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Release 4.11 arch/mips/vdso/gettimeofday.c

Directory: arch/mips/vdso
/*
 * Copyright (C) 2015 Imagination Technologies
 * Author: Alex Smith <alex.smith@imgtec.com>
 *
 * 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.
 */

#include "vdso.h"

#include <linux/compiler.h>
#include <linux/irqchip/mips-gic.h>
#include <linux/time.h>

#include <asm/clocksource.h>
#include <asm/io.h>
#include <asm/mips-cm.h>
#include <asm/unistd.h>
#include <asm/vdso.h>


static __always_inline int do_realtime_coarse(struct timespec *ts, const union mips_vdso_data *data) { u32 start_seq; do { start_seq = vdso_data_read_begin(data); ts->tv_sec = data->xtime_sec; ts->tv_nsec = data->xtime_nsec >> data->cs_shift; } while (vdso_data_read_retry(data, start_seq)); return 0; }

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static __always_inline int do_monotonic_coarse(struct timespec *ts, const union mips_vdso_data *data) { u32 start_seq; u32 to_mono_sec; u32 to_mono_nsec; do { start_seq = vdso_data_read_begin(data); ts->tv_sec = data->xtime_sec; ts->tv_nsec = data->xtime_nsec >> data->cs_shift; to_mono_sec = data->wall_to_mono_sec; to_mono_nsec = data->wall_to_mono_nsec; } while (vdso_data_read_retry(data, start_seq)); ts->tv_sec += to_mono_sec; timespec_add_ns(ts, to_mono_nsec); return 0; }

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#ifdef CONFIG_CSRC_R4K
static __always_inline u64 read_r4k_count(void) { unsigned int count; __asm__ __volatile__( " .set push\n" " .set mips32r2\n" " rdhwr %0, $2\n" " .set pop\n" : "=r" (count)); return count; }

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#endif #ifdef CONFIG_CLKSRC_MIPS_GIC
static __always_inline u64 read_gic_count(const union mips_vdso_data *data) { void __iomem *gic = get_gic(data); u32 hi, hi2, lo; do { hi = __raw_readl(gic + GIC_UMV_SH_COUNTER_63_32_OFS); lo = __raw_readl(gic + GIC_UMV_SH_COUNTER_31_00_OFS); hi2 = __raw_readl(gic + GIC_UMV_SH_COUNTER_63_32_OFS); } while (hi2 != hi); return (((u64)hi) << 32) + lo; }

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#endif
static __always_inline u64 get_ns(const union mips_vdso_data *data) { u64 cycle_now, delta, nsec; switch (data->clock_mode) { #ifdef CONFIG_CSRC_R4K case VDSO_CLOCK_R4K: cycle_now = read_r4k_count(); break; #endif #ifdef CONFIG_CLKSRC_MIPS_GIC case VDSO_CLOCK_GIC: cycle_now = read_gic_count(data); break; #endif default: return 0; } delta = (cycle_now - data->cs_cycle_last) & data->cs_mask; nsec = (delta * data->cs_mult) + data->xtime_nsec; nsec >>= data->cs_shift; return nsec; }

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static __always_inline int do_realtime(struct timespec *ts, const union mips_vdso_data *data) { u32 start_seq; u64 ns; do { start_seq = vdso_data_read_begin(data); if (data->clock_mode == VDSO_CLOCK_NONE) return -ENOSYS; ts->tv_sec = data->xtime_sec; ns = get_ns(data); } while (vdso_data_read_retry(data, start_seq)); ts->tv_nsec = 0; timespec_add_ns(ts, ns); return 0; }

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static __always_inline int do_monotonic(struct timespec *ts, const union mips_vdso_data *data) { u32 start_seq; u64 ns; u32 to_mono_sec; u32 to_mono_nsec; do { start_seq = vdso_data_read_begin(data); if (data->clock_mode == VDSO_CLOCK_NONE) return -ENOSYS; ts->tv_sec = data->xtime_sec; ns = get_ns(data); to_mono_sec = data->wall_to_mono_sec; to_mono_nsec = data->wall_to_mono_nsec; } while (vdso_data_read_retry(data, start_seq)); ts->tv_sec += to_mono_sec; ts->tv_nsec = 0; timespec_add_ns(ts, ns + to_mono_nsec); return 0; }

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#ifdef CONFIG_MIPS_CLOCK_VSYSCALL /* * This is behind the ifdef so that we don't provide the symbol when there's no * possibility of there being a usable clocksource, because there's nothing we * can do without it. When libc fails the symbol lookup it should fall back on * the standard syscall path. */
int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz) { const union mips_vdso_data *data = get_vdso_data(); struct timespec ts; int ret; ret = do_realtime(&ts, data); if (ret) return ret; if (tv) { tv->tv_sec = ts.tv_sec; tv->tv_usec = ts.tv_nsec / 1000; } if (tz) { tz->tz_minuteswest = data->tz_minuteswest; tz->tz_dsttime = data->tz_dsttime; } return 0; }

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#endif /* CONFIG_CLKSRC_MIPS_GIC */
int __vdso_clock_gettime(clockid_t clkid, struct timespec *ts) { const union mips_vdso_data *data = get_vdso_data(); int ret; switch (clkid) { case CLOCK_REALTIME_COARSE: ret = do_realtime_coarse(ts, data); break; case CLOCK_MONOTONIC_COARSE: ret = do_monotonic_coarse(ts, data); break; case CLOCK_REALTIME: ret = do_realtime(ts, data); break; case CLOCK_MONOTONIC: ret = do_monotonic(ts, data); break; default: ret = -ENOSYS; break; } /* If we return -ENOSYS libc should fall back to a syscall. */ return ret; }

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Directory: arch/mips/vdso
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