arch/powerpc/include/asm/time.h

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Common time prototypes and such for all ppc machines.
 *
 * Written by Cort Dougan (cort@cs.nmt.edu) to merge
 * Paul Mackerras' version and mine for PReP and Pmac.
 */

#ifndef __POWERPC_TIME_H
#define __POWERPC_TIME_H

#ifdef __KERNEL__
#include <linux/types.h>
#include <linux/percpu.h>

#include <asm/processor.h>
#include <asm/cpu_has_feature.h>
#include <asm/vdso/timebase.h>

/* time.c */
extern unsigned long tb_ticks_per_jiffy;
extern unsigned long tb_ticks_per_usec;
extern unsigned long tb_ticks_per_sec;
extern struct clock_event_device decrementer_clockevent;


extern void generic_calibrate_decr(void);

/* Some sane defaults: 125 MHz timebase, 1GHz processor */
extern unsigned long ppc_proc_freq;
#define DEFAULT_PROC_FREQ	(DEFAULT_TB_FREQ * 8)
extern unsigned long ppc_tb_freq;
#define DEFAULT_TB_FREQ		125000000UL

extern bool tb_invalid;

struct div_result {
	u64 result_high;
	u64 result_low;
};

static inline u64 get_vtb(void)
{
	if (cpu_has_feature(CPU_FTR_ARCH_207S))
		return mfspr(SPRN_VTB);

	return 0;
}

/* Accessor functions for the decrementer register.
 * The 4xx doesn't even have a decrementer.  I tried to use the
 * generic timer interrupt code, which seems OK, with the 4xx PIT
 * in auto-reload mode.  The problem is PIT stops counting when it
 * hits zero.  If it would wrap, we could use it just like a decrementer.
 */
static inline u64 get_dec(void)
{
	if (IS_ENABLED(CONFIG_40x))
		return mfspr(SPRN_PIT);

	return mfspr(SPRN_DEC);
}

/*
 * Note: Book E and 4xx processors differ from other PowerPC processors
 * in when the decrementer generates its interrupt: on the 1 to 0
 * transition for Book E/4xx, but on the 0 to -1 transition for others.
 */
static inline void set_dec(u64 val)
{
	if (IS_ENABLED(CONFIG_40x))
		mtspr(SPRN_PIT, (u32)val);
	else if (IS_ENABLED(CONFIG_BOOKE))
		mtspr(SPRN_DEC, val);
	else
		mtspr(SPRN_DEC, val - 1);
}

static inline unsigned long tb_ticks_since(unsigned long tstamp)
{
	return mftb() - tstamp;
}

#define mulhwu(x,y) \
({unsigned z; asm ("mulhwu %0,%1,%2" : "=r" (z) : "r" (x), "r" (y)); z;})

#ifdef CONFIG_PPC64
#define mulhdu(x,y) \
({unsigned long z; asm ("mulhdu %0,%1,%2" : "=r" (z) : "r" (x), "r" (y)); z;})
#else
extern u64 mulhdu(u64, u64);
#endif

extern void div128_by_32(u64 dividend_high, u64 dividend_low,
			 unsigned divisor, struct div_result *dr);

extern void secondary_cpu_time_init(void);
extern void __init time_init(void);

DECLARE_PER_CPU(u64, decrementers_next_tb);

/* Convert timebase ticks to nanoseconds */
unsigned long long tb_to_ns(unsigned long long tb_ticks);

/* SPLPAR */
void accumulate_stolen_time(void);

#endif /* __KERNEL__ */
#endif /* __POWERPC_TIME_H */