Re: [PATCH v5] watchdog: Add watchdog timer support for the WinSystems EBC-C384

[Guenter Roeck]

On 02/28/2016 06:44 AM, William Breathitt Gray wrote:
> The WinSystems EBC-C384 has an onboard watchdog timer. The timeout range
> supported by the watchdog timer is 1 second to 255 minutes. Timeouts
> under 256 seconds have a 1 second granularity, while the rest have a 1
> minute granularity.
>
> This driver adds watchdog timer support for this onboard watchdog timer.
> The timeout may be configured via the timeout module parameter.
>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
> Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
> Changes in v5:
>    - Round up rather than down when converting seconds to minutes
>
>   MAINTAINERS                     |   6 ++
>   drivers/watchdog/Kconfig        |   9 ++
>   drivers/watchdog/Makefile       |   1 +
>   drivers/watchdog/ebc-c384_wdt.c | 187 ++++++++++++++++++++++++++++++++++++++++
>   4 files changed, 203 insertions(+)
>   create mode 100644 drivers/watchdog/ebc-c384_wdt.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 28eb61b..66107fd 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11860,6 +11860,12 @@ M:	David HÃrdeman <david@xxxxxxxxxxx>
>   S:	Maintained
>   F:	drivers/media/rc/winbond-cir.c
>
> +WINSYSTEMS EBC-C384 WATCHDOG DRIVER
> +M:	William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
> +L:	linux-watchdog@xxxxxxxxxxxxxxx
> +S:	Maintained
> +F:	drivers/watchdog/ebc-c384_wdt.c
> +
>   WIMAX STACK
>   M:	Inaky Perez-Gonzalez <inaky.perez-gonzalez@xxxxxxxxx>
>   M:	linux-wimax@xxxxxxxxx
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 0f6d851..11f3a3d 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -713,6 +713,15 @@ config ALIM7101_WDT
>
>   	  Most people will say N.
>
> +config EBC_C384_WDT
> +	tristate "WinSystems EBC-C384 Watchdog Timer"
> +	depends on X86
> +	select WATCHDOG_CORE
> +	help
> +	  Enables watchdog timer support for the watchdog timer on the
> +	  WinSystems EBC-C384 motherboard. The timeout may be configured via
> +	  the timeout module parameter.
> +
>   config F71808E_WDT
>   	tristate "Fintek F71808E, F71862FG, F71869, F71882FG and F71889FG Watchdog"
>   	depends on X86
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index f566753..15762c8 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -88,6 +88,7 @@ obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
>   obj-$(CONFIG_ADVANTECH_WDT) += advantechwdt.o
>   obj-$(CONFIG_ALIM1535_WDT) += alim1535_wdt.o
>   obj-$(CONFIG_ALIM7101_WDT) += alim7101_wdt.o
> +obj-$(CONFIG_EBC_C384_WDT) += ebc-c384_wdt.o
>   obj-$(CONFIG_F71808E_WDT) += f71808e_wdt.o
>   obj-$(CONFIG_SP5100_TCO) += sp5100_tco.o
>   obj-$(CONFIG_GEODE_WDT) += geodewdt.o
> diff --git a/drivers/watchdog/ebc-c384_wdt.c b/drivers/watchdog/ebc-c384_wdt.c
> new file mode 100644
> index 0000000..6dec124
> --- /dev/null
> +++ b/drivers/watchdog/ebc-c384_wdt.c
> @@ -0,0 +1,187 @@
> +/*
> + * Watchdog timer driver for the WinSystems EBC-C384
> + * Copyright (C) 2016 William Breathitt Gray
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * General Public License for more details.
> + */
> +#include <linux/device.h>
> +#include <linux/dmi.h>
> +#include <linux/errno.h>
> +#include <linux/io.h>
> +#include <linux/ioport.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/platform_device.h>
> +#include <linux/types.h>
> +#include <linux/watchdog.h>
> +
> +#define MODULE_NAME		"ebc-c384_wdt"
> +#define WATCHDOG_TIMEOUT	60
> +/*
> + * The timeout value in minutes must fit in a single byte when sent to the
> + * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds.
> + */
> +#define WATCHDOG_MAX_TIMEOUT	15300
> +#define BASE_ADDR		0x564
> +#define ADDR_EXTENT		5
> +#define CFG_ADDR		(BASE_ADDR + 1)
> +#define PET_ADDR		(BASE_ADDR + 2)
> +
> +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) ")");
> +
> +static unsigned timeout;
> +module_param(timeout, uint, 0);
> +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
> +	__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
> +
> +static int ebc_c384_wdt_start(struct watchdog_device *wdev)
> +{
> +	unsigned t = wdev->timeout;
> +
> +	/* resolution is in minutes for timeouts greater than 255 seconds */
> +	if (t > 255)
> +		t = (((t - 1) / 60) + 1) * 60;
> +
> +	outb(t, PET_ADDR);
> +
> +	return 0;
> +}
> +
> +static int ebc_c384_wdt_stop(struct watchdog_device *wdev)
> +{
> +	outb(0x00, PET_ADDR);
> +
> +	return 0;
> +}
> +
> +static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t)
> +{
> +	/* resolution is in minutes for timeouts greater than 255 seconds */
> +	if (t > 255) {
> +		/* round second resolution up to minute resolution */
> +		wdev->timeout = (((t - 1) / 60) + 1) * 60;

DIV_ROUND_UP() is quite useful in this case.

Guenter

> +
> +		/* set watchdog timer for minutes */
> +		outb(0x00, CFG_ADDR);
> +	} else {
> +		wdev->timeout = t;
> +
> +		/* set watchdog timer for seconds */
> +		outb(0x80, CFG_ADDR);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct watchdog_ops ebc_c384_wdt_ops = {
> +	.start = ebc_c384_wdt_start,
> +	.stop = ebc_c384_wdt_stop,
> +	.set_timeout = ebc_c384_wdt_set_timeout
> +};
> +
> +static const struct watchdog_info ebc_c384_wdt_info = {
> +	.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT,
> +	.identity = MODULE_NAME
> +};
> +
> +static int __init ebc_c384_wdt_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct watchdog_device *wdd;
> +
> +	if (!devm_request_region(dev, BASE_ADDR, ADDR_EXTENT, dev_name(dev))) {
> +		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
> +			BASE_ADDR, BASE_ADDR + ADDR_EXTENT);
> +		return -EBUSY;
> +	}
> +
> +	wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
> +	if (!wdd)
> +		return -ENOMEM;
> +
> +	wdd->info = &ebc_c384_wdt_info;
> +	wdd->ops = &ebc_c384_wdt_ops;
> +	wdd->timeout = WATCHDOG_TIMEOUT;
> +	wdd->min_timeout = 1;
> +	wdd->max_timeout = WATCHDOG_MAX_TIMEOUT;
> +
> +	watchdog_set_nowayout(wdd, nowayout);
> +
> +	if (watchdog_init_timeout(wdd, timeout, dev))
> +		dev_warn(dev, "Invalid timeout (%u seconds), using default (%u seconds)\n",
> +			timeout, WATCHDOG_TIMEOUT);
> +
> +	platform_set_drvdata(pdev, wdd);
> +
> +	return watchdog_register_device(wdd);
> +}
> +
> +static int ebc_c384_wdt_remove(struct platform_device *pdev)
> +{
> +	struct watchdog_device *wdd = platform_get_drvdata(pdev);
> +
> +	watchdog_unregister_device(wdd);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver ebc_c384_wdt_driver = {
> +	.driver = {
> +		.name = MODULE_NAME
> +	},
> +	.remove = ebc_c384_wdt_remove
> +};
> +
> +static struct platform_device *ebc_c384_wdt_device;
> +
> +static int __init ebc_c384_wdt_init(void)
> +{
> +	int err;
> +
> +	if (!dmi_match(DMI_BOARD_NAME, "EBC-C384 SBC"))
> +		return -ENODEV;
> +
> +	ebc_c384_wdt_device = platform_device_alloc(MODULE_NAME, -1);
> +	if (!ebc_c384_wdt_device)
> +		return -ENOMEM;
> +
> +	err = platform_device_add(ebc_c384_wdt_device);
> +	if (err)
> +		goto err_platform_device;
> +
> +	err = platform_driver_probe(&ebc_c384_wdt_driver, ebc_c384_wdt_probe);
> +	if (err)
> +		goto err_platform_driver;
> +
> +	return 0;
> +
> +err_platform_driver:
> +	platform_device_del(ebc_c384_wdt_device);
> +err_platform_device:
> +	platform_device_put(ebc_c384_wdt_device);
> +	return err;
> +}
> +
> +static void __exit ebc_c384_wdt_exit(void)
> +{
> +	platform_device_unregister(ebc_c384_wdt_device);
> +	platform_driver_unregister(&ebc_c384_wdt_driver);
> +}
> +
> +module_init(ebc_c384_wdt_init);
> +module_exit(ebc_c384_wdt_exit);
> +
> +MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@xxxxxxxxx>");
> +MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:" MODULE_NAME);