Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * arch/arm/mach-iop3xx/iop321-time.c |
| 3 | * |
| 4 | * Timer code for IOP321 based systems |
| 5 | * |
| 6 | * Author: Deepak Saxena <dsaxena@mvista.com> |
| 7 | * |
| 8 | * Copyright 2002-2003 MontaVista Software Inc. |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify it |
| 11 | * under the terms of the GNU General Public License as published by the |
| 12 | * Free Software Foundation; either version 2 of the License, or (at your |
| 13 | * option) any later version. |
| 14 | */ |
| 15 | |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/interrupt.h> |
| 18 | #include <linux/time.h> |
| 19 | #include <linux/init.h> |
| 20 | #include <linux/timex.h> |
| 21 | |
| 22 | #include <asm/hardware.h> |
| 23 | #include <asm/io.h> |
| 24 | #include <asm/irq.h> |
| 25 | #include <asm/uaccess.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | #include <asm/mach/irq.h> |
| 27 | #include <asm/mach/time.h> |
| 28 | |
| 29 | #define IOP321_TIME_SYNC 0 |
| 30 | |
| 31 | static inline unsigned long get_elapsed(void) |
| 32 | { |
| 33 | return LATCH - *IOP321_TU_TCR0; |
| 34 | } |
| 35 | |
| 36 | static unsigned long iop321_gettimeoffset(void) |
| 37 | { |
| 38 | unsigned long elapsed, usec; |
| 39 | u32 tisr1, tisr2; |
| 40 | |
| 41 | /* |
| 42 | * If an interrupt was pending before we read the timer, |
| 43 | * we've already wrapped. Factor this into the time. |
| 44 | * If an interrupt was pending after we read the timer, |
| 45 | * it may have wrapped between checking the interrupt |
| 46 | * status and reading the timer. Re-read the timer to |
| 47 | * be sure its value is after the wrap. |
| 48 | */ |
| 49 | |
| 50 | asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr1)); |
| 51 | elapsed = get_elapsed(); |
| 52 | asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr2)); |
| 53 | |
| 54 | if(tisr1 & 1) |
| 55 | elapsed += LATCH; |
| 56 | else if (tisr2 & 1) |
| 57 | elapsed = LATCH + get_elapsed(); |
| 58 | |
| 59 | /* |
| 60 | * Now convert them to usec. |
| 61 | */ |
Adam Brooks | 7691d93 | 2005-09-07 17:24:36 +0100 | [diff] [blame] | 62 | usec = (unsigned long)(elapsed / (CLOCK_TICK_RATE/1000000)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | |
| 64 | return usec; |
| 65 | } |
| 66 | |
| 67 | static irqreturn_t |
| 68 | iop321_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) |
| 69 | { |
| 70 | u32 tisr; |
| 71 | |
| 72 | write_seqlock(&xtime_lock); |
| 73 | |
| 74 | asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr)); |
| 75 | tisr |= 1; |
| 76 | asm volatile("mcr p6, 0, %0, c6, c1, 0" : : "r" (tisr)); |
| 77 | |
| 78 | timer_tick(regs); |
| 79 | |
| 80 | write_sequnlock(&xtime_lock); |
| 81 | |
| 82 | return IRQ_HANDLED; |
| 83 | } |
| 84 | |
| 85 | static struct irqaction iop321_timer_irq = { |
| 86 | .name = "IOP321 Timer Tick", |
| 87 | .handler = iop321_timer_interrupt, |
Russell King | 09b8b5f | 2005-06-26 17:06:36 +0100 | [diff] [blame] | 88 | .flags = SA_INTERRUPT | SA_TIMER, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | }; |
| 90 | |
| 91 | static void __init iop321_timer_init(void) |
| 92 | { |
| 93 | u32 timer_ctl; |
| 94 | |
| 95 | setup_irq(IRQ_IOP321_TIMER0, &iop321_timer_irq); |
| 96 | |
| 97 | timer_ctl = IOP321_TMR_EN | IOP321_TMR_PRIVILEGED | IOP321_TMR_RELOAD | |
| 98 | IOP321_TMR_RATIO_1_1; |
| 99 | |
| 100 | asm volatile("mcr p6, 0, %0, c4, c1, 0" : : "r" (LATCH)); |
| 101 | |
| 102 | asm volatile("mcr p6, 0, %0, c0, c1, 0" : : "r" (timer_ctl)); |
| 103 | } |
| 104 | |
| 105 | struct sys_timer iop321_timer = { |
| 106 | .init = &iop321_timer_init, |
| 107 | .offset = iop321_gettimeoffset, |
| 108 | }; |