fbdev backend works

[retrobench] / src / fbdev / fbgfx.c

diff --git a/src/fbdev/fbgfx.c b/src/fbdev/fbgfx.c
new file mode 100644 (file)
index 0000000..1d403d8
--- /dev/null
+++ b/src/fbdev/fbgfx.c
@@ -0,0 +1,134 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <linux/fb.h>
+#include "fbgfx.h"
+
+static void cleanup(void);
+
+static int fd = -1;
+static void *vmem;
+static int vmem_size;
+static struct fb_fix_screeninfo finfo;
+static struct fb_var_screeninfo vinfo;
+static struct fb_var_screeninfo saved_vinfo;
+static int saved_vinfo_valid;
+static struct fbgfx_vmode curvm;
+
+static int init(void)
+{
+       if(fd >= 0) return 0;
+
+       if((fd = open("/dev/fb0", O_RDWR)) == -1) {
+               fprintf(stderr, "failed to open framebuffer device\n");
+               return -1;
+       }
+
+       ioctl(fd, FBIOGET_FSCREENINFO, &finfo);
+
+       curvm.pitch = finfo.line_length;
+
+       atexit(cleanup);
+       return 0;
+}
+
+static void cleanup(void)
+{
+       if(vmem) {
+               munmap(vmem, vmem_size);
+       }
+       if(fd != -1) {
+               close(fd);
+       }
+}
+
+void *fbgfx_set_video_mode(int x, int y, int depth)
+{
+       struct fb_var_screeninfo new_vinfo;
+
+       if(init() == -1) {
+               return 0;
+       }
+
+       ioctl(fd, FBIOGET_VSCREENINFO, &new_vinfo);
+       new_vinfo.xres = x;
+       new_vinfo.yres = y;
+       new_vinfo.bits_per_pixel = depth;
+
+       if(ioctl(fd, FBIOPUT_VSCREENINFO, &new_vinfo) == -1) {
+               fprintf(stderr, "failed to set video mode %dx%d %dbpp: %s\n", x, y, depth, strerror(errno));
+               return 0;
+       }
+
+       if(vmem) {
+               munmap(vmem, vmem_size);
+               vmem = 0;
+               vmem_size = 0;
+       }
+
+       return fbgfx_get_video_mode(0, 0, 0);
+}
+
+void *fbgfx_get_video_mode(int *xptr, int *yptr, int *depthptr)
+{
+       if(init() == -1) {
+               return 0;
+       }
+
+       ioctl(fd, FBIOGET_VSCREENINFO, &vinfo);
+       /*vmem_size = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;*/
+       vmem_size = finfo.smem_len;
+
+       curvm.width = vinfo.xres;
+       curvm.height = vinfo.yres;
+       curvm.bpp = vinfo.bits_per_pixel;
+       curvm.fbsize = vmem_size;
+       curvm.rshift = vinfo.red.offset;
+       curvm.gshift = vinfo.green.offset;
+       curvm.bshift = vinfo.blue.offset;
+       curvm.rmask = (0xffffffff >> (32 - vinfo.red.length)) << curvm.rshift;
+       curvm.gmask = (0xffffffff >> (32 - vinfo.green.length)) << curvm.gshift;
+       curvm.bmask = (0xffffffff >> (32 - vinfo.blue.length)) << curvm.bshift;
+
+       if(!vmem) {
+               if((vmem = mmap(0, vmem_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)) == (void*)-1) {
+                       fprintf(stderr, "failed to map video memory\n");
+                       vmem = 0;
+                       return 0;
+               }
+       }
+       if(xptr) *xptr = vinfo.xres;
+       if(yptr) *yptr = vinfo.yres;
+       if(depthptr) *depthptr = vinfo.bits_per_pixel;
+       return vmem;
+}
+
+void fbgfx_save_video_mode(void)
+{
+       if(init() == -1) {
+               return;
+       }
+
+       if(ioctl(fd, FBIOGET_VSCREENINFO, &saved_vinfo) == -1) {
+               return;
+       }
+       saved_vinfo_valid = 1;
+}
+
+void fbgfx_restore_video_mode(void)
+{
+       if(init() == -1 || !saved_vinfo_valid) {
+               return;
+       }
+       ioctl(fd, FBIOPUT_VSCREENINFO, &saved_vinfo);
+}
+
+struct fbgfx_vmode *fbgfx_video_mode_info(void)
+{
+       return &curvm;
+}