text: /*
   *	Functions to handle I2O drivers (OSMs) and I2O bus type for sysfs
   *
   *	Copyright (C) 2004	Markus Lidel <Markus.Lidel@shadowconnect.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.
   *
   *	Fixes/additions:
   *		Markus Lidel <Markus.Lidel@shadowconnect.com>
   *			initial version.
   */
  
  #include <linux/device.h>
  #include <linux/module.h>
  #include <linux/rwsem.h>
  #include "i2o.h"
  #include <linux/workqueue.h>
  #include <linux/string.h>
  #include <linux/slab.h>
  #include "core.h"
  
  #define OSM_NAME	"i2o"
  
  /* max_drivers - Maximum I2O drivers (OSMs) which could be registered */
  static unsigned int i2o_max_drivers = I2O_MAX_DRIVERS;
  module_param_named(max_drivers, i2o_max_drivers, uint, 0);
  MODULE_PARM_DESC(max_drivers, "maximum number of OSM's to support");
  
  /* I2O drivers lock and array */
  static spinlock_t i2o_drivers_lock;
  static struct i2o_driver **i2o_drivers;
  
  /**
   *	i2o_bus_match - Tell if I2O device class id matches the class ids of the I2O driver (OSM)
   *	@dev: device which should be verified
   *	@drv: the driver to match against
   *
   *	Used by the bus to check if the driver wants to handle the device.
   *
   *	Returns 1 if the class ids of the driver match the class id of the
   *	device, otherwise 0.
   */
  static int i2o_bus_match(struct device *dev, struct device_driver *drv)
  {
  	struct i2o_device *i2o_dev = to_i2o_device(dev);
  	struct i2o_driver *i2o_drv = to_i2o_driver(drv);
  	struct i2o_class_id *ids = i2o_drv->classes;
  
  	if (ids)
  		while (ids->class_id != I2O_CLASS_END) {
  			if (ids->class_id == i2o_dev->lct_data.class_id)
  				return 1;
  			ids++;
  		}
  	return 0;
  };
  
  /* I2O bus type */
  struct bus_type i2o_bus_type = {
  	.name = "i2o",
  	.match = i2o_bus_match,
  	.dev_groups = i2o_device_groups,
  };
  
  /**
   *	i2o_driver_register - Register a I2O driver (OSM) in the I2O core
   *	@drv: I2O driver which should be registered
   *
   *	Registers the OSM drv in the I2O core and creates an event queues if
   *	necessary.
   *
   *	Returns 0 on success or negative error code on failure.
   */
  int i2o_driver_register(struct i2o_driver *drv)
  {
  	struct i2o_controller *c;
  	int i;
  	int rc = 0;
  	unsigned long flags;
  
  	osm_debug("Register driver %s\n", drv->name);
  
  	if (drv->event) {
  		drv->event_queue = alloc_workqueue("%s", WQ_MEM_RECLAIM, 1,
  						   drv->name);
  		if (!drv->event_queue) {
  			osm_err("Could not initialize event queue for driver "
  				"%s\n", drv->name);
  			return -EFAULT;
  		}
  		osm_debug("Event queue initialized for driver %s\n", drv->name);
  	} else
  		drv->event_queue = NULL;
  
  	drv->driver.name = drv->name;
  	drv->driver.bus = &i2o_bus_type;
  
  	spin_lock_irqsave(&i2o_drivers_lock, flags);
  
  	for (i = 0; i2o_drivers[i]; i++)
  		if (i >= i2o_max_drivers) {
  			osm_err("too many drivers registered, increase max_drivers\n");
  			spin_unlock_irqrestore(&i2o_drivers_lock, flags);
  			rc = -EFAULT;
  			goto out;
  		}
  
  	drv->context = i;
  	i2o_drivers[i] = drv;
  
  	spin_unlock_irqrestore(&i2o_drivers_lock, flags);
  
  	osm_debug("driver %s gets context id %d\n", drv->name, drv->context);
  
  	list_for_each_entry(c, &i2o_controllers, list) {
  		struct i2o_device *i2o_dev;
  
  		i2o_driver_notify_controller_add(drv, c);
  		list_for_each_entry(i2o_dev, &c->devices, list)
  		    i2o_driver_notify_device_add(drv, i2o_dev);
  	}
  
  	rc = driver_register(&drv->driver);
  	if (rc)
  		goto out;
  
  	return 0;
  out:
  	if (drv->event_queue) {
  		destroy_workqueue(drv->event_queue);
  		drv->event_queue = NULL;
  	}
  
  	return rc;
  };
  
  /**
   *	i2o_driver_unregister - Unregister a I2O driver (OSM) from the I2O core
   *	@drv: I2O driver which should be unregistered
   *
   *	Unregisters the OSM drv from the I2O core and cleanup event queues if
   *	necessary.
   */
  void i2o_driver_unregister(struct i2o_driver *drv)
  {
  	struct i2o_controller *c;
  	unsigned long flags;
  
  	osm_debug("unregister driver %s\n", drv->name);
  
  	driver_unregister(&drv->driver);
  
  	list_for_each_entry(c, &i2o_controllers, list) {
  		struct i2o_device *i2o_dev;
  
  		list_for_each_entry(i2o_dev, &c->devices, list)
  		    i2o_driver_notify_device_remove(drv, i2o_dev);
  
  		i2o_driver_notify_controller_remove(drv, c);
  	}
  
  	spin_lock_irqsave(&i2o_drivers_lock, flags);
  	i2o_drivers[drv->context] = NULL;
  	spin_unlock_irqrestore(&i2o_drivers_lock, flags);
  
  	if (drv->event_queue) {
  		destroy_workqueue(drv->event_queue);
  		drv->event_queue = NULL;
  		osm_debug("event queue removed for %s\n", drv->name);
  	}
  };
  
  /**
   *	i2o_driver_dispatch - dispatch an I2O reply message
   *	@c: I2O controller of the message
   *	@m: I2O message number
   *
   *	The reply is delivered to the driver from which the original message
   *	was. This function is only called from interrupt context.
   *
   *	Returns 0 on success and the message should not be flushed. Returns > 0
   *	on success and if the message should be flushed afterwords. Returns
   *	negative error code on failure (the message will be flushed too).
   */
  int i2o_driver_dispatch(struct i2o_controller *c, u32 m)
  {
  	struct i2o_driver *drv;
  	struct i2o_message *msg = i2o_msg_out_to_virt(c, m);
  	u32 context = le32_to_cpu(msg->u.s.icntxt);
  	unsigned long flags;
  
  	if (unlikely(context >= i2o_max_drivers)) {
  		osm_warn("%s: Spurious reply to unknown driver %d\n", c->name,
  			 context);
  		return -EIO;
  	}
  
  	spin_lock_irqsave(&i2o_drivers_lock, flags);
  	drv = i2o_drivers[context];
  	spin_unlock_irqrestore(&i2o_drivers_lock, flags);
  
  	if (unlikely(!drv)) {
  		osm_warn("%s: Spurious reply to unknown driver %d\n", c->name,
  			 context);
  		return -EIO;
  	}
  
  	if ((le32_to_cpu(msg->u.head[1]) >> 24) == I2O_CMD_UTIL_EVT_REGISTER) {
  		struct i2o_device *dev, *tmp;
  		struct i2o_event *evt;
  		u16 size;
  		u16 tid = le32_to_cpu(msg->u.head[1]) & 0xfff;
  
  		osm_debug("event received from device %d\n", tid);
  
  		if (!drv->event)
  			return -EIO;
  
  		/* cut of header from message size (in 32-bit words) */
  		size = (le32_to_cpu(msg->u.head[0]) >> 16) - 5;
  
  		evt = kzalloc(size * 4 + sizeof(*evt), GFP_ATOMIC);
  		if (!evt)
  			return -ENOMEM;
  
  		evt->size = size;
  		evt->tcntxt = le32_to_cpu(msg->u.s.tcntxt);
  		evt->event_indicator = le32_to_cpu(msg->body[0]);
  		memcpy(&evt->data, &msg->body[1], size * 4);
  
  		list_for_each_entry_safe(dev, tmp, &c->devices, list)
  		    if (dev->lct_data.tid == tid) {
  			evt->i2o_dev = dev;
  			break;
  		}
  
  		INIT_WORK(&evt->work, drv->event);
  		queue_work(drv->event_queue, &evt->work);
  		return 1;
  	}
  
  	if (unlikely(!drv->reply)) {
  		osm_debug("%s: Reply to driver %s, but no reply function defined!\n",
  			c->name, drv->name);
  		return -EIO;
  	}
  
  	return drv->reply(c, m, msg);
  }
  
  /**
   *	i2o_driver_notify_controller_add_all - Send notify of added controller
   *	@c: newly added controller
   *
   *	Send notifications to all registered drivers that a new controller was
   *	added.
   */
  void i2o_driver_notify_controller_add_all(struct i2o_controller *c)
  {
  	int i;
  	struct i2o_driver *drv;
  
  	for (i = 0; i < i2o_max_drivers; i++) {
  		drv = i2o_drivers[i];
  
  		if (drv)
  			i2o_driver_notify_controller_add(drv, c);
  	}
  }
  
  /**
   *	i2o_driver_notify_controller_remove_all - Send notify of removed controller
   *	@c: controller that is being removed
   *
   *	Send notifications to all registered drivers that a controller was
   *	removed.
   */
  void i2o_driver_notify_controller_remove_all(struct i2o_controller *c)
  {
  	int i;
  	struct i2o_driver *drv;
  
  	for (i = 0; i < i2o_max_drivers; i++) {
  		drv = i2o_drivers[i];
  
  		if (drv)
  			i2o_driver_notify_controller_remove(drv, c);
  	}
  }
  
  /**
   *	i2o_driver_notify_device_add_all - Send notify of added device
   *	@i2o_dev: newly added I2O device
   *
   *	Send notifications to all registered drivers that a device was added.
   */
  void i2o_driver_notify_device_add_all(struct i2o_device *i2o_dev)
  {
  	int i;
  	struct i2o_driver *drv;
  
  	for (i = 0; i < i2o_max_drivers; i++) {
  		drv = i2o_drivers[i];
  
  		if (drv)
  			i2o_driver_notify_device_add(drv, i2o_dev);
  	}
  }
  
  /**
   *	i2o_driver_notify_device_remove_all - Send notify of removed device
   *	@i2o_dev: device that is being removed
   *
   *	Send notifications to all registered drivers that a device was removed.
   */
  void i2o_driver_notify_device_remove_all(struct i2o_device *i2o_dev)
  {
  	int i;
  	struct i2o_driver *drv;
  
  	for (i = 0; i < i2o_max_drivers; i++) {
  		drv = i2o_drivers[i];
  
  		if (drv)
  			i2o_driver_notify_device_remove(drv, i2o_dev);
  	}
  }
  
  /**
   *	i2o_driver_init - initialize I2O drivers (OSMs)
   *
   *	Registers the I2O bus and allocate memory for the array of OSMs.
   *
   *	Returns 0 on success or negative error code on failure.
   */
  int __init i2o_driver_init(void)
  {
  	int rc = 0;
  
  	spin_lock_init(&i2o_drivers_lock);
  
  	if ((i2o_max_drivers < 2) || (i2o_max_drivers > 64)) {
  		osm_warn("max_drivers set to %d, but must be >=2 and <= 64\n",
  			 i2o_max_drivers);
  		i2o_max_drivers = I2O_MAX_DRIVERS;
  	}
  	osm_info("max drivers = %d\n", i2o_max_drivers);
  
  	i2o_drivers =
  	    kcalloc(i2o_max_drivers, sizeof(*i2o_drivers), GFP_KERNEL);
  	if (!i2o_drivers)
  		return -ENOMEM;
  
  	rc = bus_register(&i2o_bus_type);
  
  	if (rc < 0)
  		kfree(i2o_drivers);
  
  	return rc;
  };
  
  /**
   *	i2o_driver_exit - clean up I2O drivers (OSMs)
   *
   *	Unregisters the I2O bus and frees driver array.
   */
  void i2o_driver_exit(void)
  {
  	bus_unregister(&i2o_bus_type);
  	kfree(i2o_drivers);
  };
  
  EXPORT_SYMBOL(i2o_driver_register);
  EXPORT_SYMBOL(i2o_driver_unregister);
  EXPORT_SYMBOL(i2o_driver_notify_controller_add_all);
  EXPORT_SYMBOL(i2o_driver_notify_controller_remove_all);
  EXPORT_SYMBOL(i2o_driver_notify_device_add_all);
  EXPORT_SYMBOL(i2o_driver_notify_device_remove_all);
  