;
}
memset(bits, 0, fi.smem_len);
gr_framebuffer[0].width = vi.xres;
gr_framebuffer[0].height = vi.yres;
gr_framebuffer[0].row_bytes = fi.line_length;
gr_framebuffer[0].pixel_bytes = vi.bits_per_pixel / 8;
gr_framebuffer[0].data = static_cast<uint8_t*>(bits);
memset(gr_framebuffer[0].data, 0, gr_framebuffer[0].height * gr_framebuffer[0].row_bytes);
/* check if we can use double buffering */
if (vi.yres * fi.line_length * 2 <= fi.smem_len) {
double_buffered = true;
memcpy(gr_framebuffer+1, gr_framebuffer, sizeof(GRSurface));
gr_framebuffer[1].data = gr_framebuffer[0].data +
gr_framebuffer[0].height * gr_framebuffer[0].row_bytes;
gr_draw = gr_framebuffer+1;
} else {
double_buffered = false;
// Without double-buffering, we allocate RAM for a buffer to
// draw in, and then "flipping" the buffer consists of a
// memcpy from the buffer we allocated to the framebuffer.
gr_draw = (GRSurface*) malloc(sizeof(GRSurface));
memcpy(gr_draw, gr_framebuffer, sizeof(GRSurface));
gr_draw->data = (unsigned char*) malloc(gr_draw->height * gr_draw->row_bytes);
if (!gr_draw->data) {
perror("failed to allocate in-memory surface");
return NULL;
}
}
memset(gr_draw->data, 0, gr_draw->height * gr_draw->row_bytes);
fb_fd = fd;
set_displayed_framebuffer(0);
printf("framebuffer: %d (%d x %d)\n", fb_fd, gr_draw->width, gr_draw->height);
fbdev_blank(backend, true);
fbdev_blank(backend, false);
return gr_draw;
}
static GRSurface* fbdev_flip(minui_backend* backend __unused) {
if (double_buffered) {
// Change gr_draw to point to the buffer currently displayed,
// then flip the driver so we're displaying the other buffer
// instead.
gr_draw = gr_framebuffer + displayed_buffer;
set_displayed_framebuffer(1-displayed_buffer);
} else {
// Copy from the in-memory surface to the framebuffer.
memcpy(gr_framebuffer[0].data, gr_draw->data,
gr_draw->height * gr_draw->row_bytes);
}
return gr_draw;
}
static void fbdev_exit(minui_backend* backend __unused) {
close(fb_fd);
fb_fd = -1;
if (!double_buffered && gr_draw) {
free(gr_draw->data);
free(gr_draw);
}
gr_draw = NULL;
}
