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u-boot/include/timer.h
Simon Glass c95fec3192 timer: Provide an early timer
In some cases the timer must be accessible before driver model is active.
Examples include when using CONFIG_TRACE to trace U-Boot's execution before
driver model is set up. Enable this option to use an early timer. These
functions must be supported by your timer driver: timer_early_get_count()
and timer_early_get_rate().

Signed-off-by: Simon Glass <sjg@chromium.org>
2016-02-26 08:53:10 -07:00

91 lines
2.3 KiB
C

/*
* Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#ifndef _TIMER_H_
#define _TIMER_H_
/*
* dm_timer_init - initialize a timer for time keeping. On success
* initializes gd->timer so that lib/timer can use it for future
* referrence.
*
* @return - 0 on success or error number
*/
int dm_timer_init(void);
/*
* timer_conv_64 - convert 32-bit counter value to 64-bit
*
* @count: 32-bit counter value
* @return: 64-bit counter value
*/
u64 timer_conv_64(u32 count);
/*
* Get the current timer count
*
* @dev: The timer device
* @count: pointer that returns the current timer count
* @return: 0 if OK, -ve on error
*/
int timer_get_count(struct udevice *dev, u64 *count);
/*
* Get the timer input clock frequency
*
* @dev: The timer device
* @return: the timer input clock frequency
*/
unsigned long timer_get_rate(struct udevice *dev);
/*
* struct timer_ops - Driver model timer operations
*
* The uclass interface is implemented by all timer devices which use
* driver model.
*/
struct timer_ops {
/*
* Get the current timer count
*
* @dev: The timer device
* @count: pointer that returns the current 64-bit timer count
* @return: 0 if OK, -ve on error
*/
int (*get_count)(struct udevice *dev, u64 *count);
};
/*
* struct timer_dev_priv - information about a device used by the uclass
*
* @clock_rate: the timer input clock frequency
*/
struct timer_dev_priv {
unsigned long clock_rate;
};
/**
* timer_early_get_count() - Implement timer_get_count() before driver model
*
* If CONFIG_TIMER_EARLY is enabled, this function wil be called to return
* the current timer value before the proper driver model timer is ready.
* It should be implemented by one of the timer values. This is mostly useful
* for tracing.
*/
u64 timer_early_get_count(void);
/**
* timer_early_get_rate() - Get the timer rate before driver model
*
* If CONFIG_TIMER_EARLY is enabled, this function wil be called to return
* the current timer rate in Hz before the proper driver model timer is ready.
* It should be implemented by one of the timer values. This is mostly useful
* for tracing. This corresponds to the clock_rate value in struct
* timer_dev_priv.
*/
unsigned long timer_early_get_rate(void);
#endif /* _TIMER_H_ */