///////////////////////////////////////////////////////////////////////////////////
// File     : irq_handler.c
// Date     : 01/04/2012
// Author   : alain greiner and joel porquet
// Copyright (c) UPMC-LIP6
///////////////////////////////////////////////////////////////////////////////////
// The irq_handler.c and irq_handler.h files are part of the GIET nano-kernel.
// They contain the code of the _int_demux function that handle
// the ICU (Interupt Controler Unit), and the various ISRs associated
// to the CoCLib peripherals. 
///////////////////////////////////////////////////////////////////////////////////

#include <giet_config.h>
#include <irq_handler.h>
#include <sys_handler.h>
#include <drivers.h>
#include <common.h>
#include <ctx_handler.h>
#include <hwr_mapping.h>

///////////////////////////////////////////////////////////////////////////////////
// Initialize the whole interrupt vector with the default ISR
///////////////////////////////////////////////////////////////////////////////////

__attribute__((section (".kdata"))) _isr_func_t _interrupt_vector[32] = 
                                                  { [0 ... 31] = &_isr_default };

///////////////////////////////////////////////////////////////////////////////////
// 	_int_demux()
// This functions uses an external ICU component (Interrupt Controler Unit)
// that concentrates up to 32 input interrupts lines. This component
// can support up to NB_PROCS output IRQ.
//
// This component returns the highest priority active interrupt index (smaller
// indexes have the highest priority) by reading the ICU_IT_VECTOR register.
// Any value larger than 31 means "no active interrupt", and the default ISR
// (that does nothing) is executed.
//
// The interrupt vector (32 ISR addresses array stored at _interrupt_vector
// address) is initialised with the default ISR address. The actual ISR
// addresses are supposed to be written in the interrupt vector array 
// during system initialisation.
///////////////////////////////////////////////////////////////////////////////////
void _int_demux(void)
{
    int				interrupt_index;
    _isr_func_t		isr;
    unsigned int	pid = _procid();

    // retrieves the highest priority active interrupt index 
    if (!_icu_read( pid / NB_PROCS,
                    pid % NB_PROCS,
                    ICU_IT_VECTOR,
                    (unsigned int*)&interrupt_index ) )
    {
        if (interrupt_index == -1)	// no interrupt is active 
            return;

        isr = _interrupt_vector[interrupt_index];
        isr();
    }
    else
    {
        _puts("\n[GIET ERROR] In _demux function : wrong arguments in _icu_read()\n");
        _exit();
    }
}
///////////////////////////////////////////////////////////////////////////////////
// 	_isr_default()
// The default ISR is called when no specific ISR has been installed in the
// interrupt vector. It simply displays a message on TTY0.
///////////////////////////////////////////////////////////////////////////////////
void _isr_default()
{
    _puts("\n\n!!! Default ISR !!!\n");
}

///////////////////////////////////////////////////////////////////////////////////
// 	_isr_dma()
// This ISR handles up to 8 IRQs generated by 8 independant channels of the
// multi_dma component. It acknowledges the interrupt and reset the synchronisation
// variable _dma_busy[i], after copying the status into the _dma_status[i] variable.
///////////////////////////////////////////////////////////////////////////////////
void _isr_dma_indexed( unsigned int dma_id )
{
    volatile unsigned int* dma_address;

    // compute DMA channel address
    dma_address = (unsigned int*)&seg_dma_base + (dma_id * DMA_SPAN);

    // save DMA channel status  
    _dma_status[dma_id] = dma_address[DMA_LEN]; /* save status */

    // reset DMA channel
    dma_address[DMA_RESET] = 0;					/* reset IRQ */

    // release DMA channel 
    _dma_busy[dma_id] = 0;                      /* release DMA */
}

void _isr_dma_0() { _isr_dma_indexed(0); }
void _isr_dma_1() { _isr_dma_indexed(1); }
void _isr_dma_2() { _isr_dma_indexed(2); }
void _isr_dma_3() { _isr_dma_indexed(3); }
void _isr_dma_4() { _isr_dma_indexed(4); }
void _isr_dma_5() { _isr_dma_indexed(5); }
void _isr_dma_6() { _isr_dma_indexed(6); }
void _isr_dma_7() { _isr_dma_indexed(7); }

///////////////////////////////////////////////////////////////////////////////////
// 	_isr_ioc()
// There is only one IOC controler shared by all tasks. It acknowledge the IRQ
// using the ioc base address, save the status, and set the _ioc_done variable
// to signal completion.
///////////////////////////////////////////////////////////////////////////////////
void _isr_ioc()
{
    volatile unsigned int* ioc_address;

    ioc_address = (unsigned int*)&seg_ioc_base;

    _ioc_status = ioc_address[BLOCK_DEVICE_STATUS]; /* save status & reset IRQ */
    _ioc_done   = 1;                                /* signals completion */
}

///////////////////////////////////////////////////////////////////////////////////
// 	_isr_timer_* (* = 0,1,2,3,4,5,6,7)
// This ISR handles up to 8 IRQs generated by 8 independant timers.
// It acknowledges the IRQ on TIMER[*] and displays a message on TTY0
///////////////////////////////////////////////////////////////////////////////////
void _isr_timer_indexed(unsigned int timer_id)
{
    volatile unsigned int *timer_address;

    timer_address = (unsigned int*)&seg_timer_base + (timer_id * TIMER_SPAN);

    timer_address[TIMER_RESETIRQ] = 0; /* reset IRQ */

    _puts("\n\n!!! Interrupt timer received from timer ");
    _putw( timer_id );
    _puts(" at cycle ");
    _putw( _proctime() );
    _puts("\n\n");
}

void _isr_timer_0()  { _isr_timer_indexed(0);  }
void _isr_timer_1()  { _isr_timer_indexed(1);  }
void _isr_timer_2()  { _isr_timer_indexed(2);  }
void _isr_timer_3()  { _isr_timer_indexed(3);  }
void _isr_timer_4()  { _isr_timer_indexed(4);  }
void _isr_timer_5()  { _isr_timer_indexed(5);  }
void _isr_timer_6()  { _isr_timer_indexed(6);  }
void _isr_timer_7()  { _isr_timer_indexed(7);  }

///////////////////////////////////////////////////////////////////////////////////
// _isr_tty_get_* (* = 0,1,2,3,4,5,6,7,9,10,11,12,13,14,15)
// The Giet supports up to 16 TTY terminals.
// These 16 ISRs handle the up to 16 IRQs associated to 16 independant 
// terminals, signaling that a character is available.
// There is one communication buffer _tty_get_buf[tty_id] per terminal.
// The sychronisation variable _tty_get_full[tty_id], is set by the ISR,
// and reset by the OS.
// A character is lost if the buffer is full when the ISR is executed.
///////////////////////////////////////////////////////////////////////////////////
void _isr_tty_get_indexed(unsigned int tty_id)
{
    volatile unsigned int *tty_address;

    /* compute terminal base address */
    tty_address = (unsigned int*)&seg_tty_base + (tty_id * TTY_SPAN);

    /* save character and reset IRQ */
    _tty_get_buf[tty_id] = (unsigned char)tty_address[TTY_READ];

    /* signals character available */
    _tty_get_full[tty_id] = 1;
}

void _isr_tty_get_0()  { _isr_tty_get_indexed(0);  }
void _isr_tty_get_1()  { _isr_tty_get_indexed(1);  }
void _isr_tty_get_2()  { _isr_tty_get_indexed(2);  }
void _isr_tty_get_3()  { _isr_tty_get_indexed(3);  }
void _isr_tty_get_4()  { _isr_tty_get_indexed(4);  }
void _isr_tty_get_5()  { _isr_tty_get_indexed(5);  }
void _isr_tty_get_6()  { _isr_tty_get_indexed(6);  }
void _isr_tty_get_7()  { _isr_tty_get_indexed(7);  }
void _isr_tty_get_8()  { _isr_tty_get_indexed(8);  }
void _isr_tty_get_9()  { _isr_tty_get_indexed(9);  }
void _isr_tty_get_10() { _isr_tty_get_indexed(10); }
void _isr_tty_get_11() { _isr_tty_get_indexed(11); }
void _isr_tty_get_12() { _isr_tty_get_indexed(12); }
void _isr_tty_get_13() { _isr_tty_get_indexed(13); }
void _isr_tty_get_14() { _isr_tty_get_indexed(14); }
void _isr_tty_get_15() { _isr_tty_get_indexed(15); }

/////////////////////////////////////////////////////////////////////////////////////
// _isr_switch
// This ISR is in charge of context switch. 
// It acknowledges the IRQ on TIMER[proc_id] and calls the _ctx_switch() function.
/////////////////////////////////////////////////////////////////////////////////////
void _isr_switch()
{
    volatile unsigned int *timer_address;
    unsigned int proc_id;

    proc_id = _procid();
    timer_address = (unsigned int*)&seg_timer_base + (proc_id * TIMER_SPAN);

    timer_address[TIMER_RESETIRQ] = 0; /* reset IRQ */
    _ctx_switch();
}