Merge tag 'isci-for-3.5' into misc

isci update for 3.5

1/ Rework remote-node-context (RNC) handling for proper management of
   the silicon state machine in error handling and hot-plug conditions.
   Further details below, suffice to say if the RNC is mismanaged the
   silicon state machines may lock up.

2/ Refactor the initialization code to be reused for suspend/resume support

3/ Miscellaneous bug fixes to address discovery issues and hardware
   compatibility.

RNC rework details from Jeff Skirvin:

In the controller, devices as they appear on a SAS domain (or
direct-attached SATA devices) are represented by memory structures known
as "Remote Node Contexts" (RNCs).  These structures are transferred from
main memory to the controller using a set of register commands; these
commands include setting up the context ("posting"), removing the
context ("invalidating"), and commands to control the scheduling of
commands and connections to that remote device ("suspensions" and
"resumptions").  There is a similar path to control RNC scheduling from
the protocol engine, which interprets the results of command and data
transmission and reception.

In general, the controller chooses among non-suspended RNCs to find one
that has work requiring scheduling the transmission of command and data
frames to a target.  Likewise, when a target tries to return data back
to the initiator, the state of the RNC is used by the controller to
determine how to treat the incoming request. As an example, if the RNC
is in the state "TX/RX Suspended", incoming SSP connection requests from
the target will be rejected by the controller hardware.  When an RNC is
"TX Suspended", it will not be selected by the controller hardware to
start outgoing command or data operations (with certain priority-based
exceptions).

As mentioned above, there are two sources for management of the RNC
states: commands from driver software, and the result of transmission
and reception conditions of commands and data signaled by the controller
hardware.  As an example of the latter, if an outgoing SSP command ends
with a OPEN_REJECT(BAD_DESTINATION) status, the RNC state will
transition to the "TX Suspended" state, and this is signaled by the
controller hardware in the status to the completion of the pending
command as well as signaled in a controller hardware event.  Examples of
the former are included in the patch changelogs.

Driver software is required to suspend the RNC in a "TX/RX Suspended"
condition before any outstanding commands can be terminated.  Failure to
guarantee this can lead to a complete hardware hang condition.  Earlier
versions of the driver software did not guarantee that an RNC was
correctly managed before I/O termination, and so operated in an unsafe
way.

Further, the driver performed unnecessary contortions to preserve the
remote device command state and so was more complicated than it needed
to be.  A simplifying driver assumption is that once an I/O has entered
the error handler path without having completed in the target, the
requirement on the driver is that all use of the sas_task must end.
Beyond that, recovery of operation is dependent on libsas and other
components to reset, rediscover and reconfigure the device before normal
operation can restart.  In the driver, this simplifying assumption meant
that the RNC management could be reduced to entry into the suspended
state, terminating the targeted I/O request, and resuming the RNC as
needed for device-specific management such as an SSP Abort Task or LUN
Reset Management request.

3 files changed, 39 insertions, 6 deletions

diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index 5f5ed1b8b41b..f4f1c96dca72 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -217,11 +217,29 @@ struct domain_device {
 	struct kref kref;
 };
 
-struct sas_discovery_event {
+struct sas_work {
+	struct list_head drain_node;
 	struct work_struct work;
+};
+
+static inline void INIT_SAS_WORK(struct sas_work *sw, void (*fn)(struct work_struct *))
+{
+	INIT_WORK(&sw->work, fn);
+	INIT_LIST_HEAD(&sw->drain_node);
+}
+
+struct sas_discovery_event {
+	struct sas_work work;
 	struct asd_sas_port *port;
 };
 
+static inline struct sas_discovery_event *to_sas_discovery_event(struct work_struct *work)
+{
+	struct sas_discovery_event *ev = container_of(work, typeof(*ev), work.work);
+
+	return ev;
+}
+
 struct sas_discovery {
 	struct sas_discovery_event disc_work[DISC_NUM_EVENTS];
 	unsigned long    pending;
@@ -244,7 +262,7 @@ struct asd_sas_port {
 	struct list_head destroy_list;
 	enum   sas_linkrate linkrate;
 
-	struct work_struct work;
+	struct sas_work work;
 
 /* public: */
 	int id;
@@ -270,10 +288,17 @@ struct asd_sas_port {
 };
 
 struct asd_sas_event {
-	struct work_struct work;
+	struct sas_work work;
 	struct asd_sas_phy *phy;
 };
 
+static inline struct asd_sas_event *to_asd_sas_event(struct work_struct *work)
+{
+	struct asd_sas_event *ev = container_of(work, typeof(*ev), work.work);
+
+	return ev;
+}
+
 /* The phy pretty much is controlled by the LLDD.
  * The class only reads those fields.
  */
@@ -333,10 +358,17 @@ struct scsi_core {
 };
 
 struct sas_ha_event {
-	struct work_struct work;
+	struct sas_work work;
 	struct sas_ha_struct *ha;
 };
 
+static inline struct sas_ha_event *to_sas_ha_event(struct work_struct *work)
+{
+	struct sas_ha_event *ev = container_of(work, typeof(*ev), work.work);
+
+	return ev;
+}
+
 enum sas_ha_state {
 	SAS_HA_REGISTERED,
 	SAS_HA_DRAINING,
diff --git a/include/scsi/sas.h b/include/scsi/sas.h
index a577a833603d..be3eb0bf1ac0 100644
--- a/include/scsi/sas.h
+++ b/include/scsi/sas.h
@@ -103,6 +103,7 @@ enum sas_dev_type {
 };
 
 enum sas_protocol {
+	SAS_PROTOCOL_NONE		= 0,
 	SAS_PROTOCOL_SATA		= 0x01,
 	SAS_PROTOCOL_SMP		= 0x02,
 	SAS_PROTOCOL_STP		= 0x04,
diff --git a/include/scsi/sas_ata.h b/include/scsi/sas_ata.h
index cdccd2eb7b6c..77670e823ed8 100644
--- a/include/scsi/sas_ata.h
+++ b/include/scsi/sas_ata.h
@@ -37,7 +37,7 @@ static inline int dev_is_sata(struct domain_device *dev)
 }
 
 int sas_get_ata_info(struct domain_device *dev, struct ex_phy *phy);
-int sas_ata_init_host_and_port(struct domain_device *found_dev);
+int sas_ata_init(struct domain_device *dev);
 void sas_ata_task_abort(struct sas_task *task);
 void sas_ata_strategy_handler(struct Scsi_Host *shost);
 void sas_ata_eh(struct Scsi_Host *shost, struct list_head *work_q,
@@ -52,7 +52,7 @@ static inline int dev_is_sata(struct domain_device *dev)
 {
 	return 0;
 }
-static inline int sas_ata_init_host_and_port(struct domain_device *found_dev)
+static inline int sas_ata_init(struct domain_device *dev)
 {
 	return 0;
 }