libata: add init helpers including ata_pci_prepare_native_host()

These will be used to convert LLDs to new init model.

* Add irq_handler field to port_info.  In new init model, requesting
  IRQ is LLD's responsibility and libata doesn't need to know about
  irq_handler.  Most LLDs can simply register their irq_handler but
  some need different irq_handler depending on specific chip.  The
  added port_info->irq_handler field can be used by LLDs to select
  the matching IRQ handler in such cases.

* Add ata_dummy_port_info.

* Implement ata_pci_prepare_native_host(), a helper to alloc ATA host,
  acquire all resources and init the host in one go.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 400429f..5d32c15 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -668,6 +668,7 @@
 	unsigned long		mwdma_mask;
 	unsigned long		udma_mask;
 	const struct ata_port_operations *port_ops;
+	irq_handler_t		irq_handler;
 	void 			*private_data;
 };
 
@@ -690,6 +691,7 @@
 extern const unsigned long sata_deb_timing_long[];
 
 extern const struct ata_port_operations ata_dummy_port_ops;
+extern const struct ata_port_info ata_dummy_port_info;
 
 static inline const unsigned long *
 sata_ehc_deb_timing(struct ata_eh_context *ehc)
@@ -894,6 +896,9 @@
 ata_pci_init_native_mode(struct pci_dev *pdev, struct ata_port_info **port, int portmask);
 extern int ata_pci_init_native_host(struct ata_host *host,
 				    unsigned int port_mask);
+extern int ata_pci_prepare_native_host(struct pci_dev *pdev,
+				const struct ata_port_info * const * ppi,
+				int n_ports, struct ata_host **r_host);
 extern int pci_test_config_bits(struct pci_dev *pdev, const struct pci_bits *bits);
 extern unsigned long ata_pci_default_filter(struct ata_device *, unsigned long);
 #endif /* CONFIG_PCI */