diff options
Diffstat (limited to 'minui/graphics_fbdev.c')
| -rw-r--r-- | minui/graphics_fbdev.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/minui/graphics_fbdev.c b/minui/graphics_fbdev.c new file mode 100644 index 0000000..6a6330b --- /dev/null +++ b/minui/graphics_fbdev.c @@ -0,0 +1,201 @@ +/* + * 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 <unistd.h> + +#include <fcntl.h> +#include <stdio.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 gr_surface fbdev_init(minui_backend*); +static gr_surface 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 struct 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, 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 gr_surface fbdev_init(minui_backend* backend) { + int fd; + void *bits; + + struct fb_fix_screeninfo fi; + + fd = open("/dev/graphics/fb0", O_RDWR); + if (fd < 0) { + perror("cannot open fb0"); + return NULL; + } + + 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); + + 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; + } + + 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 = 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 gr_surface fbdev_flip(minui_backend* backend) { + 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) { + close(fb_fd); + fb_fd = -1; + + if (!double_buffered && gr_draw) { + free(gr_draw->data); + free(gr_draw); + } + gr_draw = NULL; +} |