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
  24 #include <asm/mach/time.h>
  25 #include <mach/msm_iomap.h>
  26
  27 #include <asm/io.h>
  28
  29 #define MSM_DGT_BASE (MSM_GPT_BASE + 0x10)
  30 #define MSM_DGT_SHIFT (5)
  31
  32 #define TIMER_MATCH_VAL         0x0000
  33 #define TIMER_COUNT_VAL         0x0004
  34 #define TIMER_ENABLE            0x0008
  35 #define TIMER_ENABLE_CLR_ON_MATCH_EN    2
  36 #define TIMER_ENABLE_EN                 1
  37 #define TIMER_CLEAR             0x000C
  38
  39 #define CSR_PROTECTION          0x0020
  40 #define CSR_PROTECTION_EN               1
  41
  42 #define GPT_HZ 32768
  43 #define DGT_HZ 19200000 /* 19.2 MHz or 600 KHz after shift */
  44
  45 struct msm_clock {
  46         struct clock_event_device   clockevent;
  47         struct clocksource          clocksource;
  48         struct irqaction            irq;
  49         uint32_t                    regbase;
  50         uint32_t                    freq;
  51         uint32_t                    shift;
  52 };
  53
  54 static irqreturn_t msm_timer_interrupt(int irq, void *dev_id)
  55 {
  56         struct clock_event_device *evt = dev_id;
  57         evt->event_handler(evt);
  58         return IRQ_HANDLED;
  59 }
  60
  61 static cycle_t msm_gpt_read(void)
  62 {
  63         return readl(MSM_GPT_BASE + TIMER_COUNT_VAL);
  64 }
  65
  66 static cycle_t msm_dgt_read(void)
  67 {
  68         return readl(MSM_DGT_BASE + TIMER_COUNT_VAL) >> MSM_DGT_SHIFT;
  69 }
  70
  71 static int msm_timer_set_next_event(unsigned long cycles,
  72                                     struct clock_event_device *evt)
  73 {
  74         struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent);
  75         uint32_t now = readl(clock->regbase + TIMER_COUNT_VAL);
  76         uint32_t alarm = now + (cycles << clock->shift);
  77         int late;
  78
  79         writel(alarm, clock->regbase + TIMER_MATCH_VAL);
  80         now = readl(clock->regbase + TIMER_COUNT_VAL);
  81         late = now - alarm;
  82         if (late >= (-2 << clock->shift) && late < DGT_HZ*5) {
  83                 printk(KERN_NOTICE "msm_timer_set_next_event(%lu) clock %s, "
  84                        "alarm already expired, now %x, alarm %x, late %d\n",
  85                        cycles, clock->clockevent.name, now, alarm, late);
  86                 return -ETIME;
  87         }
  88         return 0;
  89 }
  90
  91 static void msm_timer_set_mode(enum clock_event_mode mode,
  92                               struct clock_event_device *evt)
  93 {
  94         struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent);
  95         switch (mode) {
  96         case CLOCK_EVT_MODE_RESUME:
  97         case CLOCK_EVT_MODE_PERIODIC:
  98                 break;
  99         case CLOCK_EVT_MODE_ONESHOT:
 100                 writel(TIMER_ENABLE_EN, clock->regbase + TIMER_ENABLE);
 101                 break;
 102         case CLOCK_EVT_MODE_UNUSED:
 103         case CLOCK_EVT_MODE_SHUTDOWN:
 104                 writel(0, clock->regbase + TIMER_ENABLE);
 105                 break;
 106         }
 107 }
 108
 109 static struct msm_clock msm_clocks[] = {
 110         {
 111                 .clockevent = {
 112                         .name           = "gp_timer",
 113                         .features       = CLOCK_EVT_FEAT_ONESHOT,
 114                         .shift          = 32,
 115                         .rating         = 200,
 116                         .set_next_event = msm_timer_set_next_event,
 117                         .set_mode       = msm_timer_set_mode,
 118                 },
 119                 .clocksource = {
 120                         .name           = "gp_timer",
 121                         .rating         = 200,
 122                         .read           = msm_gpt_read,
 123                         .mask           = CLOCKSOURCE_MASK(32),
 124                         .shift          = 24,
 125                         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 126                 },
 127                 .irq = {
 128                         .name    = "gp_timer",
 129                         .flags   = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_RISING,
 130                         .handler = msm_timer_interrupt,
 131                         .dev_id  = &msm_clocks[0].clockevent,
 132                         .irq     = INT_GP_TIMER_EXP
 133                 },
 134                 .regbase = MSM_GPT_BASE,
 135                 .freq = GPT_HZ
 136         },
 137         {
 138                 .clockevent = {
 139                         .name           = "dg_timer",
 140                         .features       = CLOCK_EVT_FEAT_ONESHOT,
 141                         .shift          = 32 + MSM_DGT_SHIFT,
 142                         .rating         = 300,
 143                         .set_next_event = msm_timer_set_next_event,
 144                         .set_mode       = msm_timer_set_mode,
 145                 },
 146                 .clocksource = {
 147                         .name           = "dg_timer",
 148                         .rating         = 300,
 149                         .read           = msm_dgt_read,
 150                         .mask           = CLOCKSOURCE_MASK((32 - MSM_DGT_SHIFT)),
 151                         .shift          = 24 - MSM_DGT_SHIFT,
 152                         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 153                 },
 154                 .irq = {
 155                         .name    = "dg_timer",
 156                         .flags   = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_RISING,
 157                         .handler = msm_timer_interrupt,
 158                         .dev_id  = &msm_clocks[1].clockevent,
 159                         .irq     = INT_DEBUG_TIMER_EXP
 160                 },
 161                 .regbase = MSM_DGT_BASE,
 162                 .freq = DGT_HZ >> MSM_DGT_SHIFT,
 163                 .shift = MSM_DGT_SHIFT
 164         }
 165 };
 166
 167 static void __init msm_timer_init(void)
 168 {
 169         int i;
 170         int res;
 171
 172         for (i = 0; i < ARRAY_SIZE(msm_clocks); i++) {
 173                 struct msm_clock *clock = &msm_clocks[i];
 174                 struct clock_event_device *ce = &clock->clockevent;
 175                 struct clocksource *cs = &clock->clocksource;
 176                 writel(0, clock->regbase + TIMER_ENABLE);
 177                 writel(0, clock->regbase + TIMER_CLEAR);
 178                 writel(~0, clock->regbase + TIMER_MATCH_VAL);
 179
 180                 ce->mult = div_sc(clock->freq, NSEC_PER_SEC, ce->shift);
 181                 /* allow at least 10 seconds to notice that the timer wrapped */
 182                 ce->max_delta_ns =
 183                         clockevent_delta2ns(0xf0000000 >> clock->shift, ce);
 184                 /* 4 gets rounded down to 3 */
 185                 ce->min_delta_ns = clockevent_delta2ns(4, ce);
 186                 ce->cpumask = cpumask_of_cpu(0);
 187
 188                 cs->mult = clocksource_hz2mult(clock->freq, cs->shift);
 189                 res = clocksource_register(cs);
 190                 if (res)
 191                         printk(KERN_ERR "msm_timer_init: clocksource_register "
 192                                "failed for %s\n", cs->name);
 193
 194                 res = setup_irq(clock->irq.irq, &clock->irq);
 195                 if (res)
 196                         printk(KERN_ERR "msm_timer_init: setup_irq "
 197                                "failed for %s\n", cs->name);
 198
 199                 clockevents_register_device(ce);
 200         }
 201 }
 202
 203 struct sys_timer msm_timer = {
 204         .init = msm_timer_init
 205 };