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/sched.h>
  41 #include <linux/spinlock.h>
  42 #include <linux/clk.h>
  43 #include <linux/err.h>
  44 #include <linux/clocksource.h>
  45 #include <linux/clockchips.h>
  46 #include <linux/io.h>
  47
  48 #include <asm/system.h>
  49 #include <mach/hardware.h>
  50 #include <asm/leds.h>
  51 #include <asm/irq.h>
  52 #include <asm/sched_clock.h>
  53
  54 #include <asm/mach/irq.h>
  55 #include <asm/mach/time.h>
  56
  57 #include <plat/common.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 ((volatile omap_mpu_timer_regs_t*)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         volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
  77         return timer->read_tim;
  78 }
  79
  80 static inline void omap_mpu_set_autoreset(int nr)
  81 {
  82         volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
  83
  84         timer->cntl = timer->cntl | MPU_TIMER_AR;
  85 }
  86
  87 static inline void omap_mpu_remove_autoreset(int nr)
  88 {
  89         volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
  90
  91         timer->cntl = timer->cntl & ~MPU_TIMER_AR;
  92 }
  93
  94 static inline void omap_mpu_timer_start(int nr, unsigned long load_val,
  95                                         int autoreset)
  96 {
  97         volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
  98         unsigned int timerflags = (MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_ST);
  99
 100         if (autoreset) timerflags |= MPU_TIMER_AR;
 101
 102         timer->cntl = MPU_TIMER_CLOCK_ENABLE;
 103         udelay(1);
 104         timer->load_tim = load_val;
 105         udelay(1);
 106         timer->cntl = timerflags;
 107 }
 108
 109 static inline void omap_mpu_timer_stop(int nr)
 110 {
 111         volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
 112
 113         timer->cntl &= ~MPU_TIMER_ST;
 114 }
 115
 116 /*
 117  * ---------------------------------------------------------------------------
 118  * MPU timer 1 ... count down to zero, interrupt, reload
 119  * ---------------------------------------------------------------------------
 120  */
 121 static int omap_mpu_set_next_event(unsigned long cycles,
 122                                    struct clock_event_device *evt)
 123 {
 124         omap_mpu_timer_start(0, cycles, 0);
 125         return 0;
 126 }
 127
 128 static void omap_mpu_set_mode(enum clock_event_mode mode,
 129                               struct clock_event_device *evt)
 130 {
 131         switch (mode) {
 132         case CLOCK_EVT_MODE_PERIODIC:
 133                 omap_mpu_set_autoreset(0);
 134                 break;
 135         case CLOCK_EVT_MODE_ONESHOT:
 136                 omap_mpu_timer_stop(0);
 137                 omap_mpu_remove_autoreset(0);
 138                 break;
 139         case CLOCK_EVT_MODE_UNUSED:
 140         case CLOCK_EVT_MODE_SHUTDOWN:
 141         case CLOCK_EVT_MODE_RESUME:
 142                 break;
 143         }
 144 }
 145
 146 static struct clock_event_device clockevent_mpu_timer1 = {
 147         .name           = "mpu_timer1",
 148         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 149         .shift          = 32,
 150         .set_next_event = omap_mpu_set_next_event,
 151         .set_mode       = omap_mpu_set_mode,
 152 };
 153
 154 static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id)
 155 {
 156         struct clock_event_device *evt = &clockevent_mpu_timer1;
 157
 158         evt->event_handler(evt);
 159
 160         return IRQ_HANDLED;
 161 }
 162
 163 static struct irqaction omap_mpu_timer1_irq = {
 164         .name           = "mpu_timer1",
 165         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
 166         .handler        = omap_mpu_timer1_interrupt,
 167 };
 168
 169 static __init void omap_init_mpu_timer(unsigned long rate)
 170 {
 171         setup_irq(INT_TIMER1, &omap_mpu_timer1_irq);
 172         omap_mpu_timer_start(0, (rate / HZ) - 1, 1);
 173
 174         clockevent_mpu_timer1.mult = div_sc(rate, NSEC_PER_SEC,
 175                                             clockevent_mpu_timer1.shift);
 176         clockevent_mpu_timer1.max_delta_ns =
 177                 clockevent_delta2ns(-1, &clockevent_mpu_timer1);
 178         clockevent_mpu_timer1.min_delta_ns =
 179                 clockevent_delta2ns(1, &clockevent_mpu_timer1);
 180
 181         clockevent_mpu_timer1.cpumask = cpumask_of(0);
 182         clockevents_register_device(&clockevent_mpu_timer1);
 183 }
 184
 185
 186 /*
 187  * ---------------------------------------------------------------------------
 188  * MPU timer 2 ... free running 32-bit clock source and scheduler clock
 189  * ---------------------------------------------------------------------------
 190  */
 191
 192 static unsigned long omap_mpu_timer2_overflows;
 193
 194 static irqreturn_t omap_mpu_timer2_interrupt(int irq, void *dev_id)
 195 {
 196         omap_mpu_timer2_overflows++;
 197         return IRQ_HANDLED;
 198 }
 199
 200 static struct irqaction omap_mpu_timer2_irq = {
 201         .name           = "mpu_timer2",
 202         .flags          = IRQF_DISABLED,
 203         .handler        = omap_mpu_timer2_interrupt,
 204 };
 205
 206 static cycle_t mpu_read(struct clocksource *cs)
 207 {
 208         return ~omap_mpu_timer_read(1);
 209 }
 210
 211 static struct clocksource clocksource_mpu = {
 212         .name           = "mpu_timer2",
 213         .rating         = 300,
 214         .read           = mpu_read,
 215         .mask           = CLOCKSOURCE_MASK(32),
 216         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 217 };
 218
 219 static DEFINE_CLOCK_DATA(cd);
 220
 221 static inline unsigned long long notrace _omap_mpu_sched_clock(void)
 222 {
 223         u32 cyc = mpu_read(&clocksource_mpu);
 224         return cyc_to_sched_clock(&cd, cyc, (u32)~0);
 225 }
 226
 227 #ifndef CONFIG_OMAP_32K_TIMER
 228 unsigned long long notrace sched_clock(void)
 229 {
 230         return _omap_mpu_sched_clock();
 231 }
 232 #else
 233 static unsigned long long notrace omap_mpu_sched_clock(void)
 234 {
 235         return _omap_mpu_sched_clock();
 236 }
 237 #endif
 238
 239 static void notrace mpu_update_sched_clock(void)
 240 {
 241         u32 cyc = mpu_read(&clocksource_mpu);
 242         update_sched_clock(&cd, cyc, (u32)~0);
 243 }
 244
 245 static void __init omap_init_clocksource(unsigned long rate)
 246 {
 247         static char err[] __initdata = KERN_ERR
 248                         "%s: can't register clocksource!\n";
 249
 250         setup_irq(INT_TIMER2, &omap_mpu_timer2_irq);
 251         omap_mpu_timer_start(1, ~0, 1);
 252         init_sched_clock(&cd, mpu_update_sched_clock, 32, rate);
 253
 254         if (clocksource_register_hz(&clocksource_mpu, rate))
 255                 printk(err, clocksource_mpu.name);
 256 }
 257
 258 static void __init omap_mpu_timer_init(void)
 259 {
 260         struct clk      *ck_ref = clk_get(NULL, "ck_ref");
 261         unsigned long   rate;
 262
 263         BUG_ON(IS_ERR(ck_ref));
 264
 265         rate = clk_get_rate(ck_ref);
 266         clk_put(ck_ref);
 267
 268         /* PTV = 0 */
 269         rate /= 2;
 270
 271         omap_init_mpu_timer(rate);
 272         omap_init_clocksource(rate);
 273 }
 274
 275 #else
 276 static inline void omap_mpu_timer_init(void)
 277 {
 278         pr_err("Bogus timer, should not happen\n");
 279 }
 280 #endif  /* CONFIG_OMAP_MPU_TIMER */
 281
 282 #if defined(CONFIG_OMAP_MPU_TIMER) && defined(CONFIG_OMAP_32K_TIMER)
 283 static unsigned long long (*preferred_sched_clock)(void);
 284
 285 unsigned long long notrace sched_clock(void)
 286 {
 287         if (!preferred_sched_clock)
 288                 return 0;
 289
 290         return preferred_sched_clock();
 291 }
 292
 293 static inline void preferred_sched_clock_init(bool use_32k_sched_clock)
 294 {
 295         if (use_32k_sched_clock)
 296                 preferred_sched_clock = omap_32k_sched_clock;
 297         else
 298                 preferred_sched_clock = omap_mpu_sched_clock;
 299 }
 300 #else
 301 static inline void preferred_sched_clock_init(bool use_32k_sched_clcok)
 302 {
 303 }
 304 #endif
 305
 306 static inline int omap_32k_timer_usable(void)
 307 {
 308         int res = false;
 309
 310         if (cpu_is_omap730() || cpu_is_omap15xx())
 311                 return res;
 312
 313 #ifdef CONFIG_OMAP_32K_TIMER
 314         res = omap_32k_timer_init();
 315 #endif
 316
 317         return res;
 318 }
 319
 320 /*
 321  * ---------------------------------------------------------------------------
 322  * Timer initialization
 323  * ---------------------------------------------------------------------------
 324  */
 325 static void __init omap_timer_init(void)
 326 {
 327         if (omap_32k_timer_usable()) {
 328                 preferred_sched_clock_init(1);
 329         } else {
 330                 omap_mpu_timer_init();
 331                 preferred_sched_clock_init(0);
 332         }
 333 }
 334
 335 struct sys_timer omap_timer = {
 336         .init           = omap_timer_init,
 337 };