arch/arm/mach-picoxcell/time.c

   1 /*
   2  * Copyright (c) 2011 Picochip Ltd., Jamie Iles
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * All enquiries to support@picochip.com
   9  */
  10 #include <linux/dw_apb_timer.h>
  11 #include <linux/of.h>
  12 #include <linux/of_address.h>
  13 #include <linux/of_irq.h>
  14 #include <linux/sched.h>
  15
  16 #include <asm/mach/time.h>
  17 #include <asm/sched_clock.h>
  18
  19 #include "common.h"
  20
  21 static void timer_get_base_and_rate(struct device_node *np,
  22                                     void __iomem **base, u32 *rate)
  23 {
  24         *base = of_iomap(np, 0);
  25
  26         if (!*base)
  27                 panic("Unable to map regs for %s", np->name);
  28
  29         if (of_property_read_u32(np, "clock-freq", rate))
  30                 panic("No clock-freq property for %s", np->name);
  31 }
  32
  33 static void picoxcell_add_clockevent(struct device_node *event_timer)
  34 {
  35         void __iomem *iobase;
  36         struct dw_apb_clock_event_device *ced;
  37         u32 irq, rate;
  38
  39         irq = irq_of_parse_and_map(event_timer, 0);
  40         if (irq == NO_IRQ)
  41                 panic("No IRQ for clock event timer");
  42
  43         timer_get_base_and_rate(event_timer, &iobase, &rate);
  44
  45         ced = dw_apb_clockevent_init(0, event_timer->name, 300, iobase, irq,
  46                                      rate);
  47         if (!ced)
  48                 panic("Unable to initialise clockevent device");
  49
  50         dw_apb_clockevent_register(ced);
  51 }
  52
  53 static void picoxcell_add_clocksource(struct device_node *source_timer)
  54 {
  55         void __iomem *iobase;
  56         struct dw_apb_clocksource *cs;
  57         u32 rate;
  58
  59         timer_get_base_and_rate(source_timer, &iobase, &rate);
  60
  61         cs = dw_apb_clocksource_init(300, source_timer->name, iobase, rate);
  62         if (!cs)
  63                 panic("Unable to initialise clocksource device");
  64
  65         dw_apb_clocksource_start(cs);
  66         dw_apb_clocksource_register(cs);
  67 }
  68
  69 static DEFINE_CLOCK_DATA(cd);
  70 static void __iomem *sched_io_base;
  71
  72 unsigned long long notrace sched_clock(void)
  73 {
  74         cycle_t cyc = sched_io_base ? __raw_readl(sched_io_base) : 0;
  75
  76         return cyc_to_sched_clock(&cd, cyc, (u32)~0);
  77 }
  78
  79 static void notrace picoxcell_update_sched_clock(void)
  80 {
  81         cycle_t cyc = sched_io_base ? __raw_readl(sched_io_base) : 0;
  82
  83         update_sched_clock(&cd, cyc, (u32)~0);
  84 }
  85
  86 static const struct of_device_id picoxcell_rtc_ids[] __initconst = {
  87         { .compatible = "picochip,pc3x2-rtc" },
  88         { /* Sentinel */ },
  89 };
  90
  91 static void picoxcell_init_sched_clock(void)
  92 {
  93         struct device_node *sched_timer;
  94         u32 rate;
  95
  96         sched_timer = of_find_matching_node(NULL, picoxcell_rtc_ids);
  97         if (!sched_timer)
  98                 panic("No RTC for sched clock to use");
  99
 100         timer_get_base_and_rate(sched_timer, &sched_io_base, &rate);
 101         of_node_put(sched_timer);
 102
 103         init_sched_clock(&cd, picoxcell_update_sched_clock, 32, rate);
 104 }
 105
 106 static const struct of_device_id picoxcell_timer_ids[] __initconst = {
 107         { .compatible = "picochip,pc3x2-timer" },
 108         {},
 109 };
 110
 111 static void __init picoxcell_timer_init(void)
 112 {
 113         struct device_node *event_timer, *source_timer;
 114
 115         event_timer = of_find_matching_node(NULL, picoxcell_timer_ids);
 116         if (!event_timer)
 117                 panic("No timer for clockevent");
 118         picoxcell_add_clockevent(event_timer);
 119
 120         source_timer = of_find_matching_node(event_timer, picoxcell_timer_ids);
 121         if (!source_timer)
 122                 panic("No timer for clocksource");
 123         picoxcell_add_clocksource(source_timer);
 124
 125         of_node_put(source_timer);
 126
 127         picoxcell_init_sched_clock();
 128 }
 129
 130 struct sys_timer picoxcell_timer = {
 131         .init = picoxcell_timer_init,
 132 };