[PATCH v1 09/18] vfio/ccw: Create an OPEN FSM Event

[Eric Farman <farman@linux.ibm.com>]

Move the process of enabling a subchannel for use by vfio-ccw
into the FSM, such that it can manage the sequence of lifecycle
events for the device.

That is, if the FSM state is NOT_OPER(erational), then do the work
that would enable the subchannel and move the FSM to STANDBY state.
An attempt to perform this event again from any of the other operating
states (IDLE, CP_PROCESSING, CP_PENDING) will convert the device back
to NOT_OPER so the configuration process can be started again.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
---
 drivers/s390/cio/vfio_ccw_drv.c     |  9 ++-------
 drivers/s390/cio/vfio_ccw_fsm.c     | 21 +++++++++++++++++++++
 drivers/s390/cio/vfio_ccw_private.h |  1 +
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index f8226db26e54..2d816dd01713 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -236,15 +236,10 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
 
 	dev_set_drvdata(&sch->dev, private);
 
-	spin_lock_irq(sch->lock);
-	sch->isc = VFIO_CCW_ISC;
-	ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
-	spin_unlock_irq(sch->lock);
-	if (ret)
+	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_OPEN);
+	if (private->state == VFIO_CCW_STATE_NOT_OPER)
 		goto out_free;
 
-	private->state = VFIO_CCW_STATE_STANDBY;
-
 	ret = mdev_register_device(&sch->dev, &vfio_ccw_mdev_ops);
 	if (ret)
 		goto out_disable;
diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index 3e1d7744c292..25db8534ded0 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -11,6 +11,8 @@
 
 #include <linux/vfio.h>
 
+#include <asm/isc.h>
+
 #include "ioasm.h"
 #include "vfio_ccw_private.h"
 
@@ -365,6 +367,20 @@ static void fsm_irq(struct vfio_ccw_private *private,
 		complete(private->completion);
 }
 
+static void fsm_open(struct vfio_ccw_private *private,
+		     enum vfio_ccw_event event)
+{
+	struct subchannel *sch = private->sch;
+	int ret;
+
+	spin_lock_irq(sch->lock);
+	sch->isc = VFIO_CCW_ISC;
+	ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
+	if (!ret)
+		private->state = VFIO_CCW_STATE_STANDBY;
+	spin_unlock_irq(sch->lock);
+}
+
 /*
  * Device statemachine
  */
@@ -374,29 +390,34 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS] = {
 		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_error,
 		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_error,
 		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_disabled_irq,
+		[VFIO_CCW_EVENT_OPEN]		= fsm_open,
 	},
 	[VFIO_CCW_STATE_STANDBY] = {
 		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
 		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_error,
 		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_error,
 		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
+		[VFIO_CCW_EVENT_OPEN]		= fsm_nop,
 	},
 	[VFIO_CCW_STATE_IDLE] = {
 		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
 		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_request,
 		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_request,
 		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
+		[VFIO_CCW_EVENT_OPEN]		= fsm_notoper,
 	},
 	[VFIO_CCW_STATE_CP_PROCESSING] = {
 		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
 		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_retry,
 		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_retry,
 		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
+		[VFIO_CCW_EVENT_OPEN]		= fsm_notoper,
 	},
 	[VFIO_CCW_STATE_CP_PENDING] = {
 		[VFIO_CCW_EVENT_NOT_OPER]	= fsm_notoper,
 		[VFIO_CCW_EVENT_IO_REQ]		= fsm_io_busy,
 		[VFIO_CCW_EVENT_ASYNC_REQ]	= fsm_async_request,
 		[VFIO_CCW_EVENT_INTERRUPT]	= fsm_irq,
+		[VFIO_CCW_EVENT_OPEN]		= fsm_notoper,
 	},
 };
diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index 2e0744ac6492..d7ba6846e5c5 100644
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -143,6 +143,7 @@ enum vfio_ccw_event {
 	VFIO_CCW_EVENT_IO_REQ,
 	VFIO_CCW_EVENT_INTERRUPT,
 	VFIO_CCW_EVENT_ASYNC_REQ,
+	VFIO_CCW_EVENT_OPEN,
 	/* last element! */
 	NR_VFIO_CCW_EVENTS
 };
-- 
2.32.0