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Diffstat (limited to 'arch/arm/mach-ks8695/time.c')
| -rw-r--r-- | arch/arm/mach-ks8695/time.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/arch/arm/mach-ks8695/time.c b/arch/arm/mach-ks8695/time.c new file mode 100644 index 00000000000..d2c86e4a72e --- /dev/null +++ b/arch/arm/mach-ks8695/time.c @@ -0,0 +1,114 @@ +/* + * arch/arm/mach-ks8695/time.c + * + * Copyright (C) 2006 Ben Dooks <ben@simtec.co.uk> + * Copyright (C) 2006 Simtec Electronics + * + * 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 <linux/init.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/kernel.h> +#include <linux/sched.h> + +#include <asm/io.h> +#include <asm/mach/time.h> + +#include <asm/arch/regs-timer.h> +#include <asm/arch/regs-irq.h> + +#include "generic.h" + +/* + * Returns number of ms since last clock interrupt. Note that interrupts + * will have been disabled by do_gettimeoffset() + */ +static unsigned long ks8695_gettimeoffset (void) +{ + unsigned long elapsed, tick2, intpending; + + /* + * Get the current number of ticks. Note that there is a race + * condition between us reading the timer and checking for an + * interrupt. We solve this by ensuring that the counter has not + * reloaded between our two reads. + */ + elapsed = __raw_readl(KS8695_TMR_VA + KS8695_T1TC) + __raw_readl(KS8695_TMR_VA + KS8695_T1PD); + do { + tick2 = elapsed; + intpending = __raw_readl(KS8695_IRQ_VA + KS8695_INTST) & (1 << KS8695_IRQ_TIMER1); + elapsed = __raw_readl(KS8695_TMR_VA + KS8695_T1TC) + __raw_readl(KS8695_TMR_VA + KS8695_T1PD); + } while (elapsed > tick2); + + /* Convert to number of ticks expired (not remaining) */ + elapsed = (CLOCK_TICK_RATE / HZ) - elapsed; + + /* Is interrupt pending? If so, then timer has been reloaded already. */ + if (intpending) + elapsed += (CLOCK_TICK_RATE / HZ); + + /* Convert ticks to usecs */ + return (unsigned long)(elapsed * (tick_nsec / 1000)) / LATCH; +} + +/* + * IRQ handler for the timer. + */ +static irqreturn_t ks8695_timer_interrupt(int irq, void *dev_id) +{ + write_seqlock(&xtime_lock); + timer_tick(); + write_sequnlock(&xtime_lock); + + return IRQ_HANDLED; +} + +static struct irqaction ks8695_timer_irq = { + .name = "ks8695_tick", + .flags = IRQF_DISABLED | IRQF_TIMER, + .handler = ks8695_timer_interrupt, +}; + +static void ks8695_timer_setup(void) +{ + unsigned long tmout = CLOCK_TICK_RATE / HZ; + unsigned long tmcon; + + /* disable timer1 */ + tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); + __raw_writel(tmcon & ~TMCON_T1EN, KS8695_TMR_VA + KS8695_TMCON); + + __raw_writel(tmout / 2, KS8695_TMR_VA + KS8695_T1TC); + __raw_writel(tmout / 2, KS8695_TMR_VA + KS8695_T1PD); + + /* re-enable timer1 */ + __raw_writel(tmcon | TMCON_T1EN, KS8695_TMR_VA + KS8695_TMCON); +} + +static void __init ks8695_timer_init (void) +{ + ks8695_timer_setup(); + + /* Enable timer interrupts */ + setup_irq(KS8695_IRQ_TIMER1, &ks8695_timer_irq); +} + +struct sys_timer ks8695_timer = { + .init = ks8695_timer_init, + .offset = ks8695_gettimeoffset, + .resume = ks8695_timer_setup, +}; |