arch/arm/mach-msm/timer.c

   1 /* linux/arch/arm/mach-msm/timer.c
   2  *
   3  * Copyright (C) 2007 Google, Inc.
   4  *
   5  * This software is licensed under the terms of the GNU General Public
   6  * License version 2, as published by the Free Software Foundation, and
   7  * may be copied, distributed, and modified under those terms.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include <linux/init.h>
  17 #include <linux/time.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/irq.h>
  20 #include <linux/clk.h>
  21 #include <linux/clockchips.h>
  22 #include <linux/delay.h>
  23 #include <linux/io.h>
  24
  25 #include <asm/mach/time.h>
  26 #include <mach/msm_iomap.h>
  27
  28 #define MSM_DGT_BASE (MSM_GPT_BASE + 0x10)
  29 #define MSM_DGT_SHIFT (5)
  30
  31 #define TIMER_MATCH_VAL         0x0000
  32 #define TIMER_COUNT_VAL         0x0004
  33 #define TIMER_ENABLE            0x0008
  34 #define TIMER_ENABLE_CLR_ON_MATCH_EN    2
  35 #define TIMER_ENABLE_EN                 1
  36 #define TIMER_CLEAR             0x000C
  37
  38 #define CSR_PROTECTION          0x0020
  39 #define CSR_PROTECTION_EN               1
  40
  41 #define GPT_HZ 32768
  42 #define DGT_HZ 19200000 /* 19.2 MHz or 600 KHz after shift */
  43
  44 struct msm_clock {
  45         struct clock_event_device   clockevent;
  46         struct clocksource          clocksource;
  47         struct irqaction            irq;
  48         uint32_t                    regbase;
  49         uint32_t                    freq;
  50         uint32_t                    shift;
  51 };
  52
  53 static irqreturn_t msm_timer_interrupt(int irq, void *dev_id)
  54 {
  55         struct clock_event_device *evt = dev_id;
  56         evt->event_handler(evt);
  57         return IRQ_HANDLED;
  58 }
  59
  60 static cycle_t msm_gpt_read(void)
  61 {
  62         return readl(MSM_GPT_BASE + TIMER_COUNT_VAL);
  63 }
  64
  65 static cycle_t msm_dgt_read(void)
  66 {
  67         return readl(MSM_DGT_BASE + TIMER_COUNT_VAL) >> MSM_DGT_SHIFT;
  68 }
  69
  70 static int msm_timer_set_next_event(unsigned long cycles,
  71                                     struct clock_event_device *evt)
  72 {
  73         struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent);
  74         uint32_t now = readl(clock->regbase + TIMER_COUNT_VAL);
  75         uint32_t alarm = now + (cycles << clock->shift);
  76         int late;
  77
  78         writel(alarm, clock->regbase + TIMER_MATCH_VAL);
  79         now = readl(clock->regbase + TIMER_COUNT_VAL);
  80         late = now - alarm;
  81         if (late >= (-2 << clock->shift) && late < DGT_HZ*5) {
  82                 printk(KERN_NOTICE "msm_timer_set_next_event(%lu) clock %s, "
  83                        "alarm already expired, now %x, alarm %x, late %d\n",
  84                        cycles, clock->clockevent.name, now, alarm, late);
  85                 return -ETIME;
  86         }
  87         return 0;
  88 }
  89
  90 static void msm_timer_set_mode(enum clock_event_mode mode,
  91                               struct clock_event_device *evt)
  92 {
  93         struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent);
  94         switch (mode) {
  95         case CLOCK_EVT_MODE_RESUME:
  96         case CLOCK_EVT_MODE_PERIODIC:
  97                 break;
  98         case CLOCK_EVT_MODE_ONESHOT:
  99                 writel(TIMER_ENABLE_EN, clock->regbase + TIMER_ENABLE);
 100                 break;
 101         case CLOCK_EVT_MODE_UNUSED:
 102         case CLOCK_EVT_MODE_SHUTDOWN:
 103                 writel(0, clock->regbase + TIMER_ENABLE);
 104                 break;
 105         }
 106 }
 107
 108 static struct msm_clock msm_clocks[] = {
 109         {
 110                 .clockevent = {
 111                         .name           = "gp_timer",
 112                         .features       = CLOCK_EVT_FEAT_ONESHOT,
 113                         .shift          = 32,
 114                         .rating         = 200,
 115                         .set_next_event = msm_timer_set_next_event,
 116                         .set_mode       = msm_timer_set_mode,
 117                 },
 118                 .clocksource = {
 119                         .name           = "gp_timer",
 120                         .rating         = 200,
 121                         .read           = msm_gpt_read,
 122                         .mask           = CLOCKSOURCE_MASK(32),
 123                         .shift          = 24,
 124                         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 125                 },
 126                 .irq = {
 127                         .name    = "gp_timer",
 128                         .flags   = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_RISING,
 129                         .handler = msm_timer_interrupt,
 130                         .dev_id  = &msm_clocks[0].clockevent,
 131                         .irq     = INT_GP_TIMER_EXP
 132                 },
 133                 .regbase = MSM_GPT_BASE,
 134                 .freq = GPT_HZ
 135         },
 136         {
 137                 .clockevent = {
 138                         .name           = "dg_timer",
 139                         .features       = CLOCK_EVT_FEAT_ONESHOT,
 140                         .shift          = 32 + MSM_DGT_SHIFT,
 141                         .rating         = 300,
 142                         .set_next_event = msm_timer_set_next_event,
 143                         .set_mode       = msm_timer_set_mode,
 144                 },
 145                 .clocksource = {
 146                         .name           = "dg_timer",
 147                         .rating         = 300,
 148                         .read           = msm_dgt_read,
 149                         .mask           = CLOCKSOURCE_MASK((32 - MSM_DGT_SHIFT)),
 150                         .shift          = 24 - MSM_DGT_SHIFT,
 151                         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 152                 },
 153                 .irq = {
 154                         .name    = "dg_timer",
 155                         .flags   = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_RISING,
 156                         .handler = msm_timer_interrupt,
 157                         .dev_id  = &msm_clocks[1].clockevent,
 158                         .irq     = INT_DEBUG_TIMER_EXP
 159                 },
 160                 .regbase = MSM_DGT_BASE,
 161                 .freq = DGT_HZ >> MSM_DGT_SHIFT,
 162                 .shift = MSM_DGT_SHIFT
 163         }
 164 };
 165
 166 static void __init msm_timer_init(void)
 167 {
 168         int i;
 169         int res;
 170
 171         for (i = 0; i < ARRAY_SIZE(msm_clocks); i++) {
 172                 struct msm_clock *clock = &msm_clocks[i];
 173                 struct clock_event_device *ce = &clock->clockevent;
 174                 struct clocksource *cs = &clock->clocksource;
 175                 writel(0, clock->regbase + TIMER_ENABLE);
 176                 writel(0, clock->regbase + TIMER_CLEAR);
 177                 writel(~0, clock->regbase + TIMER_MATCH_VAL);
 178
 179                 ce->mult = div_sc(clock->freq, NSEC_PER_SEC, ce->shift);
 180                 /* allow at least 10 seconds to notice that the timer wrapped */
 181                 ce->max_delta_ns =
 182                         clockevent_delta2ns(0xf0000000 >> clock->shift, ce);
 183                 /* 4 gets rounded down to 3 */
 184                 ce->min_delta_ns = clockevent_delta2ns(4, ce);
 185                 ce->cpumask = cpumask_of_cpu(0);
 186
 187                 cs->mult = clocksource_hz2mult(clock->freq, cs->shift);
 188                 res = clocksource_register(cs);
 189                 if (res)
 190                         printk(KERN_ERR "msm_timer_init: clocksource_register "
 191                                "failed for %s\n", cs->name);
 192
 193                 res = setup_irq(clock->irq.irq, &clock->irq);
 194                 if (res)
 195                         printk(KERN_ERR "msm_timer_init: setup_irq "
 196                                "failed for %s\n", cs->name);
 197
 198                 clockevents_register_device(ce);
 199         }
 200 }
 201
 202 struct sys_timer msm_timer = {
 203         .init = msm_timer_init
 204 };