net: stmmac: Add initial XDP support

This patch adds the initial XDP support to stmmac driver. It supports
XDP_PASS, XDP_DROP and XDP_ABORTED actions. Upcoming patches will add
support for XDP_TX and XDP_REDIRECT.

To support XDP headroom, this patch adds page_offset into RX buffer and
change the dma_sync_single_for_device|cpu(). The DMA address used for
RX operation are changed to take into page_offset too. As page_pool
can handle dma_sync_single_for_device() on behalf of driver with
PP_FLAG_DMA_SYNC_DEV flag, we skip doing that in stmmac driver.

Current stmmac driver supports split header support (SPH) in RX but
the flexibility of splitting header and payload at different position
makes it very complex to be supported for XDP processing. In addition,
jumbo frame is not supported in XDP to keep the initial codes simple.

This patch has been tested with the sample app "xdp1" located in
samples/bpf directory for both SKB and Native (XDP) mode. The burst
traffic generated using pktgen_sample03_burst_single_flow.sh in
samples/pktgen directory.

Changes in v3:
 - factor in xdp header and tail adjustment done by XDP program.
   Thanks to Jakub Kicinski for pointing out the gap in v2.

Changes in v2:
 - fix for "warning: variable 'len' set but not used" reported by lkp.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 1 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index e293423f98c3..e72224c8fbac 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -68,8 +68,9 @@ struct stmmac_tx_queue {
 
 struct stmmac_rx_buffer {
 	struct page *page;
-	struct page *sec_page;
 	dma_addr_t addr;
+	__u32 page_offset;
+	struct page *sec_page;
 	dma_addr_t sec_addr;
 };
 
@@ -269,6 +270,9 @@ struct stmmac_priv {
 
 	/* Receive Side Scaling */
 	struct stmmac_rss rss;
+
+	/* XDP BPF Program */
+	struct bpf_prog *xdp_prog;
 };
 
 enum stmmac_state {
@@ -285,6 +289,8 @@ void stmmac_set_ethtool_ops(struct net_device *netdev);
 
 void stmmac_ptp_register(struct stmmac_priv *priv);
 void stmmac_ptp_unregister(struct stmmac_priv *priv);
+int stmmac_open(struct net_device *dev);
+int stmmac_release(struct net_device *dev);
 int stmmac_resume(struct device *dev);
 int stmmac_suspend(struct device *dev);
 int stmmac_dvr_remove(struct device *dev);
@@ -298,6 +304,19 @@ int stmmac_reinit_ringparam(struct net_device *dev, u32 rx_size, u32 tx_size);
 int stmmac_bus_clks_config(struct stmmac_priv *priv, bool enabled);
 void stmmac_fpe_handshake(struct stmmac_priv *priv, bool enable);
 
+static inline bool stmmac_xdp_is_enabled(struct stmmac_priv *priv)
+{
+	return !!priv->xdp_prog;
+}
+
+static inline unsigned int stmmac_rx_offset(struct stmmac_priv *priv)
+{
+	if (stmmac_xdp_is_enabled(priv))
+		return XDP_PACKET_HEADROOM;
+
+	return 0;
+}
+
 #if IS_ENABLED(CONFIG_STMMAC_SELFTESTS)
 void stmmac_selftest_run(struct net_device *dev,
 			 struct ethtool_test *etest, u64 *buf);