Added virtqueue_dma_dev() to get DMA device for virtio. Then the
caller can do dma operation in advance. The purpose is to keep memory
mapped across multiple add/get buf operations.
Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/virtio/virtio.c | 6 ++++++
drivers/virtio/virtio_ring.c | 17 +++++++++++++++++
include/linux/virtio.h | 2 ++
3 files changed, 25 insertions(+)
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 3893dc29eb26..11c5035369e2 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -1,4 +1,5 @@
// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/dma-mapping.h>
#include <linux/virtio.h>
#include <linux/spinlock.h>
#include <linux/virtio_config.h>
@@ -243,6 +244,11 @@ static int virtio_dev_probe(struct device *_d)
u64 driver_features;
u64 driver_features_legacy;
+ _d->dma_mask = &_d->coherent_dma_mask;
+ err = dma_set_mask_and_coherent(_d, DMA_BIT_MASK(64));
+ if (err)
+ return err;
+
/* We have a driver! */
virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index fab956784564..e47f55cd125b 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2308,6 +2308,23 @@ int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
}
EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_ctx);
+/**
+ * virtqueue_dma_dev - get the dma dev
+ * @_vq: the struct virtqueue we're talking about.
+ *
+ * Returns the dma dev. That can been used for dma api.
+ */
+struct device *virtqueue_dma_dev(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ if (vq->use_dma_api)
+ return vring_dma_dev(vq);
+ else
+ return &vq->vq.vdev->dev;
+}
+EXPORT_SYMBOL_GPL(virtqueue_dma_dev);
+
/**
* virtqueue_kick_prepare - first half of split virtqueue_kick call.
* @_vq: the struct virtqueue
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 2b472514c49b..1fa50191cf0a 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -61,6 +61,8 @@ int virtqueue_add_sgs(struct virtqueue *vq,
void *data,
gfp_t gfp);
+struct device *virtqueue_dma_dev(struct virtqueue *vq);
+
bool virtqueue_kick(struct virtqueue *vq);
bool virtqueue_kick_prepare(struct virtqueue *vq);
--
2.32.0.3.g01195cf9f
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