u-boot/drivers/timer/timer-uclass.c
Bin Meng 9ca07ebbac dm: timer: Support 64-bit counter
There are timers with a 64-bit counter value but current timer
uclass driver assumes a 32-bit one. Modify timer_get_count()
to ask timer driver to always return a 64-bit counter value,
and provide an inline helper function timer_conv_64() to handle
the 32-bit/64-bit conversion automatically.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
2015-12-01 06:23:51 -07:00

64 lines
1.5 KiB
C

/*
* Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <timer.h>
DECLARE_GLOBAL_DATA_PTR;
/*
* Implement a timer uclass to work with lib/time.c. The timer is usually
* a 32/64 bits free-running up counter. The get_rate() method is used to get
* the input clock frequency of the timer. The get_count() method is used
* to get the current 64 bits count value. If the hardware is counting down,
* the value should be inversed inside the method. There may be no real
* tick, and no timer interrupt.
*/
int timer_get_count(struct udevice *dev, u64 *count)
{
const struct timer_ops *ops = device_get_ops(dev);
if (!ops->get_count)
return -ENOSYS;
return ops->get_count(dev, count);
}
unsigned long timer_get_rate(struct udevice *dev)
{
struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
return uc_priv->clock_rate;
}
static int timer_pre_probe(struct udevice *dev)
{
struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
uc_priv->clock_rate = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
"clock-frequency", 0);
return 0;
}
u64 timer_conv_64(u32 count)
{
/* increment tbh if tbl has rolled over */
if (count < gd->timebase_l)
gd->timebase_h++;
gd->timebase_l = count;
return ((u64)gd->timebase_h << 32) | gd->timebase_l;
}
UCLASS_DRIVER(timer) = {
.id = UCLASS_TIMER,
.name = "timer",
.pre_probe = timer_pre_probe,
.per_device_auto_alloc_size = sizeof(struct timer_dev_priv),
};