//////////////////////////////////////////////////////////////////////////////////////
// File     : timer_driver.c
// Date     : 23/05/2013
// Author   : alain greiner
// Copyright (c) UPMC-LIP6
//////////////////////////////////////////////////////////////////////////////////////
// The timer_driver.c and timer_driver.h files are part ot the GIET-VM nano-kernel.
// This driver supports the SoCLib vci_multi_timer component.
//
// It can exist several multi_timers in the architecture (at most one per cluster),
// and each one can contain several timers (called channels).
//
// There is two types of timers: 
// - "system" timers : one per processor, used for context switch.
//   local_id in [0, NB_PROCS_MAX-1],
// - "user" timers : requested by the task in the mapping_info data structure.
//   For each user timer, the timer_id is stored in the context of the task.
// The global index is cluster_xy * (NB_PROCS_MAX + NB_TIM_CHANNELS) + local_id
//
// The NB_PROCS_MAX and NB_TIM_CHANNELS values must be defined in hard_config.h file.
/////////////////////////////////////////////////////////////////////////////////////
// The virtual base address of the segment associated to a channel is:
//
//     seg_tim_base + cluster_xy * vseg_cluster_increment + TIMER_SPAN * timer_id
//
// The seg_tim_base and vseg_cluster_increment values must be defined 
// in the giet_vsegs.ld file.
/////////////////////////////////////////////////////////////////////////////////////

#include <giet_config.h>
#include <tim_driver.h>
#include <xcu_driver.h>
#include <tty_driver.h>
#include <utils.h>

#if !defined(X_SIZE) 
# error: You must define X_SIZE in the hard_config.h file
#endif

#if !defined(Y_SIZE) 
# error: You must define X_SIZE in the hard_config.h file
#endif

#if !defined(X_WIDTH) 
# error: You must define X_WIDTH in the hard_config.h file
#endif

#if !defined(Y_WIDTH) 
# error: You must define X_WIDTH in the hard_config.h file
#endif

#if !defined(NB_PROCS_MAX) 
# error: You must define NB_PROCS_MAX in the hard_config.h file
#endif

#if !defined(NB_TIM_CHANNELS)
#define NB_TIM_CHANNELS 0
#endif

#if ( (NB_TIM_CHANNELS + NB_PROC_MAX) > 32 )
# error: NB_TIM_CHANNELS + NB_PROCS_MAX cannot be larger than 32
#endif

///////////////////  Timer global variables ////////////////////////////////////////

#define in_unckdata __attribute__((section (".unckdata")))

#if (NB_TIM_CHANNELS > 0)
in_unckdata volatile unsigned char _user_timer_event[(1<<X_WIDTH)*(1<<Y_WIDTH)*NB_TIM_CHANNELS] 
                        = { [0 ... (((1<<X_WIDTH)*(1<<Y_WIDTH)*NB_TIM_CHANNELS) - 1)] = 0 };
#endif

////////////////////////////////////////////////////////////////////////////////////
// This function activates a timer in the vci_timer component
// by writing in the proper register the period value.
// It can be used by both the kernel to initialise a "system" timer,
// or by a task (through a system call) to configure an "user" timer.
///////////////////////////////////////////////////////////////////////////////////
void _timer_start( unsigned int cluster_xy, 
                   unsigned int local_id, 
                   unsigned int period) 
{
#if NB_TIM_CHANNELS

    // parameters checking 
    unsigned int x = cluster_xy >> Y_WIDTH;
    unsigned int y = cluster_xy & ((1<<Y_WIDTH)-1);
    if ( (x >= X_SIZE) || (y >= Y_SIZE) || (local_id >= NB_TIM_CHANNELS) )
    {
        _printf("[GIET ERROR] in _timer_start()\n");
        _exit();
    }

    unsigned int* timer_address = (unsigned int *) ((unsigned int)&seg_tim_base + 
                                  (cluster_xy * (unsigned int)&vseg_cluster_increment));

    timer_address[local_id * TIMER_SPAN + TIMER_PERIOD] = period;
    timer_address[local_id * TIMER_SPAN + TIMER_MODE] = 0x3;

#else
    _printf("[GIET ERROR] _timer_start() should not be called when NB_TIM_CHANNELS is 0\n");
    _exit();
#endif
}

//////////////////////////////////////////////////////////////////////////////
// This function desactivates a timer in the vci_timer component
// by writing in the proper register.
// Returns 0 if success, > 0 if error.
//////////////////////////////////////////////////////////////////////////////
void _timer_stop( unsigned int cluster_xy, 
                  unsigned int local_id) 
{
#if NB_TIM_CHANNELS

    // parameters checking 
    unsigned int x = cluster_xy >> Y_WIDTH;
    unsigned int y = cluster_xy & ((1<<Y_WIDTH)-1);
    if ( (x >= X_SIZE) || (y >= Y_SIZE) || (local_id >= NB_TIM_CHANNELS) )
    {
        _printf("[GIET ERROR] in _timer_stop()\n");
        _exit();
    }

    unsigned int* timer_address = (unsigned int *) ((unsigned int)&seg_tim_base + 
                                  (cluster_xy * (unsigned int)&vseg_cluster_increment));

    timer_address[local_id * TIMER_SPAN + TIMER_MODE] = 0;

#else
    _printf("[GIET ERROR] _timer_stop() should not be called when NB_TIM_CHANNELS is 0\n");
    _exit();
#endif
}

//////////////////////////////////////////////////////////////////////////////
// This function acknowlegge a timer interrupt in the vci_timer  
// component by writing in the proper register.
// It can be used by both the isr_switch() for a "system" timer, 
// or by the _isr_timer() for an "user" timer.
// Returns 0 if success, > 0 if error.
//////////////////////////////////////////////////////////////////////////////
void _timer_reset_irq( unsigned int cluster_xy, 
                       unsigned int local_id ) 
{
#if NB_TIM_CHANNELS

    // parameters checking 
    unsigned int x = cluster_xy >> Y_WIDTH;
    unsigned int y = cluster_xy & ((1<<Y_WIDTH)-1);
    if ( (x >= X_SIZE) || (y >= Y_SIZE) || (local_id >= NB_TIM_CHANNELS) )
    {
        _printf("[GIET ERROR] in _timer_reset_irq()\n");
        _exit();
    }

    unsigned int * timer_address = (unsigned int *) ((unsigned int)&seg_tim_base + 
                                   (cluster_xy * (unsigned int)&vseg_cluster_increment));

    timer_address[local_id * TIMER_SPAN + TIMER_RESETIRQ] = 0;

#else
    _printf("[GIET ERROR] _timer_reset_irq() should not be called when NB_TIM_CHANNELS is 0\n");
    _exit();
#endif
}

/////////////////////////////////////////////////////////////////////////////
// This function resets the timer counter. To do so, we re-write the period
// in the proper register, what causes the count to restart.
// The period value is read from the same (TIMER_PERIOD) register,
// this is why in appearance we do nothing useful (read a value
// from a register and write this value in the same register)
// This function is called during a context switch (user or preemptive)
//////////////////////////////////////////////////////////////////////i//////
void _timer_reset_cpt( unsigned int cluster_xy, 
                       unsigned int local_id) 
{
#if NB_TIM_CHANNELS

    // parameters checking 
    unsigned int x = cluster_xy >> Y_WIDTH;
    unsigned int y = cluster_xy & ((1<<Y_WIDTH)-1);
    if ( (x >= X_SIZE) || (y >= Y_SIZE) || (local_id >= NB_TIM_CHANNELS) )
    {
        _printf("[GIET ERROR in _timer_reset_cpt()\n");
        _exit();
    }

    // We suppose that the TIMER_MODE register value is 0x3
    unsigned int * timer_address = (unsigned int *) ((unsigned int)&seg_tim_base + 
                                   (cluster_xy * (unsigned int)&vseg_cluster_increment));

    unsigned int period = timer_address[local_id * TIMER_SPAN + TIMER_PERIOD];
    timer_address[local_id * TIMER_SPAN + TIMER_PERIOD] = period;

#else
    _printf("[GIET ERROR] _timer_reset_cpt should not be called when NB_TIM_CHANNELS is 0\n");
    _exit();
#endif
}

///////////////////////////////////////////////////////////////////////////////////
// This ISR handles the IRQs generated by the "user" timers that are
// replicated in all clusters.
// The IRQs generated by the "system" timers should be handled by _isr_switch().
// It can be a HWI or a PTI.
// The channel argument is the user timer local index.
//     timer_global_id = cluster_id*(NB_TIM_CHANNELS) + channel
// The ISR acknowledges the IRQ and registers the event in the proper entry
// of the _user_timer_event[] array, and a log message is displayed on TTY0.
///////////////////////////////////////////////////////////////////////////////////
void _timer_isr( unsigned int irq_type,   // HWI / PTI
                 unsigned int irq_id,     // index returned by XCU
                 unsigned int channel )   // user timer index
{
#if NB_TIM_CHANNELS

    unsigned int cluster_xy = _get_procid() / NB_PROCS_MAX;

    // acknowledge IRQ depending on type 
    if   ( irq_type == IRQ_TYPE_HWI )  _timer_reset_irq( cluster_xy, channel );
    else                               _xcu_timer_reset_irq( cluster_xy, irq_id );

    // register the event
    _user_timer_event[cluster_xy * NB_TIM_CHANNELS + channel] = 1;

    // display a message on TTY 0 
    _printf("\n[GIET WARNING] User Timer IRQ at cycle %d / cluster = %x / channel = %d\n",
            _get_proctime(), cluster_xy, channel );

#else
    _printf("[GIET ERROR] _timer_isr() should not be called when NB_TIM_CHANNELS == 0\n");
    _exit();
#endif
}



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