sbsa_gwdt.c
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// SPDX-License-Identifier: GPL-2.0+
/*
* Watchdog driver for SBSA
*
* Copyright 2020 NXP
*/
#include <asm/io.h>
#include <common.h>
#include <dm/device.h>
#include <dm/fdtaddr.h>
#include <dm/read.h>
#include <linux/bitops.h>
#include <linux/err.h>
#include <watchdog.h>
#include <wdt.h>
DECLARE_GLOBAL_DATA_PTR;
/* SBSA Generic Watchdog register definitions */
/* refresh frame */
#define SBSA_GWDT_WRR 0x000
/* control frame */
#define SBSA_GWDT_WCS 0x000
#define SBSA_GWDT_WOR 0x008
#define SBSA_GWDT_WCV 0x010
/* refresh/control frame */
#define SBSA_GWDT_W_IIDR 0xfcc
#define SBSA_GWDT_IDR 0xfd0
/* Watchdog Control and Status Register */
#define SBSA_GWDT_WCS_EN BIT(0)
#define SBSA_GWDT_WCS_WS0 BIT(1)
#define SBSA_GWDT_WCS_WS1 BIT(2)
struct sbsa_gwdt_priv {
void __iomem *reg_refresh;
void __iomem *reg_control;
};
static int sbsa_gwdt_reset(struct udevice *dev)
{
struct sbsa_gwdt_priv *priv = dev_get_priv(dev);
writel(0, priv->reg_refresh + SBSA_GWDT_WRR);
return 0;
}
static int sbsa_gwdt_start(struct udevice *dev, u64 timeout, ulong flags)
{
struct sbsa_gwdt_priv *priv = dev_get_priv(dev);
u32 clk;
/*
* it work in the single stage mode in u-boot,
* The first signal (WS0) is ignored,
* the timeout is (WOR * 2), so the WOR should be configured
* to half value of timeout.
*/
clk = get_tbclk();
writel(clk / (2 * 1000) * timeout,
priv->reg_control + SBSA_GWDT_WOR);
/* writing WCS will cause an explicit watchdog refresh */
writel(SBSA_GWDT_WCS_EN, priv->reg_control + SBSA_GWDT_WCS);
return 0;
}
static int sbsa_gwdt_stop(struct udevice *dev)
{
struct sbsa_gwdt_priv *priv = dev_get_priv(dev);
writel(0, priv->reg_control + SBSA_GWDT_WCS);
return 0;
}
static int sbsa_gwdt_expire_now(struct udevice *dev, ulong flags)
{
sbsa_gwdt_start(dev, 0, flags);
return 0;
}
static int sbsa_gwdt_probe(struct udevice *dev)
{
debug("%s: Probing wdt%u (sbsa-gwdt)\n", __func__, dev->seq);
return 0;
}
static int sbsa_gwdt_ofdata_to_platdata(struct udevice *dev)
{
struct sbsa_gwdt_priv *priv = dev_get_priv(dev);
priv->reg_control = (void __iomem *)dev_read_addr_index(dev, 0);
if (IS_ERR(priv->reg_control))
return PTR_ERR(priv->reg_control);
priv->reg_refresh = (void __iomem *)dev_read_addr_index(dev, 1);
if (IS_ERR(priv->reg_refresh))
return PTR_ERR(priv->reg_refresh);
return 0;
}
static const struct wdt_ops sbsa_gwdt_ops = {
.start = sbsa_gwdt_start,
.reset = sbsa_gwdt_reset,
.stop = sbsa_gwdt_stop,
.expire_now = sbsa_gwdt_expire_now,
};
static const struct udevice_id sbsa_gwdt_ids[] = {
{ .compatible = "arm,sbsa-gwdt" },
{}
};
U_BOOT_DRIVER(sbsa_gwdt) = {
.name = "sbsa_gwdt",
.id = UCLASS_WDT,
.of_match = sbsa_gwdt_ids,
.probe = sbsa_gwdt_probe,
.priv_auto_alloc_size = sizeof(struct sbsa_gwdt_priv),
.ofdata_to_platdata = sbsa_gwdt_ofdata_to_platdata,
.ops = &sbsa_gwdt_ops,
};