accel/qaic: Add QAIC_DETACH_SLICE_BO IOCTL

Once a BO is attached with slicing configuration that BO can only be used
for that particular setting. With this new feature user can detach slicing
configuration off an already sliced BO and attach new slicing configuration
using QAIC_ATTACH_SLICE_BO.

This will support BO recycling.

detach_slice_bo() detaches slicing configuration from a BO. This new
helper function can also be used in release_dbc() as we are doing the
exact same thing.

Signed-off-by: Pranjal Ramajor Asha Kanojiya <quic_pkanojiy@quicinc.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
[jhugo: add documentation for new ioctl]
Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230901172247.11410-8-quic_jhugo@quicinc.com

3 files changed, 113 insertions, 11 deletions

diff --git a/drivers/accel/qaic/qaic.h b/drivers/accel/qaic/qaic.h
index 983dcdff2cfe..e3f4c30f3ffd 100644
--- a/drivers/accel/qaic/qaic.h
+++ b/drivers/accel/qaic/qaic.h
@@ -222,7 +222,8 @@ struct qaic_bo {
 		 */
 		u32		queue_level_before;
 	} perf_stats;
-
+	/* Synchronizes BO operations */
+	struct mutex		lock;
 };
 
 struct bo_slice {
@@ -278,6 +279,7 @@ int qaic_execute_bo_ioctl(struct drm_device *dev, void *data, struct drm_file *f
 int qaic_partial_execute_bo_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv);
 int qaic_wait_bo_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv);
 int qaic_perf_stats_bo_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv);
+int qaic_detach_slice_bo_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv);
 void irq_polling_work(struct work_struct *work);
 
 #endif /* _QAIC_H_ */
diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c
index 2acb9dbac88b..c90fa6a430f6 100644
--- a/drivers/accel/qaic/qaic_data.c
+++ b/drivers/accel/qaic/qaic_data.c
@@ -624,6 +624,7 @@ static void qaic_free_object(struct drm_gem_object *obj)
 		qaic_free_sgt(bo->sgt);
 	}
 
+	mutex_destroy(&bo->lock);
 	drm_gem_object_release(obj);
 	kfree(bo);
 }
@@ -641,6 +642,7 @@ static void qaic_init_bo(struct qaic_bo *bo, bool reinit)
 		bo->sliced = false;
 		reinit_completion(&bo->xfer_done);
 	} else {
+		mutex_init(&bo->lock);
 		init_completion(&bo->xfer_done);
 	}
 	complete_all(&bo->xfer_done);
@@ -1002,10 +1004,13 @@ int qaic_attach_slice_bo_ioctl(struct drm_device *dev, void *data, struct drm_fi
 	}
 
 	bo = to_qaic_bo(obj);
+	ret = mutex_lock_interruptible(&bo->lock);
+	if (ret)
+		goto put_bo;
 
 	if (bo->sliced) {
 		ret = -EINVAL;
-		goto put_bo;
+		goto unlock_bo;
 	}
 
 	dbc = &qdev->dbc[args->hdr.dbc_id];
@@ -1029,7 +1034,7 @@ int qaic_attach_slice_bo_ioctl(struct drm_device *dev, void *data, struct drm_fi
 	bo->sliced = true;
 	list_add_tail(&bo->bo_list, &bo->dbc->bo_lists);
 	srcu_read_unlock(&dbc->ch_lock, rcu_id);
-	drm_gem_object_put(obj);
+	mutex_unlock(&bo->lock);
 	srcu_read_unlock(&qdev->dev_lock, qdev_rcu_id);
 	srcu_read_unlock(&usr->qddev_lock, usr_rcu_id);
 
@@ -1039,6 +1044,8 @@ unprepare_bo:
 	qaic_unprepare_bo(qdev, bo);
 unlock_ch_srcu:
 	srcu_read_unlock(&dbc->ch_lock, rcu_id);
+unlock_bo:
+	mutex_unlock(&bo->lock);
 put_bo:
 	drm_gem_object_put(obj);
 free_slice_ent:
@@ -1193,15 +1200,18 @@ static int send_bo_list_to_device(struct qaic_device *qdev, struct drm_file *fil
 		}
 
 		bo = to_qaic_bo(obj);
+		ret = mutex_lock_interruptible(&bo->lock);
+		if (ret)
+			goto failed_to_send_bo;
 
 		if (!bo->sliced) {
 			ret = -EINVAL;
-			goto failed_to_send_bo;
+			goto unlock_bo;
 		}
 
 		if (is_partial && pexec[i].resize > bo->base.size) {
 			ret = -EINVAL;
-			goto failed_to_send_bo;
+			goto unlock_bo;
 		}
 
 		spin_lock_irqsave(&dbc->xfer_lock, flags);
@@ -1210,7 +1220,7 @@ static int send_bo_list_to_device(struct qaic_device *qdev, struct drm_file *fil
 		if (queued) {
 			spin_unlock_irqrestore(&dbc->xfer_lock, flags);
 			ret = -EINVAL;
-			goto failed_to_send_bo;
+			goto unlock_bo;
 		}
 
 		bo->req_id = dbc->next_req_id++;
@@ -1241,17 +1251,20 @@ static int send_bo_list_to_device(struct qaic_device *qdev, struct drm_file *fil
 			if (ret) {
 				bo->queued = false;
 				spin_unlock_irqrestore(&dbc->xfer_lock, flags);
-				goto failed_to_send_bo;
+				goto unlock_bo;
 			}
 		}
 		reinit_completion(&bo->xfer_done);
 		list_add_tail(&bo->xfer_list, &dbc->xfer_list);
 		spin_unlock_irqrestore(&dbc->xfer_lock, flags);
 		dma_sync_sgtable_for_device(&qdev->pdev->dev, bo->sgt, bo->dir);
+		mutex_unlock(&bo->lock);
 	}
 
 	return 0;
 
+unlock_bo:
+	mutex_unlock(&bo->lock);
 failed_to_send_bo:
 	if (likely(obj))
 		drm_gem_object_put(obj);
@@ -1807,6 +1820,91 @@ unlock_usr_srcu:
 	return ret;
 }
 
+static void detach_slice_bo(struct qaic_device *qdev, struct qaic_bo *bo)
+{
+	qaic_free_slices_bo(bo);
+	qaic_unprepare_bo(qdev, bo);
+	qaic_init_bo(bo, true);
+	list_del(&bo->bo_list);
+	drm_gem_object_put(&bo->base);
+}
+
+int qaic_detach_slice_bo_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv)
+{
+	struct qaic_detach_slice *args = data;
+	int rcu_id, usr_rcu_id, qdev_rcu_id;
+	struct dma_bridge_chan *dbc;
+	struct drm_gem_object *obj;
+	struct qaic_device *qdev;
+	struct qaic_user *usr;
+	unsigned long flags;
+	struct qaic_bo *bo;
+	int ret;
+
+	if (args->pad != 0)
+		return -EINVAL;
+
+	usr = file_priv->driver_priv;
+	usr_rcu_id = srcu_read_lock(&usr->qddev_lock);
+	if (!usr->qddev) {
+		ret = -ENODEV;
+		goto unlock_usr_srcu;
+	}
+
+	qdev = usr->qddev->qdev;
+	qdev_rcu_id = srcu_read_lock(&qdev->dev_lock);
+	if (qdev->in_reset) {
+		ret = -ENODEV;
+		goto unlock_dev_srcu;
+	}
+
+	obj = drm_gem_object_lookup(file_priv, args->handle);
+	if (!obj) {
+		ret = -ENOENT;
+		goto unlock_dev_srcu;
+	}
+
+	bo = to_qaic_bo(obj);
+	ret = mutex_lock_interruptible(&bo->lock);
+	if (ret)
+		goto put_bo;
+
+	if (!bo->sliced) {
+		ret = -EINVAL;
+		goto unlock_bo;
+	}
+
+	dbc = bo->dbc;
+	rcu_id = srcu_read_lock(&dbc->ch_lock);
+	if (dbc->usr != usr) {
+		ret = -EINVAL;
+		goto unlock_ch_srcu;
+	}
+
+	/* Check if BO is committed to H/W for DMA */
+	spin_lock_irqsave(&dbc->xfer_lock, flags);
+	if (bo->queued) {
+		spin_unlock_irqrestore(&dbc->xfer_lock, flags);
+		ret = -EBUSY;
+		goto unlock_ch_srcu;
+	}
+	spin_unlock_irqrestore(&dbc->xfer_lock, flags);
+
+	detach_slice_bo(qdev, bo);
+
+unlock_ch_srcu:
+	srcu_read_unlock(&dbc->ch_lock, rcu_id);
+unlock_bo:
+	mutex_unlock(&bo->lock);
+put_bo:
+	drm_gem_object_put(obj);
+unlock_dev_srcu:
+	srcu_read_unlock(&qdev->dev_lock, qdev_rcu_id);
+unlock_usr_srcu:
+	srcu_read_unlock(&usr->qddev_lock, usr_rcu_id);
+	return ret;
+}
+
 static void empty_xfer_list(struct qaic_device *qdev, struct dma_bridge_chan *dbc)
 {
 	unsigned long flags;
@@ -1888,10 +1986,11 @@ void release_dbc(struct qaic_device *qdev, u32 dbc_id)
 	dbc->usr = NULL;
 
 	list_for_each_entry_safe(bo, bo_temp, &dbc->bo_lists, bo_list) {
-		qaic_free_slices_bo(bo);
-		qaic_unprepare_bo(qdev, bo);
-		qaic_init_bo(bo, true);
-		list_del(&bo->bo_list);
+		drm_gem_object_get(&bo->base);
+		mutex_lock(&bo->lock);
+		detach_slice_bo(qdev, bo);
+		mutex_unlock(&bo->lock);
+		drm_gem_object_put(&bo->base);
 	}
 
 	dbc->in_use = false;
diff --git a/drivers/accel/qaic/qaic_drv.c b/drivers/accel/qaic/qaic_drv.c
index d9e1ba64d7cf..6f58095767df 100644
--- a/drivers/accel/qaic/qaic_drv.c
+++ b/drivers/accel/qaic/qaic_drv.c
@@ -151,6 +151,7 @@ static const struct drm_ioctl_desc qaic_drm_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(QAIC_PARTIAL_EXECUTE_BO, qaic_partial_execute_bo_ioctl, 0),
 	DRM_IOCTL_DEF_DRV(QAIC_WAIT_BO, qaic_wait_bo_ioctl, 0),
 	DRM_IOCTL_DEF_DRV(QAIC_PERF_STATS_BO, qaic_perf_stats_bo_ioctl, 0),
+	DRM_IOCTL_DEF_DRV(QAIC_DETACH_SLICE_BO, qaic_detach_slice_bo_ioctl, 0),
 };
 
 static const struct drm_driver qaic_accel_driver = {