designware_wdt.c
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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2013 Altera Corporation <www.altera.com>
*/
#include <clk.h>
#include <common.h>
#include <dm.h>
#include <reset.h>
#include <wdt.h>
#include <asm/io.h>
#include <asm/utils.h>
#define DW_WDT_CR 0x00
#define DW_WDT_TORR 0x04
#define DW_WDT_CRR 0x0C
#define DW_WDT_CR_EN_OFFSET 0x00
#define DW_WDT_CR_RMOD_OFFSET 0x01
#define DW_WDT_CRR_RESTART_VAL 0x76
struct designware_wdt_priv {
void __iomem *base;
unsigned int clk_khz;
};
/*
* Set the watchdog time interval.
* Counter is 32 bit.
*/
static int designware_wdt_settimeout(void __iomem *base, unsigned int clk_khz,
unsigned int timeout)
{
signed int i;
/* calculate the timeout range value */
i = log_2_n_round_up(timeout * clk_khz) - 16;
i = clamp(i, 0, 15);
writel(i | (i << 4), base + DW_WDT_TORR);
return 0;
}
static void designware_wdt_enable(void __iomem *base)
{
writel(BIT(DW_WDT_CR_EN_OFFSET), base + DW_WDT_CR);
}
static unsigned int designware_wdt_is_enabled(void __iomem *base)
{
return readl(base + DW_WDT_CR) & BIT(0);
}
static void designware_wdt_reset_common(void __iomem *base)
{
if (designware_wdt_is_enabled(base))
/* restart the watchdog counter */
writel(DW_WDT_CRR_RESTART_VAL, base + DW_WDT_CRR);
}
#if !CONFIG_IS_ENABLED(WDT)
void hw_watchdog_reset(void)
{
designware_wdt_reset_common((void __iomem *)CONFIG_DW_WDT_BASE);
}
void hw_watchdog_init(void)
{
/* reset to disable the watchdog */
hw_watchdog_reset();
/* set timer in miliseconds */
designware_wdt_settimeout((void __iomem *)CONFIG_DW_WDT_BASE,
CONFIG_DW_WDT_CLOCK_KHZ,
CONFIG_WATCHDOG_TIMEOUT_MSECS);
/* enable the watchdog */
designware_wdt_enable((void __iomem *)CONFIG_DW_WDT_BASE);
/* reset the watchdog */
hw_watchdog_reset();
}
#else
static int designware_wdt_reset(struct udevice *dev)
{
struct designware_wdt_priv *priv = dev_get_priv(dev);
designware_wdt_reset_common(priv->base);
return 0;
}
static int designware_wdt_stop(struct udevice *dev)
{
struct designware_wdt_priv *priv = dev_get_priv(dev);
designware_wdt_reset(dev);
writel(0, priv->base + DW_WDT_CR);
return 0;
}
static int designware_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
{
struct designware_wdt_priv *priv = dev_get_priv(dev);
designware_wdt_stop(dev);
/* set timer in miliseconds */
designware_wdt_settimeout(priv->base, priv->clk_khz, timeout);
designware_wdt_enable(priv->base);
/* reset the watchdog */
return designware_wdt_reset(dev);
}
static int designware_wdt_probe(struct udevice *dev)
{
struct designware_wdt_priv *priv = dev_get_priv(dev);
__maybe_unused int ret;
priv->base = dev_remap_addr(dev);
if (!priv->base)
return -EINVAL;
#if CONFIG_IS_ENABLED(CLK)
struct clk clk;
ret = clk_get_by_index(dev, 0, &clk);
if (ret)
return ret;
priv->clk_khz = clk_get_rate(&clk);
if (!priv->clk_khz)
return -EINVAL;
#else
priv->clk_khz = CONFIG_DW_WDT_CLOCK_KHZ;
#endif
#if CONFIG_IS_ENABLED(DM_RESET)
struct reset_ctl_bulk resets;
ret = reset_get_bulk(dev, &resets);
if (ret)
return ret;
ret = reset_deassert_bulk(&resets);
if (ret)
return ret;
#endif
/* reset to disable the watchdog */
return designware_wdt_stop(dev);
}
static const struct wdt_ops designware_wdt_ops = {
.start = designware_wdt_start,
.reset = designware_wdt_reset,
.stop = designware_wdt_stop,
};
static const struct udevice_id designware_wdt_ids[] = {
{ .compatible = "snps,dw-wdt"},
{}
};
U_BOOT_DRIVER(designware_wdt) = {
.name = "designware_wdt",
.id = UCLASS_WDT,
.of_match = designware_wdt_ids,
.priv_auto_alloc_size = sizeof(struct designware_wdt_priv),
.probe = designware_wdt_probe,
.ops = &designware_wdt_ops,
.flags = DM_FLAG_PRE_RELOC,
};
#endif