1/* 2 * linux/include/asm-arm/arch-mx1ads/time.h 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 17 * 18 * Copyright (C) 2002 Shane Nay (shane@minirl.com) 19 */ 20#include <asm/system.h> 21 22/* 23 * Where is the timer (VA)? 24 */ 25#define TIMER0_VA_BASE (IO_ADDRESS(MX1ADS_TIM1_BASE)+0x00000000) 26#define TIMER1_VA_BASE (IO_ADDRESS(MX1ADS_TIM2_BASE)+0x00000000) 27 28/* 29 * How long is the timer interval? 30 * 31 * Note- 32 * Clocking is not accurate enough. Need to change the input 33 * to CLKOUT, and fix what those values are. However, 34 * first need to evaluate what a reasonable value is 35 * as several other things depend upon that clock. 36 * 37 */ 38 39#define TIMER_RELOAD (328) 40 41#define TICKS2USECS(x) ((x) * 30) 42 43#define TIM_32KHZ 0x08 44#define TIM_INTEN 0x10 45#define TIM_ENAB 0x01 46 47/* 48 * What does it look like? 49 */ 50typedef struct TimerStruct { 51 unsigned long TimerControl; 52 unsigned long TimerPrescaler; 53 unsigned long TimerCompare; 54 unsigned long TimerCapture; 55 unsigned long TimerCounter; 56 unsigned long TimerClear; /* Clear Status */ 57} TimerStruct_t; 58 59extern unsigned long (*gettimeoffset) (void); 60 61/* 62 * Returns number of ms since last clock interrupt. Note that interrupts 63 * will have been disabled by do_gettimeoffset() 64 */ 65static unsigned long 66mx1ads_gettimeoffset(void) 67{ 68 volatile TimerStruct_t *timer1 = (TimerStruct_t *) TIMER1_VA_BASE; 69 unsigned long ticks, status; 70 71 /* 72 * Get the current number of ticks. Note that there is a race 73 * condition between us reading the timer and checking for 74 * an interrupt. We get around this by ensuring that the 75 * counter has not reloaded between our two reads. 76 */ 77 ticks = timer1->TimerCounter; 78 79 /* 80 * Interrupt pending? If so, we've reloaded once already. 81 */ 82 if (timer1->TimerClear & 1) 83 ticks += TIMER_RELOAD; 84 85 /* 86 * Convert the ticks to usecs 87 */ 88 return TICKS2USECS(ticks); 89} 90 91/* 92 * IRQ handler for the timer 93 */ 94static void 95mx1ads_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) 96{ 97 volatile TimerStruct_t *timer1 = 98 (volatile TimerStruct_t *) TIMER1_VA_BASE; 99 // ...clear the interrupt 100 if (timer1->TimerClear) { 101 timer1->TimerClear = 0x0; 102 } 103 104 do_timer(regs); 105 do_profile(regs); 106} 107 108/* 109 * Set up timer interrupt, and return the current time in seconds. 110 */ 111static inline void 112setup_timer(void) 113{ 114 volatile TimerStruct_t *timer0 = 115 (volatile TimerStruct_t *) TIMER0_VA_BASE; 116 volatile TimerStruct_t *timer1 = 117 (volatile TimerStruct_t *) TIMER1_VA_BASE; 118 119 120 timer_irq.handler = mx1ads_timer_interrupt; 121 122 /* 123 * Initialise to a known state (all timers off, and timing reset) 124 */ 125 timer0->TimerControl = 0; 126 timer1->TimerControl = 0; 127 timer0->TimerPrescaler = 0; 128 timer1->TimerPrescaler = 0; 129 130 timer1->TimerCompare = 328; 131 timer1->TimerControl = (TIM_32KHZ | TIM_INTEN | TIM_ENAB); 132 133 /* 134 * Make irqs happen for the system timer 135 */ 136 setup_arm_irq(TIM2_INT, &timer_irq); 137 gettimeoffset = mx1ads_gettimeoffset; 138} 139