Subversion Repositories c0or1k

/*

 * omap GP timer driver honoring generic

 * timer library API

 *

 * Copyright (C) 2010 B Labs Ltd.

 *

 * Author: Bahadir Balban

 */

#include <libdev/io.h>

#include <l4lib/types.h>

#include "timer.h"

#define OMAP_TIMER_MAT_IT_FLAG  (1 << 0)

#define OMAP_TIMER_OVR_IT_FLAG  (1 << 1)

#define OMAP_TIMER_TCAR_IT_FLAG (1 << 2)

u32 timer_periodic_intr_status(unsigned long timer_base)

{

        volatile u32 reg = read(timer_base + OMAP_TIMER_TISR);

        return (reg & OMAP_TIMER_OVR_IT_FLAG);

}

#define OMAP_TIMER_SOFT_RESET   (1 << 1)

void timer_reset(unsigned long timer_base)

{

        /* Reset Timer */

        write(OMAP_TIMER_SOFT_RESET, timer_base + OMAP_TIMER_TIOCP);

        /* Wait for reset completion */

        while (!read(timer_base + OMAP_TIMER_TSTAT));

}

void timer_load(unsigned long timer_base, u32 value)

{

        write(value, timer_base + OMAP_TIMER_TLDR);

        write(value, timer_base + OMAP_TIMER_TCRR);

}

u32 timer_read(unsigned long timer_base)

{

        return read(timer_base + OMAP_TIMER_TCRR);

}

#define OMAP_TIMER_START        (1 << 0)

void timer_start(unsigned long timer_base)

{

        volatile u32 reg = read(timer_base + OMAP_TIMER_TCLR);

        reg |= OMAP_TIMER_START;

        write(reg, timer_base + OMAP_TIMER_TCLR);

}

void timer_stop(unsigned long timer_base)

{

        volatile u32 reg = read(timer_base + OMAP_TIMER_TCLR);

        reg &= (~OMAP_TIMER_START);

        write(reg, timer_base + OMAP_TIMER_TCLR);

}

void timer_init_periodic(unsigned long timer_base)

{

        volatile u32 reg;

        /* Reset the timer */

        timer_reset(timer_base);

        /* Set timer to autoreload mode */

        reg = read(timer_base + OMAP_TIMER_TCLR);

        reg |= (1 << OMAP_TIMER_MODE_AUTORELAOD);

        write(reg, timer_base + OMAP_TIMER_TCLR);

        /*

        * Beagle Board RevC manual:

        * overflow period = (0xffffffff - TLDR + 1)*PS*(1/TIMER_FCLK)

        * where,

        * PS: Prescaler divisor (we are not using this)

        *

        * Beagle board manual says, 26MHz oscillator present on board.

        * U-Boot divides the sys_clock by 2 if sys_clk is >19MHz,

        * so,we have sys_clk frequency = 13MHz

        *

        * TIMER_FCLK = 13MHz

        * So, for 1ms period, TLDR = 0xffffcd38

        *

        */

        timer_load(timer_base, 0xffffcd38);

        /* Clear pending Interrupts, if any */

        write(7, timer_base + OMAP_TIMER_TISR);

        /* Enable inteerupts */

        write((1 << OMAP_TIMER_INTR_OVERFLOW), timer_base + OMAP_TIMER_TIER);

}

void timer_init(unsigned long timer_base)

{

        timer_init_periodic(timer_base);

}