arch/arm/mach-omap2/timer-gp.c

   1 /*
   2  * linux/arch/arm/mach-omap2/timer-gp.c
   3  *
   4  * OMAP2 GP timer support.
   5  *
   6  * Copyright (C) 2009 Nokia Corporation
   7  *
   8  * Update to use new clocksource/clockevent layers
   9  * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
  10  * Copyright (C) 2007 MontaVista Software, Inc.
  11  *
  12  * Original driver:
  13  * Copyright (C) 2005 Nokia Corporation
  14  * Author: Paul Mundt <paul.mundt@nokia.com>
  15  *         Juha Yrjölä <juha.yrjola@nokia.com>
  16  * OMAP Dual-mode timer framework support by Timo Teras
  17  *
  18  * Some parts based off of TI's 24xx code:
  19  *
  20  * Copyright (C) 2004-2009 Texas Instruments, Inc.
  21  *
  22  * Roughly modelled after the OMAP1 MPU timer code.
  23  * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
  24  *
  25  * This file is subject to the terms and conditions of the GNU General Public
  26  * License. See the file "COPYING" in the main directory of this archive
  27  * for more details.
  28  */
  29 #include <linux/init.h>
  30 #include <linux/time.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/err.h>
  33 #include <linux/clk.h>
  34 #include <linux/delay.h>
  35 #include <linux/irq.h>
  36 #include <linux/clocksource.h>
  37 #include <linux/clockchips.h>
  38
  39 #include <asm/mach/time.h>
  40 #include <plat/dmtimer.h>
  41 #include <asm/localtimer.h>
  42 #include <asm/sched_clock.h>
  43 #include <plat/common.h>
  44 #include <plat/omap_hwmod.h>
  45
  46 #include "timer-gp.h"
  47 #include "dmtimer.h"
  48
  49 /* MAX_GPTIMER_ID: number of GPTIMERs on the chip */
  50 #define MAX_GPTIMER_ID          12
  51
  52 static struct omap_dm_timer *gptimer;
  53 static struct clock_event_device clockevent_gpt;
  54 static u8 __initdata gptimer_id = 1;
  55 static u8 __initdata inited;
  56 struct omap_dm_timer *gptimer_wakeup;
  57
  58 static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id)
  59 {
  60         struct omap_dm_timer *gpt = (struct omap_dm_timer *)dev_id;
  61         struct clock_event_device *evt = &clockevent_gpt;
  62
  63         omap_dm_timer_write_status(gpt, OMAP_TIMER_INT_OVERFLOW);
  64
  65         evt->event_handler(evt);
  66         return IRQ_HANDLED;
  67 }
  68
  69 static struct irqaction omap2_gp_timer_irq = {
  70         .name           = "gp timer",
  71         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
  72         .handler        = omap2_gp_timer_interrupt,
  73 };
  74
  75 static int omap2_gp_timer_set_next_event(unsigned long cycles,
  76                                          struct clock_event_device *evt)
  77 {
  78         omap_dm_timer_set_load_start(gptimer, 0, 0xffffffff - cycles);
  79
  80         return 0;
  81 }
  82
  83 static void omap2_gp_timer_set_mode(enum clock_event_mode mode,
  84                                     struct clock_event_device *evt)
  85 {
  86         u32 period;
  87
  88         omap_dm_timer_stop(gptimer);
  89
  90         switch (mode) {
  91         case CLOCK_EVT_MODE_PERIODIC:
  92                 period = clk_get_rate(omap_dm_timer_get_fclk(gptimer)) / HZ;
  93                 period -= 1;
  94                 omap_dm_timer_set_load_start(gptimer, 1, 0xffffffff - period);
  95                 break;
  96         case CLOCK_EVT_MODE_ONESHOT:
  97                 break;
  98         case CLOCK_EVT_MODE_UNUSED:
  99         case CLOCK_EVT_MODE_SHUTDOWN:
 100         case CLOCK_EVT_MODE_RESUME:
 101                 break;
 102         }
 103 }
 104
 105 static struct clock_event_device clockevent_gpt = {
 106         .name           = "gp timer",
 107         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 108         .shift          = 32,
 109         .rating         = 300,
 110         .set_next_event = omap2_gp_timer_set_next_event,
 111         .set_mode       = omap2_gp_timer_set_mode,
 112 };
 113
 114 /**
 115  * omap2_gp_clockevent_set_gptimer - set which GPTIMER is used for clockevents
 116  * @id: GPTIMER to use (1..MAX_GPTIMER_ID)
 117  *
 118  * Define the GPTIMER that the system should use for the tick timer.
 119  * Meant to be called from board-*.c files in the event that GPTIMER1, the
 120  * default, is unsuitable.  Returns -EINVAL on error or 0 on success.
 121  */
 122 int __init omap2_gp_clockevent_set_gptimer(u8 id)
 123 {
 124         if (id < 1 || id > MAX_GPTIMER_ID)
 125                 return -EINVAL;
 126
 127         BUG_ON(inited);
 128
 129         gptimer_id = id;
 130
 131         return 0;
 132 }
 133
 134 static void __init omap2_gp_clockevent_init(void)
 135 {
 136         u32 tick_rate;
 137         int src;
 138
 139         inited = 1;
 140
 141         gptimer = omap_dm_timer_request_specific(gptimer_id);
 142         BUG_ON(gptimer == NULL);
 143         gptimer_wakeup = gptimer;
 144
 145 #if defined(CONFIG_OMAP_32K_TIMER)
 146         src = OMAP_TIMER_SRC_32_KHZ;
 147 #else
 148         src = OMAP_TIMER_SRC_SYS_CLK;
 149         WARN(gptimer_id == 12, "WARNING: GPTIMER12 can only use the "
 150              "secure 32KiHz clock source\n");
 151 #endif
 152
 153         if (gptimer_id != 12)
 154                 WARN(IS_ERR_VALUE(omap2_system_timer_set_src(gptimer, src)),
 155                      "timer-gp: omap2_system_timer_set_src() failed\n");
 156
 157         tick_rate = clk_get_rate(omap_dm_timer_get_fclk(gptimer));
 158
 159         pr_info("OMAP clockevent source: GPTIMER%d at %u Hz\n",
 160                 gptimer_id, tick_rate);
 161
 162         omap2_gp_timer_irq.dev_id = (void *)gptimer;
 163         setup_irq(omap_dm_timer_get_irq(gptimer), &omap2_gp_timer_irq);
 164         omap_dm_timer_set_int_enable(gptimer, OMAP_TIMER_INT_OVERFLOW);
 165
 166         clockevent_gpt.mult = div_sc(tick_rate, NSEC_PER_SEC,
 167                                      clockevent_gpt.shift);
 168         clockevent_gpt.max_delta_ns =
 169                 clockevent_delta2ns(0xffffffff, &clockevent_gpt);
 170         clockevent_gpt.min_delta_ns =
 171                 clockevent_delta2ns(3, &clockevent_gpt);
 172                 /* Timer internal resynch latency. */
 173
 174         clockevent_gpt.cpumask = cpu_all_mask;
 175         clockevent_gpt.irq = omap_dm_timer_get_irq(gptimer);
 176         clockevents_register_device(&clockevent_gpt);
 177 }
 178
 179 /* Clocksource code */
 180
 181 #ifdef CONFIG_OMAP_32K_TIMER
 182 /*
 183  * When 32k-timer is enabled, don't use GPTimer for clocksource
 184  * instead, just leave default clocksource which uses the 32k
 185  * sync counter.  See clocksource setup in plat-omap/counter_32k.c
 186  */
 187
 188 static void __init omap2_gp_clocksource_init(void)
 189 {
 190         omap_init_clocksource_32k();
 191 }
 192
 193 #else
 194 /*
 195  * clocksource
 196  */
 197 static DEFINE_CLOCK_DATA(cd);
 198 static struct omap_dm_timer *gpt_clocksource;
 199 static cycle_t clocksource_read_cycles(struct clocksource *cs)
 200 {
 201         return (cycle_t)omap_dm_timer_read_counter(gpt_clocksource);
 202 }
 203
 204 static struct clocksource clocksource_gpt = {
 205         .name           = "gp timer",
 206         .rating         = 300,
 207         .read           = clocksource_read_cycles,
 208         .mask           = CLOCKSOURCE_MASK(32),
 209         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 210 };
 211
 212 static void notrace dmtimer_update_sched_clock(void)
 213 {
 214         u32 cyc;
 215
 216         cyc = omap_dm_timer_read_counter(gpt_clocksource);
 217
 218         update_sched_clock(&cd, cyc, (u32)~0);
 219 }
 220
 221 /* Setup free-running counter for clocksource */
 222 static void __init omap2_gp_clocksource_init(void)
 223 {
 224         static struct omap_dm_timer *gpt;
 225         u32 tick_rate;
 226         static char err1[] __initdata = KERN_ERR
 227                 "%s: failed to request dm-timer\n";
 228         static char err2[] __initdata = KERN_ERR
 229                 "%s: can't register clocksource!\n";
 230
 231         gpt = omap_dm_timer_request();
 232         if (!gpt)
 233                 printk(err1, clocksource_gpt.name);
 234         gpt_clocksource = gpt;
 235
 236         omap_dm_timer_set_source(gpt, OMAP_TIMER_SRC_SYS_CLK);
 237         tick_rate = clk_get_rate(omap_dm_timer_get_fclk(gpt));
 238
 239         omap_dm_timer_set_load_start(gpt, 1, 0);
 240
 241         init_sched_clock(&cd, dmtimer_update_sched_clock, 32, tick_rate);
 242
 243         if (clocksource_register_hz(&clocksource_gpt, tick_rate))
 244                 printk(err2, clocksource_gpt.name);
 245 }
 246 #endif
 247
 248 static void __init omap2_gp_timer_init(void)
 249 {
 250 #ifdef CONFIG_LOCAL_TIMERS
 251         if (cpu_is_omap44xx()) {
 252                 twd_base = ioremap(OMAP44XX_LOCAL_TWD_BASE, SZ_256);
 253                 BUG_ON(!twd_base);
 254         }
 255 #endif
 256         omap2_system_timer_init(gptimer_id);
 257
 258         omap2_gp_clockevent_init();
 259         omap2_gp_clocksource_init();
 260 }
 261
 262 struct sys_timer omap_timer = {
 263         .init   = omap2_gp_timer_init,
 264 };