arch/arm/mach-omap1/time.c

   1 /*
   2  * linux/arch/arm/mach-omap1/time.c
   3  *
   4  * OMAP Timers
   5  *
   6  * Copyright (C) 2004 Nokia Corporation
   7  * Partial timer rewrite and additional dynamic tick timer support by
   8  * Tony Lindgen <tony@atomide.com> and
   9  * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
  10  *
  11  * MPU timer code based on the older MPU timer code for OMAP
  12  * Copyright (C) 2000 RidgeRun, Inc.
  13  * Author: Greg Lonnon <glonnon@ridgerun.com>
  14  *
  15  * This program is free software; you can redistribute it and/or modify it
  16  * under the terms of the GNU General Public License as published by the
  17  * Free Software Foundation; either version 2 of the License, or (at your
  18  * option) any later version.
  19  *
  20  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  21  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  22  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
  23  * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  27  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  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 #include <linux/kernel.h>
  37 #include <linux/init.h>
  38 #include <linux/delay.h>
  39 #include <linux/interrupt.h>
  40 #include <linux/spinlock.h>
  41 #include <linux/clk.h>
  42 #include <linux/err.h>
  43 #include <linux/clocksource.h>
  44 #include <linux/clockchips.h>
  45 #include <linux/io.h>
  46 #include <linux/sched_clock.h>
  47
  48 #include <asm/irq.h>
  49
  50 #include <mach/hardware.h>
  51 #include <asm/mach/irq.h>
  52 #include <asm/mach/time.h>
  53
  54 #include "iomap.h"
  55 #include "common.h"
  56
  57 #ifdef CONFIG_OMAP_MPU_TIMER
  58
  59 #define OMAP_MPU_TIMER_BASE             OMAP_MPU_TIMER1_BASE
  60 #define OMAP_MPU_TIMER_OFFSET           0x100
  61
  62 typedef struct {
  63         u32 cntl;                       /* CNTL_TIMER, R/W */
  64         u32 load_tim;                   /* LOAD_TIM,   W */
  65         u32 read_tim;                   /* READ_TIM,   R */
  66 } omap_mpu_timer_regs_t;
  67
  68 #define omap_mpu_timer_base(n)                                                  \
  69 ((omap_mpu_timer_regs_t __iomem *)OMAP1_IO_ADDRESS(OMAP_MPU_TIMER_BASE +        \
  70                                  (n)*OMAP_MPU_TIMER_OFFSET))
  71
  72 static inline unsigned long notrace omap_mpu_timer_read(int nr)
  73 {
  74         omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
  75         return readl(&timer->read_tim);
  76 }
  77
  78 static inline void omap_mpu_set_autoreset(int nr)
  79 {
  80         omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
  81
  82         writel(readl(&timer->cntl) | MPU_TIMER_AR, &timer->cntl);
  83 }
  84
  85 static inline void omap_mpu_remove_autoreset(int nr)
  86 {
  87         omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
  88
  89         writel(readl(&timer->cntl) & ~MPU_TIMER_AR, &timer->cntl);
  90 }
  91
  92 static inline void omap_mpu_timer_start(int nr, unsigned long load_val,
  93                                         int autoreset)
  94 {
  95         omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
  96         unsigned int timerflags = MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_ST;
  97
  98         if (autoreset)
  99                 timerflags |= MPU_TIMER_AR;
 100
 101         writel(MPU_TIMER_CLOCK_ENABLE, &timer->cntl);
 102         udelay(1);
 103         writel(load_val, &timer->load_tim);
 104         udelay(1);
 105         writel(timerflags, &timer->cntl);
 106 }
 107
 108 static inline void omap_mpu_timer_stop(int nr)
 109 {
 110         omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
 111
 112         writel(readl(&timer->cntl) & ~MPU_TIMER_ST, &timer->cntl);
 113 }
 114
 115 /*
 116  * ---------------------------------------------------------------------------
 117  * MPU timer 1 ... count down to zero, interrupt, reload
 118  * ---------------------------------------------------------------------------
 119  */
 120 static int omap_mpu_set_next_event(unsigned long cycles,
 121                                    struct clock_event_device *evt)
 122 {
 123         omap_mpu_timer_start(0, cycles, 0);
 124         return 0;
 125 }
 126
 127 static int omap_mpu_set_oneshot(struct clock_event_device *evt)
 128 {
 129         omap_mpu_timer_stop(0);
 130         omap_mpu_remove_autoreset(0);
 131         return 0;
 132 }
 133
 134 static int omap_mpu_set_periodic(struct clock_event_device *evt)
 135 {
 136         omap_mpu_set_autoreset(0);
 137         return 0;
 138 }
 139
 140 static struct clock_event_device clockevent_mpu_timer1 = {
 141         .name                   = "mpu_timer1",
 142         .features               = CLOCK_EVT_FEAT_PERIODIC |
 143                                   CLOCK_EVT_FEAT_ONESHOT,
 144         .set_next_event         = omap_mpu_set_next_event,
 145         .set_state_periodic     = omap_mpu_set_periodic,
 146         .set_state_oneshot      = omap_mpu_set_oneshot,
 147 };
 148
 149 static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id)
 150 {
 151         struct clock_event_device *evt = &clockevent_mpu_timer1;
 152
 153         evt->event_handler(evt);
 154
 155         return IRQ_HANDLED;
 156 }
 157
 158 static __init void omap_init_mpu_timer(unsigned long rate)
 159 {
 160         if (request_irq(INT_TIMER1, omap_mpu_timer1_interrupt,
 161                         IRQF_TIMER | IRQF_IRQPOLL, "mpu_timer1", NULL))
 162                 pr_err("Failed to request irq %d (mpu_timer1)\n", INT_TIMER1);
 163         omap_mpu_timer_start(0, (rate / HZ) - 1, 1);
 164
 165         clockevent_mpu_timer1.cpumask = cpumask_of(0);
 166         clockevents_config_and_register(&clockevent_mpu_timer1, rate,
 167                                         1, -1);
 168 }
 169
 170
 171 /*
 172  * ---------------------------------------------------------------------------
 173  * MPU timer 2 ... free running 32-bit clock source and scheduler clock
 174  * ---------------------------------------------------------------------------
 175  */
 176
 177 static u64 notrace omap_mpu_read_sched_clock(void)
 178 {
 179         return ~omap_mpu_timer_read(1);
 180 }
 181
 182 static void __init omap_init_clocksource(unsigned long rate)
 183 {
 184         omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(1);
 185         static char err[] __initdata = KERN_ERR
 186                         "%s: can't register clocksource!\n";
 187
 188         omap_mpu_timer_start(1, ~0, 1);
 189         sched_clock_register(omap_mpu_read_sched_clock, 32, rate);
 190
 191         if (clocksource_mmio_init(&timer->read_tim, "mpu_timer2", rate,
 192                         300, 32, clocksource_mmio_readl_down))
 193                 printk(err, "mpu_timer2");
 194 }
 195
 196 static void __init omap_mpu_timer_init(void)
 197 {
 198         struct clk      *ck_ref = clk_get(NULL, "ck_ref");
 199         unsigned long   rate;
 200
 201         BUG_ON(IS_ERR(ck_ref));
 202
 203         rate = clk_get_rate(ck_ref);
 204         clk_put(ck_ref);
 205
 206         /* PTV = 0 */
 207         rate /= 2;
 208
 209         omap_init_mpu_timer(rate);
 210         omap_init_clocksource(rate);
 211 }
 212
 213 #else
 214 static inline void omap_mpu_timer_init(void)
 215 {
 216         pr_err("Bogus timer, should not happen\n");
 217 }
 218 #endif  /* CONFIG_OMAP_MPU_TIMER */
 219
 220 /*
 221  * ---------------------------------------------------------------------------
 222  * Timer initialization
 223  * ---------------------------------------------------------------------------
 224  */
 225 void __init omap1_timer_init(void)
 226 {
 227         if (omap_32k_timer_init() != 0)
 228                 omap_mpu_timer_init();
 229 }