2 * linux/arch/arm/mach-omap2/timer-gp.c
4 * OMAP2 GP timer support.
6 * Copyright (C) 2009 Nokia Corporation
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.
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
18 * Some parts based off of TI's 24xx code:
20 * Copyright (C) 2004-2009 Texas Instruments, Inc.
22 * Roughly modelled after the OMAP1 MPU timer code.
23 * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
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
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>
39 #include <asm/mach/time.h>
40 #include <plat/dmtimer.h>
41 #include <asm/localtimer.h>
45 /* MAX_GPTIMER_ID: number of GPTIMERs on the chip */
46 #define MAX_GPTIMER_ID 12
48 static struct omap_dm_timer *gptimer;
49 static struct clock_event_device clockevent_gpt;
50 static u8 __initdata gptimer_id = 1;
51 static u8 __initdata inited;
52 struct omap_dm_timer *gptimer_wakeup;
54 static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id)
56 struct omap_dm_timer *gpt = (struct omap_dm_timer *)dev_id;
57 struct clock_event_device *evt = &clockevent_gpt;
59 omap_dm_timer_write_status(gpt, OMAP_TIMER_INT_OVERFLOW);
61 evt->event_handler(evt);
65 static struct irqaction omap2_gp_timer_irq = {
67 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
68 .handler = omap2_gp_timer_interrupt,
71 static int omap2_gp_timer_set_next_event(unsigned long cycles,
72 struct clock_event_device *evt)
74 omap_dm_timer_set_load_start(gptimer, 0, 0xffffffff - cycles);
79 static void omap2_gp_timer_set_mode(enum clock_event_mode mode,
80 struct clock_event_device *evt)
84 omap_dm_timer_stop(gptimer);
87 case CLOCK_EVT_MODE_PERIODIC:
88 period = clk_get_rate(omap_dm_timer_get_fclk(gptimer)) / HZ;
90 omap_dm_timer_set_load_start(gptimer, 1, 0xffffffff - period);
92 case CLOCK_EVT_MODE_ONESHOT:
94 case CLOCK_EVT_MODE_UNUSED:
95 case CLOCK_EVT_MODE_SHUTDOWN:
96 case CLOCK_EVT_MODE_RESUME:
101 static struct clock_event_device clockevent_gpt = {
103 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
105 .set_next_event = omap2_gp_timer_set_next_event,
106 .set_mode = omap2_gp_timer_set_mode,
110 * omap2_gp_clockevent_set_gptimer - set which GPTIMER is used for clockevents
111 * @id: GPTIMER to use (1..MAX_GPTIMER_ID)
113 * Define the GPTIMER that the system should use for the tick timer.
114 * Meant to be called from board-*.c files in the event that GPTIMER1, the
115 * default, is unsuitable. Returns -EINVAL on error or 0 on success.
117 int __init omap2_gp_clockevent_set_gptimer(u8 id)
119 if (id < 1 || id > MAX_GPTIMER_ID)
129 static void __init omap2_gp_clockevent_init(void)
136 gptimer = omap_dm_timer_request_specific(gptimer_id);
137 BUG_ON(gptimer == NULL);
138 gptimer_wakeup = gptimer;
140 #if defined(CONFIG_OMAP_32K_TIMER)
141 src = OMAP_TIMER_SRC_32_KHZ;
143 src = OMAP_TIMER_SRC_SYS_CLK;
144 WARN(gptimer_id == 12, "WARNING: GPTIMER12 can only use the "
145 "secure 32KiHz clock source\n");
148 if (gptimer_id != 12)
149 WARN(IS_ERR_VALUE(omap_dm_timer_set_source(gptimer, src)),
150 "timer-gp: omap_dm_timer_set_source() failed\n");
152 tick_rate = clk_get_rate(omap_dm_timer_get_fclk(gptimer));
154 pr_info("OMAP clockevent source: GPTIMER%d at %u Hz\n",
155 gptimer_id, tick_rate);
157 omap2_gp_timer_irq.dev_id = (void *)gptimer;
158 setup_irq(omap_dm_timer_get_irq(gptimer), &omap2_gp_timer_irq);
159 omap_dm_timer_set_int_enable(gptimer, OMAP_TIMER_INT_OVERFLOW);
161 clockevent_gpt.mult = div_sc(tick_rate, NSEC_PER_SEC,
162 clockevent_gpt.shift);
163 clockevent_gpt.max_delta_ns =
164 clockevent_delta2ns(0xffffffff, &clockevent_gpt);
165 clockevent_gpt.min_delta_ns =
166 clockevent_delta2ns(3, &clockevent_gpt);
167 /* Timer internal resynch latency. */
169 clockevent_gpt.cpumask = cpumask_of(0);
170 clockevents_register_device(&clockevent_gpt);
173 /* Clocksource code */
175 #ifdef CONFIG_OMAP_32K_TIMER
177 * When 32k-timer is enabled, don't use GPTimer for clocksource
178 * instead, just leave default clocksource which uses the 32k
179 * sync counter. See clocksource setup in see plat-omap/common.c.
182 static inline void __init omap2_gp_clocksource_init(void) {}
187 static struct omap_dm_timer *gpt_clocksource;
188 static cycle_t clocksource_read_cycles(struct clocksource *cs)
190 return (cycle_t)omap_dm_timer_read_counter(gpt_clocksource);
193 static struct clocksource clocksource_gpt = {
196 .read = clocksource_read_cycles,
197 .mask = CLOCKSOURCE_MASK(32),
199 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
202 /* Setup free-running counter for clocksource */
203 static void __init omap2_gp_clocksource_init(void)
205 static struct omap_dm_timer *gpt;
206 u32 tick_rate, tick_period;
207 static char err1[] __initdata = KERN_ERR
208 "%s: failed to request dm-timer\n";
209 static char err2[] __initdata = KERN_ERR
210 "%s: can't register clocksource!\n";
212 gpt = omap_dm_timer_request();
214 printk(err1, clocksource_gpt.name);
215 gpt_clocksource = gpt;
217 omap_dm_timer_set_source(gpt, OMAP_TIMER_SRC_SYS_CLK);
218 tick_rate = clk_get_rate(omap_dm_timer_get_fclk(gpt));
219 tick_period = (tick_rate / HZ) - 1;
221 omap_dm_timer_set_load_start(gpt, 1, 0);
223 clocksource_gpt.mult =
224 clocksource_khz2mult(tick_rate/1000, clocksource_gpt.shift);
225 if (clocksource_register(&clocksource_gpt))
226 printk(err2, clocksource_gpt.name);
230 static void __init omap2_gp_timer_init(void)
232 #ifdef CONFIG_LOCAL_TIMERS
233 if (cpu_is_omap44xx()) {
234 twd_base = ioremap(OMAP44XX_LOCAL_TWD_BASE, SZ_256);
238 omap_dm_timer_init();
240 omap2_gp_clockevent_init();
241 omap2_gp_clocksource_init();
244 struct sys_timer omap_timer = {
245 .init = omap2_gp_timer_init,