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/*

 *  linux/include/asm-arm/arch-integrator/time.h

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#include <asm/system.h>

#include <asm/leds.h>

/*

 * Where is the timer (VA)?

 */

#define TIMER0_VA_BASE (IO_ADDRESS(INTEGRATOR_CT_BASE)+0x00000000)

#define TIMER1_VA_BASE (IO_ADDRESS(INTEGRATOR_CT_BASE)+0x00000100)

#define TIMER2_VA_BASE (IO_ADDRESS(INTEGRATOR_CT_BASE)+0x00000200)

#define VA_IC_BASE     IO_ADDRESS(INTEGRATOR_IC_BASE) 

/*

 * How long is the timer interval?

 */

#define TIMER_INTERVAL  (TICKS_PER_uSEC * mSEC_10)

#if TIMER_INTERVAL >= 0x100000

#define TIMER_RELOAD    (TIMER_INTERVAL >> 8)           /* Divide by 256 */

#define TIMER_CTRL      0x88                            /* Enable, Clock / 256 */

#define TICKS2USECS(x)  (256 * (x) / TICKS_PER_uSEC)

#elif TIMER_INTERVAL >= 0x10000

#define TIMER_RELOAD    (TIMER_INTERVAL >> 4)           /* Divide by 16 */

#define TIMER_CTRL      0x84                            /* Enable, Clock / 16 */

#define TICKS2USECS(x)  (16 * (x) / TICKS_PER_uSEC)

#else

#define TIMER_RELOAD    (TIMER_INTERVAL)

#define TIMER_CTRL      0x80                            /* Enable */

#define TICKS2USECS(x)  ((x) / TICKS_PER_uSEC)

#endif

/*

 * What does it look like?

 */

typedef struct TimerStruct {

        unsigned long TimerLoad;

        unsigned long TimerValue;

        unsigned long TimerControl;

        unsigned long TimerClear;

} TimerStruct_t;

extern unsigned long (*gettimeoffset)(void);

/*

 * Returns number of ms since last clock interrupt.  Note that interrupts

 * will have been disabled by do_gettimeoffset()

 */

static unsigned long integrator_gettimeoffset(void)

{

        volatile TimerStruct_t *timer1 = (TimerStruct_t *)TIMER1_VA_BASE;

        unsigned long ticks1, ticks2, status;

        /*

         * Get the current number of ticks.  Note that there is a race

         * condition between us reading the timer and checking for

         * an interrupt.  We get around this by ensuring that the

         * counter has not reloaded between our two reads.

         */

        ticks2 = timer1->TimerValue & 0xffff;

        do {

                ticks1 = ticks2;

                status = __raw_readl(VA_IC_BASE + IRQ_RAW_STATUS);

                ticks2 = timer1->TimerValue & 0xffff;

        } while (ticks2 > ticks1);

        /*

         * Number of ticks since last interrupt.

         */

        ticks1 = TIMER_RELOAD - ticks2;

        /*

         * Interrupt pending?  If so, we've reloaded once already.

         */

        if (status & IRQMASK_TIMERINT1)

                ticks1 += TIMER_RELOAD;

        /*

         * Convert the ticks to usecs

         */

        return TICKS2USECS(ticks1);

}

/*

 * IRQ handler for the timer

 */

static void integrator_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)

{

        volatile TimerStruct_t *timer1 = (volatile TimerStruct_t *)TIMER1_VA_BASE;

        // ...clear the interrupt

        timer1->TimerClear = 1;

        do_leds();

        do_timer(regs);

        do_profile(regs);

}

/*

 * Set up timer interrupt, and return the current time in seconds.

 */

static inline void setup_timer(void)

{

        volatile TimerStruct_t *timer0 = (volatile TimerStruct_t *)TIMER0_VA_BASE;

        volatile TimerStruct_t *timer1 = (volatile TimerStruct_t *)TIMER1_VA_BASE;

        volatile TimerStruct_t *timer2 = (volatile TimerStruct_t *)TIMER2_VA_BASE;

        timer_irq.handler = integrator_timer_interrupt;

        /*

         * Initialise to a known state (all timers off)

         */

        timer0->TimerControl = 0;

        timer1->TimerControl = 0;

        timer2->TimerControl = 0;

        timer1->TimerLoad    = TIMER_RELOAD;

        timer1->TimerValue   = TIMER_RELOAD;

        timer1->TimerControl = TIMER_CTRL | 0x40;       /* periodic */

        /*

         * Make irqs happen for the system timer

         */

        setup_arm_irq(IRQ_TIMERINT1, &timer_irq);

        gettimeoffset = integrator_gettimeoffset;

}