[PATCH net-next v3 6/7] net: lan966x: Add support for XDP_TX

Horatiu Vultur
2022-11-21T21:25:40Z

Extend lan966x XDP support with the action XDP_TX. In this case when the
received buffer needs to execute XDP_TX, the buffer will be moved to the
TX buffers. So a new RX buffer will be allocated.
When the TX finish with the frame, it would give back the buffer to the
page pool.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
---
.../ethernet/microchip/lan966x/lan966x_fdma.c | 78 +++++++++++++++++--
.../ethernet/microchip/lan966x/lan966x_main.c | 4 +-
.../ethernet/microchip/lan966x/lan966x_main.h | 8 ++
.../ethernet/microchip/lan966x/lan966x_xdp.c | 8 ++
4 files changed, 90 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
index f8287a6a86ed5..b14fdb8e15e22 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
@@ -411,12 +411,18 @@ static void lan966x_fdma_tx_clear_buf(struct lan966x *lan966x, int weight)
dcb_buf->dev->stats.tx_bytes += dcb_buf->len;

dcb_buf->used = false;
- dma_unmap_single(lan966x->dev,
- dcb_buf->dma_addr,
- dcb_buf->len,
- DMA_TO_DEVICE);
- if (!dcb_buf->ptp)
- dev_kfree_skb_any(dcb_buf->skb);
+ if (dcb_buf->skb) {
+ dma_unmap_single(lan966x->dev,
+ dcb_buf->dma_addr,
+ dcb_buf->len,
+ DMA_TO_DEVICE);
+
+ if (!dcb_buf->ptp)
+ dev_kfree_skb_any(dcb_buf->skb);
+ }
+
+ if (dcb_buf->xdpf)
+ xdp_return_frame_rx_napi(dcb_buf->xdpf);

clear = true;
}
@@ -549,6 +555,9 @@ static int lan966x_fdma_napi_poll(struct napi_struct *napi, int weight)
lan966x_fdma_rx_free_page(rx);
lan966x_fdma_rx_advance_dcb(rx);
goto allocate_new;
+ case FDMA_TX:
+ lan966x_fdma_rx_advance_dcb(rx);
+ continue;
case FDMA_DROP:
lan966x_fdma_rx_free_page(rx);
lan966x_fdma_rx_advance_dcb(rx);
@@ -670,6 +679,62 @@ static void lan966x_fdma_tx_start(struct lan966x_tx *tx, int next_to_use)
tx->last_in_use = next_to_use;
}

+int lan966x_fdma_xmit_xdpf(struct lan966x_port *port,
+ struct xdp_frame *xdpf,
+ struct page *page)
+{
+ struct lan966x *lan966x = port->lan966x;
+ struct lan966x_tx_dcb_buf *next_dcb_buf;
+ struct lan966x_tx *tx = &lan966x->tx;
+ dma_addr_t dma_addr;
+ int next_to_use;
+ __be32 *ifh;
+ int ret = 0;
+
+ spin_lock(&lan966x->tx_lock);
+
+ /* Get next index */
+ next_to_use = lan966x_fdma_get_next_dcb(tx);
+ if (next_to_use < 0) {
+ netif_stop_queue(port->dev);
+ ret = NETDEV_TX_BUSY;
+ goto out;
+ }
+
+ /* Generate new IFH */
+ ifh = page_address(page) + XDP_PACKET_HEADROOM;
+ memset(ifh, 0x0, sizeof(__be32) * IFH_LEN);
+ lan966x_ifh_set_bypass(ifh, 1);
+ lan966x_ifh_set_port(ifh, BIT_ULL(port->chip_port));
+
+ dma_addr = page_pool_get_dma_addr(page);
+ dma_sync_single_for_device(lan966x->dev, dma_addr + XDP_PACKET_HEADROOM,
+ xdpf->len + IFH_LEN_BYTES,
+ DMA_TO_DEVICE);
+
+ /* Setup next dcb */
+ lan966x_fdma_tx_setup_dcb(tx, next_to_use, xdpf->len + IFH_LEN_BYTES,
+ dma_addr + XDP_PACKET_HEADROOM);
+
+ /* Fill up the buffer */
+ next_dcb_buf = &tx->dcbs_buf[next_to_use];
+ next_dcb_buf->skb = NULL;
+ next_dcb_buf->xdpf = xdpf;
+ next_dcb_buf->len = xdpf->len + IFH_LEN_BYTES;
+ next_dcb_buf->dma_addr = dma_addr;
+ next_dcb_buf->used = true;
+ next_dcb_buf->ptp = false;
+ next_dcb_buf->dev = port->dev;
+
+ /* Start the transmission */
+ lan966x_fdma_tx_start(tx, next_to_use);
+
+out:
+ spin_unlock(&lan966x->tx_lock);
+
+ return ret;
+}
+
int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev)
{
struct lan966x_port *port = netdev_priv(dev);
@@ -726,6 +791,7 @@ int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev)
/* Fill up the buffer */
next_dcb_buf = &tx->dcbs_buf[next_to_use];
next_dcb_buf->skb = skb;
+ next_dcb_buf->xdpf = NULL;
next_dcb_buf->len = skb->len;
next_dcb_buf->dma_addr = dma_addr;
next_dcb_buf->used = true;
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
index 42be5d0f1f015..0b7707306da26 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
@@ -302,13 +302,13 @@ static int lan966x_port_ifh_xmit(struct sk_buff *skb,
return NETDEV_TX_BUSY;
}

-static void lan966x_ifh_set_bypass(void *ifh, u64 bypass)
+void lan966x_ifh_set_bypass(void *ifh, u64 bypass)
{
packing(ifh, &bypass, IFH_POS_BYPASS + IFH_WID_BYPASS - 1,
IFH_POS_BYPASS, IFH_LEN * 4, PACK, 0);
}

-static void lan966x_ifh_set_port(void *ifh, u64 bypass)
+void lan966x_ifh_set_port(void *ifh, u64 bypass)
{
packing(ifh, &bypass, IFH_POS_DSTS + IFH_WID_DSTS - 1,
IFH_POS_DSTS, IFH_LEN * 4, PACK, 0);
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
index 7f1231b31c924..e303a12daf88a 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
@@ -105,11 +105,13 @@ enum macaccess_entry_type {
* FDMA_PASS, frame is valid and can be used
* FDMA_ERROR, something went wrong, stop getting more frames
* FDMA_DROP, frame is dropped, but continue to get more frames
+ * FDMA_TX, frame is given to TX, but continue to get more frames
*/
enum lan966x_fdma_action {
FDMA_PASS = 0,
FDMA_ERROR,
FDMA_DROP,
+ FDMA_TX,
};

struct lan966x_port;
@@ -175,6 +177,7 @@ struct lan966x_rx {
struct lan966x_tx_dcb_buf {
struct net_device *dev;
struct sk_buff *skb;
+ struct xdp_frame *xdpf;
int len;
dma_addr_t dma_addr;
bool used;
@@ -360,6 +363,8 @@ bool lan966x_hw_offload(struct lan966x *lan966x, u32 port, struct sk_buff *skb);

void lan966x_ifh_get_src_port(void *ifh, u64 *src_port);
void lan966x_ifh_get_timestamp(void *ifh, u64 *timestamp);
+void lan966x_ifh_set_bypass(void *ifh, u64 bypass);
+void lan966x_ifh_set_port(void *ifh, u64 bypass);

void lan966x_stats_get(struct net_device *dev,
struct rtnl_link_stats64 *stats);
@@ -460,6 +465,9 @@ u32 lan966x_ptp_get_period_ps(void);
int lan966x_ptp_gettime64(struct ptp_clock_info *ptp, struct timespec64 *ts);

int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev);
+int lan966x_fdma_xmit_xdpf(struct lan966x_port *port,
+ struct xdp_frame *frame,
+ struct page *page);
int lan966x_fdma_change_mtu(struct lan966x *lan966x);
void lan966x_fdma_netdev_init(struct lan966x *lan966x, struct net_device *dev);
void lan966x_fdma_netdev_deinit(struct lan966x *lan966x, struct net_device *dev);
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c b/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
index 05c5a28206558..5fd2f3b01e179 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
@@ -54,6 +54,7 @@ int lan966x_xdp_run(struct lan966x_port *port, struct page *page, u32 data_len)
{
struct bpf_prog *xdp_prog = port->xdp_prog;
struct lan966x *lan966x = port->lan966x;
+ struct xdp_frame *xdpf;
struct xdp_buff xdp;
u32 act;

@@ -66,6 +67,13 @@ int lan966x_xdp_run(struct lan966x_port *port, struct page *page, u32 data_len)
switch (act) {
case XDP_PASS:
return FDMA_PASS;
+ case XDP_TX:
+ xdpf = xdp_convert_buff_to_frame(&xdp);
+ if (!xdpf)
+ return FDMA_DROP;
+
+ return lan966x_fdma_xmit_xdpf(port, xdpf, page) ?
+ FDMA_DROP : FDMA_TX;
default:
bpf_warn_invalid_xdp_action(port->dev, xdp_prog, act);
fallthrough;
--
2.38.0