timer-uclass.c
3.12 KB
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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
*/
#include <common.h>
#include <dm.h>
#include <dm/lists.h>
#include <dm/device-internal.h>
#include <dm/root.h>
#include <clk.h>
#include <errno.h>
#include <timer.h>
#include <linux/err.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 notrace 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 notrace timer_get_rate(struct udevice *dev)
{
struct timer_dev_priv *uc_priv = dev->uclass_priv;
return uc_priv->clock_rate;
}
static int timer_pre_probe(struct udevice *dev)
{
#if !CONFIG_IS_ENABLED(OF_PLATDATA)
struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
struct clk timer_clk;
int err;
ulong ret;
/* It is possible that a timer device has a null ofnode */
if (!dev_of_valid(dev))
return 0;
err = clk_get_by_index(dev, 0, &timer_clk);
if (!err) {
ret = clk_get_rate(&timer_clk);
if (IS_ERR_VALUE(ret))
return ret;
uc_priv->clock_rate = ret;
} else {
uc_priv->clock_rate =
dev_read_u32_default(dev, "clock-frequency", 0);
}
#endif
return 0;
}
static int timer_post_probe(struct udevice *dev)
{
struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
if (!uc_priv->clock_rate)
return -EINVAL;
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;
}
int notrace dm_timer_init(void)
{
struct udevice *dev = NULL;
__maybe_unused ofnode node;
int ret;
if (gd->timer)
return 0;
/*
* Directly access gd->dm_root to suppress error messages, if the
* virtual root driver does not yet exist.
*/
if (gd->dm_root == NULL)
return -EAGAIN;
#if !CONFIG_IS_ENABLED(OF_PLATDATA)
/* Check for a chosen timer to be used for tick */
node = ofnode_get_chosen_node("tick-timer");
if (ofnode_valid(node) &&
uclass_get_device_by_ofnode(UCLASS_TIMER, node, &dev)) {
/*
* If the timer is not marked to be bound before
* relocation, bind it anyway.
*/
if (!lists_bind_fdt(dm_root(), node, &dev, false)) {
ret = device_probe(dev);
if (ret)
return ret;
}
}
#endif
if (!dev) {
/* Fall back to the first available timer */
ret = uclass_first_device_err(UCLASS_TIMER, &dev);
if (ret)
return ret;
}
if (dev) {
gd->timer = dev;
return 0;
}
return -ENODEV;
}
UCLASS_DRIVER(timer) = {
.id = UCLASS_TIMER,
.name = "timer",
.pre_probe = timer_pre_probe,
.flags = DM_UC_FLAG_SEQ_ALIAS,
.post_probe = timer_post_probe,
.per_device_auto_alloc_size = sizeof(struct timer_dev_priv),
};