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Diffstat (limited to 'include/asm-arm/arch-integrator/time.h')
| -rw-r--r-- | include/asm-arm/arch-integrator/time.h | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/include/asm-arm/arch-integrator/time.h b/include/asm-arm/arch-integrator/time.h new file mode 100644 index 000000000..1dfb5fd68 --- /dev/null +++ b/include/asm-arm/arch-integrator/time.h @@ -0,0 +1,140 @@ +/* + * 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. + */ +extern __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; +} |