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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2021 Mark Kettenis <kettenis@openbsd.org>
*/
#include <clk.h>
#include <dm.h>
#include <wdt.h>
#include <asm/io.h>
#include <linux/delay.h>
#define APPLE_WDT_CUR_TIME 0x10
#define APPLE_WDT_BARK_TIME 0x14
#define APPLE_WDT_CTRL 0x1c
#define APPLE_WDT_CTRL_RESET_EN BIT(2)
struct apple_wdt_priv {
void *base;
ulong clk_rate;
};
static int apple_wdt_reset(struct udevice *dev)
{
struct apple_wdt_priv *priv = dev_get_priv(dev);
writel(0, priv->base + APPLE_WDT_CUR_TIME);
return 0;
}
static int apple_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
{
struct apple_wdt_priv *priv = dev_get_priv(dev);
u64 timeout;
timeout = (timeout_ms * priv->clk_rate) / 1000;
if (timeout > U32_MAX)
return -EINVAL;
writel(0, priv->base + APPLE_WDT_CUR_TIME);
writel(timeout, priv->base + APPLE_WDT_BARK_TIME);
writel(APPLE_WDT_CTRL_RESET_EN, priv->base + APPLE_WDT_CTRL);
return 0;
}
static int apple_wdt_stop(struct udevice *dev)
{
struct apple_wdt_priv *priv = dev_get_priv(dev);
writel(0, priv->base + APPLE_WDT_CTRL);
return 0;
}
static int apple_wdt_expire_now(struct udevice *dev, ulong flags)
{
int ret;
ret = apple_wdt_start(dev, 0, flags);
if (ret)
return ret;
/*
* It can take up to 25ms until the SoC actually resets, so
* wait 50ms just to be sure.
*/
mdelay(50);
return 0;
}
static const struct wdt_ops apple_wdt_ops = {
.reset = apple_wdt_reset,
.start = apple_wdt_start,
.stop = apple_wdt_stop,
.expire_now = apple_wdt_expire_now,
};
static const struct udevice_id apple_wdt_ids[] = {
{ .compatible = "apple,wdt" },
{ /* sentinel */ }
};
static int apple_wdt_probe(struct udevice *dev)
{
struct apple_wdt_priv *priv = dev_get_priv(dev);
struct clk clk;
int ret;
priv->base = dev_read_addr_ptr(dev);
if (!priv->base)
return -EINVAL;
ret = clk_get_by_index(dev, 0, &clk);
if (ret)
return ret;
ret = clk_enable(&clk);
if (ret)
return ret;
priv->clk_rate = clk_get_rate(&clk);
return 0;
}
U_BOOT_DRIVER(apple_wdt) = {
.name = "apple_wdt",
.id = UCLASS_WDT,
.of_match = apple_wdt_ids,
.priv_auto = sizeof(struct apple_wdt_priv),
.probe = apple_wdt_probe,
.ops = &apple_wdt_ops,
};
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