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>
43 /* MAX_GPTIMER_ID: number of GPTIMERs on the chip */
44 #define MAX_GPTIMER_ID 12
46 static struct omap_dm_timer
*gptimer
;
47 static struct clock_event_device clockevent_gpt
;
48 static u8 __initdata gptimer_id
= 1;
49 static u8 __initdata inited
;
50 struct omap_dm_timer
*gptimer_wakeup
;
52 static irqreturn_t
omap2_gp_timer_interrupt(int irq
, void *dev_id
)
54 struct omap_dm_timer
*gpt
= (struct omap_dm_timer
*)dev_id
;
55 struct clock_event_device
*evt
= &clockevent_gpt
;
57 omap_dm_timer_write_status(gpt
, OMAP_TIMER_INT_OVERFLOW
);
59 evt
->event_handler(evt
);
63 static struct irqaction omap2_gp_timer_irq
= {
65 .flags
= IRQF_DISABLED
| IRQF_TIMER
| IRQF_IRQPOLL
,
66 .handler
= omap2_gp_timer_interrupt
,
69 static int omap2_gp_timer_set_next_event(unsigned long cycles
,
70 struct clock_event_device
*evt
)
72 omap_dm_timer_set_load_start(gptimer
, 0, 0xffffffff - cycles
);
77 static void omap2_gp_timer_set_mode(enum clock_event_mode mode
,
78 struct clock_event_device
*evt
)
82 omap_dm_timer_stop(gptimer
);
85 case CLOCK_EVT_MODE_PERIODIC
:
86 period
= clk_get_rate(omap_dm_timer_get_fclk(gptimer
)) / HZ
;
88 omap_dm_timer_set_load_start(gptimer
, 1, 0xffffffff - period
);
90 case CLOCK_EVT_MODE_ONESHOT
:
92 case CLOCK_EVT_MODE_UNUSED
:
93 case CLOCK_EVT_MODE_SHUTDOWN
:
94 case CLOCK_EVT_MODE_RESUME
:
99 static struct clock_event_device clockevent_gpt
= {
101 .features
= CLOCK_EVT_FEAT_PERIODIC
| CLOCK_EVT_FEAT_ONESHOT
,
103 .set_next_event
= omap2_gp_timer_set_next_event
,
104 .set_mode
= omap2_gp_timer_set_mode
,
108 * omap2_gp_clockevent_set_gptimer - set which GPTIMER is used for clockevents
109 * @id: GPTIMER to use (1..MAX_GPTIMER_ID)
111 * Define the GPTIMER that the system should use for the tick timer.
112 * Meant to be called from board-*.c files in the event that GPTIMER1, the
113 * default, is unsuitable. Returns -EINVAL on error or 0 on success.
115 int __init
omap2_gp_clockevent_set_gptimer(u8 id
)
117 if (id
< 1 || id
> MAX_GPTIMER_ID
)
127 static void __init
omap2_gp_clockevent_init(void)
134 gptimer
= omap_dm_timer_request_specific(gptimer_id
);
135 BUG_ON(gptimer
== NULL
);
136 gptimer_wakeup
= gptimer
;
138 #if defined(CONFIG_OMAP_32K_TIMER)
139 src
= OMAP_TIMER_SRC_32_KHZ
;
141 src
= OMAP_TIMER_SRC_SYS_CLK
;
142 WARN(gptimer_id
== 12, "WARNING: GPTIMER12 can only use the "
143 "secure 32KiHz clock source\n");
146 if (gptimer_id
!= 12)
147 WARN(IS_ERR_VALUE(omap_dm_timer_set_source(gptimer
, src
)),
148 "timer-gp: omap_dm_timer_set_source() failed\n");
150 tick_rate
= clk_get_rate(omap_dm_timer_get_fclk(gptimer
));
152 pr_info("OMAP clockevent source: GPTIMER%d at %u Hz\n",
153 gptimer_id
, tick_rate
);
155 omap2_gp_timer_irq
.dev_id
= (void *)gptimer
;
156 setup_irq(omap_dm_timer_get_irq(gptimer
), &omap2_gp_timer_irq
);
157 omap_dm_timer_set_int_enable(gptimer
, OMAP_TIMER_INT_OVERFLOW
);
159 clockevent_gpt
.mult
= div_sc(tick_rate
, NSEC_PER_SEC
,
160 clockevent_gpt
.shift
);
161 clockevent_gpt
.max_delta_ns
=
162 clockevent_delta2ns(0xffffffff, &clockevent_gpt
);
163 clockevent_gpt
.min_delta_ns
=
164 clockevent_delta2ns(3, &clockevent_gpt
);
165 /* Timer internal resynch latency. */
167 clockevent_gpt
.cpumask
= cpumask_of(0);
168 clockevents_register_device(&clockevent_gpt
);
171 /* Clocksource code */
173 #ifdef CONFIG_OMAP_32K_TIMER
175 * When 32k-timer is enabled, don't use GPTimer for clocksource
176 * instead, just leave default clocksource which uses the 32k
177 * sync counter. See clocksource setup in see plat-omap/common.c.
180 static inline void __init
omap2_gp_clocksource_init(void) {}
185 static struct omap_dm_timer
*gpt_clocksource
;
186 static cycle_t
clocksource_read_cycles(struct clocksource
*cs
)
188 return (cycle_t
)omap_dm_timer_read_counter(gpt_clocksource
);
191 static struct clocksource clocksource_gpt
= {
194 .read
= clocksource_read_cycles
,
195 .mask
= CLOCKSOURCE_MASK(32),
197 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
200 /* Setup free-running counter for clocksource */
201 static void __init
omap2_gp_clocksource_init(void)
203 static struct omap_dm_timer
*gpt
;
204 u32 tick_rate
, tick_period
;
205 static char err1
[] __initdata
= KERN_ERR
206 "%s: failed to request dm-timer\n";
207 static char err2
[] __initdata
= KERN_ERR
208 "%s: can't register clocksource!\n";
210 gpt
= omap_dm_timer_request();
212 printk(err1
, clocksource_gpt
.name
);
213 gpt_clocksource
= gpt
;
215 omap_dm_timer_set_source(gpt
, OMAP_TIMER_SRC_SYS_CLK
);
216 tick_rate
= clk_get_rate(omap_dm_timer_get_fclk(gpt
));
217 tick_period
= (tick_rate
/ HZ
) - 1;
219 omap_dm_timer_set_load_start(gpt
, 1, 0);
221 clocksource_gpt
.mult
=
222 clocksource_khz2mult(tick_rate
/1000, clocksource_gpt
.shift
);
223 if (clocksource_register(&clocksource_gpt
))
224 printk(err2
, clocksource_gpt
.name
);
228 static void __init
omap2_gp_timer_init(void)
230 #ifdef CONFIG_LOCAL_TIMERS
231 twd_base
= ioremap(OMAP44XX_LOCAL_TWD_BASE
, SZ_256
);
234 omap_dm_timer_init();
236 omap2_gp_clockevent_init();
237 omap2_gp_clocksource_init();
240 struct sys_timer omap_timer
= {
241 .init
= omap2_gp_timer_init
,