/*
   * RapidIO enumeration and discovery support
   *
   * Copyright 2005 MontaVista Software, Inc.
   * Matt Porter <mporter@kernel.crashing.org>
   *
   * 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/kernel.h>
  
  #include <linux/delay.h>

  #include <linux/dma-mapping.h>

  #include <linux/init.h>
  #include <linux/rio.h>
  #include <linux/rio_drv.h>
  #include <linux/rio_ids.h>
  #include <linux/rio_regs.h>
  #include <linux/module.h>
  #include <linux/spinlock.h>
  #include <linux/timer.h>

  #include <linux/jiffies.h>
  #include <linux/slab.h>

  
  #include "rio.h"
  
  LIST_HEAD(rio_devices);
  static LIST_HEAD(rio_switches);
  
  #define RIO_ENUM_CMPL_MAGIC	0xdeadbeef
  
  static void rio_enum_timeout(unsigned long);

  DEFINE_SPINLOCK(rio_global_list_lock);

  static int next_destid = 0;
  static int next_switchid = 0;
  static int next_net = 0;
  
  static struct timer_list rio_enum_timer =
  TIMER_INITIALIZER(rio_enum_timeout, 0, 0);
  
  static int rio_mport_phys_table[] = {
  	RIO_EFB_PAR_EP_ID,
  	RIO_EFB_PAR_EP_REC_ID,
  	RIO_EFB_SER_EP_ID,
  	RIO_EFB_SER_EP_REC_ID,
  	-1,
  };
  
  static int rio_sport_phys_table[] = {
  	RIO_EFB_PAR_EP_FREE_ID,
  	RIO_EFB_SER_EP_FREE_ID,
  	-1,
  };

  /**
   * rio_get_device_id - Get the base/extended device id for a device
   * @port: RIO master port
   * @destid: Destination ID of device
   * @hopcount: Hopcount to device
   *
   * Reads the base/extended device id from a device. Returns the
   * 8/16-bit device ID.
   */
  static u16 rio_get_device_id(struct rio_mport *port, u16 destid, u8 hopcount)
  {
  	u32 result;
  
  	rio_mport_read_config_32(port, destid, hopcount, RIO_DID_CSR, &result);

  	return RIO_GET_DID(port->sys_size, result);

  }
  
  /**
   * rio_set_device_id - Set the base/extended device id for a device
   * @port: RIO master port
   * @destid: Destination ID of device
   * @hopcount: Hopcount to device
   * @did: Device ID value to be written
   *
   * Writes the base/extended device id from a device.
   */

  static void rio_set_device_id(struct rio_mport *port, u16 destid, u8 hopcount, u16 did)

  {
  	rio_mport_write_config_32(port, destid, hopcount, RIO_DID_CSR,

  				  RIO_SET_DID(port->sys_size, did));

  }
  
  /**
   * rio_local_set_device_id - Set the base/extended device id for a port
   * @port: RIO master port
   * @did: Device ID value to be written
   *
   * Writes the base/extended device id from a device.
   */
  static void rio_local_set_device_id(struct rio_mport *port, u16 did)
  {

  	rio_local_write_config_32(port, RIO_DID_CSR, RIO_SET_DID(port->sys_size,
  				did));

  }
  
  /**
   * rio_clear_locks- Release all host locks and signal enumeration complete
   * @port: Master port to issue transaction
   *
   * Marks the component tag CSR on each device with the enumeration
   * complete flag. When complete, it then release the host locks on
   * each device. Returns 0 on success or %-EINVAL on failure.
   */
  static int rio_clear_locks(struct rio_mport *port)
  {
  	struct rio_dev *rdev;
  	u32 result;
  	int ret = 0;
  
  	/* Write component tag CSR magic complete value */
  	rio_local_write_config_32(port, RIO_COMPONENT_TAG_CSR,
  				  RIO_ENUM_CMPL_MAGIC);
  	list_for_each_entry(rdev, &rio_devices, global_list)
  	    rio_write_config_32(rdev, RIO_COMPONENT_TAG_CSR,
  				RIO_ENUM_CMPL_MAGIC);
  
  	/* Release host device id locks */
  	rio_local_write_config_32(port, RIO_HOST_DID_LOCK_CSR,
  				  port->host_deviceid);
  	rio_local_read_config_32(port, RIO_HOST_DID_LOCK_CSR, &result);
  	if ((result & 0xffff) != 0xffff) {
  		printk(KERN_INFO
  		       "RIO: badness when releasing host lock on master port, result %8.8x
  ",
  		       result);
  		ret = -EINVAL;
  	}
  	list_for_each_entry(rdev, &rio_devices, global_list) {
  		rio_write_config_32(rdev, RIO_HOST_DID_LOCK_CSR,
  				    port->host_deviceid);
  		rio_read_config_32(rdev, RIO_HOST_DID_LOCK_CSR, &result);
  		if ((result & 0xffff) != 0xffff) {
  			printk(KERN_INFO
  			       "RIO: badness when releasing host lock on vid %4.4x did %4.4x
  ",
  			       rdev->vid, rdev->did);
  			ret = -EINVAL;
  		}
  	}
  
  	return ret;
  }
  
  /**
   * rio_enum_host- Set host lock and initialize host destination ID
   * @port: Master port to issue transaction
   *
   * Sets the local host master port lock and destination ID register
   * with the host device ID value. The host device ID value is provided
   * by the platform. Returns %0 on success or %-1 on failure.
   */
  static int rio_enum_host(struct rio_mport *port)
  {
  	u32 result;
  
  	/* Set master port host device id lock */
  	rio_local_write_config_32(port, RIO_HOST_DID_LOCK_CSR,
  				  port->host_deviceid);
  
  	rio_local_read_config_32(port, RIO_HOST_DID_LOCK_CSR, &result);
  	if ((result & 0xffff) != port->host_deviceid)
  		return -1;
  
  	/* Set master port destid and init destid ctr */
  	rio_local_set_device_id(port, port->host_deviceid);
  
  	if (next_destid == port->host_deviceid)
  		next_destid++;
  
  	return 0;
  }
  
  /**
   * rio_device_has_destid- Test if a device contains a destination ID register
   * @port: Master port to issue transaction
   * @src_ops: RIO device source operations
   * @dst_ops: RIO device destination operations
   *
   * Checks the provided @src_ops and @dst_ops for the necessary transaction
   * capabilities that indicate whether or not a device will implement a
   * destination ID register. Returns 1 if true or 0 if false.
   */
  static int rio_device_has_destid(struct rio_mport *port, int src_ops,
  				 int dst_ops)
  {

  	u32 mask = RIO_OPS_READ | RIO_OPS_WRITE | RIO_OPS_ATOMIC_TST_SWP | RIO_OPS_ATOMIC_INC | RIO_OPS_ATOMIC_DEC | RIO_OPS_ATOMIC_SET | RIO_OPS_ATOMIC_CLR;
  
  	return !!((src_ops | dst_ops) & mask);

  }
  
  /**
   * rio_release_dev- Frees a RIO device struct
   * @dev: LDM device associated with a RIO device struct
   *
   * Gets the RIO device struct associated a RIO device struct.
   * The RIO device struct is freed.
   */
  static void rio_release_dev(struct device *dev)
  {
  	struct rio_dev *rdev;
  
  	rdev = to_rio_dev(dev);
  	kfree(rdev);
  }
  
  /**
   * rio_is_switch- Tests if a RIO device has switch capabilities
   * @rdev: RIO device
   *
   * Gets the RIO device Processing Element Features register
   * contents and tests for switch capabilities. Returns 1 if
   * the device is a switch or 0 if it is not a switch.
   * The RIO device struct is freed.
   */
  static int rio_is_switch(struct rio_dev *rdev)
  {
  	if (rdev->pef & RIO_PEF_SWITCH)
  		return 1;
  	return 0;
  }
  
  /**
   * rio_route_set_ops- Sets routing operations for a particular vendor switch
   * @rdev: RIO device
   *
   * Searches the RIO route ops table for known switch types. If the vid
   * and did match a switch table entry, then set the add_entry() and
   * get_entry() ops to the table entry values.
   */
  static void rio_route_set_ops(struct rio_dev *rdev)
  {
  	struct rio_route_ops *cur = __start_rio_route_ops;
  	struct rio_route_ops *end = __end_rio_route_ops;
  
  	while (cur < end) {
  		if ((cur->vid == rdev->vid) && (cur->did == rdev->did)) {
  			pr_debug("RIO: adding routing ops for %s
  ", rio_name(rdev));
  			rdev->rswitch->add_entry = cur->add_hook;
  			rdev->rswitch->get_entry = cur->get_hook;
  		}
  		cur++;
  	}
  
  	if (!rdev->rswitch->add_entry || !rdev->rswitch->get_entry)
  		printk(KERN_ERR "RIO: missing routing ops for %s
  ",
  		       rio_name(rdev));
  }
  
  /**
   * rio_add_device- Adds a RIO device to the device model
   * @rdev: RIO device
   *
   * Adds the RIO device to the global device list and adds the RIO
   * device to the RIO device list.  Creates the generic sysfs nodes
   * for an RIO device.
   */
  static void __devinit rio_add_device(struct rio_dev *rdev)
  {
  	device_add(&rdev->dev);
  
  	spin_lock(&rio_global_list_lock);
  	list_add_tail(&rdev->global_list, &rio_devices);
  	spin_unlock(&rio_global_list_lock);
  
  	rio_create_sysfs_dev_files(rdev);
  }
  
  /**
   * rio_setup_device- Allocates and sets up a RIO device
   * @net: RIO network
   * @port: Master port to send transactions
   * @destid: Current destination ID
   * @hopcount: Current hopcount
   * @do_enum: Enumeration/Discovery mode flag
   *
   * Allocates a RIO device and configures fields based on configuration
   * space contents. If device has a destination ID register, a destination
   * ID is either assigned in enumeration mode or read from configuration
   * space in discovery mode.  If the device has switch capabilities, then
   * a switch is allocated and configured appropriately. Returns a pointer
   * to a RIO device on success or NULL on failure.
   *
   */
  static struct rio_dev *rio_setup_device(struct rio_net *net,
  					struct rio_mport *port, u16 destid,
  					u8 hopcount, int do_enum)
  {
  	struct rio_dev *rdev;
  	struct rio_switch *rswitch;
  	int result, rdid;

  	rdev = kzalloc(sizeof(struct rio_dev), GFP_KERNEL);

  	if (!rdev)
  		goto out;

  	rdev->net = net;
  	rio_mport_read_config_32(port, destid, hopcount, RIO_DEV_ID_CAR,
  				 &result);
  	rdev->did = result >> 16;
  	rdev->vid = result & 0xffff;
  	rio_mport_read_config_32(port, destid, hopcount, RIO_DEV_INFO_CAR,
  				 &rdev->device_rev);
  	rio_mport_read_config_32(port, destid, hopcount, RIO_ASM_ID_CAR,
  				 &result);
  	rdev->asm_did = result >> 16;
  	rdev->asm_vid = result & 0xffff;
  	rio_mport_read_config_32(port, destid, hopcount, RIO_ASM_INFO_CAR,
  				 &result);
  	rdev->asm_rev = result >> 16;
  	rio_mport_read_config_32(port, destid, hopcount, RIO_PEF_CAR,
  				 &rdev->pef);
  	if (rdev->pef & RIO_PEF_EXT_FEATURES)
  		rdev->efptr = result & 0xffff;
  
  	rio_mport_read_config_32(port, destid, hopcount, RIO_SRC_OPS_CAR,
  				 &rdev->src_ops);
  	rio_mport_read_config_32(port, destid, hopcount, RIO_DST_OPS_CAR,
  				 &rdev->dst_ops);

  	if (rio_device_has_destid(port, rdev->src_ops, rdev->dst_ops)) {
  		if (do_enum) {
  			rio_set_device_id(port, destid, hopcount, next_destid);
  			rdev->destid = next_destid++;
  			if (next_destid == port->host_deviceid)
  				next_destid++;
  		} else
  			rdev->destid = rio_get_device_id(port, destid, hopcount);

  	} else

  		/* Switch device has an associated destID */
  		rdev->destid = RIO_INVALID_DESTID;

  
  	/* If a PE has both switch and other functions, show it as a switch */
  	if (rio_is_switch(rdev)) {
  		rio_mport_read_config_32(port, destid, hopcount,
  					 RIO_SWP_INFO_CAR, &rdev->swpinfo);
  		rswitch = kmalloc(sizeof(struct rio_switch), GFP_KERNEL);
  		if (!rswitch) {
  			kfree(rdev);
  			rdev = NULL;
  			goto out;
  		}
  		rswitch->switchid = next_switchid;
  		rswitch->hopcount = hopcount;

  		rswitch->destid = destid;

  		rswitch->route_table = kzalloc(sizeof(u8)*
  					RIO_MAX_ROUTE_ENTRIES(port->sys_size),
  					GFP_KERNEL);
  		if (!rswitch->route_table) {
  			kfree(rdev);
  			rdev = NULL;
  			kfree(rswitch);
  			goto out;
  		}

  		/* Initialize switch route table */

  		for (rdid = 0; rdid < RIO_MAX_ROUTE_ENTRIES(port->sys_size);
  				rdid++)

  			rswitch->route_table[rdid] = RIO_INVALID_ROUTE;
  		rdev->rswitch = rswitch;

  		dev_set_name(&rdev->dev, "%02x:s:%04x", rdev->net->id,
  			     rdev->rswitch->switchid);

  		rio_route_set_ops(rdev);
  
  		list_add_tail(&rswitch->node, &rio_switches);
  
  	} else

  		dev_set_name(&rdev->dev, "%02x:e:%04x", rdev->net->id,
  			     rdev->destid);

  
  	rdev->dev.bus = &rio_bus_type;
  
  	device_initialize(&rdev->dev);
  	rdev->dev.release = rio_release_dev;
  	rio_dev_get(rdev);

  	rdev->dma_mask = DMA_32BIT_MASK;
  	rdev->dev.dma_mask = &rdev->dma_mask;
  	rdev->dev.coherent_dma_mask = DMA_32BIT_MASK;

  
  	if ((rdev->pef & RIO_PEF_INB_DOORBELL) &&
  	    (rdev->dst_ops & RIO_DST_OPS_DOORBELL))
  		rio_init_dbell_res(&rdev->riores[RIO_DOORBELL_RESOURCE],
  				   0, 0xffff);
  
  	rio_add_device(rdev);
  
        out:
  	return rdev;
  }
  
  /**
   * rio_sport_is_active- Tests if a switch port has an active connection.
   * @port: Master port to send transaction
   * @destid: Associated destination ID for switch
   * @hopcount: Hopcount to reach switch
   * @sport: Switch port number
   *
   * Reads the port error status CSR for a particular switch port to
   * determine if the port has an active link.  Returns
   * %PORT_N_ERR_STS_PORT_OK if the port is active or %0 if it is
   * inactive.
   */
  static int
  rio_sport_is_active(struct rio_mport *port, u16 destid, u8 hopcount, int sport)
  {
  	u32 result;
  	u32 ext_ftr_ptr;
  
  	int *entry = rio_sport_phys_table;
  
  	do {
  		if ((ext_ftr_ptr =
  		     rio_mport_get_feature(port, 0, destid, hopcount, *entry)))
  
  			break;
  	} while (*++entry >= 0);
  
  	if (ext_ftr_ptr)
  		rio_mport_read_config_32(port, destid, hopcount,
  					 ext_ftr_ptr +
  					 RIO_PORT_N_ERR_STS_CSR(sport),
  					 &result);
  
  	return (result & PORT_N_ERR_STS_PORT_OK);
  }
  
  /**
   * rio_route_add_entry- Add a route entry to a switch routing table
   * @mport: Master port to send transaction

   * @rswitch: Switch device

   * @table: Routing table ID
   * @route_destid: Destination ID to be routed
   * @route_port: Port number to be routed
   *
   * Calls the switch specific add_entry() method to add a route entry
   * on a switch. The route table can be specified using the @table
   * argument if a switch has per port routing tables or the normal
   * use is to specific all tables (or the global table) by passing
   * %RIO_GLOBAL_TABLE in @table. Returns %0 on success or %-EINVAL
   * on failure.
   */

  static int rio_route_add_entry(struct rio_mport *mport, struct rio_switch *rswitch,

  			       u16 table, u16 route_destid, u8 route_port)
  {

  	return rswitch->add_entry(mport, rswitch->destid,
  					rswitch->hopcount, table,

  					route_destid, route_port);
  }
  
  /**
   * rio_route_get_entry- Read a route entry in a switch routing table
   * @mport: Master port to send transaction

   * @rswitch: Switch device

   * @table: Routing table ID
   * @route_destid: Destination ID to be routed
   * @route_port: Pointer to read port number into
   *
   * Calls the switch specific get_entry() method to read a route entry
   * in a switch. The route table can be specified using the @table
   * argument if a switch has per port routing tables or the normal
   * use is to specific all tables (or the global table) by passing
   * %RIO_GLOBAL_TABLE in @table. Returns %0 on success or %-EINVAL
   * on failure.
   */
  static int

  rio_route_get_entry(struct rio_mport *mport, struct rio_switch *rswitch, u16 table,

  		    u16 route_destid, u8 * route_port)
  {

  	return rswitch->get_entry(mport, rswitch->destid,
  					rswitch->hopcount, table,

  					route_destid, route_port);
  }
  
  /**
   * rio_get_host_deviceid_lock- Reads the Host Device ID Lock CSR on a device
   * @port: Master port to send transaction
   * @hopcount: Number of hops to the device
   *
   * Used during enumeration to read the Host Device ID Lock CSR on a
   * RIO device. Returns the value of the lock register.
   */
  static u16 rio_get_host_deviceid_lock(struct rio_mport *port, u8 hopcount)
  {
  	u32 result;

  	rio_mport_read_config_32(port, RIO_ANY_DESTID(port->sys_size), hopcount,

  				 RIO_HOST_DID_LOCK_CSR, &result);
  
  	return (u16) (result & 0xffff);
  }
  
  /**
   * rio_get_swpinfo_inport- Gets the ingress port number
   * @mport: Master port to send transaction
   * @destid: Destination ID associated with the switch
   * @hopcount: Number of hops to the device
   *
   * Returns port number being used to access the switch device.
   */
  static u8
  rio_get_swpinfo_inport(struct rio_mport *mport, u16 destid, u8 hopcount)
  {
  	u32 result;
  
  	rio_mport_read_config_32(mport, destid, hopcount, RIO_SWP_INFO_CAR,
  				 &result);
  
  	return (u8) (result & 0xff);
  }
  
  /**
   * rio_get_swpinfo_tports- Gets total number of ports on the switch
   * @mport: Master port to send transaction
   * @destid: Destination ID associated with the switch
   * @hopcount: Number of hops to the device
   *
   * Returns total numbers of ports implemented by the switch device.
   */
  static u8 rio_get_swpinfo_tports(struct rio_mport *mport, u16 destid,
  				 u8 hopcount)
  {
  	u32 result;
  
  	rio_mport_read_config_32(mport, destid, hopcount, RIO_SWP_INFO_CAR,
  				 &result);
  
  	return RIO_GET_TOTAL_PORTS(result);
  }
  
  /**
   * rio_net_add_mport- Add a master port to a RIO network
   * @net: RIO network
   * @port: Master port to add
   *
   * Adds a master port to the network list of associated master
   * ports..
   */
  static void rio_net_add_mport(struct rio_net *net, struct rio_mport *port)
  {
  	spin_lock(&rio_global_list_lock);
  	list_add_tail(&port->nnode, &net->mports);
  	spin_unlock(&rio_global_list_lock);
  }
  
  /**
   * rio_enum_peer- Recursively enumerate a RIO network through a master port
   * @net: RIO network being enumerated
   * @port: Master port to send transactions
   * @hopcount: Number of hops into the network
   *
   * Recursively enumerates a RIO network.  Transactions are sent via the
   * master port passed in @port.
   */
  static int rio_enum_peer(struct rio_net *net, struct rio_mport *port,
  			 u8 hopcount)
  {
  	int port_num;
  	int num_ports;
  	int cur_destid;

  	int sw_destid;
  	int sw_inport;

  	struct rio_dev *rdev;
  	u16 destid;
  	int tmp;
  
  	if (rio_get_host_deviceid_lock(port, hopcount) == port->host_deviceid) {
  		pr_debug("RIO: PE already discovered by this host
  ");
  		/*
  		 * Already discovered by this host. Add it as another
  		 * master port for the current network.
  		 */
  		rio_net_add_mport(net, port);
  		return 0;
  	}
  
  	/* Attempt to acquire device lock */

  	rio_mport_write_config_32(port, RIO_ANY_DESTID(port->sys_size),
  				  hopcount,

  				  RIO_HOST_DID_LOCK_CSR, port->host_deviceid);
  	while ((tmp = rio_get_host_deviceid_lock(port, hopcount))
  	       < port->host_deviceid) {
  		/* Delay a bit */
  		mdelay(1);
  		/* Attempt to acquire device lock again */

  		rio_mport_write_config_32(port, RIO_ANY_DESTID(port->sys_size),
  					  hopcount,

  					  RIO_HOST_DID_LOCK_CSR,
  					  port->host_deviceid);
  	}
  
  	if (rio_get_host_deviceid_lock(port, hopcount) > port->host_deviceid) {
  		pr_debug(
  		    "RIO: PE locked by a higher priority host...retreating
  ");
  		return -1;
  	}
  
  	/* Setup new RIO device */

  	rdev = rio_setup_device(net, port, RIO_ANY_DESTID(port->sys_size),
  					hopcount, 1);
  	if (rdev) {

  		/* Add device to the global and bus/net specific list. */
  		list_add_tail(&rdev->net_list, &net->devices);
  	} else
  		return -1;
  
  	if (rio_is_switch(rdev)) {
  		next_switchid++;

  		sw_inport = rio_get_swpinfo_inport(port,
  				RIO_ANY_DESTID(port->sys_size), hopcount);

  		rio_route_add_entry(port, rdev->rswitch, RIO_GLOBAL_TABLE,
  				    port->host_deviceid, sw_inport);
  		rdev->rswitch->route_table[port->host_deviceid] = sw_inport;

  
  		for (destid = 0; destid < next_destid; destid++) {

  			if (destid == port->host_deviceid)
  				continue;
  			rio_route_add_entry(port, rdev->rswitch, RIO_GLOBAL_TABLE,
  					    destid, sw_inport);
  			rdev->rswitch->route_table[destid] = sw_inport;

  		}
  
  		num_ports =

  		    rio_get_swpinfo_tports(port, RIO_ANY_DESTID(port->sys_size),
  						hopcount);

  		pr_debug(
  		    "RIO: found %s (vid %4.4x did %4.4x) with %d ports
  ",
  		    rio_name(rdev), rdev->vid, rdev->did, num_ports);

  		sw_destid = next_destid;

  		for (port_num = 0; port_num < num_ports; port_num++) {

  			if (sw_inport == port_num)

  				continue;
  
  			cur_destid = next_destid;
  
  			if (rio_sport_is_active

  			    (port, RIO_ANY_DESTID(port->sys_size), hopcount,
  			     port_num)) {

  				pr_debug(
  				    "RIO: scanning device on port %d
  ",
  				    port_num);

  				rio_route_add_entry(port, rdev->rswitch,

  						RIO_GLOBAL_TABLE,
  						RIO_ANY_DESTID(port->sys_size),
  						port_num);

  
  				if (rio_enum_peer(net, port, hopcount + 1) < 0)
  					return -1;
  
  				/* Update routing tables */
  				if (next_destid > cur_destid) {
  					for (destid = cur_destid;
  					     destid < next_destid; destid++) {

  						if (destid == port->host_deviceid)
  							continue;
  						rio_route_add_entry(port, rdev->rswitch,

  								    RIO_GLOBAL_TABLE,
  								    destid,
  								    port_num);
  						rdev->rswitch->
  						    route_table[destid] =
  						    port_num;
  					}

  				}
  			}
  		}

  
  		/* Check for empty switch */
  		if (next_destid == sw_destid) {
  			next_destid++;
  			if (next_destid == port->host_deviceid)
  				next_destid++;
  		}
  
  		rdev->rswitch->destid = sw_destid;

  	} else
  		pr_debug("RIO: found %s (vid %4.4x did %4.4x)
  ",
  		    rio_name(rdev), rdev->vid, rdev->did);
  
  	return 0;
  }
  
  /**
   * rio_enum_complete- Tests if enumeration of a network is complete
   * @port: Master port to send transaction
   *
   * Tests the Component Tag CSR for presence of the magic enumeration
   * complete flag. Return %1 if enumeration is complete or %0 if
   * enumeration is incomplete.
   */
  static int rio_enum_complete(struct rio_mport *port)
  {
  	u32 tag_csr;
  	int ret = 0;
  
  	rio_local_read_config_32(port, RIO_COMPONENT_TAG_CSR, &tag_csr);
  
  	if (tag_csr == RIO_ENUM_CMPL_MAGIC)
  		ret = 1;
  
  	return ret;
  }
  
  /**
   * rio_disc_peer- Recursively discovers a RIO network through a master port
   * @net: RIO network being discovered
   * @port: Master port to send transactions
   * @destid: Current destination ID in network
   * @hopcount: Number of hops into the network
   *
   * Recursively discovers a RIO network.  Transactions are sent via the
   * master port passed in @port.
   */
  static int
  rio_disc_peer(struct rio_net *net, struct rio_mport *port, u16 destid,
  	      u8 hopcount)
  {
  	u8 port_num, route_port;
  	int num_ports;
  	struct rio_dev *rdev;
  	u16 ndestid;
  
  	/* Setup new RIO device */
  	if ((rdev = rio_setup_device(net, port, destid, hopcount, 0))) {
  		/* Add device to the global and bus/net specific list. */
  		list_add_tail(&rdev->net_list, &net->devices);
  	} else
  		return -1;
  
  	if (rio_is_switch(rdev)) {
  		next_switchid++;
  
  		/* Associated destid is how we accessed this switch */
  		rdev->rswitch->destid = destid;
  
  		num_ports = rio_get_swpinfo_tports(port, destid, hopcount);
  		pr_debug(
  		    "RIO: found %s (vid %4.4x did %4.4x) with %d ports
  ",
  		    rio_name(rdev), rdev->vid, rdev->did, num_ports);
  		for (port_num = 0; port_num < num_ports; port_num++) {
  			if (rio_get_swpinfo_inport(port, destid, hopcount) ==
  			    port_num)
  				continue;
  
  			if (rio_sport_is_active
  			    (port, destid, hopcount, port_num)) {
  				pr_debug(
  				    "RIO: scanning device on port %d
  ",
  				    port_num);

  				for (ndestid = 0;
  				     ndestid < RIO_ANY_DESTID(port->sys_size);

  				     ndestid++) {

  					rio_route_get_entry(port, rdev->rswitch,

  							    RIO_GLOBAL_TABLE,
  							    ndestid,
  							    &route_port);
  					if (route_port == port_num)
  						break;
  				}
  
  				if (rio_disc_peer
  				    (net, port, ndestid, hopcount + 1) < 0)
  					return -1;
  			}
  		}
  	} else
  		pr_debug("RIO: found %s (vid %4.4x did %4.4x)
  ",
  		    rio_name(rdev), rdev->vid, rdev->did);
  
  	return 0;
  }
  
  /**
   * rio_mport_is_active- Tests if master port link is active
   * @port: Master port to test
   *
   * Reads the port error status CSR for the master port to
   * determine if the port has an active link.  Returns
   * %PORT_N_ERR_STS_PORT_OK if the  master port is active
   * or %0 if it is inactive.
   */
  static int rio_mport_is_active(struct rio_mport *port)
  {
  	u32 result = 0;
  	u32 ext_ftr_ptr;
  	int *entry = rio_mport_phys_table;
  
  	do {
  		if ((ext_ftr_ptr =
  		     rio_mport_get_feature(port, 1, 0, 0, *entry)))
  			break;
  	} while (*++entry >= 0);
  
  	if (ext_ftr_ptr)
  		rio_local_read_config_32(port,
  					 ext_ftr_ptr +
  					 RIO_PORT_N_ERR_STS_CSR(port->index),
  					 &result);
  
  	return (result & PORT_N_ERR_STS_PORT_OK);
  }
  
  /**
   * rio_alloc_net- Allocate and configure a new RIO network
   * @port: Master port associated with the RIO network
   *
   * Allocates a RIO network structure, initializes per-network
   * list heads, and adds the associated master port to the
   * network list of associated master ports. Returns a
   * RIO network pointer on success or %NULL on failure.
   */
  static struct rio_net __devinit *rio_alloc_net(struct rio_mport *port)
  {
  	struct rio_net *net;

  	net = kzalloc(sizeof(struct rio_net), GFP_KERNEL);

  	if (net) {

  		INIT_LIST_HEAD(&net->node);
  		INIT_LIST_HEAD(&net->devices);
  		INIT_LIST_HEAD(&net->mports);
  		list_add_tail(&port->nnode, &net->mports);
  		net->hport = port;
  		net->id = next_net++;
  	}
  	return net;
  }
  
  /**

   * rio_update_route_tables- Updates route tables in switches
   * @port: Master port associated with the RIO network
   *
   * For each enumerated device, ensure that each switch in a system
   * has correct routing entries. Add routes for devices that where
   * unknown dirung the first enumeration pass through the switch.
   */
  static void rio_update_route_tables(struct rio_mport *port)
  {
  	struct rio_dev *rdev;
  	struct rio_switch *rswitch;
  	u8 sport;
  	u16 destid;
  
  	list_for_each_entry(rdev, &rio_devices, global_list) {
  
  		destid = (rio_is_switch(rdev))?rdev->rswitch->destid:rdev->destid;
  
  		list_for_each_entry(rswitch, &rio_switches, node) {
  
  			if (rio_is_switch(rdev)	&& (rdev->rswitch == rswitch))
  				continue;
  
  			if (RIO_INVALID_ROUTE == rswitch->route_table[destid]) {
  
  				sport = rio_get_swpinfo_inport(port,
  						rswitch->destid, rswitch->hopcount);
  
  				if (rswitch->add_entry)	{
  					rio_route_add_entry(port, rswitch, RIO_GLOBAL_TABLE, destid, sport);
  					rswitch->route_table[destid] = sport;
  				}
  			}
  		}
  	}
  }
  
  /**

   * rio_enum_mport- Start enumeration through a master port
   * @mport: Master port to send transactions
   *
   * Starts the enumeration process. If somebody has enumerated our
   * master port device, then give up. If not and we have an active
   * link, then start recursive peer enumeration. Returns %0 if
   * enumeration succeeds or %-EBUSY if enumeration fails.
   */

  int __devinit rio_enum_mport(struct rio_mport *mport)

  {
  	struct rio_net *net = NULL;
  	int rc = 0;
  
  	printk(KERN_INFO "RIO: enumerate master port %d, %s
  ", mport->id,
  	       mport->name);
  	/* If somebody else enumerated our master port device, bail. */
  	if (rio_enum_host(mport) < 0) {
  		printk(KERN_INFO
  		       "RIO: master port %d device has been enumerated by a remote host
  ",
  		       mport->id);
  		rc = -EBUSY;
  		goto out;
  	}
  
  	/* If master port has an active link, allocate net and enum peers */
  	if (rio_mport_is_active(mport)) {
  		if (!(net = rio_alloc_net(mport))) {
  			printk(KERN_ERR "RIO: failed to allocate new net
  ");
  			rc = -ENOMEM;
  			goto out;
  		}
  		if (rio_enum_peer(net, mport, 0) < 0) {
  			/* A higher priority host won enumeration, bail. */
  			printk(KERN_INFO
  			       "RIO: master port %d device has lost enumeration to a remote host
  ",
  			       mport->id);
  			rio_clear_locks(mport);
  			rc = -EBUSY;
  			goto out;
  		}

  		rio_update_route_tables(mport);

  		rio_clear_locks(mport);
  	} else {
  		printk(KERN_INFO "RIO: master port %d link inactive
  ",
  		       mport->id);
  		rc = -EINVAL;
  	}
  
        out:
  	return rc;
  }
  
  /**
   * rio_build_route_tables- Generate route tables from switch route entries
   *
   * For each switch device, generate a route table by copying existing
   * route entries from the switch.
   */
  static void rio_build_route_tables(void)
  {
  	struct rio_dev *rdev;
  	int i;
  	u8 sport;
  
  	list_for_each_entry(rdev, &rio_devices, global_list)
  	    if (rio_is_switch(rdev))

  		for (i = 0;
  		     i < RIO_MAX_ROUTE_ENTRIES(rdev->net->hport->sys_size);
  		     i++) {

  			if (rio_route_get_entry

  			    (rdev->net->hport, rdev->rswitch, RIO_GLOBAL_TABLE,
  			     i, &sport) < 0)

  				continue;
  			rdev->rswitch->route_table[i] = sport;
  		}
  }
  
  /**
   * rio_enum_timeout- Signal that enumeration timed out
   * @data: Address of timeout flag.
   *
   * When the enumeration complete timer expires, set a flag that
   * signals to the discovery process that enumeration did not
   * complete in a sane amount of time.
   */
  static void rio_enum_timeout(unsigned long data)
  {
  	/* Enumeration timed out, set flag */
  	*(int *)data = 1;
  }
  
  /**
   * rio_disc_mport- Start discovery through a master port
   * @mport: Master port to send transactions
   *
   * Starts the discovery process. If we have an active link,
   * then wait for the signal that enumeration is complete.
   * When enumeration completion is signaled, start recursive
   * peer discovery. Returns %0 if discovery succeeds or %-EBUSY
   * on failure.
   */

  int __devinit rio_disc_mport(struct rio_mport *mport)

  {
  	struct rio_net *net = NULL;
  	int enum_timeout_flag = 0;
  
  	printk(KERN_INFO "RIO: discover master port %d, %s
  ", mport->id,
  	       mport->name);
  
  	/* If master port has an active link, allocate net and discover peers */
  	if (rio_mport_is_active(mport)) {
  		if (!(net = rio_alloc_net(mport))) {
  			printk(KERN_ERR "RIO: Failed to allocate new net
  ");
  			goto bail;
  		}
  
  		pr_debug("RIO: wait for enumeration complete...");
  
  		rio_enum_timer.expires =
  		    jiffies + CONFIG_RAPIDIO_DISC_TIMEOUT * HZ;
  		rio_enum_timer.data = (unsigned long)&enum_timeout_flag;
  		add_timer(&rio_enum_timer);
  		while (!rio_enum_complete(mport)) {
  			mdelay(1);
  			if (enum_timeout_flag) {
  				del_timer_sync(&rio_enum_timer);
  				goto timeout;
  			}
  		}
  		del_timer_sync(&rio_enum_timer);
  
  		pr_debug("done
  ");

  		if (rio_disc_peer(net, mport, RIO_ANY_DESTID(mport->sys_size),
  					0) < 0) {

  			printk(KERN_INFO
  			       "RIO: master port %d device has failed discovery
  ",
  			       mport->id);
  			goto bail;
  		}
  
  		rio_build_route_tables();
  	}
  
  	return 0;
  
        timeout:
  	pr_debug("timeout
  ");
        bail:
  	return -EBUSY;
  }