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 <asm/mach/irq.h>
  51 #include <asm/mach/time.h>
  52
  53 #include "hardware.h"
  54 #include "mux.h"
  55 #include "iomap.h"
  56 #include "common.h"
  57 #include "clock.h"
  58
  59 #ifdef CONFIG_OMAP_MPU_TIMER
  60
  61 #define OMAP_MPU_TIMER_BASE             OMAP_MPU_TIMER1_BASE
  62 #define OMAP_MPU_TIMER_OFFSET           0x100
  63
  64 typedef struct {
  65         u32 cntl;                       /* CNTL_TIMER, R/W */
  66         u32 load_tim;                   /* LOAD_TIM,   W */
  67         u32 read_tim;                   /* READ_TIM,   R */
  68 } omap_mpu_timer_regs_t;
  69
  70 #define omap_mpu_timer_base(n)                                                  \
  71 ((omap_mpu_timer_regs_t __iomem *)OMAP1_IO_ADDRESS(OMAP_MPU_TIMER_BASE +        \
  72                                  (n)*OMAP_MPU_TIMER_OFFSET))
  73
  74 static inline unsigned long notrace omap_mpu_timer_read(int nr)
  75 {
  76         omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
  77         return readl(&timer->read_tim);
  78 }
  79
  80 static inline void omap_mpu_set_autoreset(int nr)
  81 {
  82         omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
  83
  84         writel(readl(&timer->cntl) | MPU_TIMER_AR, &timer->cntl);
  85 }
  86
  87 static inline void omap_mpu_remove_autoreset(int nr)
  88 {
  89         omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
  90
  91         writel(readl(&timer->cntl) & ~MPU_TIMER_AR, &timer->cntl);
  92 }
  93
  94 static inline void omap_mpu_timer_start(int nr, unsigned long load_val,
  95                                         int autoreset)
  96 {
  97         omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
  98         unsigned int timerflags = MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_ST;
  99
 100         if (autoreset)
 101                 timerflags |= MPU_TIMER_AR;
 102
 103         writel(MPU_TIMER_CLOCK_ENABLE, &timer->cntl);
 104         udelay(1);
 105         writel(load_val, &timer->load_tim);
 106         udelay(1);
 107         writel(timerflags, &timer->cntl);
 108 }
 109
 110 static inline void omap_mpu_timer_stop(int nr)
 111 {
 112         omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(nr);
 113
 114         writel(readl(&timer->cntl) & ~MPU_TIMER_ST, &timer->cntl);
 115 }
 116
 117 /*
 118  * ---------------------------------------------------------------------------
 119  * MPU timer 1 ... count down to zero, interrupt, reload
 120  * ---------------------------------------------------------------------------
 121  */
 122 static int omap_mpu_set_next_event(unsigned long cycles,
 123                                    struct clock_event_device *evt)
 124 {
 125         omap_mpu_timer_start(0, cycles, 0);
 126         return 0;
 127 }
 128
 129 static int omap_mpu_set_oneshot(struct clock_event_device *evt)
 130 {
 131         omap_mpu_timer_stop(0);
 132         omap_mpu_remove_autoreset(0);
 133         return 0;
 134 }
 135
 136 static int omap_mpu_set_periodic(struct clock_event_device *evt)
 137 {
 138         omap_mpu_set_autoreset(0);
 139         return 0;
 140 }
 141
 142 static struct clock_event_device clockevent_mpu_timer1 = {
 143         .name                   = "mpu_timer1",
 144         .features               = CLOCK_EVT_FEAT_PERIODIC |
 145                                   CLOCK_EVT_FEAT_ONESHOT,
 146         .set_next_event         = omap_mpu_set_next_event,
 147         .set_state_periodic     = omap_mpu_set_periodic,
 148         .set_state_oneshot      = omap_mpu_set_oneshot,
 149 };
 150
 151 static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id)
 152 {
 153         struct clock_event_device *evt = &clockevent_mpu_timer1;
 154
 155         evt->event_handler(evt);
 156
 157         return IRQ_HANDLED;
 158 }
 159
 160 static __init void omap_init_mpu_timer(unsigned long rate)
 161 {
 162         if (request_irq(INT_TIMER1, omap_mpu_timer1_interrupt,
 163                         IRQF_TIMER | IRQF_IRQPOLL, "mpu_timer1", NULL))
 164                 pr_err("Failed to request irq %d (mpu_timer1)\n", INT_TIMER1);
 165         omap_mpu_timer_start(0, (rate / HZ) - 1, 1);
 166
 167         clockevent_mpu_timer1.cpumask = cpumask_of(0);
 168         clockevents_config_and_register(&clockevent_mpu_timer1, rate,
 169                                         1, -1);
 170 }
 171
 172
 173 /*
 174  * ---------------------------------------------------------------------------
 175  * MPU timer 2 ... free running 32-bit clock source and scheduler clock
 176  * ---------------------------------------------------------------------------
 177  */
 178
 179 static u64 notrace omap_mpu_read_sched_clock(void)
 180 {
 181         return ~omap_mpu_timer_read(1);
 182 }
 183
 184 static void __init omap_init_clocksource(unsigned long rate)
 185 {
 186         omap_mpu_timer_regs_t __iomem *timer = omap_mpu_timer_base(1);
 187         static char err[] __initdata = KERN_ERR
 188                         "%s: can't register clocksource!\n";
 189
 190         omap_mpu_timer_start(1, ~0, 1);
 191         sched_clock_register(omap_mpu_read_sched_clock, 32, rate);
 192
 193         if (clocksource_mmio_init(&timer->read_tim, "mpu_timer2", rate,
 194                         300, 32, clocksource_mmio_readl_down))
 195                 printk(err, "mpu_timer2");
 196 }
 197
 198 static void __init omap_mpu_timer_init(void)
 199 {
 200         struct clk      *ck_ref = clk_get(NULL, "ck_ref");
 201         unsigned long   rate;
 202
 203         BUG_ON(IS_ERR(ck_ref));
 204
 205         rate = clk_get_rate(ck_ref);
 206         clk_put(ck_ref);
 207
 208         /* PTV = 0 */
 209         rate /= 2;
 210
 211         omap_init_mpu_timer(rate);
 212         omap_init_clocksource(rate);
 213 }
 214
 215 #else
 216 static inline void omap_mpu_timer_init(void)
 217 {
 218         pr_err("Bogus timer, should not happen\n");
 219 }
 220 #endif  /* CONFIG_OMAP_MPU_TIMER */
 221
 222 /*
 223  * ---------------------------------------------------------------------------
 224  * Timer initialization
 225  * ---------------------------------------------------------------------------
 226  */
 227 void __init omap1_timer_init(void)
 228 {
 229         omap1_clk_init();
 230         omap1_mux_init();
 231
 232         if (omap_32k_timer_init() != 0)
 233                 omap_mpu_timer_init();
 234 }