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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/arch/arm/mach-footbridge/dc21285-timer.c
   4  *
   5  *  Copyright (C) 1998 Russell King.
   6  *  Copyright (C) 1998 Phil Blundell
   7  */
   8 #include <linux/clockchips.h>
   9 #include <linux/clocksource.h>
  10 #include <linux/init.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/irq.h>
  13 #include <linux/sched_clock.h>
  14
  15 #include <asm/irq.h>
  16
  17 #include <asm/hardware/dec21285.h>
  18 #include <asm/mach/time.h>
  19 #include <asm/system_info.h>
  20
  21 #include "common.h"
  22
  23 static u64 cksrc_dc21285_read(struct clocksource *cs)
  24 {
  25         return cs->mask - *CSR_TIMER2_VALUE;
  26 }
  27
  28 static int cksrc_dc21285_enable(struct clocksource *cs)
  29 {
  30         *CSR_TIMER2_LOAD = cs->mask;
  31         *CSR_TIMER2_CLR = 0;
  32         *CSR_TIMER2_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_DIV16;
  33         return 0;
  34 }
  35
  36 static void cksrc_dc21285_disable(struct clocksource *cs)
  37 {
  38         *CSR_TIMER2_CNTL = 0;
  39 }
  40
  41 static struct clocksource cksrc_dc21285 = {
  42         .name           = "dc21285_timer2",
  43         .rating         = 200,
  44         .read           = cksrc_dc21285_read,
  45         .enable         = cksrc_dc21285_enable,
  46         .disable        = cksrc_dc21285_disable,
  47         .mask           = CLOCKSOURCE_MASK(24),
  48         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  49 };
  50
  51 static int ckevt_dc21285_set_next_event(unsigned long delta,
  52         struct clock_event_device *c)
  53 {
  54         *CSR_TIMER1_CLR = 0;
  55         *CSR_TIMER1_LOAD = delta;
  56         *CSR_TIMER1_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_DIV16;
  57
  58         return 0;
  59 }
  60
  61 static int ckevt_dc21285_shutdown(struct clock_event_device *c)
  62 {
  63         *CSR_TIMER1_CNTL = 0;
  64         return 0;
  65 }
  66
  67 static int ckevt_dc21285_set_periodic(struct clock_event_device *c)
  68 {
  69         *CSR_TIMER1_CLR = 0;
  70         *CSR_TIMER1_LOAD = (mem_fclk_21285 + 8 * HZ) / (16 * HZ);
  71         *CSR_TIMER1_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD |
  72                            TIMER_CNTL_DIV16;
  73         return 0;
  74 }
  75
  76 static struct clock_event_device ckevt_dc21285 = {
  77         .name                   = "dc21285_timer1",
  78         .features               = CLOCK_EVT_FEAT_PERIODIC |
  79                                   CLOCK_EVT_FEAT_ONESHOT,
  80         .rating                 = 200,
  81         .irq                    = IRQ_TIMER1,
  82         .set_next_event         = ckevt_dc21285_set_next_event,
  83         .set_state_shutdown     = ckevt_dc21285_shutdown,
  84         .set_state_periodic     = ckevt_dc21285_set_periodic,
  85         .set_state_oneshot      = ckevt_dc21285_shutdown,
  86         .tick_resume            = ckevt_dc21285_set_periodic,
  87 };
  88
  89 static irqreturn_t timer1_interrupt(int irq, void *dev_id)
  90 {
  91         struct clock_event_device *ce = dev_id;
  92
  93         *CSR_TIMER1_CLR = 0;
  94
  95         /* Stop the timer if in one-shot mode */
  96         if (clockevent_state_oneshot(ce))
  97                 *CSR_TIMER1_CNTL = 0;
  98
  99         ce->event_handler(ce);
 100
 101         return IRQ_HANDLED;
 102 }
 103
 104 /*
 105  * Set up timer interrupt.
 106  */
 107 void __init footbridge_timer_init(void)
 108 {
 109         struct clock_event_device *ce = &ckevt_dc21285;
 110         unsigned rate = DIV_ROUND_CLOSEST(mem_fclk_21285, 16);
 111
 112         clocksource_register_hz(&cksrc_dc21285, rate);
 113
 114         if (request_irq(ce->irq, timer1_interrupt, IRQF_TIMER | IRQF_IRQPOLL,
 115                         "dc21285_timer1", &ckevt_dc21285))
 116                 pr_err("Failed to request irq %d (dc21285_timer1)", ce->irq);
 117
 118         ce->cpumask = cpumask_of(smp_processor_id());
 119         clockevents_config_and_register(ce, rate, 0x4, 0xffffff);
 120 }
 121
 122 static u64 notrace footbridge_read_sched_clock(void)
 123 {
 124         return ~*CSR_TIMER3_VALUE;
 125 }
 126
 127 void __init footbridge_sched_clock(void)
 128 {
 129         unsigned rate = DIV_ROUND_CLOSEST(mem_fclk_21285, 16);
 130
 131         *CSR_TIMER3_LOAD = 0;
 132         *CSR_TIMER3_CLR = 0;
 133         *CSR_TIMER3_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_DIV16;
 134
 135         sched_clock_register(footbridge_read_sched_clock, 24, rate);
 136 }