rpi-framebuffer.c

typedef volatile struct                                          \
__attribute__((aligned(16))) _fb_info_t {
    uint32_t display_w;  //write display width
    uint32_t display_h;  //write display height
    uint32_t w;          //write framebuffer width
    uint32_t h;          //write framebuffer height
    uint32_t row_bytes;  //write 0 to get value
    uint32_t bpp;        //write bits per pixel
    uint32_t ofs_x;      //write x offset of framebuffer
    uint32_t ofs_y;      //write y offset of framebuffer
    uint32_t buf_addr;   //write 0 to get value
    uint32_t buf_size;   //write 0 to get value
} fb_info_t;

void fb_init(fb_info_t *fb_info) {
    fb_info->buf_addr = 0;
    fb_info->buf_size = 0;
    fb_info->row_bytes = 0;
    while(fb_info->buf_addr == 0) {
        mailbox_write(1, (uint32_t) (fb_info + 0x40000000));
        mailbox_read(1);
    }
}