On Mon, May 13, 2013 at 10:58:29PM +0200, johannes.thumsh...@men.de wrote:
> From: Johannes Thumshirn <johannes.thumsh...@men.de>
>
> This patch adds the driver for the watchdog devices found on MEN Mikro
> Elektronik A21 VMEbus CPU Carrier Boards. It has DT-support and uses the
> watchdog framework.
>
> Signed-off-by: Johannes Thumshirn <johannes.thumsh...@men.de>
Besides all of its problems, seems to me that could (or should) be a generic
gpio
watchdog driver, possibly with device tree bindings describing how the various
gpio pins are used.
> ---
> MAINTAINERS | 6 +
> drivers/watchdog/Kconfig | 8 +
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/mena21_wdt.c | 351
> +++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 366 insertions(+)
> create mode 100644 drivers/watchdog/mena21_wdt.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 3d7782b..3e5b3f1 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -5291,6 +5291,12 @@ F: drivers/mtd/
> F: include/linux/mtd/
> F: include/uapi/mtd/
>
> +MEN A21 WATCHDOG DRIVER
> +M: Johannes Thumshirn <johannes.thumsh...@men.de>
> +L: linux-watch...@vger.kernel.org
> +S: Supported
> +F: drivers/watchdog/mena21_wdt.c
> +
> METAG ARCHITECTURE
> M: James Hogan <james.ho...@imgtec.com>
> S: Supported
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index e89fc31..192b84d 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -1172,6 +1172,14 @@ config BOOKE_WDT_DEFAULT_TIMEOUT
>
> The value can be overridden by the wdt_period command-line parameter.
>
> +config MEN_A21_WDT
> + tristate "MEN A21 VME CPU Carrier Board Watchdog Timer"
> + select WATCHDOG_CORE
> + help
> + Watchdog driver for MEN A21 VMEbus CPU Carrier Boards.
> +
> + If unsure select N here.
> +
> # PPC64 Architecture
>
> config WATCHDOG_RTAS
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index a300b94..bffdcb1 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -143,6 +143,7 @@ obj-$(CONFIG_8xxx_WDT) += mpc8xxx_wdt.o
> obj-$(CONFIG_MV64X60_WDT) += mv64x60_wdt.o
> obj-$(CONFIG_PIKA_WDT) += pika_wdt.o
> obj-$(CONFIG_BOOKE_WDT) += booke_wdt.o
> +obj-$(CONFIG_MEN_A21_WDT) += mena21_wdt.o
>
> # PPC64 Architecture
> obj-$(CONFIG_WATCHDOG_RTAS) += wdrtas.o
> diff --git a/drivers/watchdog/mena21_wdt.c b/drivers/watchdog/mena21_wdt.c
> new file mode 100644
> index 0000000..d534f81
> --- /dev/null
> +++ b/drivers/watchdog/mena21_wdt.c
> @@ -0,0 +1,351 @@
> +/*
> + * Watchdog driver for the A21 VME CPU Boards
> + *
> + * Copyright (C) 2013 MEN Mikro Elektronik Nuernberg GmbH
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation
> + */
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/types.h>
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/platform_device.h>
> +#include <linux/watchdog.h>
> +#include <linux/uaccess.h>
> +#include <linux/gpio.h>
> +#include <linux/delay.h>
> +#include <linux/reboot.h>
> +#include <linux/bitops.h>
> +
> +static char *reset_causes[] = {
> + "Power On Reset",
> + "CPU Reset Request",
> + "Push Button",
> + "FPGA Reset Request",
> + "Watchdog",
> + "Local Power Bad",
> + "Invalid",
> + "BDI",
> +};
> +
> +#define GPIO_WD_ENAB 169
> +#define GPIO_WD_FAST 170
> +#define GPIO_WD_TRIG 171
> +
> +#define GPIO_RST_CAUSE_BASE 166
> +
> +struct a21_wdt_drv {
> + struct watchdog_device wdt;
> + struct mutex lock;
> + bool open;
> +};
> +
> +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 ssize_t rebootcause_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + unsigned int reset = 0;
> + int i;
> +
> + for (i = 0; i < 3; i++)
> + reset |= !!gpio_get_value(GPIO_RST_CAUSE_BASE + i);
The result of !! is 0 or 1, so reset will never be larger than 1.
Not sure if using fixed numbers for gpio pins is a good idea or even
correct. You might want to pass that by the gpio maintainers.
> +
> + if (reset >= 8)
> + return -EIO;
> +
Meaning this will never happen.
> + return sprintf(buf, "%s\n", reset_causes[reset]);
> +}
> +static DEVICE_ATTR(rebootcause, S_IRUGO, rebootcause_show, NULL);
> +
> +static ssize_t active_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + return sprintf(buf, "%d\n", !!gpio_get_value(GPIO_WD_ENAB));
> +}
> +static DEVICE_ATTR(active, S_IRUGO, active_show, NULL);
> +
> +static ssize_t allow_disable_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + return sprintf(buf, "%d\n", !nowayout);
> +}
> +static DEVICE_ATTR(allow_disable, S_IRUGO, allow_disable_show, NULL);
> +
> +static ssize_t fastmode_show(struct device *dev, struct device_attribute
> *attr,
> + char *buf)
> +{
> + return sprintf(buf, "%d\n", !!gpio_get_value(GPIO_WD_FAST));
> +}
> +static DEVICE_ATTR(fastmode, S_IRUGO, fastmode_show, NULL);
> +
> +static int a21_wdt_create_files(struct device *dev)
> +{
> + int ret;
> +
> + ret = device_create_file(dev, &dev_attr_rebootcause);
> + if (ret)
> + return ret;
> + ret = device_create_file(dev, &dev_attr_active);
> + if (ret)
> + return ret;
> + ret = device_create_file(dev, &dev_attr_allow_disable);
> + if (ret)
> + return ret;
> + ret = device_create_file(dev, &dev_attr_fastmode);
Wonder if the maintainer will let you bypass the infrastructure with those
attributes. I wouldn't.
> + if (ret)
> + return ret;
> +
> + return 0;
> +}
> +
> +static void a21_wdt_remove_files(struct device *dev)
> +{
> + device_remove_file(dev, &dev_attr_rebootcause);
> + device_remove_file(dev, &dev_attr_active);
> + device_remove_file(dev, &dev_attr_allow_disable);
> + device_remove_file(dev, &dev_attr_fastmode);
> +}
> +
> +static int a21_wdt_start(struct watchdog_device *wdt)
> +{
> + struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
> +
> + mutex_lock(&drv->lock);
> +
> + drv->open = true;
What is this flag for ?
> + gpio_set_value(GPIO_WD_ENAB, 1);
> +
> + mutex_unlock(&drv->lock);
> +
> + return 0;
> +}
> +
> +static int a21_wdt_stop(struct watchdog_device *wdt)
> +{
> + struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
> +
> + /* We don't stop if WDOG_NO_WAY_OUT is set */
> + if (test_bit(WDOG_NO_WAY_OUT, &wdt->status))
> + return -EINVAL;
> +
> + mutex_lock(&drv->lock);
> +
> + gpio_set_value(GPIO_WD_ENAB, 0);
> + drv->open = false;
> +
> + mutex_unlock(&drv->lock);
> +
> + return 0;
> +}
> +
> +static int a21_wdt_ping(struct watchdog_device *wdt)
> +{
> + struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
> +
> + mutex_lock(&drv->lock);
> +
> + gpio_set_value(GPIO_WD_TRIG, 0);
> + msleep(400);
Pretty long sleep. You really want to put applications to sleep for that long
when pinging the watchdog ? I'd be more than a bit concerned that this might be
problematic for applications expecting to do something else besides sleeping in
a watchdog ping call.
> + gpio_set_value(GPIO_WD_TRIG, 1);
> +
> + mutex_unlock(&drv->lock);
> +
> + return 0;
> +}
> +
> +static int a21_wdt_set_timeout(struct watchdog_device *wdt,
> + unsigned int timeout)
> +{
> + struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
> +
> + if (timeout != 1 || timeout != 30) {
Hmmm ... did you ever try to set the timeout ?
> + pr_err("Only 1 and 30 allowed as timeout\n");
dev_err is preferred for messages, but I wonder what value you expect
from this message (and other similar messages) in the error log.
> + return -EINVAL;
> + }
> +
> + mutex_lock(&drv->lock);
> +
> + if (timeout == 30)
> + gpio_set_value(GPIO_WD_FAST, 1);
> + else
> + gpio_set_value(GPIO_WD_FAST, 0);
> +
> + wdt->timeout = timeout;
> +
> + mutex_unlock(&drv->lock);
> +
> + return 0;
> +}
> +
> +static long a21_wdt_ioctl(struct watchdog_device *wdt, unsigned int cmd,
> + unsigned long arg)
> +{
> + unsigned int timeout;
> + int ret;
> + int __user *argp = (void __user *) arg;
> +
> + switch (cmd) {
> + case WDIOC_GETSUPPORT:
> + return copy_to_user(argp,
> + wdt->info, sizeof(struct watchdog_info));
> + case WDIOC_KEEPALIVE:
> + return a21_wdt_ping(wdt);
> + case WDIOC_SETTIMEOUT:
> + ret = get_user(timeout, argp);
> + if (ret)
> + return ret;
> + a21_wdt_set_timeout(wdt, timeout);
> + /* Fallthrough */
> + case WDIOC_GETTIMEOUT:
> + return put_user(wdt->timeout, argp);
> + case WDIOC_SETOPTIONS: {
> + int options;
> +
> + ret = get_user(options, argp);
> + if (ret)
> + return ret;
> + if (options & WDIOS_DISABLECARD)
> + a21_wdt_stop(wdt);
> + if (options & WDIOS_ENABLECARD)
> + a21_wdt_start(wdt);
> + break;
> + }
> + default:
> + pr_err("IOCTL 0x%x not understood\n", cmd);
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
What does this function offer that is not in the infrastructure ?
> +
> +static int a21_wdt_notify_sys(struct notifier_block *notify, unsigned long
> code,
> + void *unused)
> +{
> + if (code == SYS_DOWN || code == SYS_HALT)
> + gpio_set_value(GPIO_WD_ENAB, 0);
> +
> + return NOTIFY_DONE;
> +}
> +
> +static struct notifier_block a21_wdt_notifier = {
> + .notifier_call = a21_wdt_notify_sys,
> +};
> +
> +static const struct watchdog_info a21_wdt_info = {
> + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
> + .identity = "MEN A21 Watchdog",
> +};
> +
> +static const struct watchdog_ops a21_wdt_ops = {
> + .owner = THIS_MODULE,
> + .start = a21_wdt_start,
> + .stop = a21_wdt_stop,
> + .ping = a21_wdt_ping,
> + .set_timeout = a21_wdt_set_timeout,
> + .ioctl = a21_wdt_ioctl,
> +};
> +
> +static struct watchdog_device a21_wdt = {
> + .info = &a21_wdt_info,
> + .ops = &a21_wdt_ops,
> + .min_timeout = 1,
> + .max_timeout = 30,
> +};
> +
> +static int a21_wdt_probe(struct platform_device *pdev)
> +{
> + struct a21_wdt_drv *drv;
> + int ret;
> +
> + pr_info("MEN A21 watchdog timer driver enabled\n");
> +
pr_ -> dev_
> + drv = devm_kzalloc(&pdev->dev, sizeof(struct a21_wdt_drv), GFP_KERNEL);
> + if (!drv) {
> + dev_err(&pdev->dev,
> + "Unable to allocate memory for watchdog device\n");
> + return -ENOMEM;
> + }
> +
> + mutex_init(&drv->lock);
> + watchdog_set_nowayout(&a21_wdt, nowayout);
> + watchdog_set_drvdata(&a21_wdt, drv);
> +
> + ret = watchdog_register_device(&a21_wdt);
> + if (ret) {
> + pr_err("Cannot register watchdog device\n");
> + goto err_register_wd;
> + }
> +
> + ret = register_reboot_notifier(&a21_wdt_notifier);
> + if (ret) {
> + pr_err("Cannot register reboot notifier\n");
> + goto err_register_notif;
> + }
> +
> + ret = a21_wdt_create_files(&pdev->dev);
> + if (ret) {
> + dev_err(&pdev->dev, "Cannot create sysfs entries\n");
> + goto err_create_sysfs;
> + }
> +
> + dev_set_drvdata(&pdev->dev, drv);
> +
> + return 0;
> +
> +err_create_sysfs:
> + unregister_reboot_notifier(&a21_wdt_notifier);
> +err_register_notif:
> + watchdog_unregister_device(&drv->wdt);
> +err_register_wd:
> + mutex_destroy(&drv->lock);
> + devm_kfree(&pdev->dev, drv);
You might want to look into the reasons for using devm_ functions.
> +
> + return ret;
> +}
> +
> +static int a21_wdt_remove(struct platform_device *pdev)
> +{
> + struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);
> +
> + pr_warn("Unregistering A21 watchdog driver, board may reboot\n");
> +
> + a21_wdt_remove_files(&pdev->dev);
> +
> + watchdog_unregister_device(&drv->wdt);
> + unregister_reboot_notifier(&a21_wdt_notifier);
> +
> + mutex_destroy(&drv->lock);
> + devm_kfree(&pdev->dev, drv);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id a21_wdt_ids[] = {
> + { .compatible = "men,a021-wdt" },
> + { },
> +};
> +
> +static struct platform_driver a21_wdt_driver = {
> + .probe = a21_wdt_probe,
> + .remove = a21_wdt_remove,
> + .driver = {
> + .name = "a21-watchdog",
> + .of_match_table = a21_wdt_ids,
> + },
> +};
> +
> +module_platform_driver(a21_wdt_driver);
> +
> +MODULE_AUTHOR("MEN Mikro Elektronik");
> +MODULE_DESCRIPTION("MEN A21 Watchdog");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:a21-watchdog");
> --
> 1.7.9.5
>
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