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root/bsp/hal/arm/integrator/clock.c

DEFINITIONS

1. clock_isr
2. clock_init

   1 /*-
   2  * Copyright (c) 2008, Kohsuke Ohtani
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the author nor the names of any co-contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  30 /*
  31  * clock.c - clock driver
  32  */
  34 #include <kernel.h>
  35 #include <timer.h>
  36 #include <irq.h>
  37 #include <cpufunc.h>
  38 #include <sys/ipl.h>
  40 #include "platform.h"
  42 /* Interrupt vector for timer (TMR1) */
  43 #define CLOCK_IRQ       6
  45 /* The clock rate per second - 1Mhz */
  46 #define CLOCK_RATE      1000000L
  48 /* The initial counter value */
  49 #define TIMER_COUNT     (CLOCK_RATE / HZ)
  51 /* Timer 1 registers */
  52 #define TMR_LOAD        (*(volatile uint32_t *)(TIMER_BASE + 0x100))
  53 #define TMR_VAL         (*(volatile uint32_t *)(TIMER_BASE + 0x104))
  54 #define TMR_CTRL        (*(volatile uint32_t *)(TIMER_BASE + 0x108))
  55 #define TMR_CLR         (*(volatile uint32_t *)(TIMER_BASE + 0x10c))
  57 /* Timer control register */
  58 #define TCTRL_DISABLE   0x00
  59 #define TCTRL_ENABLE    0x80
  60 #define TCTRL_PERIODIC  0x40
  61 #define TCTRL_INTEN     0x20
  62 #define TCTRL_SCALE256  0x08
  63 #define TCTRL_SCALE16   0x04
  64 #define TCTRL_32BIT     0x02
  65 #define TCTRL_ONESHOT   0x01
  67 /*
  68  * Clock interrupt service routine.
  69  * No H/W reprogram is required.
  70  */
  71 static int
clock_isr(void *arg)
  73 {
splhigh();
timer_handler();
TMR_CLR = 0x01; /* Clear timer interrupt */
spl0();
  79         return INT_DONE;
  80 }
  82 /*
  83  * Initialize clock H/W chip.
  84  * Setup clock tick rate and install clock ISR.
  85  */
  86 void
clock_init(void)
  88 {
irq_t clock_irq;
  91         /* Setup counter value */
TMR_CTRL = TCTRL_DISABLE;
TMR_LOAD = TIMER_COUNT;
TMR_CTRL |= (TCTRL_ENABLE | TCTRL_PERIODIC);
  96         /* Install ISR */
clock_irq = irq_attach(CLOCK_IRQ, IPL_CLOCK, 0, &clock_isr,
IST_NONE, NULL);
 100         /* Enable timer interrupt */
TMR_CTRL |= TCTRL_INTEN;
DPRINTF(("Clock rate: %d ticks/sec\n", CONFIG_HZ));
 104 }