On Sun, Mar 24, 2013 at 03:22:53PM +0100, Lubomir Rintel wrote: > This adds a driver for watchdog timer hardware present on Broadcom BCM2835 SoC, > used in Raspberry Pi and Roku 2 devices. > > Interface to the Broadcom BCM2835 watchdog timer hardware is based on > "bcm2708_wdog" driver written by Luke Diamand that was obtained from branch > "rpi-3.6.y" of git://github.com/raspberrypi/linux.git > I would suggest to put that into the coments at the top of the driver. Also, if the original code has a copyright statement, you might want to copy that. > Signed-off-by: Lubomir Rintel <lkundrak@xxxxx> > Cc: Stephen Warren <swarren@xxxxxxxxxxxxx> > Cc: Wim Van Sebroeck <wim@xxxxxxxxx> > Cc: linux-rpi-kernel@xxxxxxxxxxxxxxxxxxx > Cc: linux-watchdog@xxxxxxxxxxxxxxx > --- > Changes for v2: > - Use per-device structure instead of global variables for lock and memory base > - Fix default timeout setting > - Do not leak memory if probe fails > - Style fixes > - Split out defconfig into a separate commit > - Meaningful commit message with credit > > .../bindings/watchdog/brcm,bcm2835-pm-wdog.txt | 5 + > drivers/watchdog/Kconfig | 11 ++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/bcm2835_wdt.c | 189 ++++++++++++++++++++ > 4 files changed, 206 insertions(+), 0 deletions(-) > create mode 100644 drivers/watchdog/bcm2835_wdt.c > > diff --git a/Documentation/devicetree/bindings/watchdog/brcm,bcm2835-pm-wdog.txt b/Documentation/devicetree/bindings/watchdog/brcm,bcm2835-pm-wdog.txt > index d209366..f801d71 100644 > --- a/Documentation/devicetree/bindings/watchdog/brcm,bcm2835-pm-wdog.txt > +++ b/Documentation/devicetree/bindings/watchdog/brcm,bcm2835-pm-wdog.txt > @@ -5,9 +5,14 @@ Required properties: > - compatible : should be "brcm,bcm2835-pm-wdt" > - reg : Specifies base physical address and size of the registers. > > +Optional properties: > + > +- timeout-sec : Contains the watchdog timeout in seconds > + > Example: > > watchdog { > compatible = "brcm,bcm2835-pm-wdt"; > reg = <0x7e100000 0x28>; > + timeout-sec = <10>; > }; > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index 9fcc70c..f4e4a8e 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -1098,6 +1098,17 @@ config BCM63XX_WDT > To compile this driver as a loadable module, choose M here. > The module will be called bcm63xx_wdt. > > +config BCM2835_WDT > + tristate "Broadcom BCM2835 hardware watchdog" > + depends on ARCH_BCM2835 > + select WATCHDOG_CORE > + help > + Watchdog driver for the built in watchdog hardware in Broadcom > + BCM2835 SoC. > + > + To compile this driver as a loadable module, choose M here. > + The module will be called bcm2835_wdt. > + > config LANTIQ_WDT > tristate "Lantiq SoC watchdog" > depends on LANTIQ > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index a300b94..1bf5675 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -54,6 +54,7 @@ obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o > obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o > obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o > obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o > +obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o > > # AVR32 Architecture > obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o > diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c > new file mode 100644 > index 0000000..3899638 > --- /dev/null > +++ b/drivers/watchdog/bcm2835_wdt.c > @@ -0,0 +1,189 @@ > +/* > + * Watchdog driver for Broadcom BCM2835 > + * > + * Copyright (C) 2013 Lubomir Rintel <lkundrak@xxxxx> > + * > + * 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/types.h> > +#include <linux/module.h> > +#include <linux/io.h> > +#include <linux/watchdog.h> > +#include <linux/platform_device.h> > +#include <linux/of_address.h> > +#include <linux/miscdevice.h> Just noticed - you should not need that include. > + > +#define PM_RSTC 0x1c > +#define PM_RSTS 0x20 Not used > +#define PM_WDOG 0x24 > + > +#define PM_PASSWORD 0x5a000000 > +#define PM_RSTC_WRCFG_MASK 0x00000030 Not used > +#define PM_RSTC_WRCFG_FULL_RESET 0x00000020 > +#define PM_RSTS_HADWRH_SET 0x00000040 Not used > + > +#define PM_WDOG_TIME_SET 0x000fffff > +#define PM_RSTC_WRCFG_CLR 0xffffffcf > +#define PM_RSTC_WRCFG_SET 0x00000030 Not used > +#define PM_RSTC_WRCFG_FULL_RESET 0x00000020 Defined twice > +#define PM_RSTC_RESET 0x00000102 > + > +#define SECS_TO_WDOG_TICKS(x) ((x) << 16) > +#define WDOG_TICKS_TO_SECS(x) ((x) >> 16) > + > +struct bcm2835_wdt { > + void __iomem *base; > + spinlock_t lock; > +}; > + > +static int heartbeat = -1; The parameter passed to watchdog_init_timeout is an unsigned int, so you should really use an unsigned int here. Depending on -1 being converted to maxuint is a bit of side effect programming. Easier to just set it to 0, which the watchdog core interprets as invalid as well. > +static bool nowayout = WATCHDOG_NOWAYOUT; > + > +static int bcm2835_wdt_start(struct watchdog_device *wdog) > +{ > + struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog); > + uint32_t cur; > + unsigned long flags; > + > + spin_lock_irqsave(&wdt->lock, flags); > + > + writel_relaxed(PM_PASSWORD | (SECS_TO_WDOG_TICKS(wdog->timeout) & > + PM_WDOG_TIME_SET), wdt->base + PM_WDOG); > + writel_relaxed(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) | > + PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC); > + > + spin_unlock_irqrestore(&wdt->lock, flags); > + > + return 0; > +} > + > +static int bcm2835_wdt_stop(struct watchdog_device *wdog) > +{ > + struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog); > + > + writel_relaxed(PM_PASSWORD | PM_RSTC_RESET, wdt->base + PM_RSTC); > + dev_info(wdog->dev, "Watchdog timer stopped"); > + return 0; > +} > + > +static int bcm2835_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) > +{ > + wdog->timeout = t; > + return 0; > +} > + > +static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog) > +{ > + struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog); > + > + uint32_t ret = readl_relaxed(wdt->base + PM_WDOG); > + return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET); > +} > + > +static struct watchdog_ops bcm2835_wdt_ops = { > + .owner = THIS_MODULE, > + .start = bcm2835_wdt_start, > + .stop = bcm2835_wdt_stop, > + .set_timeout = bcm2835_wdt_set_timeout, > + .get_timeleft = bcm2835_wdt_get_timeleft, > +}; > + > +static struct watchdog_info bcm2835_wdt_info = { > + .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | > + WDIOF_KEEPALIVEPING, > + .identity = "Broadcom BCM2835 Watchdog timer", > +}; > + > +static struct watchdog_device bcm2835_wdt_wdd = { > + .info = &bcm2835_wdt_info, > + .ops = &bcm2835_wdt_ops, > + .min_timeout = 1, > + .max_timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET), > + .timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET), > +}; > + > +static int bcm2835_wdt_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct device_node *np = dev->of_node; > + struct bcm2835_wdt *wdt; > + int err; > + > + wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL); > + if (!wdt) { > + dev_err(dev, "Failed to allocate memory for watchdog device"); > + return -ENOMEM; > + } > + > + spin_lock_init(&wdt->lock); > + > + wdt->base = of_iomap(np, 0); > + if (!wdt->base) { > + dev_err(dev, "Failed to remap watchdog regs"); > + return -ENODEV; > + } > + dev_info(dev, "Broadcom BCM2835 watchdog timer"); > + I think this should come later, after you are sure that there will be no failure. > + platform_set_drvdata(pdev, wdt); > + > + watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt); > + watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev); > + watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout); > + err = watchdog_register_device(&bcm2835_wdt_wdd); > + if (err) { > + dev_err(dev, "Failed to register watchdog device"); > + iounmap(wdt->base); > + } > + return err; > +} > + > +static int bcm2835_wdt_remove(struct platform_device *pdev) > +{ > + struct bcm2835_wdt *wdt = platform_get_drvdata(pdev); > + > + platform_set_drvdata(pdev, NULL); It is unnecessary to set this to NULL (the infrastructure does it for you). > + watchdog_unregister_device(&bcm2835_wdt_wdd); > + iounmap(wdt->base); > + > + return 0; > +} > + > +static void bcm2835_wdt_shutdown(struct platform_device *pdev) > +{ > + bcm2835_wdt_stop(&bcm2835_wdt_wdd); > +} > + > +static const struct of_device_id bcm2835_wdt_of_match[] = { > + { .compatible = "brcm,bcm2835-pm-wdt", }, > + {}, > +}; > +MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match); > + > +static struct platform_driver bcm2835_wdt_driver = { > + .probe = bcm2835_wdt_probe, > + .remove = bcm2835_wdt_remove, > + .shutdown = bcm2835_wdt_shutdown, > + .driver = { > + .name = "bcm2835-wdt", > + .owner = THIS_MODULE, > + .of_match_table = bcm2835_wdt_of_match, > + }, > +}; > +module_platform_driver(bcm2835_wdt_driver); > + > +module_param(heartbeat, int, 0); > +MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds"); > + > +module_param(nowayout, bool, 0); > +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" > + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); > + > +MODULE_AUTHOR("Lubomir Rintel <lkundrak@xxxxx>"); > +MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer"); > +MODULE_LICENSE("GPL"); > +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); > -- > 1.7.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html