[PATCH net-next v6 3/3] net: stmmac: add Rx HWTS metadata to XDP ZC receive pkt

From: Song Yoong Siang
Date: Sat Apr 15 2023 - 02:46:26 EST


Add receive hardware timestamp metadata support via kfunc to XDP Zero Copy
receive packets.

Signed-off-by: Song Yoong Siang <yoong.siang.song@xxxxxxxxx>
---
.../net/ethernet/stmicro/stmmac/stmmac_main.c | 22 +++++++++++++++++++
1 file changed, 22 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 2bfcc5347d6a..c0e90fda572a 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1614,6 +1614,12 @@ static int stmmac_alloc_rx_buffers_zc(struct stmmac_priv *priv,
struct stmmac_rx_queue *rx_q = &dma_conf->rx_queue[queue];
int i;

+ /* struct stmmac_xdp_buff is using cb field (maximum size of 24 bytes)
+ * in struct xdp_buff_xsk to stash driver specific information. Thus,
+ * use this macro to make sure no size violations.
+ */
+ XSK_CHECK_PRIV_TYPE(struct stmmac_xdp_buff);
+
for (i = 0; i < dma_conf->dma_rx_size; i++) {
struct stmmac_rx_buffer *buf;
dma_addr_t dma_addr;
@@ -4998,6 +5004,16 @@ static bool stmmac_rx_refill_zc(struct stmmac_priv *priv, u32 queue, u32 budget)
return ret;
}

+static struct stmmac_xdp_buff *xsk_buff_to_stmmac_ctx(struct xdp_buff *xdp)
+{
+ /* In XDP zero copy data path, xdp field in struct xdp_buff_xsk is used
+ * to represent incoming packet, whereas cb field in the same structure
+ * is used to store driver specific info. Thus, struct stmmac_xdp_buff
+ * is laid on top of xdp and cb fields of struct xdp_buff_xsk.
+ */
+ return (struct stmmac_xdp_buff *)xdp;
+}
+
static int stmmac_rx_zc(struct stmmac_priv *priv, int limit, u32 queue)
{
struct stmmac_rx_queue *rx_q = &priv->dma_conf.rx_queue[queue];
@@ -5027,6 +5043,7 @@ static int stmmac_rx_zc(struct stmmac_priv *priv, int limit, u32 queue)
}
while (count < limit) {
struct stmmac_rx_buffer *buf;
+ struct stmmac_xdp_buff *ctx;
unsigned int buf1_len = 0;
struct dma_desc *np, *p;
int entry;
@@ -5112,6 +5129,11 @@ static int stmmac_rx_zc(struct stmmac_priv *priv, int limit, u32 queue)
goto read_again;
}

+ ctx = xsk_buff_to_stmmac_ctx(buf->xdp);
+ ctx->priv = priv;
+ ctx->desc = p;
+ ctx->ndesc = np;
+
/* XDP ZC Frame only support primary buffers for now */
buf1_len = stmmac_rx_buf1_len(priv, p, status, len);
len += buf1_len;
--
2.34.1