projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| c53c9cf6 AV |
1 | /* |
| 2 | * arch/arm/mach-ks8695/time.c | |
| 3 | * | |
| 4 | * Copyright (C) 2006 Ben Dooks <ben@simtec.co.uk> | |
| 5 | * Copyright (C) 2006 Simtec Electronics | |
| 6 | * | |
| 7 | * This program is free software; you can redistribute it and/or modify | |
| 8 | * it under the terms of the GNU General Public License as published by | |
| 9 | * the Free Software Foundation; either version 2 of the License, or | |
| 10 | * (at your option) any later version. | |
| 11 | * | |
| 12 | * This program is distributed in the hope that it will be useful, | |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 15 | * GNU General Public License for more details. | |
| 16 | * | |
| 17 | * You should have received a copy of the GNU General Public License | |
| 18 | * along with this program; if not, write to the Free Software | |
| 19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
| 20 | */ | |
| 21 | ||
| 22 | #include <linux/init.h> | |
| 23 | #include <linux/interrupt.h> | |
| 24 | #include <linux/irq.h> | |
| 25 | #include <linux/kernel.h> | |
| 26 | #include <linux/sched.h> | |
| 27 | ||
| 28 | #include <asm/io.h> | |
| 29 | #include <asm/mach/time.h> | |
| 30 | ||
| 31 | #include <asm/arch/regs-timer.h> | |
| 32 | #include <asm/arch/regs-irq.h> | |
| 33 | ||
| 34 | #include "generic.h" | |
| 35 | ||
| 36 | /* | |
| 37 | * Returns number of ms since last clock interrupt. Note that interrupts | |
| 38 | * will have been disabled by do_gettimeoffset() | |
| 39 | */ | |
| 40 | static unsigned long ks8695_gettimeoffset (void) | |
| 41 | { | |
| 42 | unsigned long elapsed, tick2, intpending; | |
| 43 | ||
| 44 | /* | |
| 45 | * Get the current number of ticks. Note that there is a race | |
| 46 | * condition between us reading the timer and checking for an | |
| 47 | * interrupt. We solve this by ensuring that the counter has not | |
| 48 | * reloaded between our two reads. | |
| 49 | */ | |
| 50 | elapsed = __raw_readl(KS8695_TMR_VA + KS8695_T1TC) + __raw_readl(KS8695_TMR_VA + KS8695_T1PD); | |
| 51 | do { | |
| 52 | tick2 = elapsed; | |
| 53 | intpending = __raw_readl(KS8695_IRQ_VA + KS8695_INTST) & (1 << KS8695_IRQ_TIMER1); | |
| 54 | elapsed = __raw_readl(KS8695_TMR_VA + KS8695_T1TC) + __raw_readl(KS8695_TMR_VA + KS8695_T1PD); | |
| 55 | } while (elapsed > tick2); | |
| 56 | ||
| 57 | /* Convert to number of ticks expired (not remaining) */ | |
| 58 | elapsed = (CLOCK_TICK_RATE / HZ) - elapsed; | |
| 59 | ||
| 60 | /* Is interrupt pending? If so, then timer has been reloaded already. */ | |
| 61 | if (intpending) | |
| 62 | elapsed += (CLOCK_TICK_RATE / HZ); | |
| 63 | ||
| 64 | /* Convert ticks to usecs */ | |
| 65 | return (unsigned long)(elapsed * (tick_nsec / 1000)) / LATCH; | |
| 66 | } | |
| 67 | ||
| 68 | /* | |
| 69 | * IRQ handler for the timer. | |
| 70 | */ | |
| 71 | static irqreturn_t ks8695_timer_interrupt(int irq, void *dev_id) | |
| 72 | { | |
| 73 | write_seqlock(&xtime_lock); | |
| 74 | timer_tick(); | |
| 75 | write_sequnlock(&xtime_lock); | |
| 76 | ||
| 77 | return IRQ_HANDLED; | |
| 78 | } | |
| 79 | ||
| 80 | static struct irqaction ks8695_timer_irq = { | |
| 81 | .name = "ks8695_tick", | |
| 82 | .flags = IRQF_DISABLED | IRQF_TIMER, | |
| 83 | .handler = ks8695_timer_interrupt, | |
| 84 | }; | |
| 85 | ||
| 86 | static void ks8695_timer_setup(void) | |
| 87 | { | |
| 88 | unsigned long tmout = CLOCK_TICK_RATE / HZ; | |
| 89 | unsigned long tmcon; | |
| 90 | ||
| 91 | /* disable timer1 */ | |
| 92 | tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); | |
| 93 | __raw_writel(tmcon & ~TMCON_T1EN, KS8695_TMR_VA + KS8695_TMCON); | |
| 94 | ||
| 95 | __raw_writel(tmout / 2, KS8695_TMR_VA + KS8695_T1TC); | |
| 96 | __raw_writel(tmout / 2, KS8695_TMR_VA + KS8695_T1PD); | |
| 97 | ||
| 98 | /* re-enable timer1 */ | |
| 99 | __raw_writel(tmcon | TMCON_T1EN, KS8695_TMR_VA + KS8695_TMCON); | |
| 100 | } | |
| 101 | ||
| 102 | static void __init ks8695_timer_init (void) | |
| 103 | { | |
| 104 | ks8695_timer_setup(); | |
| 105 | ||
| 106 | /* Enable timer interrupts */ | |
| 107 | setup_irq(KS8695_IRQ_TIMER1, &ks8695_timer_irq); | |
| 108 | } | |
| 109 | ||
| 110 | struct sys_timer ks8695_timer = { | |
| 111 | .init = ks8695_timer_init, | |
| 112 | .offset = ks8695_gettimeoffset, | |
| 113 | .resume = ks8695_timer_setup, | |
| 114 | }; |