extern unsigned int GET32(unsigned int);
extern void PUT32(unsigned int, unsigned int);

#include "gpio.h"
#include "timer.h"
#define MAILBOX_FULL 0x80000000
#define MAILBOX_EMPTY 0x40000000
#define MAILBOX0READ 0x2000b880
#define MAILBOX0STATUS 0x2000b898
#define MAILBOX0WRITE 0x2000b8a0

int cmain(void)
{
    LedInit();

    // 1. Fill out the FB request
    volatile unsigned int fbInfo[256] __attribute__ ((aligned (16)));
    fbInfo[0] = 1024;   // Physical Width
    fbInfo[1] = 768;    // Physical Height
    fbInfo[2] = 1024;   // Virtual Width
    fbInfo[3] = 768;    // Virtual Height
    fbInfo[4] = 0;      // Pitch (will be filled in my GPU)
    fbInfo[5] = 16;     // Depth
    fbInfo[6] = 0;      // X offset
    fbInfo[7] = 0;      // Y offset
    fbInfo[8] = 0;      // FB pointer (will be filled in my GPU)
    fbInfo[9] = 0;      // FB Size (will be filled in my GPU)

    // 2. Send struct to GPU
    while(GET32(MAILBOX0STATUS) & MAILBOX_FULL){ } // Wait for mailbox to become available
    PUT32(MAILBOX0WRITE, (((unsigned int)&fbInfo + 0x40000000) << 4) | 1); // Offset struct addr to prevent caching

    // 3. Read Response
    unsigned int data = 0;
    while(1)
    {
        while(GET32(MAILBOX0STATUS) & MAILBOX_EMPTY){} // Wait for mail
        data = GET32(MAILBOX0READ);

        if((data &0xF) == 1) // Data on channel 1
        {
            data = data >> 4;
            break;
        }
    }

    // 4. Check if we got a valid FB response
    if(fbInfo[8] == 0)
    {
        LedOn(); // We did not get a pointer :-(
        while(1);
    }
    else
    {
        while(1)
        {
            LedOff();   // All is well
            Wait(1);
            LedOn();
            Wait(1);
        }
    }
}