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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;
}
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