drivers/clocksource/dw_apb_timer_of.c

   1 /*
   2  * Copyright (C) 2012 Altera Corporation
   3  * Copyright (c) 2011 Picochip Ltd., Jamie Iles
   4  *
   5  * Modified from mach-picoxcell/time.c
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19 #include <linux/dw_apb_timer.h>
  20 #include <linux/of.h>
  21 #include <linux/of_address.h>
  22 #include <linux/of_irq.h>
  23
  24 #include <asm/mach/time.h>
  25 #include <asm/sched_clock.h>
  26
  27 static void timer_get_base_and_rate(struct device_node *np,
  28                                     void __iomem **base, u32 *rate)
  29 {
  30         *base = of_iomap(np, 0);
  31
  32         if (!*base)
  33                 panic("Unable to map regs for %s", np->name);
  34
  35         if (of_property_read_u32(np, "clock-freq", rate) &&
  36                 of_property_read_u32(np, "clock-frequency", rate))
  37                 panic("No clock-frequency property for %s", np->name);
  38 }
  39
  40 static void add_clockevent(struct device_node *event_timer)
  41 {
  42         void __iomem *iobase;
  43         struct dw_apb_clock_event_device *ced;
  44         u32 irq, rate;
  45
  46         irq = irq_of_parse_and_map(event_timer, 0);
  47         if (irq == NO_IRQ)
  48                 panic("No IRQ for clock event timer");
  49
  50         timer_get_base_and_rate(event_timer, &iobase, &rate);
  51
  52         ced = dw_apb_clockevent_init(0, event_timer->name, 300, iobase, irq,
  53                                      rate);
  54         if (!ced)
  55                 panic("Unable to initialise clockevent device");
  56
  57         dw_apb_clockevent_register(ced);
  58 }
  59
  60 static void add_clocksource(struct device_node *source_timer)
  61 {
  62         void __iomem *iobase;
  63         struct dw_apb_clocksource *cs;
  64         u32 rate;
  65
  66         timer_get_base_and_rate(source_timer, &iobase, &rate);
  67
  68         cs = dw_apb_clocksource_init(300, source_timer->name, iobase, rate);
  69         if (!cs)
  70                 panic("Unable to initialise clocksource device");
  71
  72         dw_apb_clocksource_start(cs);
  73         dw_apb_clocksource_register(cs);
  74 }
  75
  76 static void __iomem *sched_io_base;
  77
  78 static u32 read_sched_clock(void)
  79 {
  80         return __raw_readl(sched_io_base);
  81 }
  82
  83 static const struct of_device_id sptimer_ids[] __initconst = {
  84         { .compatible = "picochip,pc3x2-rtc" },
  85         { .compatible = "snps,dw-apb-timer-sp" },
  86         { /* Sentinel */ },
  87 };
  88
  89 static void init_sched_clock(void)
  90 {
  91         struct device_node *sched_timer;
  92         u32 rate;
  93
  94         sched_timer = of_find_matching_node(NULL, sptimer_ids);
  95         if (!sched_timer)
  96                 panic("No RTC for sched clock to use");
  97
  98         timer_get_base_and_rate(sched_timer, &sched_io_base, &rate);
  99         of_node_put(sched_timer);
 100
 101         setup_sched_clock(read_sched_clock, 32, rate);
 102 }
 103
 104 static const struct of_device_id osctimer_ids[] __initconst = {
 105         { .compatible = "picochip,pc3x2-timer" },
 106         { .compatible = "snps,dw-apb-timer-osc" },
 107         {},
 108 };
 109
 110 void __init dw_apb_timer_init(void)
 111 {
 112         struct device_node *event_timer, *source_timer;
 113
 114         event_timer = of_find_matching_node(NULL, osctimer_ids);
 115         if (!event_timer)
 116                 panic("No timer for clockevent");
 117         add_clockevent(event_timer);
 118
 119         source_timer = of_find_matching_node(event_timer, osctimer_ids);
 120         if (!source_timer)
 121                 panic("No timer for clocksource");
 122         add_clocksource(source_timer);
 123
 124         of_node_put(source_timer);
 125
 126         init_sched_clock();
 127 }