libata: separate out ata_acpi_gtm_xfermask() from pacpi_discover_modes()

Finding out matching transfer mode from ACPI GTM values is useful for
other purposes too.  Separate out the function and timing tables from
pata_acpi::pacpi_discover_modes().

Other than checking shared-configuration bit after doing
ata_acpi_gtm() in pacpi_discover_modes() which should be safe, this
patch doesn't introduce any behavior change.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/include/linux/libata.h b/include/linux/libata.h
index bdb7c6e..8022e5b 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -961,6 +961,10 @@
 
 /* libata-acpi.c */
 #ifdef CONFIG_ATA_ACPI
+extern const unsigned int ata_acpi_pio_cycle[7];
+extern const unsigned int ata_acpi_mwdma_cycle[5];
+extern const unsigned int ata_acpi_udma_cycle[7];
+
 static inline const struct ata_acpi_gtm *ata_acpi_init_gtm(struct ata_port *ap)
 {
 	if (ap->pflags & ATA_PFLAG_INIT_GTM_VALID)
@@ -970,12 +974,33 @@
 extern int ata_acpi_cbl_80wire(struct ata_port *ap);
 int ata_acpi_stm(struct ata_port *ap, const struct ata_acpi_gtm *stm);
 int ata_acpi_gtm(struct ata_port *ap, struct ata_acpi_gtm *stm);
+unsigned long ata_acpi_gtm_xfermask(struct ata_device *dev,
+				    const struct ata_acpi_gtm *gtm);
+
 #else
 static inline const struct ata_acpi_gtm *ata_acpi_init_gtm(struct ata_port *ap)
 {
 	return NULL;
 }
 static inline int ata_acpi_cbl_80wire(struct ata_port *ap) { return 0; }
+
+static inline int ata_acpi_stm(const struct ata_port *ap,
+			       struct ata_acpi_gtm *stm)
+{
+	return -ENOSYS;
+}
+
+static inline int ata_acpi_gtm(const struct ata_port *ap,
+			       struct ata_acpi_gtm *stm)
+{
+	return -ENOSYS;
+}
+
+static inline unsigned int ata_acpi_gtm_xfermask(struct ata_device *dev,
+					const struct ata_acpi_gtm *gtm)
+{
+	return 0;
+}
 #endif
 
 #ifdef CONFIG_PCI