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)
40 return error ? -ret : ret;
45 static __always_inline long clock_gettime_fallback(clockid_t _clkid,
48 register struct timespec *ts asm("a1") = _ts;
49 register clockid_t clkid asm("a0") = _clkid;
50 register long ret asm("v0");
51 register long nr asm("v0") = __NR_clock_gettime;
52 register long error asm("a3");
56 : "=r" (ret), "=r" (error)
57 : "r" (clkid), "r" (ts), "r" (nr)
60 return error ? -ret : ret;
63 static __always_inline int do_realtime_coarse(struct timespec *ts,
64 const union mips_vdso_data *data)
69 start_seq = vdso_data_read_begin(data);
71 ts->tv_sec = data->xtime_sec;
72 ts->tv_nsec = data->xtime_nsec >> data->cs_shift;
73 } while (vdso_data_read_retry(data, start_seq));
78 static __always_inline int do_monotonic_coarse(struct timespec *ts,
79 const union mips_vdso_data *data)
86 start_seq = vdso_data_read_begin(data);
88 ts->tv_sec = data->xtime_sec;
89 ts->tv_nsec = data->xtime_nsec >> data->cs_shift;
91 to_mono_sec = data->wall_to_mono_sec;
92 to_mono_nsec = data->wall_to_mono_nsec;
93 } while (vdso_data_read_retry(data, start_seq));
95 ts->tv_sec += to_mono_sec;
96 timespec_add_ns(ts, to_mono_nsec);
101 #ifdef CONFIG_CSRC_R4K
103 static __always_inline u64 read_r4k_count(void)
107 __asm__ __volatile__(
119 #ifdef CONFIG_CLKSRC_MIPS_GIC
121 static __always_inline u64 read_gic_count(const union mips_vdso_data *data)
123 void __iomem *gic = get_gic(data);
127 hi = __raw_readl(gic + GIC_UMV_SH_COUNTER_63_32_OFS);
128 lo = __raw_readl(gic + GIC_UMV_SH_COUNTER_31_00_OFS);
129 hi2 = __raw_readl(gic + GIC_UMV_SH_COUNTER_63_32_OFS);
132 return (((u64)hi) << 32) + lo;
137 static __always_inline u64 get_ns(const union mips_vdso_data *data)
139 u64 cycle_now, delta, nsec;
141 switch (data->clock_mode) {
142 #ifdef CONFIG_CSRC_R4K
144 cycle_now = read_r4k_count();
147 #ifdef CONFIG_CLKSRC_MIPS_GIC
149 cycle_now = read_gic_count(data);
156 delta = (cycle_now - data->cs_cycle_last) & data->cs_mask;
158 nsec = (delta * data->cs_mult) + data->xtime_nsec;
159 nsec >>= data->cs_shift;
164 static __always_inline int do_realtime(struct timespec *ts,
165 const union mips_vdso_data *data)
171 start_seq = vdso_data_read_begin(data);
173 if (data->clock_mode == VDSO_CLOCK_NONE)
176 ts->tv_sec = data->xtime_sec;
178 } while (vdso_data_read_retry(data, start_seq));
181 timespec_add_ns(ts, ns);
186 static __always_inline int do_monotonic(struct timespec *ts,
187 const union mips_vdso_data *data)
195 start_seq = vdso_data_read_begin(data);
197 if (data->clock_mode == VDSO_CLOCK_NONE)
200 ts->tv_sec = data->xtime_sec;
203 to_mono_sec = data->wall_to_mono_sec;
204 to_mono_nsec = data->wall_to_mono_nsec;
205 } while (vdso_data_read_retry(data, start_seq));
207 ts->tv_sec += to_mono_sec;
209 timespec_add_ns(ts, ns + to_mono_nsec);
214 #ifdef CONFIG_MIPS_CLOCK_VSYSCALL
217 * This is behind the ifdef so that we don't provide the symbol when there's no
218 * possibility of there being a usable clocksource, because there's nothing we
219 * can do without it. When libc fails the symbol lookup it should fall back on
220 * the standard syscall path.
222 int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
224 const union mips_vdso_data *data = get_vdso_data();
228 ret = do_realtime(&ts, data);
230 return gettimeofday_fallback(tv, tz);
233 tv->tv_sec = ts.tv_sec;
234 tv->tv_usec = ts.tv_nsec / 1000;
238 tz->tz_minuteswest = data->tz_minuteswest;
239 tz->tz_dsttime = data->tz_dsttime;
245 #endif /* CONFIG_MIPS_CLOCK_VSYSCALL */
247 int __vdso_clock_gettime(clockid_t clkid, struct timespec *ts)
249 const union mips_vdso_data *data = get_vdso_data();
253 case CLOCK_REALTIME_COARSE:
254 ret = do_realtime_coarse(ts, data);
256 case CLOCK_MONOTONIC_COARSE:
257 ret = do_monotonic_coarse(ts, data);
260 ret = do_realtime(ts, data);
262 case CLOCK_MONOTONIC:
263 ret = do_monotonic(ts, data);
270 ret = clock_gettime_fallback(clkid, ts);