net: dpaa2-eth: AF_XDP RX zero copy support

This patch adds the support for receiving packets via the AF_XDP
zero-copy mechanism in the dpaa2-eth driver. The support is available
only on the LX2160A SoC and variants because we are relying on the HW
capability to associate a buffer pool to a specific queue (QDBIN), only
available on newer WRIOP versions.

On the control path, the dpaa2_xsk_enable_pool() function is responsible
to allocate a buffer pool (BP), setup this new BP to be used only on the
requested queue and change the consume function to point to the XSK ZC
one.
We are forced to call dev_close() in order to change the queue to buffer
pool association (dpaa2_xsk_set_bp_per_qdbin) . This also works in our
favor since at dev_close() the buffer pools will be drained and at the
later dev_open() call they will be again seeded, this time with buffers
allocated from the XSK pool if needed.

On the data path, a new software annotation type is defined to be used
only for the XSK scenarios. This will enable us to pass keep necessary
information about a packet buffer between the moment in which it was
seeded and when it's received by the driver. In the XSK case, we are
keeping the associated xdp_buff.
Depending on the action returned by the BPF program, we will do the
following:
 - XDP_PASS: copy the contents of the packet into a brand new skb,
   recycle the initial buffer.
 - XDP_TX: just enqueue the same frame descriptor back into the Tx path,
   the buffer will get automatically released into the initial BP.
 - XDP_REDIRECT: call xdp_do_redirect() and exit.

Signed-off-by: Robert-Ionut Alexa <robert-ionut.alexa@nxp.com>
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 32 insertions, 4 deletions

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
index 3c4fc46b1324..38f67b98865f 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
@@ -130,6 +130,7 @@ enum dpaa2_eth_swa_type {
 	DPAA2_ETH_SWA_SINGLE,
 	DPAA2_ETH_SWA_SG,
 	DPAA2_ETH_SWA_XDP,
+	DPAA2_ETH_SWA_XSK,
 	DPAA2_ETH_SWA_SW_TSO,
 };
 
@@ -152,6 +153,9 @@ struct dpaa2_eth_swa {
 			struct xdp_frame *xdpf;
 		} xdp;
 		struct {
+			struct xdp_buff *xdp_buff;
+		} xsk;
+		struct {
 			struct sk_buff *skb;
 			int num_sg;
 			int sgt_size;
@@ -429,12 +433,19 @@ enum dpaa2_eth_fq_type {
 };
 
 struct dpaa2_eth_priv;
+struct dpaa2_eth_channel;
+struct dpaa2_eth_fq;
 
 struct dpaa2_eth_xdp_fds {
 	struct dpaa2_fd fds[DEV_MAP_BULK_SIZE];
 	ssize_t num;
 };
 
+typedef void dpaa2_eth_consume_cb_t(struct dpaa2_eth_priv *priv,
+				    struct dpaa2_eth_channel *ch,
+				    const struct dpaa2_fd *fd,
+				    struct dpaa2_eth_fq *fq);
+
 struct dpaa2_eth_fq {
 	u32 fqid;
 	u32 tx_qdbin;
@@ -447,10 +458,7 @@ struct dpaa2_eth_fq {
 	struct dpaa2_eth_channel *channel;
 	enum dpaa2_eth_fq_type type;
 
-	void (*consume)(struct dpaa2_eth_priv *priv,
-			struct dpaa2_eth_channel *ch,
-			const struct dpaa2_fd *fd,
-			struct dpaa2_eth_fq *fq);
+	dpaa2_eth_consume_cb_t *consume;
 	struct dpaa2_eth_fq_stats stats;
 
 	struct dpaa2_eth_xdp_fds xdp_redirect_fds;
@@ -486,6 +494,8 @@ struct dpaa2_eth_channel {
 	u64 recycled_bufs[DPAA2_ETH_BUFS_PER_CMD];
 	int recycled_bufs_cnt;
 
+	bool xsk_zc;
+	struct xsk_buff_pool *xsk_pool;
 	struct dpaa2_eth_bp *bp;
 };
 
@@ -808,4 +818,22 @@ void dpaa2_eth_rx(struct dpaa2_eth_priv *priv,
 		  struct dpaa2_eth_channel *ch,
 		  const struct dpaa2_fd *fd,
 		  struct dpaa2_eth_fq *fq);
+
+struct dpaa2_eth_bp *dpaa2_eth_allocate_dpbp(struct dpaa2_eth_priv *priv);
+void dpaa2_eth_free_dpbp(struct dpaa2_eth_priv *priv,
+			 struct dpaa2_eth_bp *bp);
+
+void *dpaa2_iova_to_virt(struct iommu_domain *domain, dma_addr_t iova_addr);
+void dpaa2_eth_recycle_buf(struct dpaa2_eth_priv *priv,
+			   struct dpaa2_eth_channel *ch,
+			   dma_addr_t addr);
+
+void dpaa2_eth_xdp_enqueue(struct dpaa2_eth_priv *priv,
+			   struct dpaa2_eth_channel *ch,
+			   struct dpaa2_fd *fd,
+			   void *buf_start, u16 queue_id);
+
+int dpaa2_xsk_wakeup(struct net_device *dev, u32 qid, u32 flags);
+int dpaa2_xsk_setup_pool(struct net_device *dev, struct xsk_buff_pool *pool, u16 qid);
+
 #endif	/* __DPAA2_H */