u-boot/drivers/watchdog/designware_wdt.c
Marek Vasut cf89ef8d10 watchdog: designware: Optionally fetch clock and reset from DT
Add optional support for fetching watchdog clock rate from DT
and ungating reset via reset framework. This is optional as not
all platforms using DW WDT support the clock and reset frameworks
yet.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Chin Liang See <chin.liang.see@intel.com>
Cc: Dalon Westergreen <dwesterg@gmail.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Jagan Teki <jagan@amarulasolutions.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Philipp Tomisch <philipp.tomisch@theobroma-systems.com>
Cc: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Cc: Tien Fong Chee <tien.fong.chee@intel.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com> # roc-rk3399-pc
2020-02-05 03:01:57 +01:00

175 lines
3.7 KiB
C

// 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