diff options
author | Linus Torvalds <torvalds@woody.osdl.org> | 2006-12-07 15:40:39 -0800 |
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committer | Linus Torvalds <torvalds@woody.osdl.org> | 2006-12-07 15:40:39 -0800 |
commit | ea14fad0d416354a4e9bb1a04f32acba706f9548 (patch) | |
tree | 2c8acc5331f189aef1d40ddce3f40d6be9314e77 /arch/arm/mach-at91rm9200/at91sam926x_time.c | |
parent | 6ee7e78e7c78d871409ad4df30551c9355be7d0e (diff) | |
parent | 6705cda24fad1cb0ac82ac4f312df8ec735b39b0 (diff) |
Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (76 commits)
[ARM] 4002/1: S3C24XX: leave parent IRQs unmasked
[ARM] 4001/1: S3C24XX: shorten reboot time
[ARM] 3983/2: remove unused argument to __bug()
[ARM] 4000/1: Osiris: add third serial port in
[ARM] 3999/1: RX3715: suspend to RAM support
[ARM] 3998/1: VR1000: LED platform devices
[ARM] 3995/1: iop13xx: add iop13xx support
[ARM] 3968/1: iop13xx: add iop13xx_defconfig
[ARM] Update mach-types
[ARM] Allow gcc to optimise arm_add_memory a little more
[ARM] 3991/1: i.MX/MX1 high resolution time source
[ARM] 3990/1: i.MX/MX1 more precise PLL decode
[ARM] 3986/1: H1940: suspend to RAM support
[ARM] 3985/1: ixp4xx clocksource cleanup
[ARM] 3984/1: ixp4xx/nslu2: Fix disk LED numbering (take 2)
[ARM] 3994/1: ixp23xx: fix handling of pci master aborts
[ARM] 3981/1: sched_clock for PXA2xx
[ARM] 3980/1: extend the ARM Versatile sched_clock implementation from 32 to 63 bit
[ARM] 3979/1: extend the SA11x0 sched_clock implementation from 32 to 63 bit period
[ARM] 3978/1: macro to provide a 63-bit value from a 32-bit hardware counter
...
Diffstat (limited to 'arch/arm/mach-at91rm9200/at91sam926x_time.c')
-rw-r--r-- | arch/arm/mach-at91rm9200/at91sam926x_time.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/arch/arm/mach-at91rm9200/at91sam926x_time.c b/arch/arm/mach-at91rm9200/at91sam926x_time.c new file mode 100644 index 000000000000..99df5f6ee42e --- /dev/null +++ b/arch/arm/mach-at91rm9200/at91sam926x_time.c @@ -0,0 +1,114 @@ +/* + * linux/arch/arm/mach-at91rm9200/at91sam926x_time.c + * + * Copyright (C) 2005-2006 M. Amine SAYA, ATMEL Rousset, France + * Revision 2005 M. Nicolas Diremdjian, ATMEL Rousset, France + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/time.h> + +#include <asm/hardware.h> +#include <asm/io.h> +#include <asm/mach/time.h> + +#include <asm/arch/at91_pit.h> + + +#define PIT_CPIV(x) ((x) & AT91_PIT_CPIV) +#define PIT_PICNT(x) (((x) & AT91_PIT_PICNT) >> 20) + +/* + * Returns number of microseconds since last timer interrupt. Note that interrupts + * will have been disabled by do_gettimeofday() + * 'LATCH' is hwclock ticks (see CLOCK_TICK_RATE in timex.h) per jiffy. + * 'tick' is usecs per jiffy (linux/timex.h). + */ +static unsigned long at91sam926x_gettimeoffset(void) +{ + unsigned long elapsed; + unsigned long t = at91_sys_read(AT91_PIT_PIIR); + + elapsed = (PIT_PICNT(t) * LATCH) + PIT_CPIV(t); /* hardware clock cycles */ + + return (unsigned long)(elapsed * 1000000) / LATCH; +} + +/* + * IRQ handler for the timer. + */ +static irqreturn_t at91sam926x_timer_interrupt(int irq, void *dev_id) +{ + volatile long nr_ticks; + + if (at91_sys_read(AT91_PIT_SR) & AT91_PIT_PITS) { /* This is a shared interrupt */ + write_seqlock(&xtime_lock); + + /* Get number to ticks performed before interrupt and clear PIT interrupt */ + nr_ticks = PIT_PICNT(at91_sys_read(AT91_PIT_PIVR)); + do { + timer_tick(); + nr_ticks--; + } while (nr_ticks); + + write_sequnlock(&xtime_lock); + return IRQ_HANDLED; + } else + return IRQ_NONE; /* not handled */ +} + +static struct irqaction at91sam926x_timer_irq = { + .name = "at91_tick", + .flags = IRQF_SHARED | IRQF_DISABLED | IRQF_TIMER, + .handler = at91sam926x_timer_interrupt +}; + +void at91sam926x_timer_reset(void) +{ + /* Disable timer */ + at91_sys_write(AT91_PIT_MR, 0); + + /* Clear any pending interrupts */ + (void) at91_sys_read(AT91_PIT_PIVR); + + /* Set Period Interval timer and enable its interrupt */ + at91_sys_write(AT91_PIT_MR, (LATCH & AT91_PIT_PIV) | AT91_PIT_PITIEN | AT91_PIT_PITEN); +} + +/* + * Set up timer interrupt. + */ +void __init at91sam926x_timer_init(void) +{ + /* Initialize and enable the timer */ + at91sam926x_timer_reset(); + + /* Make IRQs happen for the system timer. */ + setup_irq(AT91_ID_SYS, &at91sam926x_timer_irq); +} + +#ifdef CONFIG_PM +static void at91sam926x_timer_suspend(void) +{ + /* Disable timer */ + at91_sys_write(AT91_PIT_MR, 0); +} +#else +#define at91sam926x_timer_suspend NULL +#endif + +struct sys_timer at91sam926x_timer = { + .init = at91sam926x_timer_init, + .offset = at91sam926x_gettimeoffset, + .suspend = at91sam926x_timer_suspend, + .resume = at91sam926x_timer_reset, +}; + |