Uwe Kleine-König | 9918cda | 2007-02-16 15:36:55 +0100 | [diff] [blame] | 1 | /* |
| 2 | * arch/arm/mach-ns9xxx/time.c |
| 3 | * |
| 4 | * Copyright (C) 2006 by Digi International Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify it |
| 8 | * under the terms of the GNU General Public License version 2 as published by |
| 9 | * the Free Software Foundation. |
| 10 | */ |
| 11 | #include <linux/jiffies.h> |
| 12 | #include <linux/interrupt.h> |
| 13 | #include <linux/irq.h> |
| 14 | #include <asm/arch-ns9xxx/regs-sys.h> |
| 15 | #include <asm/arch-ns9xxx/clock.h> |
| 16 | #include <asm/arch-ns9xxx/irqs.h> |
| 17 | #include <asm/arch/system.h> |
| 18 | #include "generic.h" |
| 19 | |
| 20 | #define TIMERCLOCKSELECT 64 |
| 21 | |
| 22 | static u32 usecs_per_tick; |
| 23 | |
| 24 | static irqreturn_t |
| 25 | ns9xxx_timer_interrupt(int irq, void *dev_id) |
| 26 | { |
Uwe Kleine-König | bf62e86 | 2007-08-07 21:08:21 +0100 | [diff] [blame] | 27 | int timerno = irq - IRQ_TIMER0; |
| 28 | u32 tc; |
| 29 | |
Uwe Kleine-König | 9918cda | 2007-02-16 15:36:55 +0100 | [diff] [blame] | 30 | write_seqlock(&xtime_lock); |
| 31 | timer_tick(); |
| 32 | write_sequnlock(&xtime_lock); |
| 33 | |
Uwe Kleine-König | bf62e86 | 2007-08-07 21:08:21 +0100 | [diff] [blame] | 34 | /* clear irq */ |
| 35 | tc = SYS_TC(timerno); |
| 36 | if (REGGET(tc, SYS_TCx, REN) == SYS_TCx_REN_DIS) { |
| 37 | REGSET(tc, SYS_TCx, TEN, DIS); |
| 38 | SYS_TC(timerno) = tc; |
| 39 | } |
| 40 | REGSET(tc, SYS_TCx, INTC, SET); |
| 41 | SYS_TC(timerno) = tc; |
| 42 | REGSET(tc, SYS_TCx, INTC, UNSET); |
| 43 | SYS_TC(timerno) = tc; |
| 44 | |
Uwe Kleine-König | 9918cda | 2007-02-16 15:36:55 +0100 | [diff] [blame] | 45 | return IRQ_HANDLED; |
| 46 | } |
| 47 | |
| 48 | static unsigned long ns9xxx_timer_gettimeoffset(void) |
| 49 | { |
| 50 | /* return the microseconds which have passed since the last interrupt |
| 51 | * was _serviced_. That is, if an interrupt is pending or the counter |
Simon Arlott | 6cbdc8c | 2007-05-11 20:40:30 +0100 | [diff] [blame] | 52 | * reloads, return one period more. */ |
Uwe Kleine-König | 9918cda | 2007-02-16 15:36:55 +0100 | [diff] [blame] | 53 | |
| 54 | u32 counter1 = SYS_TR(0); |
| 55 | int pending = SYS_ISR & (1 << IRQ_TIMER0); |
| 56 | u32 counter2 = SYS_TR(0); |
| 57 | u32 elapsed; |
| 58 | |
| 59 | if (pending || counter2 > counter1) |
| 60 | elapsed = 2 * SYS_TRC(0) - counter2; |
| 61 | else |
| 62 | elapsed = SYS_TRC(0) - counter1; |
| 63 | |
| 64 | return (elapsed * usecs_per_tick) >> 16; |
| 65 | |
| 66 | } |
| 67 | |
| 68 | static struct irqaction ns9xxx_timer_irq = { |
| 69 | .name = "NS9xxx Timer Tick", |
Bernhard Walle | b30faba | 2007-05-08 00:35:39 -0700 | [diff] [blame] | 70 | .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, |
Uwe Kleine-König | 9918cda | 2007-02-16 15:36:55 +0100 | [diff] [blame] | 71 | .handler = ns9xxx_timer_interrupt, |
| 72 | }; |
| 73 | |
| 74 | static void __init ns9xxx_timer_init(void) |
| 75 | { |
| 76 | int tc; |
| 77 | |
| 78 | usecs_per_tick = |
| 79 | SH_DIV(1000000 * TIMERCLOCKSELECT, ns9xxx_cpuclock(), 16); |
| 80 | |
| 81 | /* disable timer */ |
| 82 | if ((tc = SYS_TC(0)) & SYS_TCx_TEN) |
| 83 | SYS_TC(0) = tc & ~SYS_TCx_TEN; |
| 84 | |
| 85 | SYS_TRC(0) = SH_DIV(ns9xxx_cpuclock(), (TIMERCLOCKSELECT * HZ), 0); |
| 86 | |
| 87 | REGSET(tc, SYS_TCx, TEN, EN); |
| 88 | REGSET(tc, SYS_TCx, TLCS, DIV64); /* This must match TIMERCLOCKSELECT */ |
| 89 | REGSET(tc, SYS_TCx, INTS, EN); |
| 90 | REGSET(tc, SYS_TCx, UDS, DOWN); |
| 91 | REGSET(tc, SYS_TCx, TDBG, STOP); |
| 92 | REGSET(tc, SYS_TCx, TSZ, 32); |
| 93 | REGSET(tc, SYS_TCx, REN, EN); |
| 94 | SYS_TC(0) = tc; |
| 95 | |
| 96 | setup_irq(IRQ_TIMER0, &ns9xxx_timer_irq); |
| 97 | } |
| 98 | |
| 99 | struct sys_timer ns9xxx_timer = { |
| 100 | .init = ns9xxx_timer_init, |
| 101 | .offset = ns9xxx_timer_gettimeoffset, |
| 102 | }; |