u-boot/drivers/timer/arm_global_timer.c
William Zhang 35751c7f3f timer: sti: convert sti-timer to arm a9 global timer
STI timer is actually ARM Cortex A9 global timer. Convert the driver to
use generic global timer name and make it consistent with Linux kernel
global timer driver. This also allows any A9 based device to use this
driver.

Signed-off-by: William Zhang <william.zhang@broadcom.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Tested-by: Patrice Chotard <patrice.chotard@foss.st.com>
2022-10-31 08:55:59 -04:00

87 lines
2 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2017, STMicroelectronics - All Rights Reserved
* Author(s): Patrice Chotard, <patrice.chotard@foss.st.com> for STMicroelectronics.
*
* ARM Cortext A9 global timer driver
*/
#include <common.h>
#include <dm.h>
#include <clk.h>
#include <timer.h>
#include <linux/err.h>
#include <asm/io.h>
#include <asm/arch-armv7/globaltimer.h>
struct arm_global_timer_priv {
struct globaltimer *global_timer;
};
static u64 arm_global_timer_get_count(struct udevice *dev)
{
struct arm_global_timer_priv *priv = dev_get_priv(dev);
struct globaltimer *global_timer = priv->global_timer;
u32 low, high;
u64 timer;
u32 old = readl(&global_timer->cnt_h);
while (1) {
low = readl(&global_timer->cnt_l);
high = readl(&global_timer->cnt_h);
if (old == high)
break;
else
old = high;
}
timer = high;
return (u64)((timer << 32) | low);
}
static int arm_global_timer_probe(struct udevice *dev)
{
struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
struct arm_global_timer_priv *priv = dev_get_priv(dev);
struct clk clk;
int err;
ulong ret;
/* get arm global timer base address */
priv->global_timer = (struct globaltimer *)dev_read_addr_ptr(dev);
if (!priv->global_timer)
return -ENOENT;
err = clk_get_by_index(dev, 0, &clk);
if (!err) {
ret = clk_get_rate(&clk);
if (IS_ERR_VALUE(ret))
return ret;
uc_priv->clock_rate = ret;
} else {
uc_priv->clock_rate = CONFIG_SYS_HZ_CLOCK;
}
/* init timer */
writel(0x01, &priv->global_timer->ctl);
return 0;
}
static const struct timer_ops arm_global_timer_ops = {
.get_count = arm_global_timer_get_count,
};
static const struct udevice_id arm_global_timer_ids[] = {
{ .compatible = "arm,cortex-a9-global-timer" },
{}
};
U_BOOT_DRIVER(arm_global_timer) = {
.name = "arm_global_timer",
.id = UCLASS_TIMER,
.of_match = arm_global_timer_ids,
.priv_auto = sizeof(struct arm_global_timer_priv),
.probe = arm_global_timer_probe,
.ops = &arm_global_timer_ops,
};