#ifndef _FBTOOLS_H_
#define _FBTOOLS_H_

#include <linux/fb.h>

//a framebuffer device structure;
typedef struct fbdev{
        int fb;
        unsigned long fb_mem_offset;
        unsigned long fb_mem;
        struct fb_fix_screeninfo fb_fix;
        struct fb_var_screeninfo fb_var;
        char dev[20];
} FBDEV, *PFBDEV;

//open & init a frame buffer
//to use this function,
//you must set FBDEV.dev="/dev/fb0"
//or "/dev/fbX"
//it's your frame buffer.
int fb_open(PFBDEV pFbdev);

//close a frame buffer
int fb_close(PFBDEV pFbdev);

//get display depth
int get_display_depth(PFBDEV pFbdev);


//full screen clear
void fb_memset(void *addr, int c, size_t len);

#endif

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <asm/page.h>

#include "fbtools.h"

#define TRUE         1
#define FALSE        0
#define MAX(x,y)        ((x)>(y)?(x):(y))
#define MIN(x,y)        ((x)<(y)?(x):(y))

//open & init a frame buffer
int fb_open(PFBDEV pFbdev)
{
        pFbdev->fb = open(pFbdev->dev, O_RDWR);
        if(pFbdev->fb < 0)
        {
                printf("Error opening %s: %m. Check kernel config\n", pFbdev->dev);
                return FALSE;
        }
        if (-1 == ioctl(pFbdev->fb,FBIOGET_VSCREENINFO,&(pFbdev->fb_var)))
        {
                printf("ioctl FBIOGET_VSCREENINFO\n");
                return FALSE;
        }
        if (-1 == ioctl(pFbdev->fb,FBIOGET_FSCREENINFO,&(pFbdev->fb_fix)))
        {
                printf("ioctl FBIOGET_FSCREENINFO\n");
                return FALSE;
        }
       
        //map physics address to virtual address
        pFbdev->fb_mem_offset = (unsigned long)(pFbdev->fb_fix.smem_start) & (~PAGE_MASK);
        pFbdev->fb_mem = (unsigned long int)mmap(NULL, pFbdev->fb_fix.smem_len + pFbdev->fb_mem_offset,
                PROT_READ | PROT_WRITE, MAP_SHARED, pFbdev->fb, 0);
        if (-1L == (long) pFbdev->fb_mem)
        {
                printf("mmap error! mem:%d offset:%d\n", pFbdev->fb_mem, pFbdev->fb_mem_offset);
                return FALSE;
        }
       
        return TRUE;
}

//close frame buffer
int fb_close(PFBDEV pFbdev)
{
        close(pFbdev->fb);
        pFbdev->fb=-1;
}

//get display depth
int get_display_depth(PFBDEV pFbdev);
{
        if(pFbdev->fb<=0)
        {
                printf("fb device not open, open it first\n");
                return FALSE;
        }
        return pFbdev->fb_var.bits_per_pixel;
}

//full screen clear
void fb_memset (void *addr, int c, size_t len)
{
    memset(addr, c, len);
}

//use by test
#define DEBUG
#ifdef DEBUG
main()
{
        FBDEV fbdev;
        memset(&fbdev, 0, sizeof(FBDEV));
        strcpy(fbdev.dev, "/dev/fb0");
        if(fb_open(&fbdev)==FALSE)
        {
                printf("open frame buffer error\n");
                return;
        }
       
        fb_memset(fbdev.fb_mem + fbdev.fb_mem_offset, 0, fbdev.fb_fix.smem_len);
       
        fb_close(&fbdev);
}