[SCSI] libsas: suspend / resume support

libsas power management routines to suspend and recover the sas domain
based on a model where the lldd is allowed and expected to be
"forgetful".

sas_suspend_ha - disable event processing allowing the lldd to take down
                 links without concern for causing hotplug events.
                 Regardless of whether the lldd actually posts link down
                 messages libsas notifies the lldd that all
                 domain_devices are gone.

sas_prep_resume_ha - on the way back up before the lldd starts link
                     training clean out any spurious events that were
                     generated on the way down, and re-enable event
                     processing

sas_resume_ha - after the lldd has started and decided that all phys
		have posted link-up events this routine is called to let
		libsas start it's own timeout of any phys that did not
		resume.  After the timeout an lldd can cancel the
                phy teardown by posting a link-up event.

Storage for ex_change_count (u16) and phy_change_count (u8) are changed
to int so they can be set to -1 to indicate 'invalidated'.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jacek Danecki <jacek.danecki@intel.com>
Tested-by: Maciej Patelczyk <maciej.patelczyk@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

2 files changed, 25 insertions, 5 deletions

diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index ae33706afeb0..ef937b56f9b5 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -79,7 +79,8 @@ enum phy_event {
         PHYE_OOB_DONE         = 1,
         PHYE_OOB_ERROR        = 2,
         PHYE_SPINUP_HOLD      = 3, /* hot plug SATA, no COMWAKE sent */
-        PHY_NUM_EVENTS        = 4,
+        PHYE_RESUME_TIMEOUT   = 4,
+        PHY_NUM_EVENTS        = 5,
 };
 
 enum discover_event {
@@ -87,8 +88,10 @@ enum discover_event {
         DISCE_REVALIDATE_DOMAIN = 1,
         DISCE_PORT_GONE         = 2,
         DISCE_PROBE             = 3,
-        DISCE_DESTRUCT          = 4,
-        DISC_NUM_EVENTS         = 5,
+        DISCE_SUSPEND           = 4,
+        DISCE_RESUME            = 5,
+        DISCE_DESTRUCT          = 6,
+        DISC_NUM_EVENTS         = 7,
 };
 
 /* ---------- Expander Devices ---------- */
@@ -128,7 +131,7 @@ struct ex_phy {
         u8   attached_sas_addr[SAS_ADDR_SIZE];
         u8   attached_phy_id;
 
-        u8   phy_change_count;
+        int phy_change_count;
         enum routing_attribute routing_attr;
         u8   virtual:1;
 
@@ -141,7 +144,7 @@ struct ex_phy {
 struct expander_device {
         struct list_head children;
 
-        u16    ex_change_count;
+        int    ex_change_count;
         u16    max_route_indexes;
         u8     num_phys;
 
@@ -169,6 +172,7 @@ struct sata_device {
         enum   ata_command_set command_set;
         struct smp_resp        rps_resp; /* report_phy_sata_resp */
         u8     port_no;        /* port number, if this is a PM (Port) */
+        int    pm_result;
 
         struct ata_port *ap;
         struct ata_host ata_host;
@@ -182,6 +186,7 @@ struct ssp_device {
 
 enum {
         SAS_DEV_GONE,
+        SAS_DEV_FOUND, /* device notified to lldd */
         SAS_DEV_DESTROY,
         SAS_DEV_EH_PENDING,
         SAS_DEV_LU_RESET,
@@ -273,6 +278,7 @@ struct asd_sas_port {
         enum   sas_linkrate linkrate;
 
         struct sas_work work;
+        int suspended;
 
 /* public: */
         int id;
@@ -321,6 +327,7 @@ struct asd_sas_phy {
         unsigned long phy_events_pending;
 
         int error;
+        int suspended;
 
         struct sas_phy *phy;
 
@@ -687,6 +694,9 @@ struct sas_domain_function_template {
 
 extern int sas_register_ha(struct sas_ha_struct *);
 extern int sas_unregister_ha(struct sas_ha_struct *);
+extern void sas_prep_resume_ha(struct sas_ha_struct *sas_ha);
+extern void sas_resume_ha(struct sas_ha_struct *sas_ha);
+extern void sas_suspend_ha(struct sas_ha_struct *sas_ha);
 
 int sas_set_phy_speed(struct sas_phy *phy,
                       struct sas_phy_linkrates *rates);
diff --git a/include/scsi/sas_ata.h b/include/scsi/sas_ata.h
index 2dfbdaa0b34a..ff71a5654684 100644
--- a/include/scsi/sas_ata.h
+++ b/include/scsi/sas_ata.h
@@ -45,6 +45,8 @@ void sas_ata_eh(struct Scsi_Host *shost, struct list_head *work_q,
 void sas_ata_schedule_reset(struct domain_device *dev);
 void sas_ata_wait_eh(struct domain_device *dev);
 void sas_probe_sata(struct asd_sas_port *port);
+void sas_suspend_sata(struct asd_sas_port *port);
+void sas_resume_sata(struct asd_sas_port *port);
 void sas_ata_end_eh(struct ata_port *ap);
 #else
 
@@ -82,6 +84,14 @@ static inline void sas_probe_sata(struct asd_sas_port *port)
 {
 }
 
+static inline void sas_suspend_sata(struct asd_sas_port *port)
+{
+}
+
+static inline void sas_resume_sata(struct asd_sas_port *port)
+{
+}
+
 static inline int sas_get_ata_info(struct domain_device *dev, struct ex_phy *phy)
 {
         return 0;