2 * Copyright (C) 2015 Imagination Technologies
3 * Author: Alex Smith <alex.smith@imgtec.com>
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version.
13 #include <linux/compiler.h>
14 #include <linux/irqchip/mips-gic.h>
15 #include <linux/time.h>
17 #include <asm/clocksource.h>
19 #include <asm/mips-cm.h>
20 #include <asm/unistd.h>
23 #ifdef CONFIG_MIPS_CLOCK_VSYSCALL
25 static __always_inline long gettimeofday_fallback(struct timeval *_tv,
28 register struct timezone *tz asm("a1") = _tz;
29 register struct timeval *tv asm("a0") = _tv;
30 register long ret asm("v0");
31 register long nr asm("v0") = __NR_gettimeofday;
32 register long error asm("a3");
36 : "=r" (ret), "=r" (error)
37 : "r" (tv), "r" (tz), "r" (nr)
38 : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
39 "$14", "$15", "$24", "$25", "hi", "lo", "memory");
41 return error ? -ret : ret;
46 static __always_inline long clock_gettime_fallback(clockid_t _clkid,
49 register struct timespec *ts asm("a1") = _ts;
50 register clockid_t clkid asm("a0") = _clkid;
51 register long ret asm("v0");
52 register long nr asm("v0") = __NR_clock_gettime;
53 register long error asm("a3");
57 : "=r" (ret), "=r" (error)
58 : "r" (clkid), "r" (ts), "r" (nr)
59 : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
60 "$14", "$15", "$24", "$25", "hi", "lo", "memory");
62 return error ? -ret : ret;
65 static __always_inline int do_realtime_coarse(struct timespec *ts,
66 const union mips_vdso_data *data)
71 start_seq = vdso_data_read_begin(data);
73 ts->tv_sec = data->xtime_sec;
74 ts->tv_nsec = data->xtime_nsec >> data->cs_shift;
75 } while (vdso_data_read_retry(data, start_seq));
80 static __always_inline int do_monotonic_coarse(struct timespec *ts,
81 const union mips_vdso_data *data)
88 start_seq = vdso_data_read_begin(data);
90 ts->tv_sec = data->xtime_sec;
91 ts->tv_nsec = data->xtime_nsec >> data->cs_shift;
93 to_mono_sec = data->wall_to_mono_sec;
94 to_mono_nsec = data->wall_to_mono_nsec;
95 } while (vdso_data_read_retry(data, start_seq));
97 ts->tv_sec += to_mono_sec;
98 timespec_add_ns(ts, to_mono_nsec);
103 #ifdef CONFIG_CSRC_R4K
105 static __always_inline u64 read_r4k_count(void)
109 __asm__ __volatile__(
121 #ifdef CONFIG_CLKSRC_MIPS_GIC
123 static __always_inline u64 read_gic_count(const union mips_vdso_data *data)
125 void __iomem *gic = get_gic(data);
129 hi = __raw_readl(gic + GIC_UMV_SH_COUNTER_63_32_OFS);
130 lo = __raw_readl(gic + GIC_UMV_SH_COUNTER_31_00_OFS);
131 hi2 = __raw_readl(gic + GIC_UMV_SH_COUNTER_63_32_OFS);
134 return (((u64)hi) << 32) + lo;
139 static __always_inline u64 get_ns(const union mips_vdso_data *data)
141 u64 cycle_now, delta, nsec;
143 switch (data->clock_mode) {
144 #ifdef CONFIG_CSRC_R4K
146 cycle_now = read_r4k_count();
149 #ifdef CONFIG_CLKSRC_MIPS_GIC
151 cycle_now = read_gic_count(data);
158 delta = (cycle_now - data->cs_cycle_last) & data->cs_mask;
160 nsec = (delta * data->cs_mult) + data->xtime_nsec;
161 nsec >>= data->cs_shift;
166 static __always_inline int do_realtime(struct timespec *ts,
167 const union mips_vdso_data *data)
173 start_seq = vdso_data_read_begin(data);
175 if (data->clock_mode == VDSO_CLOCK_NONE)
178 ts->tv_sec = data->xtime_sec;
180 } while (vdso_data_read_retry(data, start_seq));
183 timespec_add_ns(ts, ns);
188 static __always_inline int do_monotonic(struct timespec *ts,
189 const union mips_vdso_data *data)
197 start_seq = vdso_data_read_begin(data);
199 if (data->clock_mode == VDSO_CLOCK_NONE)
202 ts->tv_sec = data->xtime_sec;
205 to_mono_sec = data->wall_to_mono_sec;
206 to_mono_nsec = data->wall_to_mono_nsec;
207 } while (vdso_data_read_retry(data, start_seq));
209 ts->tv_sec += to_mono_sec;
211 timespec_add_ns(ts, ns + to_mono_nsec);
216 #ifdef CONFIG_MIPS_CLOCK_VSYSCALL
219 * This is behind the ifdef so that we don't provide the symbol when there's no
220 * possibility of there being a usable clocksource, because there's nothing we
221 * can do without it. When libc fails the symbol lookup it should fall back on
222 * the standard syscall path.
224 int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
226 const union mips_vdso_data *data = get_vdso_data();
230 ret = do_realtime(&ts, data);
232 return gettimeofday_fallback(tv, tz);
235 tv->tv_sec = ts.tv_sec;
236 tv->tv_usec = ts.tv_nsec / 1000;
240 tz->tz_minuteswest = data->tz_minuteswest;
241 tz->tz_dsttime = data->tz_dsttime;
247 #endif /* CONFIG_MIPS_CLOCK_VSYSCALL */
249 int __vdso_clock_gettime(clockid_t clkid, struct timespec *ts)
251 const union mips_vdso_data *data = get_vdso_data();
255 case CLOCK_REALTIME_COARSE:
256 ret = do_realtime_coarse(ts, data);
258 case CLOCK_MONOTONIC_COARSE:
259 ret = do_monotonic_coarse(ts, data);
262 ret = do_realtime(ts, data);
264 case CLOCK_MONOTONIC:
265 ret = do_monotonic(ts, data);
272 ret = clock_gettime_fallback(clkid, ts);