Andrew Victor | c53c9cf | 2007-05-11 21:01:28 +0100 | [diff] [blame] | 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 | |
Russell King | a09e64f | 2008-08-05 16:14:15 +0100 | [diff] [blame] | 31 | #include <mach/regs-timer.h> |
| 32 | #include <mach/regs-irq.h> |
Andrew Victor | c53c9cf | 2007-05-11 21:01:28 +0100 | [diff] [blame] | 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 | { |
Andrew Victor | c53c9cf | 2007-05-11 21:01:28 +0100 | [diff] [blame] | 73 | timer_tick(); |
Andrew Victor | c53c9cf | 2007-05-11 21:01:28 +0100 | [diff] [blame] | 74 | return IRQ_HANDLED; |
| 75 | } |
| 76 | |
| 77 | static struct irqaction ks8695_timer_irq = { |
| 78 | .name = "ks8695_tick", |
| 79 | .flags = IRQF_DISABLED | IRQF_TIMER, |
| 80 | .handler = ks8695_timer_interrupt, |
| 81 | }; |
| 82 | |
| 83 | static void ks8695_timer_setup(void) |
| 84 | { |
| 85 | unsigned long tmout = CLOCK_TICK_RATE / HZ; |
| 86 | unsigned long tmcon; |
| 87 | |
| 88 | /* disable timer1 */ |
| 89 | tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON); |
| 90 | __raw_writel(tmcon & ~TMCON_T1EN, KS8695_TMR_VA + KS8695_TMCON); |
| 91 | |
| 92 | __raw_writel(tmout / 2, KS8695_TMR_VA + KS8695_T1TC); |
| 93 | __raw_writel(tmout / 2, KS8695_TMR_VA + KS8695_T1PD); |
| 94 | |
| 95 | /* re-enable timer1 */ |
| 96 | __raw_writel(tmcon | TMCON_T1EN, KS8695_TMR_VA + KS8695_TMCON); |
| 97 | } |
| 98 | |
| 99 | static void __init ks8695_timer_init (void) |
| 100 | { |
| 101 | ks8695_timer_setup(); |
| 102 | |
| 103 | /* Enable timer interrupts */ |
| 104 | setup_irq(KS8695_IRQ_TIMER1, &ks8695_timer_irq); |
| 105 | } |
| 106 | |
| 107 | struct sys_timer ks8695_timer = { |
| 108 | .init = ks8695_timer_init, |
| 109 | .offset = ks8695_gettimeoffset, |
| 110 | .resume = ks8695_timer_setup, |
| 111 | }; |