LXR linux/arch/arm/mach-gemini/time.c

   1/*
   2 *  Copyright (C) 2001-2006 Storlink, Corp.
   3 *  Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License as published by
   7 * the Free Software Foundation; either version 2 of the License, or
   8 * (at your option) any later version.
   9 */
  10#include <linux/interrupt.h>
  11#include <linux/irq.h>
  12#include <linux/io.h>
  13#include <mach/hardware.h>
  14#include <mach/global_reg.h>
  15#include <asm/mach/time.h>
  16
  17/*
  18 * Register definitions for the timers
  19 */
  20#define TIMER_COUNT(BASE_ADDR)          (BASE_ADDR  + 0x00)
  21#define TIMER_LOAD(BASE_ADDR)           (BASE_ADDR  + 0x04)
  22#define TIMER_MATCH1(BASE_ADDR)         (BASE_ADDR  + 0x08)
  23#define TIMER_MATCH2(BASE_ADDR)         (BASE_ADDR  + 0x0C)
  24#define TIMER_CR(BASE_ADDR)             (BASE_ADDR  + 0x30)
  25
  26#define TIMER_1_CR_ENABLE               (1 << 0)
  27#define TIMER_1_CR_CLOCK                (1 << 1)
  28#define TIMER_1_CR_INT                  (1 << 2)
  29#define TIMER_2_CR_ENABLE               (1 << 3)
  30#define TIMER_2_CR_CLOCK                (1 << 4)
  31#define TIMER_2_CR_INT                  (1 << 5)
  32#define TIMER_3_CR_ENABLE               (1 << 6)
  33#define TIMER_3_CR_CLOCK                (1 << 7)
  34#define TIMER_3_CR_INT                  (1 << 8)
  35
  36/*
  37 * IRQ handler for the timer
  38 */
  39static irqreturn_t gemini_timer_interrupt(int irq, void *dev_id)
  40{
  41        timer_tick();
  42
  43        return IRQ_HANDLED;
  44}
  45
  46static struct irqaction gemini_timer_irq = {
  47        .name           = "Gemini Timer Tick",
  48        .flags          = IRQF_DISABLED | IRQF_TIMER,
  49        .handler        = gemini_timer_interrupt,
  50};
  51
  52/*
  53 * Set up timer interrupt, and return the current time in seconds.
  54 */
  55void __init gemini_timer_init(void)
  56{
  57        unsigned int tick_rate, reg_v;
  58
  59        reg_v = __raw_readl(IO_ADDRESS(GEMINI_GLOBAL_BASE + GLOBAL_STATUS));
  60        tick_rate = REG_TO_AHB_SPEED(reg_v) * 1000000;
  61
  62        printk(KERN_INFO "Bus: %dMHz", tick_rate / 1000000);
  63
  64        tick_rate /= 6;         /* APB bus run AHB*(1/6) */
  65
  66        switch(reg_v & CPU_AHB_RATIO_MASK) {
  67        case CPU_AHB_1_1:
  68                printk(KERN_CONT "(1/1)\n");
  69                break;
  70        case CPU_AHB_3_2:
  71                printk(KERN_CONT "(3/2)\n");
  72                break;
  73        case CPU_AHB_24_13:
  74                printk(KERN_CONT "(24/13)\n");
  75                break;
  76        case CPU_AHB_2_1:
  77                printk(KERN_CONT "(2/1)\n");
  78                break;
  79        }
  80
  81        /*
  82         * Make irqs happen for the system timer
  83         */
  84        setup_irq(IRQ_TIMER2, &gemini_timer_irq);
  85        /* Start the timer */
  86        __raw_writel(tick_rate / HZ, TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER2_BASE)));
  87        __raw_writel(tick_rate / HZ, TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER2_BASE)));
  88        __raw_writel(TIMER_2_CR_ENABLE | TIMER_2_CR_INT, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
  89}
  90