On 9/17/20 3:39 PM, Nobuhiro Iwamatsu wrote:
> Add the watchdog driver for Toshiba Visconti series.
>
> Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@xxxxxxxxxxxxx>
> ---
> drivers/watchdog/Kconfig | 8 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/visconti_wdt.c | 192 ++++++++++++++++++++++++++++++++
> 3 files changed, 201 insertions(+)
> create mode 100644 drivers/watchdog/visconti_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index ab7aad5a1e69..0cb078ce5e9d 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -1004,6 +1004,14 @@ config PM8916_WATCHDOG
> Say Y here to include support watchdog timer embedded into the
> pm8916 module.
>
> +config VISCONTI_WATCHDOG
> + tristate "Toshiba Visconti series watchdog support"
> + depends on ARCH_VISCONTI || COMPILE_TEST
> + select WATCHDOG_CORE
> + help
> + Say Y here to include support for the watchdog timer in Toshiba
> + Visconti SoCs.
> +
> # X86 (i386 + ia64 + x86_64) Architecture
>
> config ACQUIRE_WDT
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 97bed1d3d97c..a7747e76fd29 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -95,6 +95,7 @@ obj-$(CONFIG_RTD119X_WATCHDOG) += rtd119x_wdt.o
> obj-$(CONFIG_SPRD_WATCHDOG) += sprd_wdt.o
> obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o
> obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o
> +obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o
>
> # X86 (i386 + ia64 + x86_64) Architecture
> obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
> diff --git a/drivers/watchdog/visconti_wdt.c b/drivers/watchdog/visconti_wdt.c
> new file mode 100644
> index 000000000000..b82849d68c4c
> --- /dev/null
> +++ b/drivers/watchdog/visconti_wdt.c
> @@ -0,0 +1,192 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2020 TOSHIBA CORPORATION
> + * Copyright (c) 2020 Toshiba Electronic Devices & Storage Corporation
> + * Copyright (c) 2020 Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@xxxxxxxxxxxxx>
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/clk.h>
> +#include <linux/platform_device.h>
> +#include <linux/watchdog.h>
Alphabetically, please.
> +
> +#define WDT_CNT 0x00
> +#define WDT_MIN 0x04
> +#define WDT_MAX 0x08
> +#define WDT_CTL 0x0c
> +#define WDT_CMD 0x10
> +#define WDT_CMD_CLEAR 0x4352
> +#define WDT_CMD_START_STOP 0x5354
> +#define WDT_DIV 0x30
> +
> +#define VISCONTI_WDT_FREQ 2000000 /* 2MHz */
> +#define WDT_DEFAULT_TIMEOUT 10U /* in seconds */
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, bool, 0);
> +MODULE_PARM_DESC(
> + nowayout,
> + "Watchdog cannot be stopped once started (default=" __MODULE_STRING(
> + WATCHDOG_NOWAYOUT) ")");
> +
> +struct visconti_wdt_priv {
> + struct watchdog_device wdev;
> + void __iomem *base;
> + u32 div;
> +};
> +
> +static int visconti_wdt_start(struct watchdog_device *wdev)
> +{
> + struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev);
> + u32 timeout = wdev->timeout * VISCONTI_WDT_FREQ;
> +
> + writel(priv->div, priv->base + WDT_DIV);
> + writel(0, priv->base + WDT_MIN);
> + writel(timeout, priv->base + WDT_MAX);
> + writel(0, priv->base + WDT_CTL);
> + writel(WDT_CMD_START_STOP, priv->base + WDT_CMD);
> +
> + return 0;
> +}
> +
> +static int visconti_wdt_stop(struct watchdog_device *wdev)
> +{
> + struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev);
> +
> + writel(1, priv->base + WDT_CTL);
> + writel(WDT_CMD_START_STOP, priv->base + WDT_CMD);
> +
> + return 0;
> +}
> +
> +static int visconti_wdt_ping(struct watchdog_device *wdd)
> +{
> + struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdd);
> +
> + writel(WDT_CMD_CLEAR, priv->base + WDT_CMD);
> +
> + return 0;
> +}
> +
> +static unsigned int visconti_wdt_get_timeleft(struct watchdog_device *wdev)
> +{
> + struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev);
> + u32 timeout = wdev->timeout * VISCONTI_WDT_FREQ;
> +
> + timeout -= readl(priv->base + WDT_CNT);
> +
What happens if this is negative for whatever reason ?
> + return timeout / VISCONTI_WDT_FREQ;
> +}
> +
> +static int visconti_wdt_set_timeout(struct watchdog_device *wdev,
> + unsigned int timeout)
> +{
> + u32 val;
> + struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev);
> +
> + wdev->timeout = timeout;
> + val = wdev->timeout * VISCONTI_WDT_FREQ;
> +
> + /* Clear counter before setting timeout because WDT expires */
> + writel(WDT_CMD_CLEAR, priv->base + WDT_CMD);
> + writel(val, priv->base + WDT_MAX);
> +
> + return 0;
> +}
> +
> +static const struct watchdog_info visconti_wdt_info = {
> + .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
> + .identity = "Visconti Watchdog",
> +};
> +
> +static const struct watchdog_ops visconti_wdt_ops = {
> + .owner = THIS_MODULE,
> + .start = visconti_wdt_start,
> + .stop = visconti_wdt_stop,
> + .ping = visconti_wdt_ping,
> + .get_timeleft = visconti_wdt_get_timeleft,
> + .set_timeout = visconti_wdt_set_timeout,
> +};
> +
> +static int visconti_wdt_probe(struct platform_device *pdev)
> +{
> + struct watchdog_device *wdev;
> + struct visconti_wdt_priv *priv;
> + struct device *dev = &pdev->dev;
> + struct clk *clk;
> + int ret;
> + unsigned long clk_freq;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(priv->base))
> + return PTR_ERR(priv->base);
> +
> + clk = devm_clk_get(dev, NULL);
> + if (IS_ERR(clk)) {
> + dev_err(dev, "Could not get clock\n");
devm_clk_get() can return -EPROBE_DEFER. In that case we don't
want to see an error message. Consider using dev_err_probe().
> + return PTR_ERR(clk);
> + }
> +
> + ret = clk_prepare_enable(clk);
> + if (ret) {
> + dev_err(dev, "Could not enable clock\n");
> + return ret;
> + }
> +
> + clk_freq = clk_get_rate(clk);
> + if (!clk_freq) {
> + clk_disable_unprepare(clk);
> + dev_err(dev, "Could not get clock rate\n");
> + return -EINVAL;
> + }
> +
> + priv->div = clk_freq / VISCONTI_WDT_FREQ;
> +
> + /* Initialize struct watchdog_device. */
> + wdev = &priv->wdev;
> + wdev->info = &visconti_wdt_info;
> + wdev->ops = &visconti_wdt_ops;
> + wdev->parent = dev;
> + wdev->min_timeout = 1;
> + wdev->max_timeout = 0xffffffff / VISCONTI_WDT_FREQ;
> + wdev->timeout = min(wdev->max_timeout, WDT_DEFAULT_TIMEOUT);
> +
> + watchdog_set_drvdata(wdev, priv);
> + watchdog_set_nowayout(wdev, nowayout);
> + watchdog_stop_on_unregister(wdev);
> +
> + /* This overrides the default timeout only if DT configuration was found */
> + ret = watchdog_init_timeout(wdev, 0, dev);
> + if (ret)
> + dev_warn(dev, "Specified timeout value invalid, using default\n");
> +
> + return devm_watchdog_register_device(dev, wdev);
> +}
> +
> +static const struct of_device_id visconti_wdt_of_match[] = {
> + { .compatible = "toshiba,visconti-wdt", },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, visconti_wdt_of_match);
> +
> +static struct platform_driver visconti_wdt_driver = {
> + .driver = {
> + .name = "visconti_wdt",
> + .of_match_table = visconti_wdt_of_match,
> + },
> + .probe = visconti_wdt_probe,
> +};
> +module_platform_driver(visconti_wdt_driver);
> +
> +MODULE_DESCRIPTION("TOSHIBA Visconti Watchdog Driver");
> +MODULE_AUTHOR("TOSHIBA ELECTRONIC DEVICES & STORAGE CORPORATION");
> +MODULE_AUTHOR("Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@xxxxxxxxxxxxx");
> +MODULE_LICENSE("GPL v2");
>
