diff options
Diffstat (limited to 'drivers/firmware/arm_scmi/virtio.c')
-rw-r--r-- | drivers/firmware/arm_scmi/virtio.c | 44 |
1 files changed, 31 insertions, 13 deletions
diff --git a/drivers/firmware/arm_scmi/virtio.c b/drivers/firmware/arm_scmi/virtio.c index 224577f86928..11e8efb71375 100644 --- a/drivers/firmware/arm_scmi/virtio.c +++ b/drivers/firmware/arm_scmi/virtio.c @@ -110,18 +110,16 @@ static void scmi_finalize_message(struct scmi_vio_channel *vioch, if (vioch->is_rx) { scmi_vio_feed_vq_rx(vioch, msg); } else { - unsigned long flags; - - spin_lock_irqsave(&vioch->lock, flags); + /* Here IRQs are assumed to be already disabled by the caller */ + spin_lock(&vioch->lock); list_add(&msg->list, &vioch->free_list); - spin_unlock_irqrestore(&vioch->lock, flags); + spin_unlock(&vioch->lock); } } static void scmi_vio_complete_cb(struct virtqueue *vqueue) { unsigned long ready_flags; - unsigned long flags; unsigned int length; struct scmi_vio_channel *vioch; struct scmi_vio_msg *msg; @@ -140,7 +138,8 @@ static void scmi_vio_complete_cb(struct virtqueue *vqueue) goto unlock_ready_out; } - spin_lock_irqsave(&vioch->lock, flags); + /* IRQs already disabled here no need to irqsave */ + spin_lock(&vioch->lock); if (cb_enabled) { virtqueue_disable_cb(vqueue); cb_enabled = false; @@ -151,7 +150,7 @@ static void scmi_vio_complete_cb(struct virtqueue *vqueue) goto unlock_out; cb_enabled = true; } - spin_unlock_irqrestore(&vioch->lock, flags); + spin_unlock(&vioch->lock); if (msg) { msg->rx_len = length; @@ -161,11 +160,18 @@ static void scmi_vio_complete_cb(struct virtqueue *vqueue) scmi_finalize_message(vioch, msg); } + /* + * Release ready_lock and re-enable IRQs between loop iterations + * to allow virtio_chan_free() to possibly kick in and set the + * flag vioch->ready to false even in between processing of + * messages, so as to force outstanding messages to be ignored + * when system is shutting down. + */ spin_unlock_irqrestore(&vioch->ready_lock, ready_flags); } unlock_out: - spin_unlock_irqrestore(&vioch->lock, flags); + spin_unlock(&vioch->lock); unlock_ready_out: spin_unlock_irqrestore(&vioch->ready_lock, ready_flags); } @@ -384,8 +390,11 @@ static int scmi_vio_probe(struct virtio_device *vdev) struct virtqueue *vqs[VIRTIO_SCMI_VQ_MAX_CNT]; /* Only one SCMI VirtiO device allowed */ - if (scmi_vdev) - return -EINVAL; + if (scmi_vdev) { + dev_err(dev, + "One SCMI Virtio device was already initialized: only one allowed.\n"); + return -EBUSY; + } have_vq_rx = scmi_vio_have_vq_rx(vdev); vq_cnt = have_vq_rx ? VIRTIO_SCMI_VQ_MAX_CNT : 1; @@ -428,16 +437,25 @@ static int scmi_vio_probe(struct virtio_device *vdev) } vdev->priv = channels; - scmi_vdev = vdev; + /* Ensure initialized scmi_vdev is visible */ + smp_store_mb(scmi_vdev, vdev); return 0; } static void scmi_vio_remove(struct virtio_device *vdev) { + /* + * Once we get here, virtio_chan_free() will have already been called by + * the SCMI core for any existing channel and, as a consequence, all the + * virtio channels will have been already marked NOT ready, causing any + * outstanding message on any vqueue to be ignored by complete_cb: now + * we can just stop processing buffers and destroy the vqueues. + */ vdev->config->reset(vdev); vdev->config->del_vqs(vdev); - scmi_vdev = NULL; + /* Ensure scmi_vdev is visible as NULL */ + smp_store_mb(scmi_vdev, NULL); } static int scmi_vio_validate(struct virtio_device *vdev) @@ -476,7 +494,7 @@ static int __init virtio_scmi_init(void) return register_virtio_driver(&virtio_scmi_driver); } -static void __exit virtio_scmi_exit(void) +static void virtio_scmi_exit(void) { unregister_virtio_driver(&virtio_scmi_driver); } |