u-boot/drivers/timer/arm_twd_timer.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2017-2022 Weidmüller Interface GmbH & Co. KG
* Stefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com>
*
* Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
* Copyright (C) 2011-2017 Xilinx, Inc. All rights reserved.
*
* (C) Copyright 2008
* Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
*
* (C) Copyright 2004
* Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
*
* (C) Copyright 2002-2004
* Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
*
* (C) Copyright 2003
* Texas Instruments <www.ti.com>
*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Marius Groeger <mgroeger@sysgo.de>
*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Alex Zuepke <azu@sysgo.de>
*/
#include <common.h>
#include <dm.h>
#include <fdtdec.h>
#include <timer.h>
#include <linux/bitops.h>
#include <asm/io.h>
#define SCUTIMER_CONTROL_PRESCALER_MASK 0x0000FF00 /* Prescaler */
#define SCUTIMER_CONTROL_AUTO_RELOAD_MASK 0x00000002 /* Auto-reload */
#define SCUTIMER_CONTROL_ENABLE_MASK 0x00000001 /* Timer enable */
#define TIMER_LOAD_VAL 0xFFFFFFFF
struct arm_twd_timer_regs {
u32 load; /* Timer Load Register */
u32 counter; /* Timer Counter Register */
u32 control; /* Timer Control Register */
};
struct arm_twd_timer_priv {
struct arm_twd_timer_regs *base;
};
static u64 arm_twd_timer_get_count(struct udevice *dev)
{
struct arm_twd_timer_priv *priv = dev_get_priv(dev);
struct arm_twd_timer_regs *regs = priv->base;
u32 count = TIMER_LOAD_VAL - readl(&regs->counter);
return timer_conv_64(count);
}
static int arm_twd_timer_probe(struct udevice *dev)
{
struct arm_twd_timer_priv *priv = dev_get_priv(dev);
struct arm_twd_timer_regs *regs;
fdt_addr_t addr;
addr = dev_read_addr(dev);
if (addr == FDT_ADDR_T_NONE)
return -EINVAL;
priv->base = (struct arm_twd_timer_regs *)addr;
regs = priv->base;
/* Load the timer counter register */
writel(0xFFFFFFFF, &regs->load);
/*
* Start the A9Timer device
* Enable Auto reload mode, Clear prescaler control bits
* Set prescaler value, Enable the decrementer
*/
clrsetbits_le32(&regs->control, SCUTIMER_CONTROL_PRESCALER_MASK,
SCUTIMER_CONTROL_AUTO_RELOAD_MASK |
SCUTIMER_CONTROL_ENABLE_MASK);
return 0;
}
static const struct timer_ops arm_twd_timer_ops = {
.get_count = arm_twd_timer_get_count,
};
static const struct udevice_id arm_twd_timer_ids[] = {
{ .compatible = "arm,cortex-a9-twd-timer" },
{}
};
U_BOOT_DRIVER(arm_twd_timer) = {
.name = "arm_twd_timer",
.id = UCLASS_TIMER,
.of_match = arm_twd_timer_ids,
.priv_auto = sizeof(struct arm_twd_timer_priv),
.probe = arm_twd_timer_probe,
.ops = &arm_twd_timer_ops,
};