release/src-rt-6.x/linux/linux-2.6/arch/arm/mach-netx/time.c

   1 /*
   2  * arch/arm/mach-netx/time.c
   3  *
   4  * Copyright (c) 2005 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
   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 version 2
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 #include <linux/init.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/irq.h>
  23 #include <linux/clocksource.h>
  24
  25 #include <asm/hardware.h>
  26 #include <asm/io.h>
  27 #include <asm/mach/time.h>
  28 #include <asm/arch/netx-regs.h>
  29
  30 /*
  31  * IRQ handler for the timer
  32  */
  33 static irqreturn_t
  34 netx_timer_interrupt(int irq, void *dev_id)
  35 {
  36         write_seqlock(&xtime_lock);
  37
  38         timer_tick();
  39
  40         write_sequnlock(&xtime_lock);
  41
  42         /* acknowledge interrupt */
  43         writel(COUNTER_BIT(0), NETX_GPIO_IRQ);
  44
  45         return IRQ_HANDLED;
  46 }
  47
  48 static struct irqaction netx_timer_irq = {
  49         .name           = "NetX Timer Tick",
  50         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
  51         .handler        = netx_timer_interrupt,
  52 };
  53
  54 cycle_t netx_get_cycles(void)
  55 {
  56         return readl(NETX_GPIO_COUNTER_CURRENT(1));
  57 }
  58
  59 static struct clocksource clocksource_netx = {
  60         .name           = "netx_timer",
  61         .rating         = 200,
  62         .read           = netx_get_cycles,
  63         .mask           = CLOCKSOURCE_MASK(32),
  64         .shift          = 20,
  65         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  66 };
  67
  68 /*
  69  * Set up timer interrupt
  70  */
  71 static void __init netx_timer_init(void)
  72 {
  73         /* disable timer initially */
  74         writel(0, NETX_GPIO_COUNTER_CTRL(0));
  75
  76         /* Reset the timer value to zero */
  77         writel(0, NETX_GPIO_COUNTER_CURRENT(0));
  78
  79         writel(LATCH, NETX_GPIO_COUNTER_MAX(0));
  80
  81         /* acknowledge interrupt */
  82         writel(COUNTER_BIT(0), NETX_GPIO_IRQ);
  83
  84         /* Enable the interrupt in the specific timer register and start timer */
  85         writel(COUNTER_BIT(0), NETX_GPIO_IRQ_ENABLE);
  86         writel(NETX_GPIO_COUNTER_CTRL_IRQ_EN | NETX_GPIO_COUNTER_CTRL_RUN,
  87                 NETX_GPIO_COUNTER_CTRL(0));
  88
  89         setup_irq(NETX_IRQ_TIMER0, &netx_timer_irq);
  90
  91         /* Setup timer one for clocksource */
  92         writel(0, NETX_GPIO_COUNTER_CTRL(1));
  93         writel(0, NETX_GPIO_COUNTER_CURRENT(1));
  94         writel(0xFFFFFFFF, NETX_GPIO_COUNTER_MAX(1));
  95
  96         writel(NETX_GPIO_COUNTER_CTRL_RUN,
  97                 NETX_GPIO_COUNTER_CTRL(1));
  98
  99         clocksource_netx.mult =
 100                 clocksource_hz2mult(CLOCK_TICK_RATE, clocksource_netx.shift);
 101         clocksource_register(&clocksource_netx);
 102 }
 103
 104 struct sys_timer netx_timer = {
 105         .init           = netx_timer_init,
 106 };