target/linux/xburst/patches-2.6.35/006-clocksource.patch

   1 From ebf176a38105200dca51a96ad1535c8d56235653 Mon Sep 17 00:00:00 2001
   2 From: Lars-Peter Clausen <lars@metafoo.de>
   3 Date: Sat, 19 Jun 2010 04:08:10 +0000
   4 Subject: [PATCH] MIPS: JZ4740: Add clocksource/clockevent support.
   5
   6 Add clocksource and clockevent support for the timer/counter unit on
   7 JZ4740 SoCs.
   8
   9 Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
  10 Cc: linux-mips@linux-mips.org
  11 Cc: linux-kernel@vger.kernel.org
  12 Patchwork: https://patchwork.linux-mips.org/patch/1397/
  13 Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
  14 ---
  15  arch/mips/jz4740/time.c |  144 +++++++++++++++++++++++++++++++++++++++++++++++
  16  1 files changed, 144 insertions(+), 0 deletions(-)
  17  create mode 100644 arch/mips/jz4740/time.c
  18
  19 --- /dev/null
  20 +++ b/arch/mips/jz4740/time.c
  21 @@ -0,0 +1,144 @@
  22 +/*
  23 + *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
  24 + *  JZ4740 platform time support
  25 + *
  26 + *  This program is free software; you can redistribute it and/or modify it
  27 + *  under  the terms of the GNU General  Public License as published by the
  28 + *  Free Software Foundation;  either version 2 of the License, or (at your
  29 + *  option) any later version.
  30 + *
  31 + *  You should have received a copy of the GNU General Public License along
  32 + *  with this program; if not, write to the Free Software Foundation, Inc.,
  33 + *  675 Mass Ave, Cambridge, MA 02139, USA.
  34 + *
  35 + */
  36 +
  37 +#include <linux/interrupt.h>
  38 +#include <linux/kernel.h>
  39 +#include <linux/time.h>
  40 +
  41 +#include <linux/clockchips.h>
  42 +
  43 +#include <asm/mach-jz4740/irq.h>
  44 +#include <asm/time.h>
  45 +
  46 +#include "clock.h"
  47 +#include "timer.h"
  48 +
  49 +#define TIMER_CLOCKEVENT 0
  50 +#define TIMER_CLOCKSOURCE 1
  51 +
  52 +static uint16_t jz4740_jiffies_per_tick;
  53 +
  54 +static cycle_t jz4740_clocksource_read(struct clocksource *cs)
  55 +{
  56 +       return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
  57 +}
  58 +
  59 +static struct clocksource jz4740_clocksource = {
  60 +       .name = "jz4740-timer",
  61 +       .rating = 200,
  62 +       .read = jz4740_clocksource_read,
  63 +       .mask = CLOCKSOURCE_MASK(16),
  64 +       .flags = CLOCK_SOURCE_IS_CONTINUOUS,
  65 +};
  66 +
  67 +static irqreturn_t jz4740_clockevent_irq(int irq, void *devid)
  68 +{
  69 +       struct clock_event_device *cd = devid;
  70 +
  71 +       jz4740_timer_ack_full(TIMER_CLOCKEVENT);
  72 +
  73 +       if (cd->mode != CLOCK_EVT_MODE_PERIODIC)
  74 +               jz4740_timer_disable(TIMER_CLOCKEVENT);
  75 +
  76 +       cd->event_handler(cd);
  77 +
  78 +       return IRQ_HANDLED;
  79 +}
  80 +
  81 +static void jz4740_clockevent_set_mode(enum clock_event_mode mode,
  82 +       struct clock_event_device *cd)
  83 +{
  84 +       switch (mode) {
  85 +       case CLOCK_EVT_MODE_PERIODIC:
  86 +               jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
  87 +               jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
  88 +       case CLOCK_EVT_MODE_RESUME:
  89 +               jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
  90 +               jz4740_timer_enable(TIMER_CLOCKEVENT);
  91 +               break;
  92 +       case CLOCK_EVT_MODE_ONESHOT:
  93 +       case CLOCK_EVT_MODE_SHUTDOWN:
  94 +               jz4740_timer_disable(TIMER_CLOCKEVENT);
  95 +               break;
  96 +       default:
  97 +               break;
  98 +       }
  99 +}
 100 +
 101 +static int jz4740_clockevent_set_next(unsigned long evt,
 102 +       struct clock_event_device *cd)
 103 +{
 104 +       jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
 105 +       jz4740_timer_set_period(TIMER_CLOCKEVENT, evt);
 106 +       jz4740_timer_enable(TIMER_CLOCKEVENT);
 107 +
 108 +       return 0;
 109 +}
 110 +
 111 +static struct clock_event_device jz4740_clockevent = {
 112 +       .name = "jz4740-timer",
 113 +       .features = CLOCK_EVT_FEAT_PERIODIC,
 114 +       .set_next_event = jz4740_clockevent_set_next,
 115 +       .set_mode = jz4740_clockevent_set_mode,
 116 +       .rating = 200,
 117 +       .irq = JZ4740_IRQ_TCU0,
 118 +};
 119 +
 120 +static struct irqaction timer_irqaction = {
 121 +       .handler        = jz4740_clockevent_irq,
 122 +       .flags          = IRQF_PERCPU | IRQF_TIMER,
 123 +       .name           = "jz4740-timerirq",
 124 +       .dev_id         = &jz4740_clockevent,
 125 +};
 126 +
 127 +void __init plat_time_init(void)
 128 +{
 129 +       int ret;
 130 +       uint32_t clk_rate;
 131 +       uint16_t ctrl;
 132 +
 133 +       jz4740_timer_init();
 134 +
 135 +       clk_rate = jz4740_clock_bdata.ext_rate >> 4;
 136 +       jz4740_jiffies_per_tick = DIV_ROUND_CLOSEST(clk_rate, HZ);
 137 +
 138 +       clockevent_set_clock(&jz4740_clockevent, clk_rate);
 139 +       jz4740_clockevent.min_delta_ns = clockevent_delta2ns(100, &jz4740_clockevent);
 140 +       jz4740_clockevent.max_delta_ns = clockevent_delta2ns(0xffff, &jz4740_clockevent);
 141 +       jz4740_clockevent.cpumask = cpumask_of(0);
 142 +
 143 +       clockevents_register_device(&jz4740_clockevent);
 144 +
 145 +       clocksource_set_clock(&jz4740_clocksource, clk_rate);
 146 +       ret = clocksource_register(&jz4740_clocksource);
 147 +
 148 +       if (ret)
 149 +               printk(KERN_ERR "Failed to register clocksource: %d\n", ret);
 150 +
 151 +       setup_irq(JZ4740_IRQ_TCU0, &timer_irqaction);
 152 +
 153 +       ctrl = JZ_TIMER_CTRL_PRESCALE_16 | JZ_TIMER_CTRL_SRC_EXT;
 154 +
 155 +       jz4740_timer_set_ctrl(TIMER_CLOCKEVENT, ctrl);
 156 +       jz4740_timer_set_ctrl(TIMER_CLOCKSOURCE, ctrl);
 157 +
 158 +       jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
 159 +       jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
 160 +
 161 +       jz4740_timer_set_period(TIMER_CLOCKSOURCE, 0xffff);
 162 +
 163 +       jz4740_timer_enable(TIMER_CLOCKEVENT);
 164 +       jz4740_timer_enable(TIMER_CLOCKSOURCE);
 165 +}