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65 lines
1.3 KiB
65 lines
1.3 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* DEC I/O ASIC's counter clocksource |
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* |
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* Copyright (C) 2008 Yoichi Yuasa <[email protected]> |
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*/ |
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#include <linux/clocksource.h> |
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#include <linux/sched_clock.h> |
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#include <linux/init.h> |
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#include <asm/ds1287.h> |
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#include <asm/time.h> |
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#include <asm/dec/ioasic.h> |
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#include <asm/dec/ioasic_addrs.h> |
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static u64 dec_ioasic_hpt_read(struct clocksource *cs) |
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{ |
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return ioasic_read(IO_REG_FCTR); |
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} |
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static struct clocksource clocksource_dec = { |
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.name = "dec-ioasic", |
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.read = dec_ioasic_hpt_read, |
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.mask = CLOCKSOURCE_MASK(32), |
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.flags = CLOCK_SOURCE_IS_CONTINUOUS, |
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}; |
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static u64 notrace dec_ioasic_read_sched_clock(void) |
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{ |
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return ioasic_read(IO_REG_FCTR); |
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} |
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int __init dec_ioasic_clocksource_init(void) |
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{ |
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unsigned int freq; |
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u32 start, end; |
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int i = HZ / 8; |
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ds1287_timer_state(); |
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while (!ds1287_timer_state()) |
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; |
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start = dec_ioasic_hpt_read(&clocksource_dec); |
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while (i--) |
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while (!ds1287_timer_state()) |
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; |
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end = dec_ioasic_hpt_read(&clocksource_dec); |
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freq = (end - start) * 8; |
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/* An early revision of the I/O ASIC didn't have the counter. */ |
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if (!freq) |
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return -ENXIO; |
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printk(KERN_INFO "I/O ASIC clock frequency %dHz\n", freq); |
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clocksource_dec.rating = 200 + freq / 10000000; |
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clocksource_register_hz(&clocksource_dec, freq); |
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sched_clock_register(dec_ioasic_read_sched_clock, 32, freq); |
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return 0; |
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}
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