2 * linux/arch/arm/mach-omap2/timer-gp.c
4 * OMAP2 GP timer support.
6 * Update to use new clocksource/clockevent layers
7 * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
8 * Copyright (C) 2007 MontaVista Software, Inc.
11 * Copyright (C) 2005 Nokia Corporation
12 * Author: Paul Mundt <paul.mundt@nokia.com>
13 * Juha Yrjölä <juha.yrjola@nokia.com>
14 * OMAP Dual-mode timer framework support by Timo Teras
16 * Some parts based off of TI's 24xx code:
18 * Copyright (C) 2004 Texas Instruments, Inc.
20 * Roughly modelled after the OMAP1 MPU timer code.
22 * This file is subject to the terms and conditions of the GNU General Public
23 * License. See the file "COPYING" in the main directory of this archive
26 #include <linux/init.h>
27 #include <linux/time.h>
28 #include <linux/interrupt.h>
29 #include <linux/err.h>
30 #include <linux/clk.h>
31 #include <linux/delay.h>
32 #include <linux/irq.h>
33 #include <linux/clocksource.h>
34 #include <linux/clockchips.h>
36 #include <asm/mach/time.h>
37 #include <mach/dmtimer.h>
39 static struct omap_dm_timer
*gptimer
;
40 static struct clock_event_device clockevent_gpt
;
42 static irqreturn_t
omap2_gp_timer_interrupt(int irq
, void *dev_id
)
44 struct omap_dm_timer
*gpt
= (struct omap_dm_timer
*)dev_id
;
45 struct clock_event_device
*evt
= &clockevent_gpt
;
47 omap_dm_timer_write_status(gpt
, OMAP_TIMER_INT_OVERFLOW
);
49 evt
->event_handler(evt
);
53 static struct irqaction omap2_gp_timer_irq
= {
55 .flags
= IRQF_DISABLED
| IRQF_TIMER
| IRQF_IRQPOLL
,
56 .handler
= omap2_gp_timer_interrupt
,
59 static int omap2_gp_timer_set_next_event(unsigned long cycles
,
60 struct clock_event_device
*evt
)
62 omap_dm_timer_set_load_start(gptimer
, 0, 0xffffffff - cycles
);
67 static void omap2_gp_timer_set_mode(enum clock_event_mode mode
,
68 struct clock_event_device
*evt
)
72 omap_dm_timer_stop(gptimer
);
75 case CLOCK_EVT_MODE_PERIODIC
:
76 period
= clk_get_rate(omap_dm_timer_get_fclk(gptimer
)) / HZ
;
79 omap_dm_timer_set_load_start(gptimer
, 1, 0xffffffff - period
);
81 case CLOCK_EVT_MODE_ONESHOT
:
83 case CLOCK_EVT_MODE_UNUSED
:
84 case CLOCK_EVT_MODE_SHUTDOWN
:
85 case CLOCK_EVT_MODE_RESUME
:
90 static struct clock_event_device clockevent_gpt
= {
92 .features
= CLOCK_EVT_FEAT_PERIODIC
| CLOCK_EVT_FEAT_ONESHOT
,
94 .set_next_event
= omap2_gp_timer_set_next_event
,
95 .set_mode
= omap2_gp_timer_set_mode
,
98 static void __init
omap2_gp_clockevent_init(void)
102 gptimer
= omap_dm_timer_request_specific(1);
103 BUG_ON(gptimer
== NULL
);
105 #if defined(CONFIG_OMAP_32K_TIMER)
106 omap_dm_timer_set_source(gptimer
, OMAP_TIMER_SRC_32_KHZ
);
108 omap_dm_timer_set_source(gptimer
, OMAP_TIMER_SRC_SYS_CLK
);
110 tick_rate
= clk_get_rate(omap_dm_timer_get_fclk(gptimer
));
112 omap2_gp_timer_irq
.dev_id
= (void *)gptimer
;
113 setup_irq(omap_dm_timer_get_irq(gptimer
), &omap2_gp_timer_irq
);
114 omap_dm_timer_set_int_enable(gptimer
, OMAP_TIMER_INT_OVERFLOW
);
116 clockevent_gpt
.mult
= div_sc(tick_rate
, NSEC_PER_SEC
,
117 clockevent_gpt
.shift
);
118 clockevent_gpt
.max_delta_ns
=
119 clockevent_delta2ns(0xffffffff, &clockevent_gpt
);
120 clockevent_gpt
.min_delta_ns
=
121 clockevent_delta2ns(3, &clockevent_gpt
);
122 /* Timer internal resynch latency. */
124 clockevent_gpt
.cpumask
= cpumask_of(0);
125 clockevents_register_device(&clockevent_gpt
);
128 #ifdef CONFIG_OMAP_32K_TIMER
130 * When 32k-timer is enabled, don't use GPTimer for clocksource
131 * instead, just leave default clocksource which uses the 32k
132 * sync counter. See clocksource setup in see plat-omap/common.c.
135 static inline void __init
omap2_gp_clocksource_init(void) {}
140 static struct omap_dm_timer
*gpt_clocksource
;
141 static cycle_t
clocksource_read_cycles(struct clocksource
*cs
)
143 return (cycle_t
)omap_dm_timer_read_counter(gpt_clocksource
);
146 static struct clocksource clocksource_gpt
= {
149 .read
= clocksource_read_cycles
,
150 .mask
= CLOCKSOURCE_MASK(32),
152 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
155 /* Setup free-running counter for clocksource */
156 static void __init
omap2_gp_clocksource_init(void)
158 static struct omap_dm_timer
*gpt
;
159 u32 tick_rate
, tick_period
;
160 static char err1
[] __initdata
= KERN_ERR
161 "%s: failed to request dm-timer\n";
162 static char err2
[] __initdata
= KERN_ERR
163 "%s: can't register clocksource!\n";
165 gpt
= omap_dm_timer_request();
167 printk(err1
, clocksource_gpt
.name
);
168 gpt_clocksource
= gpt
;
170 omap_dm_timer_set_source(gpt
, OMAP_TIMER_SRC_SYS_CLK
);
171 tick_rate
= clk_get_rate(omap_dm_timer_get_fclk(gpt
));
172 tick_period
= (tick_rate
/ HZ
) - 1;
174 omap_dm_timer_set_load_start(gpt
, 1, 0);
176 clocksource_gpt
.mult
=
177 clocksource_khz2mult(tick_rate
/1000, clocksource_gpt
.shift
);
178 if (clocksource_register(&clocksource_gpt
))
179 printk(err2
, clocksource_gpt
.name
);
183 static void __init
omap2_gp_timer_init(void)
185 omap_dm_timer_init();
187 omap2_gp_clockevent_init();
188 omap2_gp_clocksource_init();
191 struct sys_timer omap_timer
= {
192 .init
= omap2_gp_timer_init
,