[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.c

@@ -647,19 +647,26 @@ void sci_port_setup_transports(struct isci_port *iport, u32 device_id)
 	}
 }
 
-static void sci_port_activate_phy(struct isci_port *iport, struct isci_phy *iphy,
-				  bool do_notify_user)
+static void sci_port_resume_phy(struct isci_port *iport, struct isci_phy *iphy)
+{
+	sci_phy_resume(iphy);
+	iport->enabled_phy_mask |= 1 << iphy->phy_index;
+}
+
+static void sci_port_activate_phy(struct isci_port *iport,
+				  struct isci_phy *iphy,
+				  u8 flags)
 {
 	struct isci_host *ihost = iport->owning_controller;
 
-	if (iphy->protocol != SCIC_SDS_PHY_PROTOCOL_SATA)
+	if (iphy->protocol != SCIC_SDS_PHY_PROTOCOL_SATA && (flags & PF_RESUME))
 		sci_phy_resume(iphy);
 
 	iport->active_phy_mask |= 1 << iphy->phy_index;
 
 	sci_controller_clear_invalid_phy(ihost, iphy);
 
-	if (do_notify_user == true)
+	if (flags & PF_NOTIFY)
 		isci_port_link_up(ihost, iport, iphy);
 }
 
@@ -669,6 +676,7 @@ void sci_port_deactivate_phy(struct isci_port *iport, struct isci_phy *iphy,
 	struct isci_host *ihost = iport->owning_controller;
 
 	iport->active_phy_mask &= ~(1 << iphy->phy_index);
+	iport->enabled_phy_mask &= ~(1 << iphy->phy_index);
 	if (!iport->active_phy_mask)
 		iport->last_active_phy = iphy->phy_index;
 
@@ -705,18 +713,16 @@ static void sci_port_invalid_link_up(struct isci_port *iport, struct isci_phy *i
  * sci_port_general_link_up_handler - phy can be assigned to port?
  * @sci_port: sci_port object for which has a phy that has gone link up.
  * @sci_phy: This is the struct isci_phy object that has gone link up.
- * @do_notify_user: This parameter specifies whether to inform the user (via
- *    sci_port_link_up()) as to the fact that a new phy as become ready.
+ * @flags: PF_RESUME, PF_NOTIFY to sci_port_activate_phy
  *
- * Determine if this phy can be assigned to this
- * port . If the phy is not a valid PHY for
- * this port then the function will notify the user. A PHY can only be
- * part of a port if it's attached SAS ADDRESS is the same as all other PHYs in
- * the same port. none
+ * Determine if this phy can be assigned to this port . If the phy is
+ * not a valid PHY for this port then the function will notify the user.
+ * A PHY can only be part of a port if it's attached SAS ADDRESS is the
+ * same as all other PHYs in the same port.
  */
 static void sci_port_general_link_up_handler(struct isci_port *iport,
-						  struct isci_phy *iphy,
-						  bool do_notify_user)
+					     struct isci_phy *iphy,
+					     u8 flags)
 {
 	struct sci_sas_address port_sas_address;
 	struct sci_sas_address phy_sas_address;
@@ -734,7 +740,7 @@ static void sci_port_general_link_up_handler(struct isci_port *iport,
 	    iport->active_phy_mask == 0) {
 		struct sci_base_state_machine *sm = &iport->sm;
 
-		sci_port_activate_phy(iport, iphy, do_notify_user);
+		sci_port_activate_phy(iport, iphy, flags);
 		if (sm->current_state_id == SCI_PORT_RESETTING)
 			port_state_machine_change(iport, SCI_PORT_READY);
 	} else
@@ -785,11 +791,16 @@ bool sci_port_link_detected(
 	struct isci_phy *iphy)
 {
 	if ((iport->logical_port_index != SCIC_SDS_DUMMY_PORT) &&
-	    (iphy->protocol == SCIC_SDS_PHY_PROTOCOL_SATA) &&
-	    sci_port_is_wide(iport)) {
-		sci_port_invalid_link_up(iport, iphy);
-
-		return false;
+	    (iphy->protocol == SCIC_SDS_PHY_PROTOCOL_SATA)) {
+		if (sci_port_is_wide(iport)) {
+			sci_port_invalid_link_up(iport, iphy);
+			return false;
+		} else {
+			struct isci_host *ihost = iport->owning_controller;
+			struct isci_port *dst_port = &(ihost->ports[iphy->phy_index]);
+			writel(iphy->phy_index,
+			       &dst_port->port_pe_configuration_register[iphy->phy_index]);
+		}
 	}
 
 	return true;
@@ -979,6 +990,13 @@ static void sci_port_ready_substate_waiting_enter(struct sci_base_state_machine
 	}
 }
 
+static void scic_sds_port_ready_substate_waiting_exit(
+					struct sci_base_state_machine *sm)
+{
+	struct isci_port *iport = container_of(sm, typeof(*iport), sm);
+	sci_port_resume_port_task_scheduler(iport);
+}
+
 static void sci_port_ready_substate_operational_enter(struct sci_base_state_machine *sm)
 {
 	u32 index;
@@ -992,13 +1010,13 @@ static void sci_port_ready_substate_operational_enter(struct sci_base_state_mach
 			writel(iport->physical_port_index,
 				&iport->port_pe_configuration_register[
 					iport->phy_table[index]->phy_index]);
+			if (((iport->active_phy_mask^iport->enabled_phy_mask) & (1 << index)) != 0)
+				sci_port_resume_phy(iport, iport->phy_table[index]);
 		}
 	}
 
 	sci_port_update_viit_entry(iport);
 
-	sci_port_resume_port_task_scheduler(iport);
-
 	/*
 	 * Post the dummy task for the port so the hardware can schedule
 	 * io correctly
@@ -1065,20 +1083,9 @@ static void sci_port_ready_substate_configuring_enter(struct sci_base_state_mach
 	if (iport->active_phy_mask == 0) {
 		isci_port_not_ready(ihost, iport);
 
-		port_state_machine_change(iport,
-					  SCI_PORT_SUB_WAITING);
-	} else if (iport->started_request_count == 0)
-		port_state_machine_change(iport,
-					  SCI_PORT_SUB_OPERATIONAL);
-}
-
-static void sci_port_ready_substate_configuring_exit(struct sci_base_state_machine *sm)
-{
-	struct isci_port *iport = container_of(sm, typeof(*iport), sm);
-
-	sci_port_suspend_port_task_scheduler(iport);
-	if (iport->ready_exit)
-		sci_port_invalidate_dummy_remote_node(iport);
+		port_state_machine_change(iport, SCI_PORT_SUB_WAITING);
+	} else
+		port_state_machine_change(iport, SCI_PORT_SUB_OPERATIONAL);
 }
 
 enum sci_status sci_port_start(struct isci_port *iport)
@@ -1256,7 +1263,7 @@ enum sci_status sci_port_add_phy(struct isci_port *iport,
 		if (status != SCI_SUCCESS)
 			return status;
 
-		sci_port_general_link_up_handler(iport, iphy, true);
+		sci_port_general_link_up_handler(iport, iphy, PF_NOTIFY|PF_RESUME);
 		iport->not_ready_reason = SCIC_PORT_NOT_READY_RECONFIGURING;
 		port_state_machine_change(iport, SCI_PORT_SUB_CONFIGURING);
 
@@ -1266,7 +1273,7 @@ enum sci_status sci_port_add_phy(struct isci_port *iport,
 
 		if (status != SCI_SUCCESS)
 			return status;
-		sci_port_general_link_up_handler(iport, iphy, true);
+		sci_port_general_link_up_handler(iport, iphy, PF_NOTIFY);
 
 		/* Re-enter the configuring state since this may be the last phy in
 		 * the port.
@@ -1342,13 +1349,13 @@ enum sci_status sci_port_link_up(struct isci_port *iport,
 		/* Since this is the first phy going link up for the port we
 		 * can just enable it and continue
 		 */
-		sci_port_activate_phy(iport, iphy, true);
+		sci_port_activate_phy(iport, iphy, PF_NOTIFY|PF_RESUME);
 
 		port_state_machine_change(iport,
 					  SCI_PORT_SUB_OPERATIONAL);
 		return SCI_SUCCESS;
 	case SCI_PORT_SUB_OPERATIONAL:
-		sci_port_general_link_up_handler(iport, iphy, true);
+		sci_port_general_link_up_handler(iport, iphy, PF_NOTIFY|PF_RESUME);
 		return SCI_SUCCESS;
 	case SCI_PORT_RESETTING:
 		/* TODO We should  make  sure  that  the phy  that  has gone
@@ -1365,7 +1372,7 @@ enum sci_status sci_port_link_up(struct isci_port *iport,
 		/* In the resetting state we don't notify the user regarding
 		 * link up and link down notifications.
 		 */
-		sci_port_general_link_up_handler(iport, iphy, false);
+		sci_port_general_link_up_handler(iport, iphy, PF_RESUME);
 		return SCI_SUCCESS;
 	default:
 		dev_warn(sciport_to_dev(iport),
@@ -1588,14 +1595,14 @@ static const struct sci_base_state sci_port_state_table[] = {
 	},
 	[SCI_PORT_SUB_WAITING] = {
 		.enter_state = sci_port_ready_substate_waiting_enter,
+		.exit_state  = scic_sds_port_ready_substate_waiting_exit,
 	},
 	[SCI_PORT_SUB_OPERATIONAL] = {
 		.enter_state = sci_port_ready_substate_operational_enter,
 		.exit_state  = sci_port_ready_substate_operational_exit
 	},
 	[SCI_PORT_SUB_CONFIGURING] = {
-		.enter_state = sci_port_ready_substate_configuring_enter,
-		.exit_state  = sci_port_ready_substate_configuring_exit
+		.enter_state = sci_port_ready_substate_configuring_enter
 	},
 	[SCI_PORT_RESETTING] = {
 		.exit_state  = sci_port_resetting_state_exit
@@ -1613,6 +1620,7 @@ void sci_port_construct(struct isci_port *iport, u8 index,
 	iport->logical_port_index  = SCIC_SDS_DUMMY_PORT;
 	iport->physical_port_index = index;
 	iport->active_phy_mask     = 0;
+	iport->enabled_phy_mask    = 0;
 	iport->last_active_phy     = 0;
 	iport->ready_exit	   = false;
 

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;