arch/arm/mach-footbridge/dc21285-timer.c

   1 /*
   2  *  linux/arch/arm/mach-footbridge/dc21285-timer.c
   3  *
   4  *  Copyright (C) 1998 Russell King.
   5  *  Copyright (C) 1998 Phil Blundell
   6  */
   7 #include <linux/clockchips.h>
   8 #include <linux/clocksource.h>
   9 #include <linux/init.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/irq.h>
  12
  13 #include <asm/irq.h>
  14
  15 #include <asm/hardware/dec21285.h>
  16 #include <asm/mach/time.h>
  17
  18 #include "common.h"
  19
  20 static cycle_t cksrc_dc21285_read(struct clocksource *cs)
  21 {
  22         return cs->mask - *CSR_TIMER2_VALUE;
  23 }
  24
  25 static int cksrc_dc21285_enable(struct clocksource *cs)
  26 {
  27         *CSR_TIMER2_LOAD = cs->mask;
  28         *CSR_TIMER2_CLR = 0;
  29         *CSR_TIMER2_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_DIV16;
  30         return 0;
  31 }
  32
  33 static void cksrc_dc21285_disable(struct clocksource *cs)
  34 {
  35         *CSR_TIMER2_CNTL = 0;
  36 }
  37
  38 static struct clocksource cksrc_dc21285 = {
  39         .name           = "dc21285_timer2",
  40         .rating         = 200,
  41         .read           = cksrc_dc21285_read,
  42         .enable         = cksrc_dc21285_enable,
  43         .disable        = cksrc_dc21285_disable,
  44         .mask           = CLOCKSOURCE_MASK(24),
  45         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  46 };
  47
  48 static void ckevt_dc21285_set_mode(enum clock_event_mode mode,
  49         struct clock_event_device *c)
  50 {
  51         switch (mode) {
  52         case CLOCK_EVT_MODE_RESUME:
  53         case CLOCK_EVT_MODE_PERIODIC:
  54                 *CSR_TIMER1_CLR = 0;
  55                 *CSR_TIMER1_LOAD = (mem_fclk_21285 + 8 * HZ) / (16 * HZ);
  56                 *CSR_TIMER1_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD |
  57                                    TIMER_CNTL_DIV16;
  58                 break;
  59
  60         default:
  61                 *CSR_TIMER1_CNTL = 0;
  62                 break;
  63         }
  64 }
  65
  66 static struct clock_event_device ckevt_dc21285 = {
  67         .name           = "dc21285_timer1",
  68         .features       = CLOCK_EVT_FEAT_PERIODIC,
  69         .rating         = 200,
  70         .irq            = IRQ_TIMER1,
  71         .set_mode       = ckevt_dc21285_set_mode,
  72 };
  73
  74 static irqreturn_t timer1_interrupt(int irq, void *dev_id)
  75 {
  76         struct clock_event_device *ce = dev_id;
  77
  78         *CSR_TIMER1_CLR = 0;
  79
  80         ce->event_handler(ce);
  81
  82         return IRQ_HANDLED;
  83 }
  84
  85 static struct irqaction footbridge_timer_irq = {
  86         .name           = "dc21285_timer1",
  87         .handler        = timer1_interrupt,
  88         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
  89         .dev_id         = &ckevt_dc21285,
  90 };
  91
  92 /*
  93  * Set up timer interrupt.
  94  */
  95 static void __init footbridge_timer_init(void)
  96 {
  97         struct clock_event_device *ce = &ckevt_dc21285;
  98
  99         clocksource_register_hz(&cksrc_dc21285, (mem_fclk_21285 + 8) / 16);
 100
 101         setup_irq(ce->irq, &footbridge_timer_irq);
 102
 103         clockevents_calc_mult_shift(ce, mem_fclk_21285, 5);
 104         ce->max_delta_ns = clockevent_delta2ns(0xffffff, ce);
 105         ce->min_delta_ns = clockevent_delta2ns(0x000004, ce);
 106
 107         clockevents_register_device(ce);
 108 }
 109
 110 struct sys_timer footbridge_timer = {
 111         .init           = footbridge_timer_init,
 112 };