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c942fddf | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
4247417d YY |
2 | /* |
3 | * DEC I/O ASIC's counter clocksource | |
4 | * | |
70342287 | 5 | * Copyright (C) 2008 Yoichi Yuasa <yuasa@linux-mips.org> |
4247417d YY |
6 | */ |
7 | #include <linux/clocksource.h> | |
7cb24b70 | 8 | #include <linux/sched_clock.h> |
4247417d YY |
9 | #include <linux/init.h> |
10 | ||
11 | #include <asm/ds1287.h> | |
12 | #include <asm/time.h> | |
13 | #include <asm/dec/ioasic.h> | |
14 | #include <asm/dec/ioasic_addrs.h> | |
15 | ||
a5a1d1c2 | 16 | static u64 dec_ioasic_hpt_read(struct clocksource *cs) |
4247417d YY |
17 | { |
18 | return ioasic_read(IO_REG_FCTR); | |
19 | } | |
20 | ||
21 | static struct clocksource clocksource_dec = { | |
22 | .name = "dec-ioasic", | |
23 | .read = dec_ioasic_hpt_read, | |
24 | .mask = CLOCKSOURCE_MASK(32), | |
25 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | |
26 | }; | |
27 | ||
7cb24b70 DZ |
28 | static u64 notrace dec_ioasic_read_sched_clock(void) |
29 | { | |
30 | return ioasic_read(IO_REG_FCTR); | |
31 | } | |
32 | ||
daed1285 | 33 | int __init dec_ioasic_clocksource_init(void) |
4247417d YY |
34 | { |
35 | unsigned int freq; | |
36 | u32 start, end; | |
8533966a | 37 | int i = HZ / 8; |
4247417d | 38 | |
8533966a | 39 | ds1287_timer_state(); |
4247417d YY |
40 | while (!ds1287_timer_state()) |
41 | ; | |
42 | ||
8e19608e | 43 | start = dec_ioasic_hpt_read(&clocksource_dec); |
4247417d YY |
44 | |
45 | while (i--) | |
46 | while (!ds1287_timer_state()) | |
47 | ; | |
48 | ||
8e19608e | 49 | end = dec_ioasic_hpt_read(&clocksource_dec); |
4247417d | 50 | |
8533966a | 51 | freq = (end - start) * 8; |
daed1285 MR |
52 | |
53 | /* An early revision of the I/O ASIC didn't have the counter. */ | |
54 | if (!freq) | |
55 | return -ENXIO; | |
56 | ||
4247417d YY |
57 | printk(KERN_INFO "I/O ASIC clock frequency %dHz\n", freq); |
58 | ||
59 | clocksource_dec.rating = 200 + freq / 10000000; | |
75c4fd8c | 60 | clocksource_register_hz(&clocksource_dec, freq); |
7cb24b70 DZ |
61 | |
62 | sched_clock_register(dec_ioasic_read_sched_clock, 32, freq); | |
63 | ||
daed1285 | 64 | return 0; |
4247417d | 65 | } |