Call xpt_bus_register during attach context, then freeze and do not release

until domain discovery is complete.  This fixes an isci(4) bug on FreeBSD 7.x
where devices weren't always appearing after boot without an explicit rescan.

Sponsored by: Intel
Reported and tested by: <rpokala at panasas dot com>
Reviewed by: scottl
Approved by: scottl

3 files changed, 43 insertions, 12 deletions

diff --git a/sys/dev/isci/isci.h b/sys/dev/isci/isci.h
index 66a0330..70ba16a 100644
--- a/sys/dev/isci/isci.h
+++ b/sys/dev/isci/isci.h
@@ -122,6 +122,7 @@ struct ISCI_CONTROLLER
 	SCI_CONTROLLER_HANDLE_T	scif_controller_handle;
 	struct ISCI_DOMAIN	domain[SCI_MAX_DOMAINS];
 	BOOL			is_started;
+	BOOL			has_been_scanned;
 	uint32_t		initial_discovery_mask;
 	BOOL			is_frozen;
 	uint8_t			*remote_device_memory;
diff --git a/sys/dev/isci/isci_controller.c b/sys/dev/isci/isci_controller.c
index f240928..38d91ac 100644
--- a/sys/dev/isci/isci_controller.c
+++ b/sys/dev/isci/isci_controller.c
@@ -36,6 +36,9 @@ __FBSDID("$FreeBSD$");
 #include <sys/conf.h>
 #include <sys/malloc.h>
 
+#include <cam/cam_periph.h>
+#include <cam/cam_xpt_periph.h>
+
 #include <dev/isci/scil/sci_memory_descriptor_list.h>
 #include <dev/isci/scil/sci_memory_descriptor_list_decorator.h>
 
@@ -300,6 +303,16 @@ SCI_STATUS isci_controller_initialize(struct ISCI_CONTROLLER *controller)
 	TUNABLE_INT_FETCH("hw.isci.io_shortage", &io_shortage);
 	controller->sim_queue_depth += io_shortage;
 
+	/* Attach to CAM using xpt_bus_register now, then immediately freeze
+	 *  the simq.  It will get released later when initial domain discovery
+	 *  is complete.
+	 */
+	controller->has_been_scanned = FALSE;
+	mtx_lock(&controller->lock);
+	isci_controller_attach_to_cam(controller);
+	xpt_freeze_simq(controller->sim, 1);
+	mtx_unlock(&controller->lock);
+
 	return (scif_controller_initialize(controller->scif_controller_handle));
 }
 
@@ -441,13 +454,13 @@ void isci_controller_start(void *controller_handle)
 void isci_controller_domain_discovery_complete(
     struct ISCI_CONTROLLER *isci_controller, struct ISCI_DOMAIN *isci_domain)
 {
-	if (isci_controller->sim == NULL)
+	if (!isci_controller->has_been_scanned)
 	{
-		/* Controller has not been attached to CAM yet.  We'll clear
+		/* Controller has not been scanned yet.  We'll clear
 		 *  the discovery bit for this domain, then check if all bits
 		 *  are now clear.  That would indicate that all domains are
-		 *  done with discovery and we can then attach the controller
-		 *  to CAM.
+		 *  done with discovery and we can then proceed with initial
+		 *  scan.
 		 */
 
 		isci_controller->initial_discovery_mask &=
@@ -457,7 +470,25 @@ void isci_controller_domain_discovery_complete(
 			struct isci_softc *driver = isci_controller->isci;
 			uint8_t next_index = isci_controller->index + 1;
 
-			isci_controller_attach_to_cam(isci_controller);
+			isci_controller->has_been_scanned = TRUE;
+
+			/* Unfreeze simq to allow initial scan to proceed. */
+			xpt_release_simq(isci_controller->sim, TRUE);
+
+#if __FreeBSD_version < 800000
+			/* When driver is loaded after boot, we need to
+			 *  explicitly rescan here for versions <8.0, because
+			 *  CAM only automatically scans new buses at boot
+			 *  time.
+			 */
+			union ccb *ccb = xpt_alloc_ccb_nowait();
+
+			xpt_create_path(&ccb->ccb_h.path, xpt_periph,
+			    cam_sim_path(isci_controller->sim),
+			    CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
+
+			xpt_rescan(ccb);
+#endif
 
 			if (next_index < driver->controller_count) {
 				/*  There are more controllers that need to
diff --git a/sys/dev/isci/isci_remote_device.c b/sys/dev/isci/isci_remote_device.c
index 2388dae..d22b4d4 100644
--- a/sys/dev/isci/isci_remote_device.c
+++ b/sys/dev/isci/isci_remote_device.c
@@ -74,13 +74,12 @@ scif_cb_remote_device_ready(SCI_CONTROLLER_HANDLE_T controller,
 		isci_controller->remote_device[device_index] =
 		    isci_remote_device;
 
-		if (isci_controller->sim != NULL) {
-			/* The sim object is not NULL, meaning we have attached
-			 *  the controller to CAM already.  In that case, create
-			 *  a CCB to instruct CAM to rescan this device.
-			 * If the sim object is NULL, this device will get
-			 *  scanned as part of the initial scan when the
-			 *  controller is attached to CAM.
+		if (isci_controller->has_been_scanned) {
+			/* The sim object has been scanned at least once
+			 *  already.  In that case, create a CCB to instruct
+			 *  CAM to rescan this device.
+			 * If the sim object has not been scanned, this device
+			 *  will get scanned as part of the initial scan.
 			 */
 			union ccb *ccb = xpt_alloc_ccb_nowait();