[PATCH v4 5/6] mips: ls1c300: add watchdog support

[Stefan Roese]

On 7/23/23 06:39, Du Huanpeng wrote:
> Signed-off-by: Du Huanpeng <dhu at hodcarrier.org>

A small description is always helpful (mandatory) in the commit text.
Please add at least one or two sentences here.

> ---
>   drivers/watchdog/Kconfig      |   8 +++
>   drivers/watchdog/Makefile     |   1 +
>   drivers/watchdog/lsmips_wdt.c | 128 ++++++++++++++++++++++++++++++++++
>   3 files changed, 137 insertions(+)
>   create mode 100644 drivers/watchdog/lsmips_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 646663528a..f60011e5b3 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -171,6 +171,14 @@ config WDT_GPIO
>   	  doc/device-tree-bindings/watchdog/gpio-wdt.txt for
>   	  information on how to describe the watchdog in device tree.
>   
> +config WDT_LSMIPS
> +	bool "Loongson MIPS watchdog timer support"
> +	depends on WDT
> +	help
> +	  Select this to enable watchdog timer for Loongson SoCs.
> +	  The watchdog timer is stopped when initialized.
> +	  It performs full SoC reset.
> +
>   config WDT_MAX6370
>   	bool "MAX6370 watchdog timer support"
>   	depends on WDT
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index fd5d9c7376..8afd61a4fc 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -30,6 +30,7 @@ obj-$(CONFIG_WDT_ORION) += orion_wdt.o
>   obj-$(CONFIG_WDT_CDNS) += cdns_wdt.o
>   obj-$(CONFIG_WDT_FTWDT010) += ftwdt010_wdt.o
>   obj-$(CONFIG_WDT_GPIO) += gpio_wdt.o
> +obj-$(CONFIG_WDT_LSMIPS) += lsmips_wdt.o
>   obj-$(CONFIG_WDT_MAX6370) += max6370_wdt.o
>   obj-$(CONFIG_WDT_MESON_GXBB) += meson_gxbb_wdt.o
>   obj-$(CONFIG_WDT_MPC8xxx) += mpc8xxx_wdt.o
> diff --git a/drivers/watchdog/lsmips_wdt.c b/drivers/watchdog/lsmips_wdt.c
> new file mode 100644
> index 0000000000..69006d332d
> --- /dev/null
> +++ b/drivers/watchdog/lsmips_wdt.c
> @@ -0,0 +1,128 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Watchdog driver for MediaTek SoCs
> + *
> + * Copyright (C) 2018 MediaTek Inc.
> + * Author: Ryder Lee <ryder.lee at mediatek.com>
> + *
> + * based on: drivers/watchdog/mtk_wdt.c
> + * Copyright (C) 2020-2023 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <hang.h>
> +#include <wdt.h>
> +#include <asm/io.h>
> +#include <clk.h>
> +
> +
> +struct lsmips_wdt_priv {
> +	void __iomem *base;
> +#define WDT_EN		0
> +#define WDT_TIMER	4
> +#define WDT_SET		8
> +	ulong clock;
> +	unsigned long timeout;
> +};
> +
> +static int lsmips_wdt_reset(struct udevice *dev)
> +{
> +	struct lsmips_wdt_priv *priv = dev_get_priv(dev);
> +
> +	writel(priv->timeout, priv->base + WDT_TIMER);
> +	writel(1, priv->base + WDT_SET);
> +
> +	return 0;
> +}
> +
> +static int lsmips_wdt_stop(struct udevice *dev)
> +{
> +	struct lsmips_wdt_priv *priv = dev_get_priv(dev);
> +
> +	writel(0, priv->base + WDT_EN);
> +	return 0;
> +}
> +
> +static int lsmips_wdt_expire_now(struct udevice *dev, ulong flags)
> +{
> +	struct lsmips_wdt_priv *priv = dev_get_priv(dev);
> +
> +	writel(1, priv->base + WDT_EN);
> +	writel(1, priv->base + WDT_TIMER);
> +	writel(1, priv->base + WDT_SET);
> +
> +	hang();
> +	return 0;
> +}
> +
> +static int lsmips_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
> +{
> +	struct lsmips_wdt_priv *priv = dev_get_priv(dev);
> +	unsigned int timeout;
> +	const unsigned int MSEC_PER_SEC = 1000;

Upper case variable names are very unusual. Why not use a macro / define
instead?

Nitpicking:

Reverse X-mas tree ordering of the variable declarations is preferred.

> +
> +	timeout = U32_MAX / (priv->clock / MSEC_PER_SEC);
> +
> +	if (timeout < timeout_ms)
> +		timeout = U32_MAX;
> +	else
> +		timeout = timeout_ms * (priv->clock / MSEC_PER_SEC);
> +
> +	debug("WDT: reload  = %08x\n", timeout);
> +
> +	writel(1, priv->base + WDT_EN);
> +	writel(timeout, priv->base + WDT_TIMER);
> +	writel(1, priv->base + WDT_SET);
> +
> +	priv->timeout = timeout;
> +
> +	return 0;
> +}
> +
> +static int lsmips_wdt_probe(struct udevice *dev)
> +{
> +	struct lsmips_wdt_priv *priv = dev_get_priv(dev);
> +	struct clk cl;
> +	ulong clock;
> +
> +	priv->base = dev_remap_addr(dev);
> +	if (!priv->base)
> +		return -ENOENT;
> +
> +	if (clk_get_by_index(dev, 0, &cl) == 0)
> +		clock = clk_get_rate(&cl);
> +
> +	debug("WDT: clock = %ld\n", clock);
> +
> +	if (IS_ERR_VALUE(clock)) {
> +		dev_err(dev, "failed to get rate\n");
> +		return clock;
> +	}
> +
> +	priv->clock = clock;
> +	writel(0, priv->base + WDT_EN);
> +	return 0;
> +}
> +
> +static const struct wdt_ops lsmips_wdt_ops = {
> +	.start = lsmips_wdt_start,
> +	.reset = lsmips_wdt_reset,
> +	.stop = lsmips_wdt_stop,
> +	.expire_now = lsmips_wdt_expire_now,
> +};
> +
> +static const struct udevice_id lsmips_wdt_ids[] = {
> +	{ .compatible = "loongson,ls1c300-wdt"},

I was not able to find this compatible property in the Linux source
tree. Is this WDT not supported there?

Thanks,
Stefan