/*
   * SCSI RDMA (SRP) transport class
   *
   * Copyright (C) 2007 FUJITA Tomonori <tomof@acm.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, version 2 of the
   * License.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   * 02110-1301 USA
   */
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/jiffies.h>
  #include <linux/err.h>
  #include <linux/slab.h>
  #include <linux/string.h>
  
  #include <scsi/scsi.h>
  #include <scsi/scsi_device.h>
  #include <scsi/scsi_host.h>
  #include <scsi/scsi_transport.h>
  #include <scsi/scsi_transport_srp.h>

  #include "scsi_transport_srp_internal.h"

  
  struct srp_host_attrs {
  	atomic_t next_port_id;
  };
  #define to_srp_host_attrs(host)	((struct srp_host_attrs *)(host)->shost_data)
  
  #define SRP_HOST_ATTRS 0

  #define SRP_RPORT_ATTRS 2

  
  struct srp_internal {
  	struct scsi_transport_template t;
  	struct srp_function_template *f;

  	struct device_attribute *host_attrs[SRP_HOST_ATTRS + 1];

  	struct device_attribute *rport_attrs[SRP_RPORT_ATTRS + 1];
  	struct device_attribute private_rport_attrs[SRP_RPORT_ATTRS];

  	struct transport_container rport_attr_cont;
  };
  
  #define to_srp_internal(tmpl) container_of(tmpl, struct srp_internal, t)
  
  #define	dev_to_rport(d)	container_of(d, struct srp_rport, dev)

  #define transport_class_to_srp_rport(dev) dev_to_rport((dev)->parent)

  
  static int srp_host_setup(struct transport_container *tc, struct device *dev,

  			  struct device *cdev)

  {
  	struct Scsi_Host *shost = dev_to_shost(dev);
  	struct srp_host_attrs *srp_host = to_srp_host_attrs(shost);
  
  	atomic_set(&srp_host->next_port_id, 0);
  	return 0;
  }
  
  static DECLARE_TRANSPORT_CLASS(srp_host_class, "srp_host", srp_host_setup,
  			       NULL, NULL);
  
  static DECLARE_TRANSPORT_CLASS(srp_rport_class, "srp_remote_ports",
  			       NULL, NULL, NULL);
  
  #define SETUP_TEMPLATE(attrb, field, perm, test, ro_test, ro_perm)	\

  	i->private_##attrb[count] = dev_attr_##field;		\

  	i->private_##attrb[count].attr.mode = perm;			\
  	if (ro_test) {							\
  		i->private_##attrb[count].attr.mode = ro_perm;		\
  		i->private_##attrb[count].store = NULL;			\
  	}								\
  	i->attrb[count] = &i->private_##attrb[count];			\
  	if (test)							\
  		count++
  
  #define SETUP_RPORT_ATTRIBUTE_RD(field)					\
  	SETUP_TEMPLATE(rport_attrs, field, S_IRUGO, 1, 0, 0)
  
  #define SETUP_RPORT_ATTRIBUTE_RW(field)					\
  	SETUP_TEMPLATE(rport_attrs, field, S_IRUGO | S_IWUSR,		\
  		       1, 1, S_IRUGO)
  
  #define SRP_PID(p) \
  	(p)->port_id[0], (p)->port_id[1], (p)->port_id[2], (p)->port_id[3], \
  	(p)->port_id[4], (p)->port_id[5], (p)->port_id[6], (p)->port_id[7], \
  	(p)->port_id[8], (p)->port_id[9], (p)->port_id[10], (p)->port_id[11], \
  	(p)->port_id[12], (p)->port_id[13], (p)->port_id[14], (p)->port_id[15]
  
  #define SRP_PID_FMT "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:" \
  	"%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x"
  
  static ssize_t

  show_srp_rport_id(struct device *dev, struct device_attribute *attr,
  		  char *buf)

  {

  	struct srp_rport *rport = transport_class_to_srp_rport(dev);

  	return sprintf(buf, SRP_PID_FMT "
  ", SRP_PID(rport));
  }

  static DEVICE_ATTR(port_id, S_IRUGO, show_srp_rport_id, NULL);

  static const struct {
  	u32 value;
  	char *name;
  } srp_rport_role_names[] = {
  	{SRP_RPORT_ROLE_INITIATOR, "SRP Initiator"},
  	{SRP_RPORT_ROLE_TARGET, "SRP Target"},
  };
  
  static ssize_t

  show_srp_rport_roles(struct device *dev, struct device_attribute *attr,
  		     char *buf)

  {

  	struct srp_rport *rport = transport_class_to_srp_rport(dev);

  	int i;
  	char *name = NULL;
  
  	for (i = 0; i < ARRAY_SIZE(srp_rport_role_names); i++)
  		if (srp_rport_role_names[i].value == rport->roles) {
  			name = srp_rport_role_names[i].name;
  			break;
  		}
  	return sprintf(buf, "%s
  ", name ? : "unknown");
  }

  static DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);

  static void srp_rport_release(struct device *dev)
  {
  	struct srp_rport *rport = dev_to_rport(dev);
  
  	put_device(dev->parent);
  	kfree(rport);
  }
  
  static int scsi_is_srp_rport(const struct device *dev)
  {
  	return dev->release == srp_rport_release;
  }
  
  static int srp_rport_match(struct attribute_container *cont,
  			   struct device *dev)
  {
  	struct Scsi_Host *shost;
  	struct srp_internal *i;
  
  	if (!scsi_is_srp_rport(dev))
  		return 0;
  
  	shost = dev_to_shost(dev->parent);
  	if (!shost->transportt)
  		return 0;
  	if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
  		return 0;
  
  	i = to_srp_internal(shost->transportt);
  	return &i->rport_attr_cont.ac == cont;
  }
  
  static int srp_host_match(struct attribute_container *cont, struct device *dev)
  {
  	struct Scsi_Host *shost;
  	struct srp_internal *i;
  
  	if (!scsi_is_host_device(dev))
  		return 0;
  
  	shost = dev_to_shost(dev);
  	if (!shost->transportt)
  		return 0;
  	if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
  		return 0;
  
  	i = to_srp_internal(shost->transportt);
  	return &i->t.host_attrs.ac == cont;
  }
  
  /**
   * srp_rport_add - add a SRP remote port to the device hierarchy

   * @shost:	scsi host the remote port is connected to.
   * @ids:	The port id for the remote port.
   *

   * Publishes a port to the rest of the system.

   */
  struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
  				struct srp_rport_identifiers *ids)
  {
  	struct srp_rport *rport;
  	struct device *parent = &shost->shost_gendev;
  	int id, ret;
  
  	rport = kzalloc(sizeof(*rport), GFP_KERNEL);
  	if (!rport)
  		return ERR_PTR(-ENOMEM);
  
  	device_initialize(&rport->dev);
  
  	rport->dev.parent = get_device(parent);
  	rport->dev.release = srp_rport_release;
  
  	memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));

  	rport->roles = ids->roles;

  
  	id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);

  	dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);

  
  	transport_setup_device(&rport->dev);
  
  	ret = device_add(&rport->dev);
  	if (ret) {
  		transport_destroy_device(&rport->dev);
  		put_device(&rport->dev);
  		return ERR_PTR(ret);
  	}

  	if (shost->active_mode & MODE_TARGET &&
  	    ids->roles == SRP_RPORT_ROLE_INITIATOR) {

  		ret = srp_tgt_it_nexus_create(shost, (unsigned long)rport,
  					      rport->port_id);

  		if (ret) {
  			device_del(&rport->dev);
  			transport_destroy_device(&rport->dev);
  			put_device(&rport->dev);
  			return ERR_PTR(ret);
  		}
  	}

  	transport_add_device(&rport->dev);
  	transport_configure_device(&rport->dev);
  
  	return rport;
  }
  EXPORT_SYMBOL_GPL(srp_rport_add);
  
  /**

   * srp_rport_del  -  remove a SRP remote port
   * @rport:	SRP remote port to remove

   *
   * Removes the specified SRP remote port.
   */
  void srp_rport_del(struct srp_rport *rport)
  {
  	struct device *dev = &rport->dev;

  	struct Scsi_Host *shost = dev_to_shost(dev->parent);

  	if (shost->active_mode & MODE_TARGET &&
  	    rport->roles == SRP_RPORT_ROLE_INITIATOR)
  		srp_tgt_it_nexus_destroy(shost, (unsigned long)rport);

  	transport_remove_device(dev);
  	device_del(dev);
  	transport_destroy_device(dev);
  	put_device(dev);
  }
  EXPORT_SYMBOL_GPL(srp_rport_del);
  
  static int do_srp_rport_del(struct device *dev, void *data)
  {

  	if (scsi_is_srp_rport(dev))
  		srp_rport_del(dev_to_rport(dev));

  	return 0;
  }
  
  /**

   * srp_remove_host  -  tear down a Scsi_Host's SRP data structures

   * @shost:	Scsi Host that is torn down
   *
   * Removes all SRP remote ports for a given Scsi_Host.
   * Must be called just before scsi_remove_host for SRP HBAs.
   */
  void srp_remove_host(struct Scsi_Host *shost)
  {
  	device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
  }
  EXPORT_SYMBOL_GPL(srp_remove_host);

  static int srp_tsk_mgmt_response(struct Scsi_Host *shost, u64 nexus, u64 tm_id,
  				 int result)

  {
  	struct srp_internal *i = to_srp_internal(shost->transportt);

  	return i->f->tsk_mgmt_response(shost, nexus, tm_id, result);
  }
  
  static int srp_it_nexus_response(struct Scsi_Host *shost, u64 nexus, int result)
  {
  	struct srp_internal *i = to_srp_internal(shost->transportt);
  	return i->f->it_nexus_response(shost, nexus, result);

  }

  /**

   * srp_attach_transport  -  instantiate SRP transport template

   * @ft:		SRP transport class function template
   */
  struct scsi_transport_template *
  srp_attach_transport(struct srp_function_template *ft)
  {
  	int count;
  	struct srp_internal *i;
  
  	i = kzalloc(sizeof(*i), GFP_KERNEL);
  	if (!i)
  		return NULL;

  	i->t.tsk_mgmt_response = srp_tsk_mgmt_response;

  	i->t.it_nexus_response = srp_it_nexus_response;

  	i->t.host_size = sizeof(struct srp_host_attrs);
  	i->t.host_attrs.ac.attrs = &i->host_attrs[0];
  	i->t.host_attrs.ac.class = &srp_host_class.class;
  	i->t.host_attrs.ac.match = srp_host_match;
  	i->host_attrs[0] = NULL;
  	transport_container_register(&i->t.host_attrs);
  
  	i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
  	i->rport_attr_cont.ac.class = &srp_rport_class.class;
  	i->rport_attr_cont.ac.match = srp_rport_match;
  	transport_container_register(&i->rport_attr_cont);
  
  	count = 0;
  	SETUP_RPORT_ATTRIBUTE_RD(port_id);

  	SETUP_RPORT_ATTRIBUTE_RD(roles);

  	i->rport_attrs[count] = NULL;
  
  	i->f = ft;
  
  	return &i->t;
  }
  EXPORT_SYMBOL_GPL(srp_attach_transport);
  
  /**

   * srp_release_transport  -  release SRP transport template instance

   * @t:		transport template instance
   */
  void srp_release_transport(struct scsi_transport_template *t)
  {
  	struct srp_internal *i = to_srp_internal(t);
  
  	transport_container_unregister(&i->t.host_attrs);
  	transport_container_unregister(&i->rport_attr_cont);
  
  	kfree(i);
  }
  EXPORT_SYMBOL_GPL(srp_release_transport);
  
  static __init int srp_transport_init(void)
  {
  	int ret;
  
  	ret = transport_class_register(&srp_host_class);
  	if (ret)
  		return ret;
  	ret = transport_class_register(&srp_rport_class);
  	if (ret)
  		goto unregister_host_class;
  
  	return 0;
  unregister_host_class:
  	transport_class_unregister(&srp_host_class);
  	return ret;
  }
  
  static void __exit srp_transport_exit(void)
  {
  	transport_class_unregister(&srp_host_class);
  	transport_class_unregister(&srp_rport_class);
  }
  
  MODULE_AUTHOR("FUJITA Tomonori");
  MODULE_DESCRIPTION("SRP Transport Attributes");
  MODULE_LICENSE("GPL");
  
  module_init(srp_transport_init);
  module_exit(srp_transport_exit);