Commit | Line | Data |
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4247417d YY |
1 | /* |
2 | * DEC I/O ASIC's counter clocksource | |
3 | * | |
70342287 | 4 | * Copyright (C) 2008 Yoichi Yuasa <yuasa@linux-mips.org> |
4247417d YY |
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. | |
4247417d YY |
15 | */ |
16 | #include <linux/clocksource.h> | |
7cb24b70 | 17 | #include <linux/sched_clock.h> |
4247417d YY |
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 | ||
8e19608e | 25 | static cycle_t dec_ioasic_hpt_read(struct clocksource *cs) |
4247417d YY |
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 | ||
7cb24b70 DCZ |
37 | static u64 notrace dec_ioasic_read_sched_clock(void) |
38 | { | |
39 | return ioasic_read(IO_REG_FCTR); | |
40 | } | |
41 | ||
daed1285 | 42 | int __init dec_ioasic_clocksource_init(void) |
4247417d YY |
43 | { |
44 | unsigned int freq; | |
45 | u32 start, end; | |
8533966a | 46 | int i = HZ / 8; |
4247417d | 47 | |
8533966a | 48 | ds1287_timer_state(); |
4247417d YY |
49 | while (!ds1287_timer_state()) |
50 | ; | |
51 | ||
8e19608e | 52 | start = dec_ioasic_hpt_read(&clocksource_dec); |
4247417d YY |
53 | |
54 | while (i--) | |
55 | while (!ds1287_timer_state()) | |
56 | ; | |
57 | ||
8e19608e | 58 | end = dec_ioasic_hpt_read(&clocksource_dec); |
4247417d | 59 | |
8533966a | 60 | freq = (end - start) * 8; |
daed1285 MR |
61 | |
62 | /* An early revision of the I/O ASIC didn't have the counter. */ | |
63 | if (!freq) | |
64 | return -ENXIO; | |
65 | ||
4247417d YY |
66 | printk(KERN_INFO "I/O ASIC clock frequency %dHz\n", freq); |
67 | ||
68 | clocksource_dec.rating = 200 + freq / 10000000; | |
75c4fd8c | 69 | clocksource_register_hz(&clocksource_dec, freq); |
7cb24b70 DCZ |
70 | |
71 | sched_clock_register(dec_ioasic_read_sched_clock, 32, freq); | |
72 | ||
daed1285 | 73 | return 0; |
4247417d | 74 | } |