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
  15 #include <asm/mach/time.h>
  16 #include <asm/sched_clock.h>
  17
  18 #include "common.h"
  19
  20 static void timer_get_base_and_rate(struct device_node *np,
  21                                     void __iomem **base, u32 *rate)
  22 {
  23         *base = of_iomap(np, 0);
  24
  25         if (!*base)
  26                 panic("Unable to map regs for %s", np->name);
  27
  28         if (of_property_read_u32(np, "clock-freq", rate))
  29                 panic("No clock-freq property for %s", np->name);
  30 }
  31
  32 static void picoxcell_add_clockevent(struct device_node *event_timer)
  33 {
  34         void __iomem *iobase;
  35         struct dw_apb_clock_event_device *ced;
  36         u32 irq, rate;
  37
  38         irq = irq_of_parse_and_map(event_timer, 0);
  39         if (irq == NO_IRQ)
  40                 panic("No IRQ for clock event timer");
  41
  42         timer_get_base_and_rate(event_timer, &iobase, &rate);
  43
  44         ced = dw_apb_clockevent_init(0, event_timer->name, 300, iobase, irq,
  45                                      rate);
  46         if (!ced)
  47                 panic("Unable to initialise clockevent device");
  48
  49         dw_apb_clockevent_register(ced);
  50 }
  51
  52 static void picoxcell_add_clocksource(struct device_node *source_timer)
  53 {
  54         void __iomem *iobase;
  55         struct dw_apb_clocksource *cs;
  56         u32 rate;
  57
  58         timer_get_base_and_rate(source_timer, &iobase, &rate);
  59
  60         cs = dw_apb_clocksource_init(300, source_timer->name, iobase, rate);
  61         if (!cs)
  62                 panic("Unable to initialise clocksource device");
  63
  64         dw_apb_clocksource_start(cs);
  65         dw_apb_clocksource_register(cs);
  66 }
  67
  68 static void __iomem *sched_io_base;
  69
  70 unsigned u32 notrace picoxcell_read_sched_clock(void)
  71 {
  72         return __raw_readl(sched_io_base);
  73 }
  74
  75 static const struct of_device_id picoxcell_rtc_ids[] __initconst = {
  76         { .compatible = "picochip,pc3x2-rtc" },
  77         { /* Sentinel */ },
  78 };
  79
  80 static void picoxcell_init_sched_clock(void)
  81 {
  82         struct device_node *sched_timer;
  83         u32 rate;
  84
  85         sched_timer = of_find_matching_node(NULL, picoxcell_rtc_ids);
  86         if (!sched_timer)
  87                 panic("No RTC for sched clock to use");
  88
  89         timer_get_base_and_rate(sched_timer, &sched_io_base, &rate);
  90         of_node_put(sched_timer);
  91
  92         setup_sched_clock(picoxcell_read_sched_clock, 32, rate);
  93 }
  94
  95 static const struct of_device_id picoxcell_timer_ids[] __initconst = {
  96         { .compatible = "picochip,pc3x2-timer" },
  97         {},
  98 };
  99
 100 static void __init picoxcell_timer_init(void)
 101 {
 102         struct device_node *event_timer, *source_timer;
 103
 104         event_timer = of_find_matching_node(NULL, picoxcell_timer_ids);
 105         if (!event_timer)
 106                 panic("No timer for clockevent");
 107         picoxcell_add_clockevent(event_timer);
 108
 109         source_timer = of_find_matching_node(event_timer, picoxcell_timer_ids);
 110         if (!source_timer)
 111                 panic("No timer for clocksource");
 112         picoxcell_add_clocksource(source_timer);
 113
 114         of_node_put(source_timer);
 115
 116         picoxcell_init_sched_clock();
 117 }
 118
 119 struct sys_timer picoxcell_timer = {
 120         .init = picoxcell_timer_init,
 121 };