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.

1 files changed, 57 insertions, 6 deletions

diff --git a/drivers/scsi/isci/remote_device.h b/drivers/scsi/isci/remote_device.h
index 58637ee08f55..7674caae1d88 100644
--- a/drivers/scsi/isci/remote_device.h
+++ b/drivers/scsi/isci/remote_device.h
@@ -85,27 +85,38 @@ struct isci_remote_device {
 	#define IDEV_GONE 3
 	#define IDEV_IO_READY 4
 	#define IDEV_IO_NCQERROR 5
+	#define IDEV_RNC_LLHANG_ENABLED 6
+	#define IDEV_ABORT_PATH_ACTIVE 7
+	#define IDEV_ABORT_PATH_RESUME_PENDING 8
 	unsigned long flags;
 	struct kref kref;
 	struct isci_port *isci_port;
 	struct domain_device *domain_dev;
 	struct list_head node;
-	struct list_head reqs_in_process;
 	struct sci_base_state_machine sm;
 	u32 device_port_width;
 	enum sas_linkrate connection_rate;
-	bool is_direct_attached;
 	struct isci_port *owning_port;
 	struct sci_remote_node_context rnc;
 	/* XXX unify with device reference counting and delete */
 	u32 started_request_count;
 	struct isci_request *working_request;
 	u32 not_ready_reason;
+	scics_sds_remote_node_context_callback abort_resume_cb;
+	void *abort_resume_cbparam;
 };
 
 #define ISCI_REMOTE_DEVICE_START_TIMEOUT 5000
 
 /* device reference routines must be called under sci_lock */
+static inline struct isci_remote_device *isci_get_device(
+	struct isci_remote_device *idev)
+{
+	if (idev)
+		kref_get(&idev->kref);
+	return idev;
+}
+
 static inline struct isci_remote_device *isci_lookup_device(struct domain_device *dev)
 {
 	struct isci_remote_device *idev = dev->lldd_dev;
@@ -302,6 +313,8 @@ static inline void sci_remote_device_decrement_request_count(struct isci_remote_
 		idev->started_request_count--;
 }
 
+void isci_dev_set_hang_detection_timeout(struct isci_remote_device *idev, u32 timeout);
+
 enum sci_status sci_remote_device_frame_handler(
 	struct isci_remote_device *idev,
 	u32 frame_index);
@@ -325,12 +338,50 @@ enum sci_status sci_remote_device_complete_io(
 	struct isci_remote_device *idev,
 	struct isci_request *ireq);
 
-enum sci_status sci_remote_device_suspend(
-	struct isci_remote_device *idev,
-	u32 suspend_type);
-
 void sci_remote_device_post_request(
 	struct isci_remote_device *idev,
 	u32 request);
 
+enum sci_status sci_remote_device_terminate_requests(
+	struct isci_remote_device *idev);
+
+int isci_remote_device_is_safe_to_abort(
+	struct isci_remote_device *idev);
+
+enum sci_status
+sci_remote_device_abort_requests_pending_abort(
+	struct isci_remote_device *idev);
+
+enum sci_status isci_remote_device_suspend(
+	struct isci_host *ihost,
+	struct isci_remote_device *idev);
+
+enum sci_status sci_remote_device_resume(
+	struct isci_remote_device *idev,
+	scics_sds_remote_node_context_callback cb_fn,
+	void *cb_p);
+
+enum sci_status isci_remote_device_resume_from_abort(
+	struct isci_host *ihost,
+	struct isci_remote_device *idev);
+
+enum sci_status isci_remote_device_reset(
+	struct isci_host *ihost,
+	struct isci_remote_device *idev);
+
+enum sci_status isci_remote_device_reset_complete(
+	struct isci_host *ihost,
+	struct isci_remote_device *idev);
+
+enum sci_status isci_remote_device_suspend_terminate(
+	struct isci_host *ihost,
+	struct isci_remote_device *idev,
+	struct isci_request *ireq);
+
+enum sci_status isci_remote_device_terminate_requests(
+	struct isci_host *ihost,
+	struct isci_remote_device *idev,
+	struct isci_request *ireq);
+enum sci_status sci_remote_device_suspend(struct isci_remote_device *idev,
+					  enum sci_remote_node_suspension_reasons reason);
 #endif /* !defined(_ISCI_REMOTE_DEVICE_H_) */