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Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
90 lines
1.9 KiB
C
90 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Support code for virtual Ranchu board for MIPS.
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*
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* Author: Miodrag Dinic <miodrag.dinic@mips.com>
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*/
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#include <linux/of_address.h>
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#include <linux/types.h>
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#include <asm/machine.h>
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#include <asm/mipsregs.h>
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#include <asm/time.h>
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#define GOLDFISH_TIMER_LOW 0x00
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#define GOLDFISH_TIMER_HIGH 0x04
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static __init u64 read_rtc_time(void __iomem *base)
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{
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u32 time_low;
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u32 time_high;
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/*
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* Reading the low address latches the high value
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* as well so there is no fear that we may read
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* inaccurate high value.
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*/
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time_low = readl(base + GOLDFISH_TIMER_LOW);
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time_high = readl(base + GOLDFISH_TIMER_HIGH);
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return ((u64)time_high << 32) | time_low;
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}
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static __init unsigned int ranchu_measure_hpt_freq(void)
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{
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u64 rtc_start, rtc_current, rtc_delta;
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unsigned int start, count;
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struct device_node *np;
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void __iomem *rtc_base;
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np = of_find_compatible_node(NULL, NULL, "google,goldfish-rtc");
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if (!np)
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panic("%s(): Failed to find 'google,goldfish-rtc' dt node!",
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__func__);
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rtc_base = of_iomap(np, 0);
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if (!rtc_base)
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panic("%s(): Failed to ioremap Goldfish RTC base!", __func__);
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/*
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* Poll the nanosecond resolution RTC for one
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* second to calibrate the CPU frequency.
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*/
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rtc_start = read_rtc_time(rtc_base);
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start = read_c0_count();
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do {
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rtc_current = read_rtc_time(rtc_base);
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rtc_delta = rtc_current - rtc_start;
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} while (rtc_delta < NSEC_PER_SEC);
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count = read_c0_count() - start;
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/*
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* Make sure the frequency will be a round number.
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* Without this correction, the returned value may vary
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* between subsequent emulation executions.
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*
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* TODO: Set this value using device tree.
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*/
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count += 5000;
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count -= count % 10000;
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iounmap(rtc_base);
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return count;
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}
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static const struct of_device_id ranchu_of_match[] __initconst = {
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{
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.compatible = "mti,ranchu",
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},
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{}
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};
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MIPS_MACHINE(ranchu) = {
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.matches = ranchu_of_match,
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.measure_hpt_freq = ranchu_measure_hpt_freq,
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};
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