[PATCH 2/3] watchdog: add driver for Cortina Gemini watchdog
Guenter Roeck
linux at roeck-us.net
Sun Jan 22 22:50:03 PST 2017
On 01/22/2017 02:39 PM, Linus Walleij wrote:
> This add support for the Cortina systems Gemini (SL3516)
> SoC watchdog.
>
> I have tried to use all the right new kernel interfaces
> and tested with busybox' "watchdog" command both to kick
> and get timeouts and reboots.
>
> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
> ---
> drivers/watchdog/Kconfig | 11 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/gemini_wdt.c | 241 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 253 insertions(+)
> create mode 100644 drivers/watchdog/gemini_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index acb00b53a520..3e5ab6712a1e 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -301,6 +301,17 @@ config 977_WATCHDOG
>
> Not sure? It's safe to say N.
>
> +config GEMINI_WATCHDOG
> + tristate "Gemini watchdog"
> + depends on ARCH_GEMINI
> + select WATCHDOG_CORE
> + help
> + Say Y here if to include support for the watchdog timer
> + embedded in the Cortina Systems Gemini family of devices.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called gemini_wdt.
> +
> config IXP4XX_WATCHDOG
> tristate "IXP4xx Watchdog"
> depends on ARCH_IXP4XX
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 0c3d35e3c334..953d033b1152 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -45,6 +45,7 @@ obj-$(CONFIG_OMAP_WATCHDOG) += omap_wdt.o
> obj-$(CONFIG_TWL4030_WATCHDOG) += twl4030_wdt.o
> obj-$(CONFIG_21285_WATCHDOG) += wdt285.o
> obj-$(CONFIG_977_WATCHDOG) += wdt977.o
> +obj-$(CONFIG_GEMINI_WATCHDOG) += gemini_wdt.o
> obj-$(CONFIG_IXP4XX_WATCHDOG) += ixp4xx_wdt.o
> obj-$(CONFIG_KS8695_WATCHDOG) += ks8695_wdt.o
> obj-$(CONFIG_S3C2410_WATCHDOG) += s3c2410_wdt.o
> diff --git a/drivers/watchdog/gemini_wdt.c b/drivers/watchdog/gemini_wdt.c
> new file mode 100644
> index 000000000000..11e457538061
> --- /dev/null
> +++ b/drivers/watchdog/gemini_wdt.c
> @@ -0,0 +1,241 @@
> +/*
> + * Watchdog driver for Cortina Systems Gemini SoC
> + *
> + * Copyright (C) 2017 Linus Walleij <linus.walleij at linaro.org>
> + *
> + * Inspired by the out-of-tree drivers from OpenWRT:
> + * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas at teltonika.lt>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/io.h>
> +#include <linux/platform_device.h>
> +#include <linux/watchdog.h>
> +#include <linux/slab.h>
> +#include <linux/bitops.h>
> +#include <linux/of_device.h>
> +#include <linux/interrupt.h>
> +
Alphabetic order please
> +#define GEMINI_WDCOUNTER 0x0
> +#define GEMINI_WDLOAD 0x4
> +#define GEMINI_WDRESTART 0x8
> +#define GEMINI_WDCR 0xC
> +
> +#define WDRESTART_MAGIC 0x5AB9
> +
> +#define WDCR_CLOCK_5MHZ BIT(4)
> +#define WDCR_SYS_RST BIT(1)
> +#define WDCR_ENABLE BIT(0)
> +
> +#define WDT_CLOCK 5000000 /* 5 MHz */
> +
> +struct gemini_wdt {
> + struct watchdog_device wdd;
> + struct device *dev;
> + void __iomem *base;
> + bool enabled;
Not needed; see below
> +};
> +
> +static inline
> +struct gemini_wdt *to_gemini_wdt(struct watchdog_device *wdd)
> +{
> + return container_of(wdd, struct gemini_wdt, wdd);
> +}
> +
> +static int gemini_wdt_start(struct watchdog_device *wdd)
> +{
> + struct gemini_wdt *gwdt = to_gemini_wdt(wdd);
> +
> + writel(wdd->timeout * WDT_CLOCK, gwdt->base + GEMINI_WDLOAD);
> + writel(WDRESTART_MAGIC, gwdt->base + GEMINI_WDRESTART);
> + /* set clock before enabling */
> + writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST,
> + gwdt->base + GEMINI_WDCR);
> + writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST | WDCR_ENABLE,
> + gwdt->base + GEMINI_WDCR);
> + gwdt->enabled = true;
> +
> + return 0;
> +}
> +
> +static int gemini_wdt_stop(struct watchdog_device *wdd)
> +{
> + struct gemini_wdt *gwdt = to_gemini_wdt(wdd);
> +
> + writel(0, gwdt->base + GEMINI_WDCR);
> +
> + return 0;
> +}
> +
> +static int gemini_wdt_ping(struct watchdog_device *wdd)
> +{
> + struct gemini_wdt *gwdt = to_gemini_wdt(wdd);
> +
> + writel(WDRESTART_MAGIC, gwdt->base + GEMINI_WDRESTART);
> +
> + return 0;
> +}
> +
> +static int gemini_wdt_set_timeout(struct watchdog_device *wdd,
> + unsigned int timeout)
> +{
> + wdd->timeout = timeout;
> + return gemini_wdt_start(wdd);
The watchdog does not have to be active when this function is called.
> +}
> +
> +static irqreturn_t gemini_wdt_interrupt(int irq, void *data)
> +{
> + struct gemini_wdt *gwdt = data;
> +
> + dev_crit(gwdt->dev, "watchdog is barking!\n");
> +
Nothing else ? No reboot ?
> + return IRQ_HANDLED;
> +}
> +
> +static const struct watchdog_ops gemini_wdt_ops = {
> + .start = gemini_wdt_start,
> + .stop = gemini_wdt_stop,
> + .ping = gemini_wdt_ping,
> + .set_timeout = gemini_wdt_set_timeout,
> + .owner = THIS_MODULE,
> +};
> +
> +static const struct watchdog_info gemini_wdt_info = {
> + .options = WDIOF_KEEPALIVEPING
> + | WDIOF_MAGICCLOSE
> + | WDIOF_SETTIMEOUT,
> + .identity = KBUILD_MODNAME,
> +};
> +
> +
> +static int gemini_wdt_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct resource *res;
> + struct gemini_wdt *gwdt;
> + unsigned int reg;
> + int irq;
> + int ret;
> +
> + gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
> + if (!gwdt)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + gwdt->base = devm_ioremap_resource(dev, res);
> + if (IS_ERR(gwdt->base))
> + return PTR_ERR(gwdt->base);
> +
> + irq = platform_get_irq(pdev, 0);
> + if (!irq)
> + return -EINVAL;
> +
> + gwdt->dev = dev;
> + gwdt->wdd.info = &gemini_wdt_info;
> + gwdt->wdd.ops = &gemini_wdt_ops;
> + gwdt->wdd.min_timeout = 1;
> + gwdt->wdd.max_timeout = (0xFFFFFFFF / WDT_CLOCK);
Unnecessary ( )
> + gwdt->wdd.parent = dev;
> + gwdt->enabled = false;
> +
> + /*
> + * If 'timeout-sec' unspecified in devicetree, assume a 13 second
> + * default, unless the max timeout is less than 13 seconds, then use
> + * the max instead.
> + */
> + gwdt->wdd.timeout = min(gwdt->wdd.max_timeout, 13U);
WDT_CLOCK is a constant 5000000, meaning the maximum is known to be 858.
Isn't this a lot of complexity for pretty much nothing ?
> + watchdog_init_timeout(&gwdt->wdd, 0, dev);
> +
> + reg = readw(gwdt->base + GEMINI_WDCR);
> + if (reg & WDCR_ENABLE) {
> + /* Watchdog was enabled by the bootloader, disable it. */
> + reg &= ~(WDCR_ENABLE);
Unnecessary ( ).
> + writel(reg, gwdt->base + GEMINI_WDCR);
> + }
> +
> + ret = devm_request_irq(dev, irq, gemini_wdt_interrupt, 0,
> + "watchdog bark", gwdt);
> + if (ret)
> + return ret;
> +
> + ret = watchdog_register_device(&gwdt->wdd);
devm_watchdog_register_device ? then you can drop the remove function.
> + if (ret) {
> + dev_err(&pdev->dev, "failed to register watchdog\n");
> + return ret;
> + }
> +
> + /* Set up platform driver data */
> + platform_set_drvdata(pdev, gwdt);
> + dev_info(dev, "Gemini watchdog driver enabled\n");
> +
> + return 0;
> +}
> +
> +static int gemini_wdt_remove(struct platform_device *pdev)
> +{
> + struct gemini_wdt *gwdt = platform_get_drvdata(pdev);
> +
> + watchdog_unregister_device(&gwdt->wdd);
> + platform_set_drvdata(pdev, NULL);
> +
Unnecessary (probably gets you a 0day warning)
> + return 0;
> +}
> +
> +static int __maybe_unused gemini_wdt_suspend(struct device *dev)
> +{
> + struct gemini_wdt *gwdt = dev_get_drvdata(dev);
> + unsigned int reg;
> +
> + reg = readw(gwdt->base + GEMINI_WDCR);
> + reg &= ~(WDCR_ENABLE);
Unnecessary ( )
> + writel(reg, gwdt->base + GEMINI_WDCR);
> +
> + return 0;
> +}
> +
> +static int __maybe_unused gemini_wdt_resume(struct device *dev)
> +{
> + struct gemini_wdt *gwdt = dev_get_drvdata(dev);
> + unsigned int reg;
> +
> + if (gwdt->enabled) {
if (watchdog_active(&gwdt->wdd)) {
> + reg = readw(gwdt->base + GEMINI_WDCR);
> + reg |= WDCR_ENABLE;
> + writel(reg, gwdt->base + GEMINI_WDCR);
> + }
> +
> + return 0;
> +}
> +
> +static const struct dev_pm_ops gemini_wdt_dev_pm_ops = {
> + SET_SYSTEM_SLEEP_PM_OPS(gemini_wdt_suspend,
> + gemini_wdt_resume)
> +};
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id gemini_wdt_match[] = {
> + { .compatible = "cortina,gemini-watchdog" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, gemini_wdt_match);
> +#endif
> +
> +static struct platform_driver gemini_wdt_driver = {
> + .probe = gemini_wdt_probe,
> + .remove = gemini_wdt_remove,
> + .driver = {
> + .name = "gemini-wdt",
> + .of_match_table = of_match_ptr(gemini_wdt_match),
> + .pm = &gemini_wdt_dev_pm_ops,
> + },
> +};
> +module_platform_driver(gemini_wdt_driver);
> +MODULE_AUTHOR("Linus Walleij");
> +MODULE_DESCRIPTION("Watchdog driver for Gemini");
> +MODULE_LICENSE("GPL");
>
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