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clock: incorporate dummy clocksource into core clock code 

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Antony Pavlov 2014-12-02 03:03:28 +03:00 committed by Sascha Hauer
parent 704f59fe65
commit fbb3be3845
4 changed files with 28 additions and 75 deletions
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20
common/clock.c
View File

@ -22,6 +22,7 @@
*/
#include <common.h>
#include <init.h>
#include <asm-generic/div64.h>
#include <clock.h>
#include <poller.h>
@ -35,6 +36,16 @@ static uint64_t time_ns;
*/
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
*/
@ -44,8 +55,13 @@ uint64_t get_time_ns(void)
uint64_t cycle_now, cycle_delta;
uint64_t ns_offset;
if (!cs)
return 0;
if (!cs) {
static uint64_t dummy_counter;
dummy_counter += CONFIG_CLOCKSOURCE_DUMMY_RATE;
return dummy_counter;
}
/* read clocksource: */
cycle_now = cs->read() & cs->mask;

27
drivers/clocksource/Kconfig
View File

@ -18,28 +18,21 @@ config CLOCKSOURCE_DIGIC
bool
depends on ARCH_DIGIC
config CLOCKSOURCE_DUMMY
bool "Enable dummy software-only clocksource"
config CLOCKSOURCE_DUMMY_RATE
int
prompt "dummy clocksource rate"
default 1000
help
When porting barebox to a new SoC there might be a case
of broken or absent clocksource. This causes barebox serial
console to be non functional.
To solve the problem this software-only clocksource driver is used.
WARNING!!! This clocksource doesn't provide correct timing.
To adjust this clocksource please use CONFIG_CLOCKSOURCE_DUMMY_RATE.
To solve the problem barebox has built-in software-only clocksource.
The software-only clocksource is used only if no hardware clocksource
is registered. This can help if initialization order is wrong so that
the time functions are used before the real clocksource was initialized.
WARNING!!! Built-in software-only clocksource doesn't provide correct timing.
The option CONFIG_CLOCKSOURCE_DUMMY_RATE is used to adjust this clocksource.
The bigger rate valuest makes clocksource "faster".
It's possible to add this clocksource unconditionally.
This clocksource starts very early (pure_initcall) so
real clocksource will take over.
This can help if initialization order is wrong so that
the time functions are used before the real clocksource
was initialized.
config CLOCKSOURCE_DUMMY_RATE
int
prompt "dummy clocksource rate"
depends on CLOCKSOURCE_DUMMY
default 1000
config CLOCKSOURCE_MVEBU
bool

1
drivers/clocksource/Makefile
View File

@ -3,7 +3,6 @@ obj-$(CONFIG_ARM_SMP_TWD) += arm_smp_twd.o
obj-$(CONFIG_CLOCKSOURCE_BCM2835) += bcm2835.o
obj-$(CONFIG_CLOCKSOURCE_CLPS711X) += clps711x.o
obj-$(CONFIG_CLOCKSOURCE_DIGIC) += digic.o
obj-$(CONFIG_CLOCKSOURCE_DUMMY) += dummy.o
obj-$(CONFIG_CLOCKSOURCE_MVEBU) += mvebu.o
obj-$(CONFIG_CLOCKSOURCE_NOMADIK) += nomadik.o
obj-$(CONFIG_CLOCKSOURCE_ORION) += orion.o

55
drivers/clocksource/dummy.c
View File

@ -1,55 +0,0 @@
/*
* Copyright (C) 2013 Antony Pavlov <antonynpavlov@gmail.com>
*
* This file is part of barebox.
* 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 <clock.h>
static uint64_t dummy_counter;
static uint64_t dummy_cs_read(void)
{
static int first;
if (!first) {
pr_warn("Warning: Using dummy clocksource\n");
first = 1;
}
dummy_counter += CONFIG_CLOCKSOURCE_DUMMY_RATE;
return dummy_counter;
}
static struct clocksource dummy_cs = {
.read = dummy_cs_read,
.mask = CLOCKSOURCE_MASK(32),
};
static int clocksource_init(void)
{
dummy_counter = 0;
clocks_calc_mult_shift(&dummy_cs.mult, &dummy_cs.shift,
100000000, NSEC_PER_SEC, 10);
pr_debug("clocksource_init: mult=%08x, shift=%08x\n",
dummy_cs.mult, dummy_cs.shift);
return init_clock(&dummy_cs);
}
pure_initcall(clocksource_init);