u-boot/drivers/watchdog/ast2600_wdt.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (c) 2020 Aspeed Technology, Inc
 */

#include <common.h>
#include <dm.h>
#include <errno.h>
#include <log.h>
#include <wdt.h>
#include <asm/io.h>
#include <asm/arch/wdt_ast2600.h>
#include <linux/err.h>

struct ast2600_wdt_priv {
	struct ast2600_wdt *regs;
};

static int ast2600_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
{
	struct ast2600_wdt_priv *priv = dev_get_priv(dev);
	struct ast2600_wdt *wdt = priv->regs;

	/* WDT counts in the 1MHz frequency, namely 1us */
	writel((u32)(timeout_ms * 1000), &wdt->counter_reload_val);
	writel(WDT_COUNTER_RESTART_VAL, &wdt->counter_restart);
	writel(WDT_CTRL_EN | WDT_CTRL_RESET, &wdt->ctrl);

	return 0;
}

static int ast2600_wdt_stop(struct udevice *dev)
{
	struct ast2600_wdt_priv *priv = dev_get_priv(dev);
	struct ast2600_wdt *wdt = priv->regs;

	clrbits_le32(&wdt->ctrl, WDT_CTRL_EN);

	writel(WDT_RESET_MASK1_DEFAULT, &wdt->reset_mask1);
	writel(WDT_RESET_MASK2_DEFAULT, &wdt->reset_mask2);

	return 0;
}

static int ast2600_wdt_reset(struct udevice *dev)
{
	struct ast2600_wdt_priv *priv = dev_get_priv(dev);
	struct ast2600_wdt *wdt = priv->regs;

	writel(WDT_COUNTER_RESTART_VAL, &wdt->counter_restart);

	return 0;
}

static int ast2600_wdt_expire_now(struct udevice *dev, ulong flags)
{
	int ret;
	struct ast2600_wdt_priv *priv = dev_get_priv(dev);
	struct ast2600_wdt *wdt = priv->regs;

	ret = ast2600_wdt_start(dev, 1, flags);
	if (ret)
		return ret;

	while (readl(&wdt->ctrl) & WDT_CTRL_EN)
		;

	return ast2600_wdt_stop(dev);
}

static int ast2600_wdt_of_to_plat(struct udevice *dev)
{
	struct ast2600_wdt_priv *priv = dev_get_priv(dev);

	priv->regs = dev_read_addr_ptr(dev);
	if (!priv->regs)
		return -EINVAL;

	return 0;
}

static const struct wdt_ops ast2600_wdt_ops = {
	.start = ast2600_wdt_start,
	.reset = ast2600_wdt_reset,
	.stop = ast2600_wdt_stop,
	.expire_now = ast2600_wdt_expire_now,
};

static const struct udevice_id ast2600_wdt_ids[] = {
	{ .compatible = "aspeed,ast2600-wdt" },
	{ }
};

static int ast2600_wdt_probe(struct udevice *dev)
{
	debug("%s() wdt%u\n", __func__, dev_seq(dev));
	ast2600_wdt_stop(dev);

	return 0;
}

U_BOOT_DRIVER(ast2600_wdt) = {
	.name = "ast2600_wdt",
	.id = UCLASS_WDT,
	.of_match = ast2600_wdt_ids,
	.probe = ast2600_wdt_probe,
	.priv_auto = sizeof(struct ast2600_wdt_priv),
	.of_to_plat = ast2600_wdt_of_to_plat,
	.ops = &ast2600_wdt_ops,
};