BaS_gcc/net/net_timer.c

/*
 * File:        net_timer.c
 * Purpose:     Provide a timer use by the BaS network as a timeout
 *              indicator
 *
 * Notes:
 */

#include "net_timer.h"
#include "bas_printf.h"
#include "MCF5475.h"
#include "interrupts.h"

//#define DBG_TMR
#ifdef DBG_TMR
#define dbg(format, arg...) do { xprintf("DEBUG: %s(): " format, __FUNCTION__, ##arg); } while (0)
#else
#define dbg(format, arg...) do { ; } while (0)
#endif /* DBG_TMR */


#if defined(MACHINE_FIREBEE)
#include "firebee.h"
#elif defined(MACHINE_M5484LITE)
#include "m5484l.h"
#elif defined(MACHINE_M54455)
#include "m54455.h"
#else
#error unknown machine!
#endif

static NET_TIMER net_timer[4] =
{
    {0, 0, 0, 0, 0, 0, 0},
    {0, 0, 0, 0, 0, 0, 0},
    {0, 0, 0, 0, 0, 0, 0},
    {0, 0, 0, 0, 0, 0, 0}
};


bool timer_default_isr(void *not_used, NET_TIMER *t)
{
    (void) not_used;

    /*
     * Clear the pending event
     */
    MCF_GPT_GMS(t->ch) = 0;

    dbg("timer isr called for timer channel %d\r\n");

    /*
     * Clear the reference - the desired seconds have expired
     */
    t->reference = 0;

    return 1;
}

void timer_irq_enable(uint8_t ch)
{
    /*
     * Setup the appropriate ICR
     */
    MCF_INTC_ICR(TIMER_VECTOR(ch) - 64) = MCF_INTC_ICR_IP(net_timer[ch].pri) |
                                          MCF_INTC_ICR_IL(net_timer[ch].lvl);

    /*
     * Unmask the FEC interrupt in the interrupt controller
     */
    if (ch == 3)
    {
        MCF_INTC_IMRH &= ~MCF_INTC_IMRH_INT_MASK59;
    }
    else if (ch == 2)
    {
        MCF_INTC_IMRH &= ~MCF_INTC_IMRH_INT_MASK60;
    }
    else if (ch == 1)
    {
        MCF_INTC_IMRH &= ~MCF_INTC_IMRH_INT_MASK61;
    }
    else
    {
        MCF_INTC_IMRH &= ~MCF_INTC_IMRH_INT_MASK62;
    }
}

bool timer_set_secs(uint8_t ch, uint32_t secs)
{
    uint16_t timeout;

    /*
     * Reset the timer
     */
    MCF_GPT_GMS(ch) = 0;

    /*
     * Get the timeout in seconds
     */
    timeout = (uint16_t)(secs * net_timer[ch].cnt);

    /*
     * Set the reference indicating that we have not yet reached the
     * desired timeout
     */
    net_timer[ch].reference = 1;

    /*
     * Enable timer interrupt to the processor
     */
    timer_irq_enable(ch);

    /*
     * Enable the timer using the pre-calculated values
     */
    MCF_GPT_GCIR(ch) = (0
            | MCF_GPT_GCIR_CNT(timeout)
            | MCF_GPT_GCIR_PRE(net_timer[ch].pre)
            );
    MCF_GPT_GMS(ch) = net_timer[ch].gms;

    return true;
}

uint32_t timer_get_reference(uint8_t ch)
{
    return (uint32_t) net_timer[ch].reference;
}

bool timer_init(uint8_t ch, uint8_t lvl, uint8_t pri)
{
    /*
     * Initialize the timer to expire after one second
     *
     * This routine should only be called by the project (board) specific
     * initialization code.
     */
    if (!((ch <= 3) && (lvl <= 7) && (lvl >= 1) && (pri <= 7)))
    {
        dbg("illegal parameters (ch=%d, lvl=%d, pri=%d)\r\n", ch, lvl, pri);

        return false;
    }

    /*
     * Reset the timer
     */
    MCF_GPT_GMS(ch) = 0;

    /*
     * Save off the channel, and interrupt lvl/pri information
     */
    net_timer[ch].ch = ch;
    net_timer[ch].lvl = lvl;
    net_timer[ch].pri = pri;

    /*
     * Register the timer interrupt handler
     */
    if (!isr_register_handler(TIMER_VECTOR(ch), 3, 0,
                (bool (*)(void *,void *)) timer_default_isr,
                NULL,
                (void *) &net_timer[ch])
       )
    {
        dbg("could not register timer interrupt handler\r\n");
        return false;
    }
    dbg("timer handler registered\r\n", __FUNCTION__);

    /*
     * Calculate the require CNT value to get a 1 second timeout
     *
     * 1 sec = CNT * Clk Period * PRE
     * CNT = 1 sec / (Clk Period * PRE)
     * CNT = Clk Freq / PRE
     *
     * The system clock frequency is defined as SYSTEM_CLOCK and
     * is given in MHz. We need to multiple it by 1000000 to get the
     * true value.  If we assume PRE to be the maximum of 0xFFFF,
     * then the CNT value needed to achieve a 1 second timeout is
     * given by:
     *
     * CNT = SYSTEM_CLOCK * (1000000/0xFFFF)
     */
    net_timer[ch].pre = 0xFFFF;
    net_timer[ch].cnt = (uint16_t) ((SYSCLK / 1000) * (1000000 / 0xFFFF));

    /*
     * Save off the appropriate mode select register value
     */
    net_timer[ch].gms = (0
            | MCF_GPT_GMS_TMS_GPIO
            | MCF_GPT_GMS_IEN
            | MCF_GPT_GMS_SC
            | MCF_GPT_GMS_CE
            );

    return true;
}