/**************************************************************************** * drivers/timers/watchdog.c * * Copyright (C) 2012 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_WATCHDOG /**************************************************************************** * Private Type Definitions ****************************************************************************/ /* This structure describes the state of the upper half driver */ struct watchdog_upperhalf_s { uint8_t crefs; /* The number of times the device has been opened */ sem_t exclsem; /* Supports mutual exclusion */ FAR char *path; /* Registration path */ /* The contained lower-half driver */ FAR struct watchdog_lowerhalf_s *lower; }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ static int wdog_open(FAR struct file *filep); static int wdog_close(FAR struct file *filep); static ssize_t wdog_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t wdog_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); static int wdog_ioctl(FAR struct file *filep, int cmd, unsigned long arg); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_wdogops = { wdog_open, /* open */ wdog_close, /* close */ wdog_read, /* read */ wdog_write, /* write */ 0, /* seek */ wdog_ioctl /* ioctl */ #ifndef CONFIG_DISABLE_POLL , 0 /* poll */ #endif }; /**************************************************************************** * Private Functions ****************************************************************************/ /************************************************************************************ * Name: wdog_open * * Description: * This function is called whenever the watchdog timer device is opened. * ************************************************************************************/ static int wdog_open(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct watchdog_upperhalf_s *upper = inode->i_private; uint8_t tmp; int ret; wdinfo("crefs: %d\n", upper->crefs); /* Get exclusive access to the device structures */ ret = sem_wait(&upper->exclsem); if (ret < 0) { ret = -get_errno(); goto errout; } /* Increment the count of references to the device. If this the first * time that the driver has been opened for this device, then initialize * the device. */ tmp = upper->crefs + 1; if (tmp == 0) { /* More than 255 opens; uint8_t overflows to zero */ ret = -EMFILE; goto errout_with_sem; } /* Save the new open count */ upper->crefs = tmp; ret = OK; errout_with_sem: sem_post(&upper->exclsem); errout: return ret; } /************************************************************************************ * Name: wdog_close * * Description: * This function is called when the watchdog timer device is closed. * ************************************************************************************/ static int wdog_close(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct watchdog_upperhalf_s *upper = inode->i_private; int ret; wdinfo("crefs: %d\n", upper->crefs); /* Get exclusive access to the device structures */ ret = sem_wait(&upper->exclsem); if (ret < 0) { ret = -get_errno(); goto errout; } /* Decrement the references to the driver. If the reference count will * decrement to 0, then uninitialize the driver. */ if (upper->crefs > 0) { upper->crefs--; } sem_post(&upper->exclsem); ret = OK; errout: return ret; } /************************************************************************************ * Name: wdog_read * * Description: * A dummy read method. This is provided only to satisfy the VFS layer. * ************************************************************************************/ static ssize_t wdog_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { /* Return zero -- usually meaning end-of-file */ return 0; } /************************************************************************************ * Name: wdog_write * * Description: * A dummy write method. This is provided only to satisfy the VFS layer. * ************************************************************************************/ static ssize_t wdog_write(FAR struct file *filep, FAR const char *buffer, size_t buflen) { return 0; } /************************************************************************************ * Name: wdog_ioctl * * Description: * The standard ioctl method. This is where ALL of the watchdog timer work is * done. * ************************************************************************************/ static int wdog_ioctl(FAR struct file *filep, int cmd, unsigned long arg) { FAR struct inode *inode = filep->f_inode; FAR struct watchdog_upperhalf_s *upper; FAR struct watchdog_lowerhalf_s *lower; int ret; wdinfo("cmd: %d arg: %ld\n", cmd, arg); upper = inode->i_private; DEBUGASSERT(upper != NULL); lower = upper->lower; DEBUGASSERT(lower != NULL); /* Get exclusive access to the device structures */ ret = sem_wait(&upper->exclsem); if (ret < 0) { return ret; } /* Handle built-in ioctl commands */ switch (cmd) { /* cmd: WDIOC_START * Description: Start the watchdog timer * Argument: Ignored */ case WDIOC_START: { /* Start the watchdog timer, resetting the time to the current timeout */ DEBUGASSERT(lower->ops->start); /* Required */ ret = lower->ops->start(lower); } break; /* cmd: WDIOC_STOP * Description: Stop the watchdog timer * Argument: Ignored */ case WDIOC_STOP: { /* Stop the watchdog timer */ DEBUGASSERT(lower->ops->stop); /* Required */ ret = lower->ops->stop(lower); } break; /* cmd: WDIOC_GETSTATUS * Description: Get the status of the watchdog timer. * Argument: A writeable pointer to struct watchdog_status_s. */ case WDIOC_GETSTATUS: { FAR struct watchdog_status_s *status; /* Get the current watchdog timer status */ if (lower->ops->getstatus) /* Optional */ { status = (FAR struct watchdog_status_s *)((uintptr_t)arg); if (status) { ret = lower->ops->getstatus(lower, status); } else { ret = -EINVAL; } } else { ret = -ENOSYS; } } break; /* cmd: WDIOC_SETTIMEOUT * Description: Reset the watchdog timeout to this value * Argument: A 32-bit timeout value in milliseconds. */ case WDIOC_SETTIMEOUT: { /* Set a new timeout value (and reset the watchdog timer) */ if (lower->ops->settimeout) /* Optional */ { ret = lower->ops->settimeout(lower, (uint32_t)arg); } else { ret = -ENOSYS; } } break; /* cmd: WDIOC_CAPTURE * Description: Do not reset. Instead, called this handler. * Argument: A pointer to struct watchdog_capture_s. */ case WDIOC_CAPTURE: { FAR struct watchdog_capture_s *capture; /* Don't reset on watchdog timer timeout; instead, call this user * provider timeout handler. NOTE: Providing handler==NULL will * restore the reset behavior. */ if (lower->ops->capture) /* Optional */ { capture = (FAR struct watchdog_capture_s *)((uintptr_t)arg); if (capture) { capture->oldhandler = lower->ops->capture(lower, capture->newhandler); ret = OK; } else { ret = -EINVAL; } } else { ret = -ENOSYS; } } break; /* cmd: WDIOC_KEEPALIVE * Description: Reset the watchdog timer ("ping", "pet the dog") * Argument: Argument: Ignored */ case WDIOC_KEEPALIVE: { /* Reset the watchdog timer to the current timeout value, prevent any * imminent watchdog timeouts. This is sometimes referred as * "pinging" the watchdog timer or "petting the dog". */ if (lower->ops->keepalive) /* Optional */ { ret = lower->ops->keepalive(lower); } else { ret = -ENOSYS; } } break; /* Any unrecognized IOCTL commands might be platform-specific ioctl commands */ default: { wdinfo("Forwarding unrecognized cmd: %d arg: %ld\n", cmd, arg); /* An ioctl commands that are not recognized by the "upper-half" * driver are forwarded to the lower half driver through this * method. */ if (lower->ops->ioctl) /* Optional */ { ret = lower->ops->ioctl(lower, cmd, arg); } else { ret = -ENOSYS; } } break; } sem_post(&upper->exclsem); return ret; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: watchdog_register * * Description: * This function binds an instance of a "lower half" watchdog driver with the * "upper half" watchdog device and registers that device so that can be used * by application code. * * When this function is called, the "lower half" driver should be in the * disabled state (as if the stop() method had already been called). * * Input parameters: * dev path - The full path to the driver to be registers in the NuttX * pseudo-filesystem. The recommended convention is to name all watchdog * drivers as "/dev/watchdog0", "/dev/watchdog1", etc. where the driver * path differs only in the "minor" number at the end of the device name. * lower - A pointer to an instance of lower half watchdog driver. This * instance is bound to the watchdog driver and must persists as long as * the driver persists. * * Returned Value: * On success, a non-NULL handle is returned to the caller. In the event * of any failure, a NULL value is returned. * ****************************************************************************/ FAR void *watchdog_register(FAR const char *path, FAR struct watchdog_lowerhalf_s *lower) { FAR struct watchdog_upperhalf_s *upper; int ret; DEBUGASSERT(path && lower); wdinfo("Entry: path=%s\n", path); /* Allocate the upper-half data structure */ upper = (FAR struct watchdog_upperhalf_s *) kmm_zalloc(sizeof(struct watchdog_upperhalf_s)); if (!upper) { wderr("Upper half allocation failed\n"); goto errout; } /* Initialize the watchdog timer device structure (it was already zeroed * by kmm_zalloc()). */ sem_init(&upper->exclsem, 0, 1); upper->lower = lower; /* Copy the registration path */ upper->path = strdup(path); if (!upper->path) { wderr("Path allocation failed\n"); goto errout_with_upper; } /* Register the watchdog timer device */ ret = register_driver(path, &g_wdogops, 0666, upper); if (ret < 0) { wderr("register_driver failed: %d\n", ret); goto errout_with_path; } return (FAR void *)upper; errout_with_path: kmm_free(upper->path); errout_with_upper: sem_destroy(&upper->exclsem); kmm_free(upper); errout: return NULL; } /**************************************************************************** * Name: watchdog_unregister * * Description: * This function can be called to disable and unregister the watchdog * device driver. * * Input parameters: * handle - This is the handle that was returned by watchdog_register() * * Returned Value: * None * ****************************************************************************/ void watchdog_unregister(FAR void *handle) { FAR struct watchdog_upperhalf_s *upper; FAR struct watchdog_lowerhalf_s *lower; /* Recover the pointer to the upper-half driver state */ upper = (FAR struct watchdog_upperhalf_s *)handle; DEBUGASSERT(upper != NULL); lower = upper->lower; DEBUGASSERT(lower != NULL); wdinfo("Unregistering: %s\n", upper->path); /* Disable the watchdog timer */ DEBUGASSERT(lower->ops->stop); /* Required */ (void)lower->ops->stop(lower); /* Unregister the watchdog timer device */ (void)unregister_driver(upper->path); /* Then free all of the driver resources */ kmm_free(upper->path); sem_destroy(&upper->exclsem); kmm_free(upper); } #endif /* CONFIG_WATCHDOG */