[SCSI] isci: fix, prevent port from getting stuck in the 'configuring' state

When expander connected in x2 or x4 mode and with IO runnning, if
a cable from wideport is plugged out from the phy, IO's start failing
on all the targets.

Observed that when cable is pulled with IO running, cominit is
happening on all the links and IO's start dropping to 0 and eventually
the whole IO fails. Second observation, target is trying to open and
SCU is responding with "Open reject no destination".

A cause of the problem is when the port went from the "ready
configuring substate" back to "ready configuring substate" as a result
of phy being pulled off, scic suspended the port task scheduler
register. As a result no IO was allowed and in the "substate
configuring enter" routine the IO never goes back to 0. As a result
the port never comes out of "ready substate configuring".

The patch adds a mechanism of activate and deactivate phy when a port
link up, which fixes the problem.

Signed-off-by: Bartek Nowakowski <bartek.nowakowski@intel.com>
Signed-off-by: Maciej Trela <maciej.trela@intel.com>
Signed-off-by: Marcin Tomczak <marcin.tomczak@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/isci/port.h

@@ -63,6 +63,9 @@
 
 #define SCIC_SDS_DUMMY_PORT   0xFF
 
+#define PF_NOTIFY (1 << 0)
+#define PF_RESUME (1 << 1)
+
 struct isci_phy;
 struct isci_host;
 
@@ -83,6 +86,8 @@ enum isci_status {
  * @logical_port_index: software port index
  * @physical_port_index: hardware port index
  * @active_phy_mask: identifies phy members
+ * @enabled_phy_mask: phy mask for the port
+ *                    that are already part of the port
  * @reserved_tag:
  * @reserved_rni: reserver for port task scheduler workaround
  * @started_request_count: reference count for outstanding commands
@@ -104,6 +109,7 @@ struct isci_port {
 	u8 logical_port_index;
 	u8 physical_port_index;
 	u8 active_phy_mask;
+	u8 enabled_phy_mask;
 	u8 last_active_phy;
 	u16 reserved_rni;
 	u16 reserved_tag;