arch/arm/mach-at91/at91x40_time.c

   1 /*
   2  * arch/arm/mach-at91/at91x40_time.c
   3  *
   4  * (C) Copyright 2007, Greg Ungerer <gerg@snapgear.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/init.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/irq.h>
  25 #include <linux/time.h>
  26 #include <linux/io.h>
  27 #include <mach/hardware.h>
  28 #include <asm/mach/time.h>
  29
  30 #include "at91_tc.h"
  31
  32 #define at91_tc_read(field) \
  33         __raw_readl(AT91_IO_P2V(AT91_TC) + field)
  34
  35 #define at91_tc_write(field, value) \
  36         __raw_writel(value, AT91_IO_P2V(AT91_TC) + field)
  37
  38 /*
  39  *      3 counter/timer units present.
  40  */
  41 #define AT91_TC_CLK0BASE        0
  42 #define AT91_TC_CLK1BASE        0x40
  43 #define AT91_TC_CLK2BASE        0x80
  44
  45 static u32 at91x40_gettimeoffset(void)
  46 {
  47         return (at91_tc_read(AT91_TC_CLK1BASE + AT91_TC_CV) * 1000000 /
  48                 (AT91X40_MASTER_CLOCK / 128)) * 1000;
  49 }
  50
  51 static irqreturn_t at91x40_timer_interrupt(int irq, void *dev_id)
  52 {
  53         at91_tc_read(AT91_TC_CLK1BASE + AT91_TC_SR);
  54         timer_tick();
  55         return IRQ_HANDLED;
  56 }
  57
  58 static struct irqaction at91x40_timer_irq = {
  59         .name           = "at91_tick",
  60         .flags          = IRQF_TIMER,
  61         .handler        = at91x40_timer_interrupt
  62 };
  63
  64 void __init at91x40_timer_init(void)
  65 {
  66         unsigned int v;
  67
  68         arch_gettimeoffset = at91x40_gettimeoffset;
  69
  70         at91_tc_write(AT91_TC_BCR, 0);
  71         v = at91_tc_read(AT91_TC_BMR);
  72         v = (v & ~AT91_TC_TC1XC1S) | AT91_TC_TC1XC1S_NONE;
  73         at91_tc_write(AT91_TC_BMR, v);
  74
  75         at91_tc_write(AT91_TC_CLK1BASE + AT91_TC_CCR, AT91_TC_CLKDIS);
  76         at91_tc_write(AT91_TC_CLK1BASE + AT91_TC_CMR, (AT91_TC_TIMER_CLOCK4 | AT91_TC_CPCTRG));
  77         at91_tc_write(AT91_TC_CLK1BASE + AT91_TC_IDR, 0xffffffff);
  78         at91_tc_write(AT91_TC_CLK1BASE + AT91_TC_RC, (AT91X40_MASTER_CLOCK / 128) / HZ - 1);
  79         at91_tc_write(AT91_TC_CLK1BASE + AT91_TC_IER, (1<<4));
  80
  81         setup_irq(AT91X40_ID_TC1, &at91x40_timer_irq);
  82
  83         at91_tc_write(AT91_TC_CLK1BASE + AT91_TC_CCR, (AT91_TC_SWTRG | AT91_TC_CLKEN));
  84 }