Re: [PATCH v2] watchdog: Add driver for Altera Watchdog Timer
From: Jamie Iles
Date: Tue Feb 08 2011 - 12:14:05 EST
Hi Tobias,
One very pedantic comment, otherwise looks great!
On Tue, Feb 08, 2011 at 02:22:02PM +0100, Tobias Klauser wrote:
> This driver adds support for the Altera Timer in the Watchdog Timer
> configuration. This component is usually found on SOPC (System on
> Programmable Chip) for Altera FPGAs.
>
> Signed-off-by: Tobias Klauser <tklauser@xxxxxxxxxx>
Reviewed-by: Jamie Iles <jamie@xxxxxxxxxxxxx>.
> ---
>
> Thanks a lot to Jamie Iles for reviewing the first submitted version of this
> driver.
>
> changes for v2:
> - Get driver properties from devicetree (and document them), thus the
> driver depends on OF
> - Do not select WATCHDOG_NOWAYOUT, but instead implement a software
> timer resetting the watchdog timer when the device is not open
> - Only support a single instance of the watchdog, so the private data
> can be kept in static data
> - Use devm_* functions in altera_wdt_probe to simplify cleanup and
> error handling
> - Remove empty altera_wdt_shutdown function
> - Add MODULE_LICENSE (GPL)
>
> .../devicetree/bindings/watchdog/altera_wdt.txt | 7 +
> drivers/watchdog/Kconfig | 8 +
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/altera_wdt.c | 310 ++++++++++++++++++++
> 4 files changed, 326 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/watchdog/altera_wdt.txt
> create mode 100644 drivers/watchdog/altera_wdt.c
>
> diff --git a/Documentation/devicetree/bindings/watchdog/altera_wdt.txt b/Documentation/devicetree/bindings/watchdog/altera_wdt.txt
> new file mode 100644
> index 0000000..16ac949
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/watchdog/altera_wdt.txt
> @@ -0,0 +1,7 @@
> +Altera Watchdog Timer
> +
> +Required properties:
> +- compatible : should be "ALTR,wdt-1.0"
> +- clock-frequency : frequency of the clock input
> +- timeout : load value of the timer (number of clock ticks until watchdog
> + resets)
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index bd6a33d..ebcafb0 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -69,6 +69,14 @@ config WM8350_WATCHDOG
> Support for the watchdog in the WM8350 AudioPlus PMIC. When
> the watchdog triggers the system will be reset.
>
> +config ALTERA_WDT
> + tristate "Altera Watchdog Timer"
> + depends on OF
> + help
> + Support for the Altera Timer in the Watchdog Timer configuration. This
> + component is found on SOPC (System on Programmable Chip) for Altera
> + FPGAs.
> +
> # ALPHA Architecture
>
> # ARM Architecture
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index fd9c8c0..48a2167 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -153,4 +153,5 @@ obj-$(CONFIG_WATCHDOG_CP1XXX) += cpwd.o
> obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
> obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
> obj-$(CONFIG_MAX63XX_WATCHDOG) += max63xx_wdt.o
> +obj-$(CONFIG_ALTERA_WDT) += altera_wdt.o
> obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
> diff --git a/drivers/watchdog/altera_wdt.c b/drivers/watchdog/altera_wdt.c
> new file mode 100644
> index 0000000..dbced1e
> --- /dev/null
> +++ b/drivers/watchdog/altera_wdt.c
> @@ -0,0 +1,310 @@
> +/*
> + * Driver for the Altera Watchdog Timer
> + *
> + * Copyright (C) 2011 Tobias Klauser <tklauser@xxxxxxxxxx>
> + * Copyright (C) 2005 Walter Goossens
> + *
> + * Originally based on wdt.c which is
> + *
> + * Copyright (C) 1995-1997 Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
> + *
> + * Software timeout heartbeat code based on pika_wdt.c which is
> + *
> + * Copyright (c) 2008 PIKA Technologies
> + *
> + * 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; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/miscdevice.h>
> +#include <linux/watchdog.h>
> +#include <linux/platform_device.h>
> +#include <linux/fs.h>
> +#include <linux/init.h>
> +#include <linux/jiffies.h>
> +#include <linux/timer.h>
> +#include <linux/io.h>
> +#include <linux/uaccess.h>
> +#include <linux/of_platform.h>
> +
> +#define WATCHDOG_NAME "altera_wdt"
> +
> +/* Register offsets */
> +#define ALTERA_WDT_STATUS 0x00
> +#define ALTERA_WDT_CONTROL 0x04
> +#define ALTERA_WDT_PERIODL 0x08
> +#define ALTERA_WDT_PERIODH 0x0C
> +
> +#define ALTERA_WDT_RUN_BIT 0x04
> +
> +/* User land timeout */
> +#define WDT_HEARTBEAT 15
> +static int heartbeat = WDT_HEARTBEAT;
> +module_param(heartbeat, int, 0);
> +MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
> + "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
> +
> +static int nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, int, 0);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
> + "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +
> +static struct {
> + void __iomem *base;
> + unsigned long wdt_timeout; /* timeout of the hardware timer */
> +
> + unsigned long next_heartbeat; /* the next_heartbeat for the timer */
> + unsigned long is_open;
> + char expect_close;
> + struct timer_list timer; /* software timer that pings the watchdog */
> +} altera_wdt_priv;
> +
> +/*
> + * Start the watchdog. Once it has been started, it cannot be stopped anymore.
> + */
> +static int altera_wdt_setup(void)
> +{
> + u32 control = readl(altera_wdt_priv.base + ALTERA_WDT_CONTROL);
> +
> + writel(control | ALTERA_WDT_RUN_BIT, altera_wdt_priv.base + ALTERA_WDT_CONTROL);
> + return 0;
> +}
Looks like this could be made static void.
Jamie
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