[SCSI] isci: oem parameter format v1.3 (cable select)

v1.3 allows the attenuation of the attached cables to be specified to
the driver in terms of 'short', 'medium', and 'long' (see probe_roms.h).
These settings (per phy) are retrieved from the platform oem-parameters
(BIOS rom) or via a module parameter override.

Reviewed-by: Jiangbi Liu <jiangbi.liu@intel.com>
Signed-off-by: Jeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/isci/host.h

@@ -447,6 +447,24 @@ static inline bool is_c1(struct pci_dev *pdev)
 	return false;
 }
 
+enum cable_selections {
+	short_cable     = 0,
+	long_cable      = 1,
+	medium_cable    = 2,
+	undefined_cable = 3
+};
+
+#define CABLE_OVERRIDE_DISABLED (0x10000)
+
+static inline int is_cable_select_overridden(void)
+{
+	return cable_selection_override < CABLE_OVERRIDE_DISABLED;
+}
+
+enum cable_selections decode_cable_selection(struct isci_host *ihost, int phy);
+void validate_cable_selections(struct isci_host *ihost);
+char *lookup_cable_names(enum cable_selections);
+
 /* set hw control for 'activity', even though active enclosures seem to drive
  * the activity led on their own.  Skip setting FSENG control on 'status' due
  * to unexpected operation and 'error' due to not being a supported automatic