From: Pierre Morel <pmorel@xxxxxxxxxxxxxxxxxx>
As virtio-1 introduced the possibility of the device manipulating the
status byte, revision 2 of the virtio-ccw transport introduced a means
of getting the status byte from the device via READ_STATUS. Let's wire
it up for revisions >= 2 and fall back to returning the stored status
byte if not supported.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
---
drivers/s390/virtio/virtio_ccw.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 639ed4e6afd1..01e3dcfd7c64 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -145,6 +145,7 @@ static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
#define CCW_CMD_WRITE_CONF 0x21
#define CCW_CMD_WRITE_STATUS 0x31
#define CCW_CMD_READ_VQ_CONF 0x32
+#define CCW_CMD_READ_STATUS 0x72
#define CCW_CMD_SET_IND_ADAPTER 0x73
#define CCW_CMD_SET_VIRTIO_REV 0x83
@@ -160,6 +161,7 @@ static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
#define VIRTIO_CCW_DOING_SET_CONF_IND 0x04000000
#define VIRTIO_CCW_DOING_SET_IND_ADAPTER 0x08000000
#define VIRTIO_CCW_DOING_SET_VIRTIO_REV 0x10000000
+#define VIRTIO_CCW_DOING_READ_STATUS 0x20000000
#define VIRTIO_CCW_INTPARM_MASK 0xffff0000
static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev)
@@ -892,6 +894,28 @@ static void virtio_ccw_set_config(struct virtio_device *vdev,
static u8 virtio_ccw_get_status(struct virtio_device *vdev)
{
struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+ u8 old_status = *vcdev->status;
+ struct ccw1 *ccw;
+
+ if (vcdev->revision < 1)
+ return *vcdev->status;
+
+ ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+ if (!ccw)
+ return old_status;
+
+ ccw->cmd_code = CCW_CMD_READ_STATUS;
+ ccw->flags = 0;
+ ccw->count = sizeof(*vcdev->status);
+ ccw->cda = (__u32)(unsigned long)vcdev->status;
+ ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_STATUS);
+/*
+ * If the channel program failed (should only happen if the device
+ * was hotunplugged, and then we clean up via the machine check
+ * handler anyway), vcdev->status was not overwritten and we just
+ * return the old status, which is fine.
+*/
+ kfree(ccw);
return *vcdev->status;
}
@@ -987,6 +1011,7 @@ static void virtio_ccw_check_activity(struct virtio_ccw_device *vcdev,
case VIRTIO_CCW_DOING_READ_CONFIG:
case VIRTIO_CCW_DOING_WRITE_CONFIG:
case VIRTIO_CCW_DOING_WRITE_STATUS:
+ case VIRTIO_CCW_DOING_READ_STATUS:
case VIRTIO_CCW_DOING_SET_VQ:
case VIRTIO_CCW_DOING_SET_IND:
case VIRTIO_CCW_DOING_SET_CONF_IND:
--
2.11.0
--
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