From e376fd664b1547e29e264e3cfb97553a1be9054b Mon Sep 17 00:00:00 2001 From: Jesper Juhl Date: Thu, 26 May 2011 11:12:53 +0200 Subject: watchdog: Intel SCU Watchdog: Fix build and remove duplicate code MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Trying to build the Intel SCU Watchdog fails for me with gcc 4.6.0 - $ gcc --version | head -n 1 gcc (GCC) 4.6.0 20110513 (prerelease) like this : CC drivers/watchdog/intel_scu_watchdog.o In file included from drivers/watchdog/intel_scu_watchdog.c:49:0: /home/jj/src/linux-2.6/arch/x86/include/asm/apb_timer.h: In function ‘apbt_time_init’: /home/jj/src/linux-2.6/arch/x86/include/asm/apb_timer.h:65:42: warning: ‘return’ with a value, in function returning void [enabled by default] drivers/watchdog/intel_scu_watchdog.c: In function ‘intel_scu_watchdog_init’: drivers/watchdog/intel_scu_watchdog.c:468:2: error: implicit declaration of function ‘sfi_get_mtmr’ [-Werror=implicit-function-declaration] drivers/watchdog/intel_scu_watchdog.c:468:32: warning: assignment makes pointer from integer without a cast [enabled by default] cc1: some warnings being treated as errors make[1]: *** [drivers/watchdog/intel_scu_watchdog.o] Error 1 make: *** [drivers/watchdog/intel_scu_watchdog.o] Error 2 Additionally, linux/types.h is needlessly being included twice in drivers/watchdog/intel_scu_watchdog.c Signed-off-by: Jesper Juhl Signed-off-by: Wim Van Sebroeck --- drivers/watchdog/Kconfig | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'drivers/watchdog/Kconfig') diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 022f9eb0b7bf..9536d386bb38 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -535,8 +535,7 @@ config I6300ESB_WDT config INTEL_SCU_WATCHDOG bool "Intel SCU Watchdog for Mobile Platforms" - depends on WATCHDOG - depends on INTEL_SCU_IPC + depends on X86_MRST ---help--- Hardware driver for the watchdog time built into the Intel SCU for Intel Mobile Platforms. -- cgit v1.2.3 From 2a75ca4a43e4276e6da2c75bea672a03e8e900fb Mon Sep 17 00:00:00 2001 From: Olaf Hering Date: Fri, 15 Jul 2011 23:23:33 +0200 Subject: watchdog: fix hpwdt Kconfig regression in 3.0-rc Remove Kconfig regression caused by commit a4616153deae053b29a2b7dd9ec4b2a225accfc5 "watchdog: hpwdt: build hpwdt as module by default with NMI_DECODING enabled" With the above change applied, hpwdt will be enabled unconditionally by just entering the Watchdog subscreen in menuconfig. Since this driver is not essential to boot any box it should remain disabled until it gets manually enabled, just like all other drivers. Signed-off-by: Olaf Hering Cc: Tony Camuso Signed-off-by: Wim Van Sebroeck Signed-off-by: Andrew Morton --- drivers/watchdog/Kconfig | 1 - 1 file changed, 1 deletion(-) (limited to 'drivers/watchdog/Kconfig') diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 9536d386bb38..c57419bf08f1 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -600,7 +600,6 @@ config IT87_WDT config HP_WATCHDOG tristate "HP ProLiant iLO2+ Hardware Watchdog Timer" depends on X86 - default m help A software monitoring watchdog and NMI sourcing driver. This driver will detect lockups and provide a stack trace. This is a driver that -- cgit v1.2.3 From f71d26bb6503e9b11b91444819b2f96872baaab8 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Sat, 16 Jul 2011 12:25:49 -0700 Subject: watchdog: hpwdt depends on PCI hpwdt is a PCI driver so it should depend on PCI. Fixes these build errors: drivers/watchdog/hpwdt.c:762: error: implicit declaration of function 'pci_iomap' drivers/watchdog/hpwdt.c:762: warning: assignment makes pointer from integer without a cast drivers/watchdog/hpwdt.c:797: error: implicit declaration of function 'pci_iounmap' Signed-off-by: Randy Dunlap Signed-off-by: Wim Van Sebroeck Cc: Thomas Mingarelli --- drivers/watchdog/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/watchdog/Kconfig') diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index c57419bf08f1..21d816e9dfa5 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -599,7 +599,7 @@ config IT87_WDT config HP_WATCHDOG tristate "HP ProLiant iLO2+ Hardware Watchdog Timer" - depends on X86 + depends on X86 && PCI help A software monitoring watchdog and NMI sourcing driver. This driver will detect lockups and provide a stack trace. This is a driver that -- cgit v1.2.3 From c9353ae1c69ba13ec9d29ab4f2dae881c2c06a58 Mon Sep 17 00:00:00 2001 From: Jamie Iles Date: Mon, 24 Jan 2011 12:19:12 +0000 Subject: watchdog: add support for the Synopsys DesignWare WDT The Synopsys DesignWare watchdog is found in several ARM based systems and provides a choice of 16 timeout periods depending on the clock input. The watchdog cannot be disabled once started. Signed-off-by: Jamie Iles Acked-by: Viresh Kumar Signed-off-by: Wim Van Sebroeck --- drivers/watchdog/Kconfig | 9 ++ drivers/watchdog/Makefile | 1 + drivers/watchdog/dw_wdt.c | 376 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 386 insertions(+) create mode 100644 drivers/watchdog/dw_wdt.c (limited to 'drivers/watchdog/Kconfig') diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 21d816e9dfa5..de78d0ab041f 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -186,6 +186,15 @@ config SA1100_WATCHDOG To compile this driver as a module, choose M here: the module will be called sa1100_wdt. +config DW_WATCHDOG + tristate "Synopsys DesignWare watchdog" + depends on ARM && HAVE_CLK + help + Say Y here if to include support for the Synopsys DesignWare + watchdog timer found in many ARM chips. + To compile this driver as a module, choose M here: the + module will be called dw_wdt. + config MPCORE_WATCHDOG tristate "MPcore watchdog" depends on HAVE_ARM_TWD diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index ed26f7094e47..b2ddff704ae0 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -37,6 +37,7 @@ obj-$(CONFIG_IXP4XX_WATCHDOG) += ixp4xx_wdt.o obj-$(CONFIG_KS8695_WATCHDOG) += ks8695_wdt.o obj-$(CONFIG_S3C2410_WATCHDOG) += s3c2410_wdt.o obj-$(CONFIG_SA1100_WATCHDOG) += sa1100_wdt.o +obj-$(CONFIG_DW_WATCHDOG) += dw_wdt.o obj-$(CONFIG_MPCORE_WATCHDOG) += mpcore_wdt.o obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c new file mode 100644 index 000000000000..f10f8c0abba4 --- /dev/null +++ b/drivers/watchdog/dw_wdt.c @@ -0,0 +1,376 @@ +/* + * Copyright 2010-2011 Picochip Ltd., Jamie Iles + * http://www.picochip.com + * + * 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. + * + * This file implements a driver for the Synopsys DesignWare watchdog device + * in the many ARM subsystems. The watchdog has 16 different timeout periods + * and these are a function of the input clock frequency. + * + * The DesignWare watchdog cannot be stopped once it has been started so we + * use a software timer to implement a ping that will keep the watchdog alive. + * If we receive an expected close for the watchdog then we keep the timer + * running, otherwise the timer is stopped and the watchdog will expire. + */ +#define pr_fmt(fmt) "dw_wdt: " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define WDOG_CONTROL_REG_OFFSET 0x00 +#define WDOG_CONTROL_REG_WDT_EN_MASK 0x01 +#define WDOG_TIMEOUT_RANGE_REG_OFFSET 0x04 +#define WDOG_CURRENT_COUNT_REG_OFFSET 0x08 +#define WDOG_COUNTER_RESTART_REG_OFFSET 0x0c +#define WDOG_COUNTER_RESTART_KICK_VALUE 0x76 + +/* The maximum TOP (timeout period) value that can be set in the watchdog. */ +#define DW_WDT_MAX_TOP 15 + +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) ")"); + +#define WDT_TIMEOUT (HZ / 2) + +static struct { + spinlock_t lock; + void __iomem *regs; + struct clk *clk; + unsigned long in_use; + unsigned long next_heartbeat; + struct timer_list timer; + int expect_close; +} dw_wdt; + +static inline int dw_wdt_is_enabled(void) +{ + return readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET) & + WDOG_CONTROL_REG_WDT_EN_MASK; +} + +static inline int dw_wdt_top_in_seconds(unsigned top) +{ + /* + * There are 16 possible timeout values in 0..15 where the number of + * cycles is 2 ^ (16 + i) and the watchdog counts down. + */ + return (1 << (16 + top)) / clk_get_rate(dw_wdt.clk); +} + +static int dw_wdt_get_top(void) +{ + int top = readl(dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET) & 0xF; + + return dw_wdt_top_in_seconds(top); +} + +static inline void dw_wdt_set_next_heartbeat(void) +{ + dw_wdt.next_heartbeat = jiffies + dw_wdt_get_top() * HZ; +} + +static int dw_wdt_set_top(unsigned top_s) +{ + int i, top_val = DW_WDT_MAX_TOP; + + /* + * Iterate over the timeout values until we find the closest match. We + * always look for >=. + */ + for (i = 0; i <= DW_WDT_MAX_TOP; ++i) + if (dw_wdt_top_in_seconds(i) >= top_s) { + top_val = i; + break; + } + + /* Set the new value in the watchdog. */ + writel(top_val, dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); + + dw_wdt_set_next_heartbeat(); + + return dw_wdt_top_in_seconds(top_val); +} + +static void dw_wdt_keepalive(void) +{ + writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs + + WDOG_COUNTER_RESTART_REG_OFFSET); +} + +static void dw_wdt_ping(unsigned long data) +{ + if (time_before(jiffies, dw_wdt.next_heartbeat) || + (!nowayout && !dw_wdt.in_use)) { + dw_wdt_keepalive(); + mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT); + } else + pr_crit("keepalive missed, machine will reset\n"); +} + +static int dw_wdt_open(struct inode *inode, struct file *filp) +{ + if (test_and_set_bit(0, &dw_wdt.in_use)) + return -EBUSY; + + /* Make sure we don't get unloaded. */ + __module_get(THIS_MODULE); + + spin_lock(&dw_wdt.lock); + if (!dw_wdt_is_enabled()) { + /* + * The watchdog is not currently enabled. Set the timeout to + * the maximum and then start it. + */ + dw_wdt_set_top(DW_WDT_MAX_TOP); + writel(WDOG_CONTROL_REG_WDT_EN_MASK, + dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); + } + + dw_wdt_set_next_heartbeat(); + + spin_unlock(&dw_wdt.lock); + + return nonseekable_open(inode, filp); +} + +ssize_t dw_wdt_write(struct file *filp, const char __user *buf, size_t len, + loff_t *offset) +{ + if (!len) + return 0; + + if (!nowayout) { + size_t i; + + dw_wdt.expect_close = 0; + + for (i = 0; i < len; ++i) { + char c; + + if (get_user(c, buf + i)) + return -EFAULT; + + if (c == 'V') { + dw_wdt.expect_close = 1; + break; + } + } + } + + dw_wdt_set_next_heartbeat(); + mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT); + + return len; +} + +static u32 dw_wdt_time_left(void) +{ + return readl(dw_wdt.regs + WDOG_CURRENT_COUNT_REG_OFFSET) / + clk_get_rate(dw_wdt.clk); +} + +static const struct watchdog_info dw_wdt_ident = { + .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | + WDIOF_MAGICCLOSE, + .identity = "Synopsys DesignWare Watchdog", +}; + +static long dw_wdt_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) +{ + unsigned long val; + int timeout; + + switch (cmd) { + case WDIOC_GETSUPPORT: + return copy_to_user((struct watchdog_info *)arg, &dw_wdt_ident, + sizeof(dw_wdt_ident)) ? -EFAULT : 0; + + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, (int *)arg); + + case WDIOC_KEEPALIVE: + dw_wdt_set_next_heartbeat(); + return 0; + + case WDIOC_SETTIMEOUT: + if (get_user(val, (int __user *)arg)) + return -EFAULT; + timeout = dw_wdt_set_top(val); + return put_user(timeout , (int __user *)arg); + + case WDIOC_GETTIMEOUT: + return put_user(dw_wdt_get_top(), (int __user *)arg); + + case WDIOC_GETTIMELEFT: + /* Get the time left until expiry. */ + if (get_user(val, (int __user *)arg)) + return -EFAULT; + return put_user(dw_wdt_time_left(), (int __user *)arg); + + default: + return -ENOTTY; + } +} + +static int dw_wdt_release(struct inode *inode, struct file *filp) +{ + clear_bit(0, &dw_wdt.in_use); + + if (!dw_wdt.expect_close) { + del_timer(&dw_wdt.timer); + + if (!nowayout) + pr_crit("unexpected close, system will reboot soon\n"); + else + pr_crit("watchdog cannot be disabled, system will reboot soon\n"); + } + + dw_wdt.expect_close = 0; + + return 0; +} + +#ifdef CONFIG_PM +static int dw_wdt_suspend(struct device *dev) +{ + clk_disable(dw_wdt.clk); + + return 0; +} + +static int dw_wdt_resume(struct device *dev) +{ + int err = clk_enable(dw_wdt.clk); + + if (err) + return err; + + dw_wdt_keepalive(); + + return 0; +} + +static const struct dev_pm_ops dw_wdt_pm_ops = { + .suspend = dw_wdt_suspend, + .resume = dw_wdt_resume, +}; +#endif /* CONFIG_PM */ + +static const struct file_operations wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .open = dw_wdt_open, + .write = dw_wdt_write, + .unlocked_ioctl = dw_wdt_ioctl, + .release = dw_wdt_release +}; + +static struct miscdevice dw_wdt_miscdev = { + .fops = &wdt_fops, + .name = "watchdog", + .minor = WATCHDOG_MINOR, +}; + +static int __devinit dw_wdt_drv_probe(struct platform_device *pdev) +{ + int ret; + struct resource *mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + + if (!mem) + return -EINVAL; + + if (!devm_request_mem_region(&pdev->dev, mem->start, resource_size(mem), + "dw_wdt")) + return -ENOMEM; + + dw_wdt.regs = devm_ioremap(&pdev->dev, mem->start, resource_size(mem)); + if (!dw_wdt.regs) + return -ENOMEM; + + dw_wdt.clk = clk_get(&pdev->dev, NULL); + if (IS_ERR(dw_wdt.clk)) + return PTR_ERR(dw_wdt.clk); + + ret = clk_enable(dw_wdt.clk); + if (ret) + goto out_put_clk; + + spin_lock_init(&dw_wdt.lock); + + ret = misc_register(&dw_wdt_miscdev); + if (ret) + goto out_disable_clk; + + dw_wdt_set_next_heartbeat(); + setup_timer(&dw_wdt.timer, dw_wdt_ping, 0); + mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT); + + return 0; + +out_disable_clk: + clk_disable(dw_wdt.clk); +out_put_clk: + clk_put(dw_wdt.clk); + + return ret; +} + +static int __devexit dw_wdt_drv_remove(struct platform_device *pdev) +{ + misc_deregister(&dw_wdt_miscdev); + + clk_disable(dw_wdt.clk); + clk_put(dw_wdt.clk); + + return 0; +} + +static struct platform_driver dw_wdt_driver = { + .probe = dw_wdt_drv_probe, + .remove = __devexit_p(dw_wdt_drv_remove), + .driver = { + .name = "dw_wdt", + .owner = THIS_MODULE, +#ifdef CONFIG_PM + .pm = &dw_wdt_pm_ops, +#endif /* CONFIG_PM */ + }, +}; + +static int __init dw_wdt_watchdog_init(void) +{ + return platform_driver_register(&dw_wdt_driver); +} +module_init(dw_wdt_watchdog_init); + +static void __exit dw_wdt_watchdog_exit(void) +{ + platform_driver_unregister(&dw_wdt_driver); +} +module_exit(dw_wdt_watchdog_exit); + +MODULE_AUTHOR("Jamie Iles"); +MODULE_DESCRIPTION("Synopsys DesignWare Watchdog Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); -- cgit v1.2.3 From bfbc5e272d8aa92f6f9b05361e76e87075111e48 Mon Sep 17 00:00:00 2001 From: Sascha Hauer Date: Thu, 3 Mar 2011 14:30:59 +0100 Subject: watchdog: i.MX: use IMX_HAVE_PLATFORM_IMX2_WDT to depend on MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The i.MX architecture provides IMX_HAVE_PLATFORM_* macros to signal that a selected SoC supports a certain hardware. Use them instead of depending on ARCH_* directly. Signed-off-by: Sascha Hauer Acked-by: Uwe Kleine-König Signed-off-by: Wim Van Sebroeck Cc: linux-watchdog@vger.kernel.org --- drivers/watchdog/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/watchdog/Kconfig') diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index de78d0ab041f..df6b8ff26c9d 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -330,7 +330,7 @@ config MAX63XX_WATCHDOG config IMX2_WDT tristate "IMX2+ Watchdog" - depends on ARCH_MX2 || ARCH_MX25 || ARCH_MX3 || ARCH_MX5 + depends on IMX_HAVE_PLATFORM_IMX2_WDT help This is the driver for the hardware watchdog on the Freescale IMX2 and later processors. -- cgit v1.2.3 From e9659e69b0094ea2cc92716e2b1cd6a7db9caf2e Mon Sep 17 00:00:00 2001 From: Alejandro Cabrera Date: Thu, 2 Jun 2011 22:13:11 +0100 Subject: watchdog: Add Xilinx watchdog timer driver Watchdog timer device driver for Xilinx xps_timebase_wdt compatible ip cores. It takes watchdog timer configuration from device tree and it needs that its parent has defined the property "clock-frecuency". It is compatible with watchdog timer kernel API, so user apps like watchdogd may talk with it. Signed-off-by: Alejandro Cabrera Signed-off-by: Wim Van Sebroeck --- drivers/watchdog/Kconfig | 14 ++ drivers/watchdog/Makefile | 3 + drivers/watchdog/of_xilinx_wdt.c | 433 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 450 insertions(+) create mode 100644 drivers/watchdog/of_xilinx_wdt.c (limited to 'drivers/watchdog/Kconfig') diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index df6b8ff26c9d..0635e72e0794 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -888,6 +888,20 @@ config M54xx_WATCHDOG To compile this driver as a module, choose M here: the module will be called m54xx_wdt. +# MicroBlaze Architecture + +config XILINX_WATCHDOG + tristate "Xilinx Watchdog timer" + depends on MICROBLAZE + ---help--- + Watchdog driver for the xps_timebase_wdt ip core. + + IMPORTANT: The xps_timebase_wdt parent must have the property + "clock-frequency" at device tree. + + To compile this driver as a module, choose M here: the + module will be called of_xilinx_wdt. + # MIPS Architecture config ATH79_WDT diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index b2ddff704ae0..9eaa212398d7 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -110,6 +110,9 @@ obj-$(CONFIG_INTEL_SCU_WATCHDOG) += intel_scu_watchdog.o # M68K Architecture obj-$(CONFIG_M54xx_WATCHDOG) += m54xx_wdt.o +# MicroBlaze Architecture +obj-$(CONFIG_XILINX_WATCHDOG) += of_xilinx_wdt.o + # MIPS Architecture obj-$(CONFIG_ATH79_WDT) += ath79_wdt.o obj-$(CONFIG_BCM47XX_WDT) += bcm47xx_wdt.o diff --git a/drivers/watchdog/of_xilinx_wdt.c b/drivers/watchdog/of_xilinx_wdt.c new file mode 100644 index 000000000000..4ec741ac952c --- /dev/null +++ b/drivers/watchdog/of_xilinx_wdt.c @@ -0,0 +1,433 @@ +/* +* of_xilinx_wdt.c 1.01 A Watchdog Device Driver for Xilinx xps_timebase_wdt +* +* (C) Copyright 2011 (Alejandro Cabrera ) +* +* ----------------------- +* +* 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. +* +* ----------------------- +* 30-May-2011 Alejandro Cabrera +* - If "xlnx,wdt-enable-once" wasn't found on device tree the +* module will use CONFIG_WATCHDOG_NOWAYOUT +* - If the device tree parameters ("clock-frequency" and +* "xlnx,wdt-interval") wasn't found the driver won't +* know the wdt reset interval +*/ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* Register offsets for the Wdt device */ +#define XWT_TWCSR0_OFFSET 0x0 /* Control/Status Register0 */ +#define XWT_TWCSR1_OFFSET 0x4 /* Control/Status Register1 */ +#define XWT_TBR_OFFSET 0x8 /* Timebase Register Offset */ + +/* Control/Status Register Masks */ +#define XWT_CSR0_WRS_MASK 0x00000008 /* Reset status */ +#define XWT_CSR0_WDS_MASK 0x00000004 /* Timer state */ +#define XWT_CSR0_EWDT1_MASK 0x00000002 /* Enable bit 1 */ + +/* Control/Status Register 0/1 bits */ +#define XWT_CSRX_EWDT2_MASK 0x00000001 /* Enable bit 2 */ + +/* SelfTest constants */ +#define XWT_MAX_SELFTEST_LOOP_COUNT 0x00010000 +#define XWT_TIMER_FAILED 0xFFFFFFFF + +#define WATCHDOG_NAME "Xilinx Watchdog" +#define PFX WATCHDOG_NAME ": " + +struct xwdt_device { + struct resource res; + void __iomem *base; + u32 nowayout; + u32 wdt_interval; + u32 boot_status; +}; + +static struct xwdt_device xdev; + +static u32 timeout; +static u32 control_status_reg; +static u8 expect_close; +static u8 no_timeout; +static unsigned long driver_open; + +static DEFINE_SPINLOCK(spinlock); + +static void xwdt_start(void) +{ + spin_lock(&spinlock); + + /* Clean previous status and enable the watchdog timer */ + control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET); + control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK); + + iowrite32((control_status_reg | XWT_CSR0_EWDT1_MASK), + xdev.base + XWT_TWCSR0_OFFSET); + + iowrite32(XWT_CSRX_EWDT2_MASK, xdev.base + XWT_TWCSR1_OFFSET); + + spin_unlock(&spinlock); +} + +static void xwdt_stop(void) +{ + spin_lock(&spinlock); + + control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET); + + iowrite32((control_status_reg & ~XWT_CSR0_EWDT1_MASK), + xdev.base + XWT_TWCSR0_OFFSET); + + iowrite32(0, xdev.base + XWT_TWCSR1_OFFSET); + + spin_unlock(&spinlock); + printk(KERN_INFO PFX "Stopped!\n"); +} + +static void xwdt_keepalive(void) +{ + spin_lock(&spinlock); + + control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET); + control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK); + iowrite32(control_status_reg, xdev.base + XWT_TWCSR0_OFFSET); + + spin_unlock(&spinlock); +} + +static void xwdt_get_status(int *status) +{ + int new_status; + + spin_lock(&spinlock); + + control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET); + new_status = ((control_status_reg & + (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK)) != 0); + spin_unlock(&spinlock); + + *status = 0; + if (new_status & 1) + *status |= WDIOF_CARDRESET; +} + +static u32 xwdt_selftest(void) +{ + int i; + u32 timer_value1; + u32 timer_value2; + + spin_lock(&spinlock); + + timer_value1 = ioread32(xdev.base + XWT_TBR_OFFSET); + timer_value2 = ioread32(xdev.base + XWT_TBR_OFFSET); + + for (i = 0; + ((i <= XWT_MAX_SELFTEST_LOOP_COUNT) && + (timer_value2 == timer_value1)); i++) { + timer_value2 = ioread32(xdev.base + XWT_TBR_OFFSET); + } + + spin_unlock(&spinlock); + + if (timer_value2 != timer_value1) + return ~XWT_TIMER_FAILED; + else + return XWT_TIMER_FAILED; +} + +static int xwdt_open(struct inode *inode, struct file *file) +{ + /* Only one process can handle the wdt at a time */ + if (test_and_set_bit(0, &driver_open)) + return -EBUSY; + + /* Make sure that the module are always loaded...*/ + if (xdev.nowayout) + __module_get(THIS_MODULE); + + xwdt_start(); + printk(KERN_INFO PFX "Started...\n"); + + return nonseekable_open(inode, file); +} + +static int xwdt_release(struct inode *inode, struct file *file) +{ + if (expect_close == 42) { + xwdt_stop(); + } else { + printk(KERN_CRIT PFX + "Unexpected close, not stopping watchdog!\n"); + xwdt_keepalive(); + } + + clear_bit(0, &driver_open); + expect_close = 0; + return 0; +} + +/* + * xwdt_write: + * @file: file handle to the watchdog + * @buf: buffer to write (unused as data does not matter here + * @count: count of bytes + * @ppos: pointer to the position to write. No seeks allowed + * + * A write to a watchdog device is defined as a keepalive signal. Any + * write of data will do, as we don't define content meaning. + */ +static ssize_t xwdt_write(struct file *file, const char __user *buf, + size_t len, loff_t *ppos) +{ + if (len) { + if (!xdev.nowayout) { + size_t i; + + /* In case it was set long ago */ + expect_close = 0; + + for (i = 0; i != len; i++) { + char c; + + if (get_user(c, buf + i)) + return -EFAULT; + if (c == 'V') + expect_close = 42; + } + } + xwdt_keepalive(); + } + return len; +} + +static const struct watchdog_info ident = { + .options = WDIOF_MAGICCLOSE | + WDIOF_KEEPALIVEPING, + .firmware_version = 1, + .identity = WATCHDOG_NAME, +}; + +/* + * xwdt_ioctl: + * @file: file handle to the device + * @cmd: watchdog command + * @arg: argument pointer + * + * The watchdog API defines a common set of functions for all watchdogs + * according to their available features. + */ +static long xwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + int status; + + union { + struct watchdog_info __user *ident; + int __user *i; + } uarg; + + uarg.i = (int __user *)arg; + + switch (cmd) { + case WDIOC_GETSUPPORT: + return copy_to_user(uarg.ident, &ident, + sizeof(ident)) ? -EFAULT : 0; + + case WDIOC_GETBOOTSTATUS: + return put_user(xdev.boot_status, uarg.i); + + case WDIOC_GETSTATUS: + xwdt_get_status(&status); + return put_user(status, uarg.i); + + case WDIOC_KEEPALIVE: + xwdt_keepalive(); + return 0; + + case WDIOC_GETTIMEOUT: + if (no_timeout) + return -ENOTTY; + else + return put_user(timeout, uarg.i); + + default: + return -ENOTTY; + } +} + +static const struct file_operations xwdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = xwdt_write, + .open = xwdt_open, + .release = xwdt_release, + .unlocked_ioctl = xwdt_ioctl, +}; + +static struct miscdevice xwdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &xwdt_fops, +}; + +static int __devinit xwdt_probe(struct platform_device *pdev) +{ + int rc; + u32 *tmptr; + u32 *pfreq; + + no_timeout = 0; + + pfreq = (u32 *)of_get_property(pdev->dev.of_node->parent, + "clock-frequency", NULL); + + if (pfreq == NULL) { + printk(KERN_WARNING PFX + "The watchdog clock frequency cannot be obtained!\n"); + no_timeout = 1; + } + + rc = of_address_to_resource(pdev->dev.of_node, 0, &xdev.res); + if (rc) { + printk(KERN_WARNING PFX "invalid address!\n"); + return rc; + } + + tmptr = (u32 *)of_get_property(pdev->dev.of_node, + "xlnx,wdt-interval", NULL); + if (tmptr == NULL) { + printk(KERN_WARNING PFX "Parameter \"xlnx,wdt-interval\"" + " not found in device tree!\n"); + no_timeout = 1; + } else { + xdev.wdt_interval = *tmptr; + } + + tmptr = (u32 *)of_get_property(pdev->dev.of_node, + "xlnx,wdt-enable-once", NULL); + if (tmptr == NULL) { + printk(KERN_WARNING PFX "Parameter \"xlnx,wdt-enable-once\"" + " not found in device tree!\n"); + xdev.nowayout = WATCHDOG_NOWAYOUT; + } + +/* + * Twice of the 2^wdt_interval / freq because the first wdt overflow is + * ignored (interrupt), reset is only generated at second wdt overflow + */ + if (!no_timeout) + timeout = 2 * ((1<"); +MODULE_DESCRIPTION("Xilinx Watchdog driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); -- cgit v1.2.3 From 43316044d4f64da008d6aca7d4b60771b9a24eb8 Mon Sep 17 00:00:00 2001 From: Wim Van Sebroeck Date: Fri, 22 Jul 2011 18:55:18 +0000 Subject: watchdog: WatchDog Timer Driver Core - Add basic framework The WatchDog Timer Driver Core is a framework that contains the common code for all watchdog-driver's. It also introduces a watchdog device structure and the operations that go with it. This is the introduction of this framework. This part supports the minimal watchdog userspace API (or with other words: the functionality to use /dev/watchdog's open, release and write functionality as defined in the simplest watchdog API). Extra functionality will follow in the next set of patches. Signed-off-by: Alan Cox Signed-off-by: Wim Van Sebroeck Acked-by: Arnd Bergmann Acked-by: Wolfram Sang --- Documentation/watchdog/00-INDEX | 2 + Documentation/watchdog/watchdog-kernel-api.txt | 119 +++++++++++++ drivers/watchdog/Kconfig | 11 ++ drivers/watchdog/Makefile | 4 + drivers/watchdog/watchdog_core.c | 101 +++++++++++ drivers/watchdog/watchdog_dev.c | 235 +++++++++++++++++++++++++ drivers/watchdog/watchdog_dev.h | 33 ++++ include/linux/watchdog.h | 61 +++++++ 8 files changed, 566 insertions(+) create mode 100644 Documentation/watchdog/watchdog-kernel-api.txt create mode 100644 drivers/watchdog/watchdog_core.c create mode 100644 drivers/watchdog/watchdog_dev.c create mode 100644 drivers/watchdog/watchdog_dev.h (limited to 'drivers/watchdog/Kconfig') diff --git a/Documentation/watchdog/00-INDEX b/Documentation/watchdog/00-INDEX index ee994513a9b1..fc51128071c2 100644 --- a/Documentation/watchdog/00-INDEX +++ b/Documentation/watchdog/00-INDEX @@ -8,6 +8,8 @@ src/ - directory holding watchdog related example programs. watchdog-api.txt - description of the Linux Watchdog driver API. +watchdog-kernel-api.txt + - description of the Linux WatchDog Timer Driver Core kernel API. watchdog-parameters.txt - information on driver parameters (for drivers other than the ones that have driver-specific files here) diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt new file mode 100644 index 000000000000..3db67e74b80e --- /dev/null +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -0,0 +1,119 @@ +The Linux WatchDog Timer Driver Core kernel API. +=============================================== +Last reviewed: 22-Jul-2011 + +Wim Van Sebroeck + +Introduction +------------ +This document does not describe what a WatchDog Timer (WDT) Driver or Device is. +It also does not describe the API which can be used by user space to communicate +with a WatchDog Timer. If you want to know this then please read the following +file: Documentation/watchdog/watchdog-api.txt . + +So what does this document describe? It describes the API that can be used by +WatchDog Timer Drivers that want to use the WatchDog Timer Driver Core +Framework. This framework provides all interfacing towards user space so that +the same code does not have to be reproduced each time. This also means that +a watchdog timer driver then only needs to provide the different routines +(operations) that control the watchdog timer (WDT). + +The API +------- +Each watchdog timer driver that wants to use the WatchDog Timer Driver Core +must #include (you would have to do this anyway when +writing a watchdog device driver). This include file contains following +register/unregister routines: + +extern int watchdog_register_device(struct watchdog_device *); +extern void watchdog_unregister_device(struct watchdog_device *); + +The watchdog_register_device routine registers a watchdog timer device. +The parameter of this routine is a pointer to a watchdog_device structure. +This routine returns zero on success and a negative errno code for failure. + +The watchdog_unregister_device routine deregisters a registered watchdog timer +device. The parameter of this routine is the pointer to the registered +watchdog_device structure. + +The watchdog device structure looks like this: + +struct watchdog_device { + const struct watchdog_info *info; + const struct watchdog_ops *ops; + void *driver_data; + unsigned long status; +}; + +It contains following fields: +* info: a pointer to a watchdog_info structure. This structure gives some + additional information about the watchdog timer itself. (Like it's unique name) +* ops: a pointer to the list of watchdog operations that the watchdog supports. +* driver_data: a pointer to the drivers private data of a watchdog device. + This data should only be accessed via the watchdog_set_drvadata and + watchdog_get_drvdata routines. +* status: this field contains a number of status bits that give extra + information about the status of the device (Like: is the device opened via + the /dev/watchdog interface or not, ...). + +The list of watchdog operations is defined as: + +struct watchdog_ops { + struct module *owner; + /* mandatory operations */ + int (*start)(struct watchdog_device *); + int (*stop)(struct watchdog_device *); + /* optional operations */ + int (*ping)(struct watchdog_device *); +}; + +It is important that you first define the module owner of the watchdog timer +driver's operations. This module owner will be used to lock the module when +the watchdog is active. (This to avoid a system crash when you unload the +module and /dev/watchdog is still open). +Some operations are mandatory and some are optional. The mandatory operations +are: +* start: this is a pointer to the routine that starts the watchdog timer + device. + The routine needs a pointer to the watchdog timer device structure as a + parameter. It returns zero on success or a negative errno code for failure. +* stop: with this routine the watchdog timer device is being stopped. + The routine needs a pointer to the watchdog timer device structure as a + parameter. It returns zero on success or a negative errno code for failure. + Some watchdog timer hardware can only be started and not be stopped. The + driver supporting this hardware needs to make sure that a start and stop + routine is being provided. This can be done by using a timer in the driver + that regularly sends a keepalive ping to the watchdog timer hardware. + +Not all watchdog timer hardware supports the same functionality. That's why +all other routines/operations are optional. They only need to be provided if +they are supported. These optional routines/operations are: +* ping: this is the routine that sends a keepalive ping to the watchdog timer + hardware. + The routine needs a pointer to the watchdog timer device structure as a + parameter. It returns zero on success or a negative errno code for failure. + Most hardware that does not support this as a separate function uses the + start function to restart the watchdog timer hardware. And that's also what + the watchdog timer driver core does: to send a keepalive ping to the watchdog + timer hardware it will either use the ping operation (when available) or the + start operation (when the ping operation is not available). + +The status bits should (preferably) be set with the set_bit and clear_bit alike +bit-operations. The status bits that are defined are: +* WDOG_DEV_OPEN: this status bit shows whether or not the watchdog device + was opened via /dev/watchdog. + (This bit should only be used by the WatchDog Timer Driver Core). + +To get or set driver specific data the following two helper functions should be +used: + +static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data) +static inline void *watchdog_get_drvdata(struct watchdog_device *wdd) + +The watchdog_set_drvdata function allows you to add driver specific data. The +arguments of this function are the watchdog device where you want to add the +driver specific data to and a pointer to the data itself. + +The watchdog_get_drvdata function allows you to retrieve driver specific data. +The argument of this function is the watchdog device where you want to retrieve +data from. The function retruns the pointer to the driver specific data. diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 0635e72e0794..f441726ddf2b 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -28,6 +28,17 @@ menuconfig WATCHDOG if WATCHDOG +config WATCHDOG_CORE + bool "WatchDog Timer Driver Core" + ---help--- + Say Y here if you want to use the new watchdog timer driver core. + This driver provides a framework for all watchdog timer drivers + and gives them the /dev/watchdog interface (and later also the + sysfs interface). + + To compile this driver as a module, choose M here: the module will + be called watchdog. + config WATCHDOG_NOWAYOUT bool "Disable watchdog shutdown on close" help diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index 9eaa212398d7..55bd5740e910 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -2,6 +2,10 @@ # Makefile for the WatchDog device drivers. # +# The WatchDog Timer Driver Core. +watchdog-objs += watchdog_core.o watchdog_dev.o +obj-$(CONFIG_WATCHDOG_CORE) += watchdog.o + # Only one watchdog can succeed. We probe the ISA/PCI/USB based # watchdog-cards first, then the architecture specific watchdog # drivers and then the architecture independent "softdog" driver. diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c new file mode 100644 index 000000000000..47fc1267ad4e --- /dev/null +++ b/drivers/watchdog/watchdog_core.c @@ -0,0 +1,101 @@ +/* + * watchdog_core.c + * + * (c) Copyright 2008-2011 Alan Cox , + * All Rights Reserved. + * + * (c) Copyright 2008-2011 Wim Van Sebroeck . + * + * This source code is part of the generic code that can be used + * by all the watchdog timer drivers. + * + * Based on source code of the following authors: + * Matt Domsch , + * Rob Radez , + * Rusty Lynch + * Satyam Sharma + * Randy Dunlap + * + * 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. + * + * Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw. + * admit liability nor provide warranty for any of this software. + * This material is provided "AS-IS" and at no charge. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include /* For EXPORT_SYMBOL/module stuff/... */ +#include /* For standard types */ +#include /* For the -ENODEV/... values */ +#include /* For printk/panic/... */ +#include /* For watchdog specific items */ +#include /* For __init/__exit/... */ + +#include "watchdog_dev.h" /* For watchdog_dev_register/... */ + +/** + * watchdog_register_device() - register a watchdog device + * @wdd: watchdog device + * + * Register a watchdog device with the kernel so that the + * watchdog timer can be accessed from userspace. + * + * A zero is returned on success and a negative errno code for + * failure. + */ +int watchdog_register_device(struct watchdog_device *wdd) +{ + int ret; + + if (wdd == NULL || wdd->info == NULL || wdd->ops == NULL) + return -EINVAL; + + /* Mandatory operations need to be supported */ + if (wdd->ops->start == NULL || wdd->ops->stop == NULL) + return -EINVAL; + + /* + * Note: now that all watchdog_device data has been verified, we + * will not check this anymore in other functions. If data gets + * corrupted in a later stage then we expect a kernel panic! + */ + + /* We only support 1 watchdog device via the /dev/watchdog interface */ + ret = watchdog_dev_register(wdd); + if (ret) { + pr_err("error registering /dev/watchdog (err=%d).\n", ret); + return ret; + } + + return 0; +} +EXPORT_SYMBOL_GPL(watchdog_register_device); + +/** + * watchdog_unregister_device() - unregister a watchdog device + * @wdd: watchdog device to unregister + * + * Unregister a watchdog device that was previously successfully + * registered with watchdog_register_device(). + */ +void watchdog_unregister_device(struct watchdog_device *wdd) +{ + int ret; + + if (wdd == NULL) + return; + + ret = watchdog_dev_unregister(wdd); + if (ret) + pr_err("error unregistering /dev/watchdog (err=%d).\n", ret); +} +EXPORT_SYMBOL_GPL(watchdog_unregister_device); + +MODULE_AUTHOR("Alan Cox "); +MODULE_AUTHOR("Wim Van Sebroeck "); +MODULE_DESCRIPTION("WatchDog Timer Driver Core"); +MODULE_LICENSE("GPL"); diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c new file mode 100644 index 000000000000..366f49ce69b8 --- /dev/null +++ b/drivers/watchdog/watchdog_dev.c @@ -0,0 +1,235 @@ +/* + * watchdog_dev.c + * + * (c) Copyright 2008-2011 Alan Cox , + * All Rights Reserved. + * + * (c) Copyright 2008-2011 Wim Van Sebroeck . + * + * + * This source code is part of the generic code that can be used + * by all the watchdog timer drivers. + * + * This part of the generic code takes care of the following + * misc device: /dev/watchdog. + * + * Based on source code of the following authors: + * Matt Domsch , + * Rob Radez , + * Rusty Lynch + * Satyam Sharma + * Randy Dunlap + * + * 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. + * + * Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw. + * admit liability nor provide warranty for any of this software. + * This material is provided "AS-IS" and at no charge. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include /* For module stuff/... */ +#include /* For standard types (like size_t) */ +#include /* For the -ENODEV/... values */ +#include /* For printk/panic/... */ +#include /* For file operations */ +#include /* For watchdog specific items */ +#include /* For handling misc devices */ +#include /* For __init/__exit/... */ +#include /* For copy_to_user/put_user/... */ + +/* make sure we only register one /dev/watchdog device */ +static unsigned long watchdog_dev_busy; +/* the watchdog device behind /dev/watchdog */ +static struct watchdog_device *wdd; + +/* + * watchdog_ping: ping the watchdog. + * @wddev: the watchdog device to ping + * + * If the watchdog has no own ping operation then it needs to be + * restarted via the start operation. This wrapper function does + * exactly that. + */ + +static int watchdog_ping(struct watchdog_device *wddev) +{ + if (wddev->ops->ping) + return wddev->ops->ping(wddev); /* ping the watchdog */ + else + return wddev->ops->start(wddev); /* restart the watchdog */ +} + +/* + * watchdog_write: writes to the watchdog. + * @file: file from VFS + * @data: user address of data + * @len: length of data + * @ppos: pointer to the file offset + * + * A write to a watchdog device is defined as a keepalive ping. + */ + +static ssize_t watchdog_write(struct file *file, const char __user *data, + size_t len, loff_t *ppos) +{ + size_t i; + char c; + + if (len == 0) + return 0; + + for (i = 0; i != len; i++) { + if (get_user(c, data + i)) + return -EFAULT; + } + + /* someone wrote to us, so we send the watchdog a keepalive ping */ + watchdog_ping(wdd); + + return len; +} + +/* + * watchdog_open: open the /dev/watchdog device. + * @inode: inode of device + * @file: file handle to device + * + * When the /dev/watchdog device gets opened, we start the watchdog. + * Watch out: the /dev/watchdog device is single open, so we make sure + * it can only be opened once. + */ + +static int watchdog_open(struct inode *inode, struct file *file) +{ + int err = -EBUSY; + + /* the watchdog is single open! */ + if (test_and_set_bit(WDOG_DEV_OPEN, &wdd->status)) + return -EBUSY; + + /* + * If the /dev/watchdog device is open, we don't want the module + * to be unloaded. + */ + if (!try_module_get(wdd->ops->owner)) + goto out; + + err = wdd->ops->start(wdd); + if (err < 0) + goto out_mod; + + /* dev/watchdog is a virtual (and thus non-seekable) filesystem */ + return nonseekable_open(inode, file); + +out_mod: + module_put(wdd->ops->owner); +out: + clear_bit(WDOG_DEV_OPEN, &wdd->status); + return err; +} + +/* + * watchdog_release: release the /dev/watchdog device. + * @inode: inode of device + * @file: file handle to device + * + * This is the code for when /dev/watchdog gets closed. + */ + +static int watchdog_release(struct inode *inode, struct file *file) +{ + int err; + + err = wdd->ops->stop(wdd); + if (err != 0) { + pr_crit("%s: watchdog did not stop!\n", wdd->info->identity); + watchdog_ping(wdd); + } + + /* Allow the owner module to be unloaded again */ + module_put(wdd->ops->owner); + + /* make sure that /dev/watchdog can be re-opened */ + clear_bit(WDOG_DEV_OPEN, &wdd->status); + + return 0; +} + +static const struct file_operations watchdog_fops = { + .owner = THIS_MODULE, + .write = watchdog_write, + .open = watchdog_open, + .release = watchdog_release, +}; + +static struct miscdevice watchdog_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &watchdog_fops, +}; + +/* + * watchdog_dev_register: + * @watchdog: watchdog device + * + * Register a watchdog device as /dev/watchdog. /dev/watchdog + * is actually a miscdevice and thus we set it up like that. + */ + +int watchdog_dev_register(struct watchdog_device *watchdog) +{ + int err; + + /* Only one device can register for /dev/watchdog */ + if (test_and_set_bit(0, &watchdog_dev_busy)) { + pr_err("only one watchdog can use /dev/watchdog.\n"); + return -EBUSY; + } + + wdd = watchdog; + + err = misc_register(&watchdog_miscdev); + if (err != 0) { + pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n", + watchdog->info->identity, WATCHDOG_MINOR, err); + goto out; + } + + return 0; + +out: + wdd = NULL; + clear_bit(0, &watchdog_dev_busy); + return err; +} + +/* + * watchdog_dev_unregister: + * @watchdog: watchdog device + * + * Deregister the /dev/watchdog device. + */ + +int watchdog_dev_unregister(struct watchdog_device *watchdog) +{ + /* Check that a watchdog device was registered in the past */ + if (!test_bit(0, &watchdog_dev_busy) || !wdd) + return -ENODEV; + + /* We can only unregister the watchdog device that was registered */ + if (watchdog != wdd) { + pr_err("%s: watchdog was not registered as /dev/watchdog.\n", + watchdog->info->identity); + return -ENODEV; + } + + misc_deregister(&watchdog_miscdev); + wdd = NULL; + clear_bit(0, &watchdog_dev_busy); + return 0; +} diff --git a/drivers/watchdog/watchdog_dev.h b/drivers/watchdog/watchdog_dev.h new file mode 100644 index 000000000000..bc7612be25ce --- /dev/null +++ b/drivers/watchdog/watchdog_dev.h @@ -0,0 +1,33 @@ +/* + * watchdog_core.h + * + * (c) Copyright 2008-2011 Alan Cox , + * All Rights Reserved. + * + * (c) Copyright 2008-2011 Wim Van Sebroeck . + * + * This source code is part of the generic code that can be used + * by all the watchdog timer drivers. + * + * Based on source code of the following authors: + * Matt Domsch , + * Rob Radez , + * Rusty Lynch + * Satyam Sharma + * Randy Dunlap + * + * 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. + * + * Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw. + * admit liability nor provide warranty for any of this software. + * This material is provided "AS-IS" and at no charge. + */ + +/* + * Functions/procedures to be called by the core + */ +int watchdog_dev_register(struct watchdog_device *); +int watchdog_dev_unregister(struct watchdog_device *); diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index 011bcfeb9f09..5ab31bfd2906 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -59,6 +59,67 @@ struct watchdog_info { #define WATCHDOG_NOWAYOUT 0 #endif +struct watchdog_ops; +struct watchdog_device; + +/** struct watchdog_ops - The watchdog-devices operations + * + * @owner: The module owner. + * @start: The routine for starting the watchdog device. + * @stop: The routine for stopping the watchdog device. + * @ping: The routine that sends a keepalive ping to the watchdog device. + * + * The watchdog_ops structure contains a list of low-level operations + * that control a watchdog device. It also contains the module that owns + * these operations. The start and stop function are mandatory, all other + * functions are optonal. + */ +struct watchdog_ops { + struct module *owner; + /* mandatory operations */ + int (*start)(struct watchdog_device *); + int (*stop)(struct watchdog_device *); + /* optional operations */ + int (*ping)(struct watchdog_device *); +}; + +/** struct watchdog_device - The structure that defines a watchdog device + * + * @info: Pointer to a watchdog_info structure. + * @ops: Pointer to the list of watchdog operations. + * @driver-data:Pointer to the drivers private data. + * @status: Field that contains the devices internal status bits. + * + * The watchdog_device structure contains all information about a + * watchdog timer device. + * + * The driver-data field may not be accessed directly. It must be accessed + * via the watchdog_set_drvdata and watchdog_get_drvdata helpers. + */ +struct watchdog_device { + const struct watchdog_info *info; + const struct watchdog_ops *ops; + void *driver_data; + unsigned long status; +/* Bit numbers for status flags */ +#define WDOG_DEV_OPEN 1 /* Opened via /dev/watchdog ? */ +}; + +/* Use the following functions to manipulate watchdog driver specific data */ +static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data) +{ + wdd->driver_data = data; +} + +static inline void *watchdog_get_drvdata(struct watchdog_device *wdd) +{ + return wdd->driver_data; +} + +/* drivers/watchdog/core/watchdog_core.c */ +extern int watchdog_register_device(struct watchdog_device *); +extern void watchdog_unregister_device(struct watchdog_device *); + #endif /* __KERNEL__ */ #endif /* ifndef _LINUX_WATCHDOG_H */ -- cgit v1.2.3 From 7abdd34dbf58bf271db7ee6551f2ff72204a83fd Mon Sep 17 00:00:00 2001 From: Josh Boyer Date: Sat, 30 Jul 2011 10:18:48 -0400 Subject: watchdog: Cleanup WATCHDOG_CORE help text The newly added WATCHDOG_CORE option is a bool, but the help text suggests it can be built as a module. Fix it up. Signed-off-by: Josh Boyer Signed-off-by: Wim Van Sebroeck --- drivers/watchdog/Kconfig | 3 --- 1 file changed, 3 deletions(-) (limited to 'drivers/watchdog/Kconfig') diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index f441726ddf2b..86b0735e6aa0 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -36,9 +36,6 @@ config WATCHDOG_CORE and gives them the /dev/watchdog interface (and later also the sysfs interface). - To compile this driver as a module, choose M here: the module will - be called watchdog. - config WATCHDOG_NOWAYOUT bool "Disable watchdog shutdown on close" help -- cgit v1.2.3