xref: /openbmc/linux/drivers/rapidio/rio-scan.c (revision 42bc47b3)

/*
 * RapidIO enumeration and discovery support
 *
 * Copyright 2005 MontaVista Software, Inc.
 * Matt Porter <mporter@kernel.crashing.org>
 *
 * Copyright 2009 Integrated Device Technology, Inc.
 * Alex Bounine <alexandre.bounine@idt.com>
 * - Added Port-Write/Error Management initialization and handling
 *
 * Copyright 2009 Sysgo AG
 * Thomas Moll <thomas.moll@sysgo.com>
 * - Added Input- Output- enable functionality, to allow full communication
 *
 * 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/sched.h>
#include <linux/jiffies.h>
#include <linux/slab.h>

#include "rio.h"

static void rio_init_em(struct rio_dev *rdev);

struct rio_id_table {
	u16 start;	/* logical minimal id */
	u32 max;	/* max number of IDs in table */
	spinlock_t lock;
	unsigned long table[0];
};

static int next_destid = 0;
static int next_comptag = 1;

/**
 * rio_destid_alloc - Allocate next available destID for given network
 * @net: RIO network
 *
 * Returns next available device destination ID for the specified RIO network.
 * Marks allocated ID as one in use.
 * Returns RIO_INVALID_DESTID if new destID is not available.
 */
static u16 rio_destid_alloc(struct rio_net *net)
{
	int destid;
	struct rio_id_table *idtab = (struct rio_id_table *)net->enum_data;

	spin_lock(&idtab->lock);
	destid = find_first_zero_bit(idtab->table, idtab->max);

	if (destid < idtab->max) {
		set_bit(destid, idtab->table);
		destid += idtab->start;
	} else
		destid = RIO_INVALID_DESTID;

	spin_unlock(&idtab->lock);
	return (u16)destid;
}

/**
 * rio_destid_reserve - Reserve the specified destID
 * @net: RIO network
 * @destid: destID to reserve
 *
 * Tries to reserve the specified destID.
 * Returns 0 if successful.
 */
static int rio_destid_reserve(struct rio_net *net, u16 destid)
{
	int oldbit;
	struct rio_id_table *idtab = (struct rio_id_table *)net->enum_data;

	destid -= idtab->start;
	spin_lock(&idtab->lock);
	oldbit = test_and_set_bit(destid, idtab->table);
	spin_unlock(&idtab->lock);
	return oldbit;
}

/**
 * rio_destid_free - free a previously allocated destID
 * @net: RIO network
 * @destid: destID to free
 *
 * Makes the specified destID available for use.
 */
static void rio_destid_free(struct rio_net *net, u16 destid)
{
	struct rio_id_table *idtab = (struct rio_id_table *)net->enum_data;

	destid -= idtab->start;
	spin_lock(&idtab->lock);
	clear_bit(destid, idtab->table);
	spin_unlock(&idtab->lock);
}

/**
 * rio_destid_first - return first destID in use
 * @net: RIO network
 */
static u16 rio_destid_first(struct rio_net *net)
{
	int destid;
	struct rio_id_table *idtab = (struct rio_id_table *)net->enum_data;

	spin_lock(&idtab->lock);
	destid = find_first_bit(idtab->table, idtab->max);
	if (destid >= idtab->max)
		destid = RIO_INVALID_DESTID;
	else
		destid += idtab->start;
	spin_unlock(&idtab->lock);
	return (u16)destid;
}

/**
 * rio_destid_next - return next destID in use
 * @net: RIO network
 * @from: destination ID from which search shall continue
 */
static u16 rio_destid_next(struct rio_net *net, u16 from)
{
	int destid;
	struct rio_id_table *idtab = (struct rio_id_table *)net->enum_data;

	spin_lock(&idtab->lock);
	destid = find_next_bit(idtab->table, idtab->max, from);
	if (destid >= idtab->max)
		destid = RIO_INVALID_DESTID;
	else
		destid += idtab->start;
	spin_unlock(&idtab->lock);
	return (u16)destid;
}

/**
 * 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_clear_locks- Release all host locks and signal enumeration complete
 * @net: RIO network to run on
 *
 * 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_net *net)
{
	struct rio_mport *port = net->hport;
	struct rio_dev *rdev;
	u32 result;
	int ret = 0;

	/* 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\n",
		       result);
		ret = -EINVAL;
	}
	list_for_each_entry(rdev, &net->devices, net_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\n",
			       rdev->vid, rdev->did);
			ret = -EINVAL;
		}

		/* Mark device as discovered and enable master */
		rio_read_config_32(rdev,
				   rdev->phys_efptr + RIO_PORT_GEN_CTL_CSR,
				   &result);
		result |= RIO_PORT_GEN_DISCOVERED | RIO_PORT_GEN_MASTER;
		rio_write_config_32(rdev,
				    rdev->phys_efptr + RIO_PORT_GEN_CTL_CSR,
				    result);
	}

	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);
	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_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)
{
	int ret = 0;
	struct rio_dev *rdev;
	struct rio_switch *rswitch = NULL;
	int result, rdid;
	size_t size;
	u32 swpinfo = 0;

	size = sizeof(struct rio_dev);
	if (rio_mport_read_config_32(port, destid, hopcount,
				     RIO_PEF_CAR, &result))
		return NULL;

	if (result & (RIO_PEF_SWITCH | RIO_PEF_MULTIPORT)) {
		rio_mport_read_config_32(port, destid, hopcount,
					 RIO_SWP_INFO_CAR, &swpinfo);
		if (result & RIO_PEF_SWITCH) {
			size += (RIO_GET_TOTAL_PORTS(swpinfo) *
				sizeof(rswitch->nextdev[0])) + sizeof(*rswitch);
		}
	}

	rdev = kzalloc(size, GFP_KERNEL);
	if (!rdev)
		return NULL;

	rdev->net = net;
	rdev->pef = result;
	rdev->swpinfo = swpinfo;
	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;
	if (rdev->pef & RIO_PEF_EXT_FEATURES) {
		rdev->efptr = result & 0xffff;
		rdev->phys_efptr = rio_mport_get_physefb(port, 0, destid,
						hopcount, &rdev->phys_rmap);
		pr_debug("RIO: %s Register Map %d device\n",
			 __func__, rdev->phys_rmap);

		rdev->em_efptr = rio_mport_get_feature(port, 0, destid,
						hopcount, RIO_EFB_ERR_MGMNT);
		if (!rdev->em_efptr)
			rdev->em_efptr = rio_mport_get_feature(port, 0, destid,
						hopcount, RIO_EFB_ERR_MGMNT_HS);
	}

	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 (do_enum) {
		/* Assign component tag to device */
		if (next_comptag >= 0x10000) {
			pr_err("RIO: Component Tag Counter Overflow\n");
			goto cleanup;
		}
		rio_mport_write_config_32(port, destid, hopcount,
					  RIO_COMPONENT_TAG_CSR, next_comptag);
		rdev->comp_tag = next_comptag++;
		rdev->do_enum = true;
	}  else {
		rio_mport_read_config_32(port, destid, hopcount,
					 RIO_COMPONENT_TAG_CSR,
					 &rdev->comp_tag);
	}

	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;
			next_destid = rio_destid_alloc(net);
		} else
			rdev->destid = rio_get_device_id(port, destid, hopcount);

		rdev->hopcount = 0xff;
	} else {
		/* Switch device has an associated destID which
		 * will be adjusted later
		 */
		rdev->destid = destid;
		rdev->hopcount = hopcount;
	}

	/* If a PE has both switch and other functions, show it as a switch */
	if (rio_is_switch(rdev)) {
		rswitch = rdev->rswitch;
		rswitch->port_ok = 0;
		spin_lock_init(&rswitch->lock);
		rswitch->route_table =
			kzalloc(RIO_MAX_ROUTE_ENTRIES(port->sys_size),
				GFP_KERNEL);
		if (!rswitch->route_table)
			goto cleanup;
		/* Initialize switch route table */
		for (rdid = 0; rdid < RIO_MAX_ROUTE_ENTRIES(port->sys_size);
				rdid++)
			rswitch->route_table[rdid] = RIO_INVALID_ROUTE;
		dev_set_name(&rdev->dev, "%02x:s:%04x", rdev->net->id,
			     rdev->comp_tag & RIO_CTAG_UDEVID);

		if (do_enum)
			rio_route_clr_table(rdev, RIO_GLOBAL_TABLE, 0);
	} else {
		if (do_enum)
			/*Enable Input Output Port (transmitter receiver)*/
			rio_enable_rx_tx_port(port, 0, destid, hopcount, 0);

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

	rdev->dev.parent = &net->dev;
	rio_attach_device(rdev);
	rdev->dev.release = rio_release_dev;
	rdev->dma_mask = DMA_BIT_MASK(32);
	rdev->dev.dma_mask = &rdev->dma_mask;
	rdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);

	if (rdev->dst_ops & RIO_DST_OPS_DOORBELL)
		rio_init_dbell_res(&rdev->riores[RIO_DOORBELL_RESOURCE],
				   0, 0xffff);

	ret = rio_add_device(rdev);
	if (ret)
		goto cleanup;

	rio_dev_get(rdev);

	return rdev;

cleanup:
	if (rswitch)
		kfree(rswitch->route_table);

	kfree(rdev);
	return NULL;
}

/**
 * rio_sport_is_active- Tests if a switch port has an active connection.
 * @rdev: RapidIO device object
 * @sp: Switch port number
 *
 * Reads the port error status CSR for a particular switch port to
 * determine if the port has an active link.  Returns
 * %RIO_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_dev *rdev, int sp)
{
	u32 result = 0;

	rio_read_config_32(rdev, RIO_DEV_PORT_N_ERR_STS_CSR(rdev, sp),
			   &result);

	return result & RIO_PORT_N_ERR_STS_PORT_OK;
}

/**
 * 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_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
 * @prev: Previous RIO device connected to the enumerated one
 * @prev_port: Port on previous RIO device
 *
 * 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, struct rio_dev *prev, int prev_port)
{
	struct rio_dev *rdev;
	u32 regval;
	int tmp;

	if (rio_mport_chk_dev_access(port,
			RIO_ANY_DESTID(port->sys_size), hopcount)) {
		pr_debug("RIO: device access check failed\n");
		return -1;
	}

	if (rio_get_host_deviceid_lock(port, hopcount) == port->host_deviceid) {
		pr_debug("RIO: PE already discovered by this host\n");
		/*
		 * Already discovered by this host. Add it as another
		 * link to the existing device.
		 */
		rio_mport_read_config_32(port, RIO_ANY_DESTID(port->sys_size),
				hopcount, RIO_COMPONENT_TAG_CSR, &regval);

		if (regval) {
			rdev = rio_get_comptag((regval & 0xffff), NULL);

			if (rdev && prev && rio_is_switch(prev)) {
				pr_debug("RIO: redundant path to %s\n",
					 rio_name(rdev));
				prev->rswitch->nextdev[prev_port] = rdev;
			}
		}

		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\n");
		return -1;
	}

	/* Setup new RIO device */
	rdev = rio_setup_device(net, port, RIO_ANY_DESTID(port->sys_size),
					hopcount, 1);
	if (rdev) {
		rdev->prev = prev;
		if (prev && rio_is_switch(prev))
			prev->rswitch->nextdev[prev_port] = rdev;
	} else
		return -1;

	if (rio_is_switch(rdev)) {
		int sw_destid;
		int cur_destid;
		int sw_inport;
		u16 destid;
		int port_num;

		sw_inport = RIO_GET_PORT_NUM(rdev->swpinfo);
		rio_route_add_entry(rdev, RIO_GLOBAL_TABLE,
				    port->host_deviceid, sw_inport, 0);
		rdev->rswitch->route_table[port->host_deviceid] = sw_inport;

		destid = rio_destid_first(net);
		while (destid != RIO_INVALID_DESTID && destid < next_destid) {
			if (destid != port->host_deviceid) {
				rio_route_add_entry(rdev, RIO_GLOBAL_TABLE,
						    destid, sw_inport, 0);
				rdev->rswitch->route_table[destid] = sw_inport;
			}
			destid = rio_destid_next(net, destid + 1);
		}
		pr_debug(
		    "RIO: found %s (vid %4.4x did %4.4x) with %d ports\n",
		    rio_name(rdev), rdev->vid, rdev->did,
		    RIO_GET_TOTAL_PORTS(rdev->swpinfo));
		sw_destid = next_destid;
		for (port_num = 0;
		     port_num < RIO_GET_TOTAL_PORTS(rdev->swpinfo);
		     port_num++) {
			if (sw_inport == port_num) {
				rio_enable_rx_tx_port(port, 0,
					      RIO_ANY_DESTID(port->sys_size),
					      hopcount, port_num);
				rdev->rswitch->port_ok |= (1 << port_num);
				continue;
			}

			cur_destid = next_destid;

			if (rio_sport_is_active(rdev, port_num)) {
				pr_debug(
				    "RIO: scanning device on port %d\n",
				    port_num);
				rio_enable_rx_tx_port(port, 0,
					      RIO_ANY_DESTID(port->sys_size),
					      hopcount, port_num);
				rdev->rswitch->port_ok |= (1 << port_num);
				rio_route_add_entry(rdev, RIO_GLOBAL_TABLE,
						RIO_ANY_DESTID(port->sys_size),
						port_num, 0);

				if (rio_enum_peer(net, port, hopcount + 1,
						  rdev, port_num) < 0)
					return -1;

				/* Update routing tables */
				destid = rio_destid_next(net, cur_destid + 1);
				if (destid != RIO_INVALID_DESTID) {
					for (destid = cur_destid;
					     destid < next_destid;) {
						if (destid != port->host_deviceid) {
							rio_route_add_entry(rdev,
								    RIO_GLOBAL_TABLE,
								    destid,
								    port_num,
								    0);
							rdev->rswitch->
								route_table[destid] =
								port_num;
						}
						destid = rio_destid_next(net,
								destid + 1);
					}
				}
			} else {
				/* If switch supports Error Management,
				 * set PORT_LOCKOUT bit for unused port
				 */
				if (rdev->em_efptr)
					rio_set_port_lockout(rdev, port_num, 1);

				rdev->rswitch->port_ok &= ~(1 << port_num);
			}
		}

		/* Direct Port-write messages to the enumeratiing host */
		if ((rdev->src_ops & RIO_SRC_OPS_PORT_WRITE) &&
		    (rdev->em_efptr)) {
			rio_write_config_32(rdev,
					rdev->em_efptr + RIO_EM_PW_TGT_DEVID,
					(port->host_deviceid << 16) |
					(port->sys_size << 15));
		}

		rio_init_em(rdev);

		/* Check for empty switch */
		if (next_destid == sw_destid)
			next_destid = rio_destid_alloc(net);

		rdev->destid = sw_destid;
	} else
		pr_debug("RIO: found %s (vid %4.4x did %4.4x)\n",
		    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 PGCCSR discovered bit for non-zero value (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 regval;

	rio_local_read_config_32(port, port->phys_efptr + RIO_PORT_GEN_CTL_CSR,
				 &regval);
	return (regval & RIO_PORT_GEN_DISCOVERED) ? 1 : 0;
}

/**
 * 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
 * @prev: previous rio_dev
 * @prev_port: previous port number
 *
 * 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, struct rio_dev *prev, int prev_port)
{
	u8 port_num, route_port;
	struct rio_dev *rdev;
	u16 ndestid;

	/* Setup new RIO device */
	if ((rdev = rio_setup_device(net, port, destid, hopcount, 0))) {
		rdev->prev = prev;
		if (prev && rio_is_switch(prev))
			prev->rswitch->nextdev[prev_port] = rdev;
	} else
		return -1;

	if (rio_is_switch(rdev)) {
		/* Associated destid is how we accessed this switch */
		rdev->destid = destid;

		pr_debug(
		    "RIO: found %s (vid %4.4x did %4.4x) with %d ports\n",
		    rio_name(rdev), rdev->vid, rdev->did,
		    RIO_GET_TOTAL_PORTS(rdev->swpinfo));
		for (port_num = 0;
		     port_num < RIO_GET_TOTAL_PORTS(rdev->swpinfo);
		     port_num++) {
			if (RIO_GET_PORT_NUM(rdev->swpinfo) == port_num)
				continue;

			if (rio_sport_is_active(rdev, port_num)) {
				pr_debug(
				    "RIO: scanning device on port %d\n",
				    port_num);

				rio_lock_device(port, destid, hopcount, 1000);

				for (ndestid = 0;
				     ndestid < RIO_ANY_DESTID(port->sys_size);
				     ndestid++) {
					rio_route_get_entry(rdev,
							    RIO_GLOBAL_TABLE,
							    ndestid,
							    &route_port, 0);
					if (route_port == port_num)
						break;
				}

				if (ndestid == RIO_ANY_DESTID(port->sys_size))
					continue;
				rio_unlock_device(port, destid, hopcount);
				if (rio_disc_peer(net, port, ndestid,
					hopcount + 1, rdev, port_num) < 0)
					return -1;
			}
		}
	} else
		pr_debug("RIO: found %s (vid %4.4x did %4.4x)\n",
		    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
 * %RIO_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;

	rio_local_read_config_32(port,
		port->phys_efptr +
			RIO_PORT_N_ERR_STS_CSR(port->index, port->phys_rmap),
		&result);
	return result & RIO_PORT_N_ERR_STS_PORT_OK;
}

static void rio_scan_release_net(struct rio_net *net)
{
	pr_debug("RIO-SCAN: %s: net_%d\n", __func__, net->id);
	kfree(net->enum_data);
}

static void rio_scan_release_dev(struct device *dev)
{
	struct rio_net *net;

	net = to_rio_net(dev);
	pr_debug("RIO-SCAN: %s: net_%d\n", __func__, net->id);
	kfree(net);
}

/*
 * rio_scan_alloc_net - Allocate and configure a new RIO network
 * @mport: Master port associated with the RIO network
 * @do_enum: Enumeration/Discovery mode flag
 * @start: logical minimal start id for new net
 *
 * Allocates a new RIO network structure and initializes enumerator-specific
 * part of it (if required).
 * Returns a RIO network pointer on success or %NULL on failure.
 */
static struct rio_net *rio_scan_alloc_net(struct rio_mport *mport,
					  int do_enum, u16 start)
{
	struct rio_net *net;

	net = rio_alloc_net(mport);

	if (net && do_enum) {
		struct rio_id_table *idtab;
		size_t size;

		size = sizeof(struct rio_id_table) +
				BITS_TO_LONGS(
					RIO_MAX_ROUTE_ENTRIES(mport->sys_size)
					) * sizeof(long);

		idtab = kzalloc(size, GFP_KERNEL);

		if (idtab == NULL) {
			pr_err("RIO: failed to allocate destID table\n");
			rio_free_net(net);
			net = NULL;
		} else {
			net->enum_data = idtab;
			net->release = rio_scan_release_net;
			idtab->start = start;
			idtab->max = RIO_MAX_ROUTE_ENTRIES(mport->sys_size);
			spin_lock_init(&idtab->lock);
		}
	}

	if (net) {
		net->id = mport->id;
		net->hport = mport;
		dev_set_name(&net->dev, "rnet_%d", net->id);
		net->dev.parent = &mport->dev;
		net->dev.release = rio_scan_release_dev;
		rio_add_net(net);
	}

	return net;
}

/**
 * rio_update_route_tables- Updates route tables in switches
 * @net: RIO network to run update on
 *
 * For each enumerated device, ensure that each switch in a system
 * has correct routing entries. Add routes for devices that where
 * unknown during the first enumeration pass through the switch.
 */
static void rio_update_route_tables(struct rio_net *net)
{
	struct rio_dev *rdev, *swrdev;
	struct rio_switch *rswitch;
	u8 sport;
	u16 destid;

	list_for_each_entry(rdev, &net->devices, net_list) {

		destid = rdev->destid;

		list_for_each_entry(rswitch, &net->switches, node) {

			if (rio_is_switch(rdev)	&& (rdev->rswitch == rswitch))
				continue;

			if (RIO_INVALID_ROUTE == rswitch->route_table[destid]) {
				swrdev = sw_to_rio_dev(rswitch);

				/* Skip if destid ends in empty switch*/
				if (swrdev->destid == destid)
					continue;

				sport = RIO_GET_PORT_NUM(swrdev->swpinfo);

				rio_route_add_entry(swrdev, RIO_GLOBAL_TABLE,
						    destid, sport, 0);
				rswitch->route_table[destid] = sport;
			}
		}
	}
}

/**
 * rio_init_em - Initializes RIO Error Management (for switches)
 * @rdev: RIO device
 *
 * For each enumerated switch, call device-specific error management
 * initialization routine (if supplied by the switch driver).
 */
static void rio_init_em(struct rio_dev *rdev)
{
	if (rio_is_switch(rdev) && (rdev->em_efptr) &&
	    rdev->rswitch->ops && rdev->rswitch->ops->em_init) {
		rdev->rswitch->ops->em_init(rdev);
	}
}

/**
 * rio_enum_mport- Start enumeration through a master port
 * @mport: Master port to send transactions
 * @flags: Enumeration control flags
 *
 * 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.
 */
static int rio_enum_mport(struct rio_mport *mport, u32 flags)
{
	struct rio_net *net = NULL;
	int rc = 0;

	printk(KERN_INFO "RIO: enumerate master port %d, %s\n", mport->id,
	       mport->name);

	/*
	 * To avoid multiple start requests (repeat enumeration is not supported
	 * by this method) check if enumeration/discovery was performed for this
	 * mport: if mport was added into the list of mports for a net exit
	 * with error.
	 */
	if (mport->nnode.next || mport->nnode.prev)
		return -EBUSY;

	/* 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\n",
		       mport->id);
		rc = -EBUSY;
		goto out;
	}

	/* If master port has an active link, allocate net and enum peers */
	if (rio_mport_is_active(mport)) {
		net = rio_scan_alloc_net(mport, 1, 0);
		if (!net) {
			printk(KERN_ERR "RIO: failed to allocate new net\n");
			rc = -ENOMEM;
			goto out;
		}

		/* reserve mport destID in new net */
		rio_destid_reserve(net, mport->host_deviceid);

		/* Enable Input Output Port (transmitter receiver) */
		rio_enable_rx_tx_port(mport, 1, 0, 0, 0);

		/* Set component tag for host */
		rio_local_write_config_32(mport, RIO_COMPONENT_TAG_CSR,
					  next_comptag++);

		next_destid = rio_destid_alloc(net);

		if (rio_enum_peer(net, mport, 0, NULL, 0) < 0) {
			/* A higher priority host won enumeration, bail. */
			printk(KERN_INFO
			       "RIO: master port %d device has lost enumeration to a remote host\n",
			       mport->id);
			rio_clear_locks(net);
			rc = -EBUSY;
			goto out;
		}
		/* free the last allocated destID (unused) */
		rio_destid_free(net, next_destid);
		rio_update_route_tables(net);
		rio_clear_locks(net);
		rio_pw_enable(mport, 1);
	} else {
		printk(KERN_INFO "RIO: master port %d link inactive\n",
		       mport->id);
		rc = -EINVAL;
	}

      out:
	return rc;
}

/**
 * rio_build_route_tables- Generate route tables from switch route entries
 * @net: RIO network to run route tables scan on
 *
 * For each switch device, generate a route table by copying existing
 * route entries from the switch.
 */
static void rio_build_route_tables(struct rio_net *net)
{
	struct rio_switch *rswitch;
	struct rio_dev *rdev;
	int i;
	u8 sport;

	list_for_each_entry(rswitch, &net->switches, node) {
		rdev = sw_to_rio_dev(rswitch);

		rio_lock_device(net->hport, rdev->destid,
				rdev->hopcount, 1000);
		for (i = 0;
		     i < RIO_MAX_ROUTE_ENTRIES(net->hport->sys_size);
		     i++) {
			if (rio_route_get_entry(rdev, RIO_GLOBAL_TABLE,
						i, &sport, 0) < 0)
				continue;
			rswitch->route_table[i] = sport;
		}

		rio_unlock_device(net->hport, rdev->destid, rdev->hopcount);
	}
}

/**
 * rio_disc_mport- Start discovery through a master port
 * @mport: Master port to send transactions
 * @flags: discovery control flags
 *
 * Starts the discovery process. If we have an active link,
 * then wait for the signal that enumeration is complete (if wait
 * is allowed).
 * When enumeration completion is signaled, start recursive
 * peer discovery. Returns %0 if discovery succeeds or %-EBUSY
 * on failure.
 */
static int rio_disc_mport(struct rio_mport *mport, u32 flags)
{
	struct rio_net *net = NULL;
	unsigned long to_end;

	printk(KERN_INFO "RIO: discover master port %d, %s\n", mport->id,
	       mport->name);

	/* If master port has an active link, allocate net and discover peers */
	if (rio_mport_is_active(mport)) {
		if (rio_enum_complete(mport))
			goto enum_done;
		else if (flags & RIO_SCAN_ENUM_NO_WAIT)
			return -EAGAIN;

		pr_debug("RIO: wait for enumeration to complete...\n");

		to_end = jiffies + CONFIG_RAPIDIO_DISC_TIMEOUT * HZ;
		while (time_before(jiffies, to_end)) {
			if (rio_enum_complete(mport))
				goto enum_done;
			msleep(10);
		}

		pr_debug("RIO: discovery timeout on mport %d %s\n",
			 mport->id, mport->name);
		goto bail;
enum_done:
		pr_debug("RIO: ... enumeration done\n");

		net = rio_scan_alloc_net(mport, 0, 0);
		if (!net) {
			printk(KERN_ERR "RIO: Failed to allocate new net\n");
			goto bail;
		}

		/* Read DestID assigned by enumerator */
		rio_local_read_config_32(mport, RIO_DID_CSR,
					 &mport->host_deviceid);
		mport->host_deviceid = RIO_GET_DID(mport->sys_size,
						   mport->host_deviceid);

		if (rio_disc_peer(net, mport, RIO_ANY_DESTID(mport->sys_size),
					0, NULL, 0) < 0) {
			printk(KERN_INFO
			       "RIO: master port %d device has failed discovery\n",
			       mport->id);
			goto bail;
		}

		rio_build_route_tables(net);
	}

	return 0;
bail:
	return -EBUSY;
}

static struct rio_scan rio_scan_ops = {
	.owner = THIS_MODULE,
	.enumerate = rio_enum_mport,
	.discover = rio_disc_mport,
};

static bool scan;
module_param(scan, bool, 0);
MODULE_PARM_DESC(scan, "Start RapidIO network enumeration/discovery "
			"(default = 0)");

/**
 * rio_basic_attach:
 *
 * When this enumeration/discovery method is loaded as a module this function
 * registers its specific enumeration and discover routines for all available
 * RapidIO mport devices. The "scan" command line parameter controls ability of
 * the module to start RapidIO enumeration/discovery automatically.
 *
 * Returns 0 for success or -EIO if unable to register itself.
 *
 * This enumeration/discovery method cannot be unloaded and therefore does not
 * provide a matching cleanup_module routine.
 */

static int __init rio_basic_attach(void)
{
	if (rio_register_scan(RIO_MPORT_ANY, &rio_scan_ops))
		return -EIO;
	if (scan)
		rio_init_mports();
	return 0;
}

late_initcall(rio_basic_attach);

MODULE_DESCRIPTION("Basic RapidIO enumeration/discovery");
MODULE_LICENSE("GPL");