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 #include <mach/at91_tc.h>
  30
  31 /*
  32  *      3 counter/timer units present.
  33  */
  34 #define AT91_TC_CLK0BASE        0
  35 #define AT91_TC_CLK1BASE        0x40
  36 #define AT91_TC_CLK2BASE        0x80
  37
  38 static unsigned long at91x40_gettimeoffset(void)
  39 {
  40         return (at91_sys_read(AT91_TC + AT91_TC_CLK1BASE + AT91_TC_CV) * 1000000 / (AT91X40_MASTER_CLOCK / 128));
  41 }
  42
  43 static irqreturn_t at91x40_timer_interrupt(int irq, void *dev_id)
  44 {
  45         at91_sys_read(AT91_TC + AT91_TC_CLK1BASE + AT91_TC_SR);
  46         timer_tick();
  47         return IRQ_HANDLED;
  48 }
  49
  50 static struct irqaction at91x40_timer_irq = {
  51         .name           = "at91_tick",
  52         .flags          = IRQF_DISABLED | IRQF_TIMER,
  53         .handler        = at91x40_timer_interrupt
  54 };
  55
  56 void __init at91x40_timer_init(void)
  57 {
  58         unsigned int v;
  59
  60         at91_sys_write(AT91_TC + AT91_TC_BCR, 0);
  61         v = at91_sys_read(AT91_TC + AT91_TC_BMR);
  62         v = (v & ~AT91_TC_TC1XC1S) | AT91_TC_TC1XC1S_NONE;
  63         at91_sys_write(AT91_TC + AT91_TC_BMR, v);
  64
  65         at91_sys_write(AT91_TC + AT91_TC_CLK1BASE + AT91_TC_CCR, AT91_TC_CLKDIS);
  66         at91_sys_write(AT91_TC + AT91_TC_CLK1BASE + AT91_TC_CMR, (AT91_TC_TIMER_CLOCK4 | AT91_TC_CPCTRG));
  67         at91_sys_write(AT91_TC + AT91_TC_CLK1BASE + AT91_TC_IDR, 0xffffffff);
  68         at91_sys_write(AT91_TC + AT91_TC_CLK1BASE + AT91_TC_RC, (AT91X40_MASTER_CLOCK / 128) / HZ - 1);
  69         at91_sys_write(AT91_TC + AT91_TC_CLK1BASE + AT91_TC_IER, (1<<4));
  70
  71         setup_irq(AT91X40_ID_TC1, &at91x40_timer_irq);
  72
  73         at91_sys_write(AT91_TC + AT91_TC_CLK1BASE + AT91_TC_CCR, (AT91_TC_SWTRG | AT91_TC_CLKEN));
  74 }
  75
  76 struct sys_timer at91x40_timer = {
  77         .init   = at91x40_timer_init,
  78         .offset = at91x40_gettimeoffset,
  79 };
  80