From: Eric Farman <farman@linux.ibm.com>
Date: Thu, 7 Jul 2022 15:57:34 +0200
Subject: vfio/ccw: Create an OPEN FSM Event
Git-commit: 62ec0d49e683c25e35927a942c64433878de143c
Patch-mainline: v6.0-rc1
References: bsc#1205701

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>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/20220707135737.720765-9-farman@linux.ibm.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
---
 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(-)

--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -231,15 +231,10 @@ static int vfio_ccw_sch_probe(struct sub
 
 	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_driver);
 	if (ret)
 		goto out_disable;
--- 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"
 
@@ -368,6 +370,20 @@ static void fsm_irq(struct vfio_ccw_priv
 		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
  */
@@ -377,29 +393,34 @@ fsm_func_t *vfio_ccw_jumptable[NR_VFIO_C
 		[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_notoper,
 	},
 	[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,
 	},
 };
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -142,6 +142,7 @@ 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
 };