Signed-off-by: Peter Mamonov <pmamonov@gmail.com> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
221 lines
5.4 KiB
C
221 lines
5.4 KiB
C
/*
|
|
* clock.c - generic clocksource implementation
|
|
*
|
|
* This file contains the clocksource implementation from the Linux
|
|
* kernel originally by John Stultz
|
|
*
|
|
* Copyright (C) 2004, 2005 IBM, John Stultz (johnstul@us.ibm.com)
|
|
* Copyright (c) 2007 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
|
|
*
|
|
* See file CREDITS for list of people who contributed to this
|
|
* project.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2
|
|
* as published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
*/
|
|
|
|
#include <common.h>
|
|
#include <init.h>
|
|
#include <asm-generic/div64.h>
|
|
#include <clock.h>
|
|
#include <poller.h>
|
|
|
|
static struct clocksource *current_clock;
|
|
static uint64_t time_ns;
|
|
|
|
/*
|
|
* The first timestamp when the clocksource is registered.
|
|
* Useful for measuring the time spent in barebox.
|
|
*/
|
|
uint64_t time_beginning;
|
|
|
|
static int dummy_csrc_warn(void)
|
|
{
|
|
if (!current_clock) {
|
|
pr_warn("Warning: Using dummy clocksource\n");
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
late_initcall(dummy_csrc_warn);
|
|
|
|
/**
|
|
* get_time_ns - get current timestamp in nanoseconds
|
|
*/
|
|
uint64_t get_time_ns(void)
|
|
{
|
|
struct clocksource *cs = current_clock;
|
|
uint64_t cycle_now, cycle_delta;
|
|
uint64_t ns_offset;
|
|
|
|
if (!cs) {
|
|
static uint64_t dummy_counter;
|
|
|
|
dummy_counter += CONFIG_CLOCKSOURCE_DUMMY_RATE;
|
|
|
|
return dummy_counter;
|
|
}
|
|
|
|
/* read clocksource: */
|
|
cycle_now = cs->read() & cs->mask;
|
|
|
|
/* calculate the delta since the last call: */
|
|
cycle_delta = (cycle_now - cs->cycle_last) & cs->mask;
|
|
|
|
/* convert to nanoseconds: */
|
|
ns_offset = cyc2ns(cs, cycle_delta);
|
|
|
|
cs->cycle_last = cycle_now;
|
|
|
|
time_ns += ns_offset;
|
|
return time_ns;
|
|
}
|
|
EXPORT_SYMBOL(get_time_ns);
|
|
|
|
/**
|
|
* clocks_calc_mult_shift - calculate mult/shift factors for scaled math of clocks
|
|
* @mult: pointer to mult variable
|
|
* @shift: pointer to shift variable
|
|
* @from: frequency to convert from
|
|
* @to: frequency to convert to
|
|
* @maxsec: guaranteed runtime conversion range in seconds
|
|
*
|
|
* The function evaluates the shift/mult pair for the scaled math
|
|
* operations of clocksources and clockevents.
|
|
*
|
|
* @to and @from are frequency values in HZ. For clock sources @to is
|
|
* NSEC_PER_SEC == 1GHz and @from is the counter frequency. For clock
|
|
* event @to is the counter frequency and @from is NSEC_PER_SEC.
|
|
*
|
|
* The @maxsec conversion range argument controls the time frame in
|
|
* seconds which must be covered by the runtime conversion with the
|
|
* calculated mult and shift factors. This guarantees that no 64bit
|
|
* overflow happens when the input value of the conversion is
|
|
* multiplied with the calculated mult factor. Larger ranges may
|
|
* reduce the conversion accuracy by chosing smaller mult and shift
|
|
* factors.
|
|
*/
|
|
|
|
void clocks_calc_mult_shift(uint32_t *mult, uint32_t *shift, uint32_t from, uint32_t to, uint32_t maxsec)
|
|
{
|
|
uint64_t tmp;
|
|
uint32_t sft, sftacc = 32;
|
|
|
|
/*
|
|
* Calculate the shift factor which is limiting the conversion
|
|
* range:
|
|
*/
|
|
tmp = ((uint64_t)maxsec * from) >> 32;
|
|
while (tmp) {
|
|
tmp >>= 1;
|
|
sftacc--;
|
|
}
|
|
|
|
/*
|
|
* Find the conversion shift/mult pair which has the best
|
|
* accuracy and fits the maxsec conversion range:
|
|
*/
|
|
for (sft = 32; sft > 0; sft--) {
|
|
tmp = (uint64_t) to << sft;
|
|
tmp += from / 2;
|
|
do_div(tmp, from);
|
|
if ((tmp >> sftacc) == 0)
|
|
break;
|
|
}
|
|
*mult = tmp;
|
|
*shift = sft;
|
|
}
|
|
|
|
|
|
/**
|
|
* clocksource_hz2mult - calculates mult from hz and shift
|
|
* @hz: Clocksource frequency in Hz
|
|
* @shift_constant: Clocksource shift factor
|
|
*
|
|
* Helper functions that converts a hz counter
|
|
* frequency to a timsource multiplier, given the
|
|
* clocksource shift value
|
|
*/
|
|
uint32_t clocksource_hz2mult(uint32_t hz, uint32_t shift_constant)
|
|
{
|
|
/* hz = cyc/(Billion ns)
|
|
* mult/2^shift = ns/cyc
|
|
* mult = ns/cyc * 2^shift
|
|
* mult = 1Billion/hz * 2^shift
|
|
* mult = 1000000000 * 2^shift / hz
|
|
* mult = (1000000000<<shift) / hz
|
|
*/
|
|
uint64_t tmp = ((uint64_t)1000000000) << shift_constant;
|
|
|
|
tmp += hz/2; /* round for do_div */
|
|
do_div(tmp, hz);
|
|
|
|
return (uint32_t)tmp;
|
|
}
|
|
|
|
int is_timeout_non_interruptible(uint64_t start_ns, uint64_t time_offset_ns)
|
|
{
|
|
if ((int64_t)(start_ns + time_offset_ns - get_time_ns()) < 0)
|
|
return 1;
|
|
else
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(is_timeout_non_interruptible);
|
|
|
|
int is_timeout(uint64_t start_ns, uint64_t time_offset_ns)
|
|
{
|
|
if (time_offset_ns >= 100 * USECOND)
|
|
poller_call();
|
|
|
|
return is_timeout_non_interruptible(start_ns, time_offset_ns);
|
|
}
|
|
EXPORT_SYMBOL(is_timeout);
|
|
|
|
void ndelay(unsigned long nsecs)
|
|
{
|
|
uint64_t start = get_time_ns();
|
|
|
|
while(!is_timeout_non_interruptible(start, nsecs));
|
|
}
|
|
EXPORT_SYMBOL(ndelay);
|
|
|
|
void udelay(unsigned long usecs)
|
|
{
|
|
uint64_t start = get_time_ns();
|
|
|
|
while(!is_timeout(start, usecs * USECOND));
|
|
}
|
|
EXPORT_SYMBOL(udelay);
|
|
|
|
void mdelay(unsigned long msecs)
|
|
{
|
|
uint64_t start = get_time_ns();
|
|
|
|
while(!is_timeout(start, msecs * MSECOND));
|
|
}
|
|
EXPORT_SYMBOL(mdelay);
|
|
|
|
void mdelay_non_interruptible(unsigned long msecs)
|
|
{
|
|
uint64_t start = get_time_ns();
|
|
|
|
while (!is_timeout_non_interruptible(start, msecs * MSECOND))
|
|
;
|
|
}
|
|
EXPORT_SYMBOL(mdelay_non_interruptible);
|
|
|
|
int init_clock(struct clocksource *cs)
|
|
{
|
|
current_clock = cs;
|
|
time_beginning = get_time_ns();
|
|
|
|
return 0;
|
|
}
|