libata: separate out ata_host_alloc() and ata_host_register()

Reorganize ata_host_alloc() and its subroutines into the following
three functions.

* ata_host_alloc() : allocates host and its ports.  shost is not
  registered automatically.

* ata_scsi_add_hosts() : allocates and adds shosts associated with an
  ATA host.  Used by ata_host_register().

* ata_host_register() : takes a fully initialized ata_host structure
  and registers it to libata layer and probes it.

Only ata_host_alloc() and ata_host_register() are exported.
ata_device_add() is rewritten using the above functions.  This patch
does not introduce any observable behavior change.  Things worth
mentioning.

* print_id is assigned at registration time and LLDs are allowed to
  overallocate ports and reduce host->n_ports during initialization.
  ata_host_register() will throw away unused ports automatically.

* All SCSI host initialization stuff now resides in
  ata_scsi_add_hosts() in libata-scsi.c, where it should be.

* ipr is now the only user of ata_host_init().  Either kill it by
  converting ipr to use ata_host_alloc() and friends or rename and
  move it to libata-scsi.c

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 1f1e3a5..b4d5253 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -52,6 +52,7 @@
 	ATA_DNXFER_QUIET	= (1 << 31),
 };
 
+extern unsigned int ata_print_id;
 extern struct workqueue_struct *ata_aux_wq;
 extern int atapi_enabled;
 extern int atapi_dmadir;
@@ -92,10 +93,9 @@
 extern void ata_dev_init(struct ata_device *dev);
 extern int ata_task_ioctl(struct scsi_device *scsidev, void __user *arg);
 extern int ata_cmd_ioctl(struct scsi_device *scsidev, void __user *arg);
-extern void ata_port_init(struct ata_port *ap, struct ata_host *host,
-			  const struct ata_probe_ent *ent, unsigned int port_no);
 extern struct ata_probe_ent *ata_probe_ent_alloc(struct device *dev,
 						 const struct ata_port_info *port);
+extern struct ata_port *ata_port_alloc(struct ata_host *host);
 
 /* libata-acpi.c */
 #ifdef CONFIG_SATA_ACPI
@@ -113,8 +113,8 @@
 #endif
 
 /* libata-scsi.c */
-extern struct scsi_transport_template ata_scsi_transport_template;
-
+extern int ata_scsi_add_hosts(struct ata_host *host,
+			      struct scsi_host_template *sht);
 extern void ata_scsi_scan_host(struct ata_port *ap);
 extern int ata_scsi_offline_dev(struct ata_device *dev);
 extern void ata_scsi_hotplug(struct work_struct *work);