1b2441318SGreg Kroah-Hartman /* SPDX-License-Identifier: GPL-2.0 */ 21965aae3SH. Peter Anvin #ifndef _ASM_X86_TIMER_H 31965aae3SH. Peter Anvin #define _ASM_X86_TIMER_H 4bb898558SAl Viro #include <linux/pm.h> 5bb898558SAl Viro #include <linux/percpu.h> 68e6dafd6SIngo Molnar #include <linux/interrupt.h> 75dd12c21SPeter Zijlstra #include <linux/math64.h> 8bb898558SAl Viro 9bb898558SAl Viro #define TICK_SIZE (tick_nsec / 1000) 10bb898558SAl Viro 11bb898558SAl Viro unsigned long long native_sched_clock(void); 1225c1a411SStephen Rothwell extern void recalibrate_cpu_khz(void); 13bb898558SAl Viro 14bb898558SAl Viro extern int no_timer_check; 15bb898558SAl Viro 16698eff63SPeter Zijlstra extern bool using_native_sched_clock(void); 17698eff63SPeter Zijlstra 1820d1c86aSPeter Zijlstra /* 1920d1c86aSPeter Zijlstra * We use the full linear equation: f(x) = a + b*x, in order to allow 2020d1c86aSPeter Zijlstra * a continuous function in the face of dynamic freq changes. 2120d1c86aSPeter Zijlstra * 2220d1c86aSPeter Zijlstra * Continuity means that when our frequency changes our slope (b); we want to 2320d1c86aSPeter Zijlstra * ensure that: f(t) == f'(t), which gives: a + b*t == a' + b'*t. 2420d1c86aSPeter Zijlstra * 2520d1c86aSPeter Zijlstra * Without an offset (a) the above would not be possible. 2620d1c86aSPeter Zijlstra * 2720d1c86aSPeter Zijlstra * See the comment near cycles_2_ns() for details on how we compute (b). 2820d1c86aSPeter Zijlstra */ 2920d1c86aSPeter Zijlstra struct cyc2ns_data { 3020d1c86aSPeter Zijlstra u32 cyc2ns_mul; 3120d1c86aSPeter Zijlstra u32 cyc2ns_shift; 3220d1c86aSPeter Zijlstra u64 cyc2ns_offset; 3359eaef78SPeter Zijlstra }; /* 16 bytes */ 3420d1c86aSPeter Zijlstra 3559eaef78SPeter Zijlstra extern void cyc2ns_read_begin(struct cyc2ns_data *); 3659eaef78SPeter Zijlstra extern void cyc2ns_read_end(void); 37bb898558SAl Viro 381965aae3SH. Peter Anvin #endif /* _ASM_X86_TIMER_H */ 39