arch/arm/mach-mmp/time.c

   1 /*
   2  * linux/arch/arm/mach-mmp/time.c
   3  *
   4  *   Support for clocksource and clockevents
   5  *
   6  * Copyright (C) 2008 Marvell International Ltd.
   7  * All rights reserved.
   8  *
   9  *   2008-04-11: Jason Chagas <Jason.chagas@marvell.com>
  10  *   2008-10-08: Bin Yang <bin.yang@marvell.com>
  11  *
  12  * The timers module actually includes three timers, each timer with up to
  13  * three match comparators. Timer #0 is used here in free-running mode as
  14  * the clock source, and match comparator #1 used as clock event device.
  15  *
  16  * This program is free software; you can redistribute it and/or modify
  17  * it under the terms of the GNU General Public License version 2 as
  18  * published by the Free Software Foundation.
  19  */
  20
  21 #include <linux/init.h>
  22 #include <linux/kernel.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/clockchips.h>
  25
  26 #include <linux/io.h>
  27 #include <linux/irq.h>
  28 #include <linux/of.h>
  29 #include <linux/of_address.h>
  30 #include <linux/of_irq.h>
  31 #include <linux/sched_clock.h>
  32
  33 #include <mach/addr-map.h>
  34 #include <mach/regs-timers.h>
  35 #include <mach/regs-apbc.h>
  36 #include <mach/irqs.h>
  37 #include <mach/cputype.h>
  38 #include <asm/mach/time.h>
  39
  40 #include "clock.h"
  41
  42 #define TIMERS_VIRT_BASE        TIMERS1_VIRT_BASE
  43
  44 #define MAX_DELTA               (0xfffffffe)
  45 #define MIN_DELTA               (16)
  46
  47 static void __iomem *mmp_timer_base = TIMERS_VIRT_BASE;
  48
  49 /*
  50  * FIXME: the timer needs some delay to stablize the counter capture
  51  */
  52 static inline uint32_t timer_read(void)
  53 {
  54         int delay = 100;
  55
  56         __raw_writel(1, mmp_timer_base + TMR_CVWR(1));
  57
  58         while (delay--)
  59                 cpu_relax();
  60
  61         return __raw_readl(mmp_timer_base + TMR_CVWR(1));
  62 }
  63
  64 static u32 notrace mmp_read_sched_clock(void)
  65 {
  66         return timer_read();
  67 }
  68
  69 static irqreturn_t timer_interrupt(int irq, void *dev_id)
  70 {
  71         struct clock_event_device *c = dev_id;
  72
  73         /*
  74          * Clear pending interrupt status.
  75          */
  76         __raw_writel(0x01, mmp_timer_base + TMR_ICR(0));
  77
  78         /*
  79          * Disable timer 0.
  80          */
  81         __raw_writel(0x02, mmp_timer_base + TMR_CER);
  82
  83         c->event_handler(c);
  84
  85         return IRQ_HANDLED;
  86 }
  87
  88 static int timer_set_next_event(unsigned long delta,
  89                                 struct clock_event_device *dev)
  90 {
  91         unsigned long flags;
  92
  93         local_irq_save(flags);
  94
  95         /*
  96          * Disable timer 0.
  97          */
  98         __raw_writel(0x02, mmp_timer_base + TMR_CER);
  99
 100         /*
 101          * Clear and enable timer match 0 interrupt.
 102          */
 103         __raw_writel(0x01, mmp_timer_base + TMR_ICR(0));
 104         __raw_writel(0x01, mmp_timer_base + TMR_IER(0));
 105
 106         /*
 107          * Setup new clockevent timer value.
 108          */
 109         __raw_writel(delta - 1, mmp_timer_base + TMR_TN_MM(0, 0));
 110
 111         /*
 112          * Enable timer 0.
 113          */
 114         __raw_writel(0x03, mmp_timer_base + TMR_CER);
 115
 116         local_irq_restore(flags);
 117
 118         return 0;
 119 }
 120
 121 static void timer_set_mode(enum clock_event_mode mode,
 122                            struct clock_event_device *dev)
 123 {
 124         unsigned long flags;
 125
 126         local_irq_save(flags);
 127         switch (mode) {
 128         case CLOCK_EVT_MODE_ONESHOT:
 129         case CLOCK_EVT_MODE_UNUSED:
 130         case CLOCK_EVT_MODE_SHUTDOWN:
 131                 /* disable the matching interrupt */
 132                 __raw_writel(0x00, mmp_timer_base + TMR_IER(0));
 133                 break;
 134         case CLOCK_EVT_MODE_RESUME:
 135         case CLOCK_EVT_MODE_PERIODIC:
 136                 break;
 137         }
 138         local_irq_restore(flags);
 139 }
 140
 141 static struct clock_event_device ckevt = {
 142         .name           = "clockevent",
 143         .features       = CLOCK_EVT_FEAT_ONESHOT,
 144         .rating         = 200,
 145         .set_next_event = timer_set_next_event,
 146         .set_mode       = timer_set_mode,
 147 };
 148
 149 static cycle_t clksrc_read(struct clocksource *cs)
 150 {
 151         return timer_read();
 152 }
 153
 154 static struct clocksource cksrc = {
 155         .name           = "clocksource",
 156         .rating         = 200,
 157         .read           = clksrc_read,
 158         .mask           = CLOCKSOURCE_MASK(32),
 159         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 160 };
 161
 162 static void __init timer_config(void)
 163 {
 164         uint32_t ccr = __raw_readl(mmp_timer_base + TMR_CCR);
 165
 166         __raw_writel(0x0, mmp_timer_base + TMR_CER); /* disable */
 167
 168         ccr &= (cpu_is_mmp2()) ? (TMR_CCR_CS_0(0) | TMR_CCR_CS_1(0)) :
 169                 (TMR_CCR_CS_0(3) | TMR_CCR_CS_1(3));
 170         __raw_writel(ccr, mmp_timer_base + TMR_CCR);
 171
 172         /* set timer 0 to periodic mode, and timer 1 to free-running mode */
 173         __raw_writel(0x2, mmp_timer_base + TMR_CMR);
 174
 175         __raw_writel(0x1, mmp_timer_base + TMR_PLCR(0)); /* periodic */
 176         __raw_writel(0x7, mmp_timer_base + TMR_ICR(0));  /* clear status */
 177         __raw_writel(0x0, mmp_timer_base + TMR_IER(0));
 178
 179         __raw_writel(0x0, mmp_timer_base + TMR_PLCR(1)); /* free-running */
 180         __raw_writel(0x7, mmp_timer_base + TMR_ICR(1));  /* clear status */
 181         __raw_writel(0x0, mmp_timer_base + TMR_IER(1));
 182
 183         /* enable timer 1 counter */
 184         __raw_writel(0x2, mmp_timer_base + TMR_CER);
 185 }
 186
 187 static struct irqaction timer_irq = {
 188         .name           = "timer",
 189         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
 190         .handler        = timer_interrupt,
 191         .dev_id         = &ckevt,
 192 };
 193
 194 void __init timer_init(int irq)
 195 {
 196         timer_config();
 197
 198         setup_sched_clock(mmp_read_sched_clock, 32, CLOCK_TICK_RATE);
 199
 200         ckevt.cpumask = cpumask_of(0);
 201
 202         setup_irq(irq, &timer_irq);
 203
 204         clocksource_register_hz(&cksrc, CLOCK_TICK_RATE);
 205         clockevents_config_and_register(&ckevt, CLOCK_TICK_RATE,
 206                                         MIN_DELTA, MAX_DELTA);
 207 }
 208
 209 #ifdef CONFIG_OF
 210 static struct of_device_id mmp_timer_dt_ids[] = {
 211         { .compatible = "mrvl,mmp-timer", },
 212         {}
 213 };
 214
 215 void __init mmp_dt_init_timer(void)
 216 {
 217         struct device_node *np;
 218         int irq, ret;
 219
 220         np = of_find_matching_node(NULL, mmp_timer_dt_ids);
 221         if (!np) {
 222                 ret = -ENODEV;
 223                 goto out;
 224         }
 225
 226         irq = irq_of_parse_and_map(np, 0);
 227         if (!irq) {
 228                 ret = -EINVAL;
 229                 goto out;
 230         }
 231         mmp_timer_base = of_iomap(np, 0);
 232         if (!mmp_timer_base) {
 233                 ret = -ENOMEM;
 234                 goto out;
 235         }
 236         timer_init(irq);
 237         return;
 238 out:
 239         pr_err("Failed to get timer from device tree with error:%d\n", ret);
 240 }
 241 #endif