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  */
  39 static irqreturn_t gemini_timer_interrupt(int irq, void *dev_id)
  40 {
  41         timer_tick();
  42
  43         return IRQ_HANDLED;
  44 }
  45
  46 static 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  */
  55 void __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 }