xref: /linux/arch/arm/mach-shmobile/timer.c (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
1 /*
2  * SH-Mobile Timer
3  *
4  * Copyright (C) 2010  Magnus Damm
5  * Copyright (C) 2002 - 2009  Paul Mundt
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; version 2 of the License.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
19  *
20  */
21 #include <linux/platform_device.h>
22 #include <linux/delay.h>
23 #include <asm/mach/time.h>
24 #include <asm/smp_twd.h>
25 
26 void __init shmobile_setup_delay(unsigned int max_cpu_core_mhz,
27 				 unsigned int mult, unsigned int div)
28 {
29 	/* calculate a worst-case loops-per-jiffy value
30 	 * based on maximum cpu core mhz setting and the
31 	 * __delay() implementation in arch/arm/lib/delay.S
32 	 *
33 	 * this will result in a longer delay than expected
34 	 * when the cpu core runs on lower frequencies.
35 	 */
36 
37 	unsigned int value = (1000000 * mult) / (HZ * div);
38 
39 	if (!preset_lpj)
40 		preset_lpj = max_cpu_core_mhz * value;
41 }
42 
43 static void __init shmobile_late_time_init(void)
44 {
45 	/*
46 	 * Make sure all compiled-in early timers register themselves.
47 	 *
48 	 * Run probe() for two "earlytimer" devices, these will be the
49 	 * clockevents and clocksource devices respectively. In the event
50 	 * that only a clockevents device is available, we -ENODEV on the
51 	 * clocksource and the jiffies clocksource is used transparently
52 	 * instead. No error handling is necessary here.
53 	 */
54 	early_platform_driver_register_all("earlytimer");
55 	early_platform_driver_probe("earlytimer", 2, 0);
56 }
57 
58 void __init shmobile_earlytimer_init(void)
59 {
60 	late_time_init = shmobile_late_time_init;
61 }
62 
63 static void __init shmobile_timer_init(void)
64 {
65 }
66 
67 struct sys_timer shmobile_timer = {
68 	.init		= shmobile_timer_init,
69 };
70