Yoichi Yuasa | 4247417 | 2008-04-24 09:48:40 +0900 | [diff] [blame] | 1 | /* |
| 2 | * DEC I/O ASIC's counter clocksource |
| 3 | * |
Ralf Baechle | 7034228 | 2013-01-22 12:59:30 +0100 | [diff] [blame] | 4 | * Copyright (C) 2008 Yoichi Yuasa <yuasa@linux-mips.org> |
Yoichi Yuasa | 4247417 | 2008-04-24 09:48:40 +0900 | [diff] [blame] | 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 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. |
Yoichi Yuasa | 4247417 | 2008-04-24 09:48:40 +0900 | [diff] [blame] | 15 | */ |
| 16 | #include <linux/clocksource.h> |
Deng-Cheng Zhu | 7cb24b7 | 2015-03-07 10:30:28 -0800 | [diff] [blame] | 17 | #include <linux/sched_clock.h> |
Yoichi Yuasa | 4247417 | 2008-04-24 09:48:40 +0900 | [diff] [blame] | 18 | #include <linux/init.h> |
| 19 | |
| 20 | #include <asm/ds1287.h> |
| 21 | #include <asm/time.h> |
| 22 | #include <asm/dec/ioasic.h> |
| 23 | #include <asm/dec/ioasic_addrs.h> |
| 24 | |
Magnus Damm | 8e19608 | 2009-04-21 12:24:00 -0700 | [diff] [blame] | 25 | static cycle_t dec_ioasic_hpt_read(struct clocksource *cs) |
Yoichi Yuasa | 4247417 | 2008-04-24 09:48:40 +0900 | [diff] [blame] | 26 | { |
| 27 | return ioasic_read(IO_REG_FCTR); |
| 28 | } |
| 29 | |
| 30 | static struct clocksource clocksource_dec = { |
| 31 | .name = "dec-ioasic", |
| 32 | .read = dec_ioasic_hpt_read, |
| 33 | .mask = CLOCKSOURCE_MASK(32), |
| 34 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
| 35 | }; |
| 36 | |
Deng-Cheng Zhu | 7cb24b7 | 2015-03-07 10:30:28 -0800 | [diff] [blame] | 37 | static u64 notrace dec_ioasic_read_sched_clock(void) |
| 38 | { |
| 39 | return ioasic_read(IO_REG_FCTR); |
| 40 | } |
| 41 | |
Maciej W. Rozycki | daed128 | 2013-09-12 12:01:53 +0100 | [diff] [blame] | 42 | int __init dec_ioasic_clocksource_init(void) |
Yoichi Yuasa | 4247417 | 2008-04-24 09:48:40 +0900 | [diff] [blame] | 43 | { |
| 44 | unsigned int freq; |
| 45 | u32 start, end; |
Maciej W. Rozycki | 8533966 | 2013-09-04 23:47:45 +0100 | [diff] [blame] | 46 | int i = HZ / 8; |
Yoichi Yuasa | 4247417 | 2008-04-24 09:48:40 +0900 | [diff] [blame] | 47 | |
Maciej W. Rozycki | 8533966 | 2013-09-04 23:47:45 +0100 | [diff] [blame] | 48 | ds1287_timer_state(); |
Yoichi Yuasa | 4247417 | 2008-04-24 09:48:40 +0900 | [diff] [blame] | 49 | while (!ds1287_timer_state()) |
| 50 | ; |
| 51 | |
Magnus Damm | 8e19608 | 2009-04-21 12:24:00 -0700 | [diff] [blame] | 52 | start = dec_ioasic_hpt_read(&clocksource_dec); |
Yoichi Yuasa | 4247417 | 2008-04-24 09:48:40 +0900 | [diff] [blame] | 53 | |
| 54 | while (i--) |
| 55 | while (!ds1287_timer_state()) |
| 56 | ; |
| 57 | |
Magnus Damm | 8e19608 | 2009-04-21 12:24:00 -0700 | [diff] [blame] | 58 | end = dec_ioasic_hpt_read(&clocksource_dec); |
Yoichi Yuasa | 4247417 | 2008-04-24 09:48:40 +0900 | [diff] [blame] | 59 | |
Maciej W. Rozycki | 8533966 | 2013-09-04 23:47:45 +0100 | [diff] [blame] | 60 | freq = (end - start) * 8; |
Maciej W. Rozycki | daed128 | 2013-09-12 12:01:53 +0100 | [diff] [blame] | 61 | |
| 62 | /* An early revision of the I/O ASIC didn't have the counter. */ |
| 63 | if (!freq) |
| 64 | return -ENXIO; |
| 65 | |
Yoichi Yuasa | 4247417 | 2008-04-24 09:48:40 +0900 | [diff] [blame] | 66 | printk(KERN_INFO "I/O ASIC clock frequency %dHz\n", freq); |
| 67 | |
| 68 | clocksource_dec.rating = 200 + freq / 10000000; |
John Stultz | 75c4fd8 | 2010-04-26 20:23:11 -0700 | [diff] [blame] | 69 | clocksource_register_hz(&clocksource_dec, freq); |
Deng-Cheng Zhu | 7cb24b7 | 2015-03-07 10:30:28 -0800 | [diff] [blame] | 70 | |
| 71 | sched_clock_register(dec_ioasic_read_sched_clock, 32, freq); |
| 72 | |
Maciej W. Rozycki | daed128 | 2013-09-12 12:01:53 +0100 | [diff] [blame] | 73 | return 0; |
Yoichi Yuasa | 4247417 | 2008-04-24 09:48:40 +0900 | [diff] [blame] | 74 | } |