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net: stmmac: Add Tx HWTS support to XDP ZC
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This patch enables transmit hardware timestamp support to XDP zero copy
via XDP Tx metadata framework.

This patchset is tested with tools/testing/selftests/bpf/xdp_hw_metadata
on Intel Tiger Lake platform. Below are the test steps and results.

Command on DUT:
sudo ./xdp_hw_metadata <interface name>
sudo hwstamp_ctl -i <interface name> -t 1 -r 1

Command on Link Partner:
echo -n xdp | nc -u -q1 <destination IPv4 addr> 9091

Result:
xsk_ring_cons__peek: 1
0x55bbbf08b6d0: rx_desc[2]->addr=8c100 addr=8c100 comp_addr=8c100 EoP
No rx_hash err=-95
rx_timestamp:  1677762688429141540 (sec:1677762688.4291)
HW RX-time:   1677762688429141540 (sec:1677762688.4291) delta to User RX-time sec:0.0003 (250.665 usec)
XDP RX-time:   1677762688429375597 (sec:1677762688.4294) delta to User RX-time sec:0.0000 (16.608 usec)
0x55bbbf08b6d0: ping-pong with csum=561c (want f488) csum_start=34 csum_offset=6
0x55bbbf08b6d0: complete tx idx=2 addr=2008
tx_timestamp:  1677762688431127273 (sec:1677762688.4311)
HW TX-complete-time:   1677762688431127273 (sec:1677762688.4311) delta to User TX-complete-time sec:0.0083 (8331.655 usec)
XDP RX-time:   1677762688429375597 (sec:1677762688.4294) delta to User TX-complete-time sec:0.0101 (10083.331 usec)
HW RX-time:   1677762688429141540 (sec:1677762688.4291) delta to HW TX-complete-time sec:0.0020 (1985.733 usec)
0x55bbbf08b6d0: complete rx idx=130 addr=8c100

Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20231127190319.1190813-6-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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@yoongsiang2
yoongsiang2 authored and Alexei Starovoitov committed Nov 29, 2023
1 parent ec706a8 commit 1347b41
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Showing 2 changed files with 75 additions and 1 deletion.
12 changes: 12 additions & 0 deletions drivers/net/ethernet/stmicro/stmmac/stmmac.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,7 @@ struct stmmac_tx_info {
bool last_segment;
bool is_jumbo;
enum stmmac_txbuf_type buf_type;
struct xsk_tx_metadata_compl xsk_meta;
};

#define STMMAC_TBS_AVAIL BIT(0)
Expand Down Expand Up @@ -100,6 +101,17 @@ struct stmmac_xdp_buff {
struct dma_desc *ndesc;
};

struct stmmac_metadata_request {
struct stmmac_priv *priv;
struct dma_desc *tx_desc;
bool *set_ic;
};

struct stmmac_xsk_tx_complete {
struct stmmac_priv *priv;
struct dma_desc *desc;
};

struct stmmac_rx_queue {
u32 rx_count_frames;
u32 queue_index;
Expand Down
64 changes: 63 additions & 1 deletion drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2430,6 +2430,46 @@ static void stmmac_dma_operation_mode(struct stmmac_priv *priv)
}
}

static void stmmac_xsk_request_timestamp(void *_priv)
{
struct stmmac_metadata_request *meta_req = _priv;

stmmac_enable_tx_timestamp(meta_req->priv, meta_req->tx_desc);
*meta_req->set_ic = true;
}

static u64 stmmac_xsk_fill_timestamp(void *_priv)
{
struct stmmac_xsk_tx_complete *tx_compl = _priv;
struct stmmac_priv *priv = tx_compl->priv;
struct dma_desc *desc = tx_compl->desc;
bool found = false;
u64 ns = 0;

if (!priv->hwts_tx_en)
return 0;

/* check tx tstamp status */
if (stmmac_get_tx_timestamp_status(priv, desc)) {
stmmac_get_timestamp(priv, desc, priv->adv_ts, &ns);
found = true;
} else if (!stmmac_get_mac_tx_timestamp(priv, priv->hw, &ns)) {
found = true;
}

if (found) {
ns -= priv->plat->cdc_error_adj;
return ns_to_ktime(ns);
}

return 0;
}

static const struct xsk_tx_metadata_ops stmmac_xsk_tx_metadata_ops = {
.tmo_request_timestamp = stmmac_xsk_request_timestamp,
.tmo_fill_timestamp = stmmac_xsk_fill_timestamp,
};

static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget)
{
struct netdev_queue *nq = netdev_get_tx_queue(priv->dev, queue);
Expand All @@ -2449,6 +2489,8 @@ static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget)
budget = min(budget, stmmac_tx_avail(priv, queue));

while (budget-- > 0) {
struct stmmac_metadata_request meta_req;
struct xsk_tx_metadata *meta = NULL;
dma_addr_t dma_addr;
bool set_ic;

Expand All @@ -2472,6 +2514,7 @@ static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget)
tx_desc = tx_q->dma_tx + entry;

dma_addr = xsk_buff_raw_get_dma(pool, xdp_desc.addr);
meta = xsk_buff_get_metadata(pool, xdp_desc.addr);
xsk_buff_raw_dma_sync_for_device(pool, dma_addr, xdp_desc.len);

tx_q->tx_skbuff_dma[entry].buf_type = STMMAC_TXBUF_T_XSK_TX;
Expand Down Expand Up @@ -2499,6 +2542,11 @@ static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget)
else
set_ic = false;

meta_req.priv = priv;
meta_req.tx_desc = tx_desc;
meta_req.set_ic = &set_ic;
xsk_tx_metadata_request(meta, &stmmac_xsk_tx_metadata_ops,
&meta_req);
if (set_ic) {
tx_q->tx_count_frames = 0;
stmmac_set_tx_ic(priv, tx_desc);
Expand All @@ -2511,6 +2559,9 @@ static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget)

stmmac_enable_dma_transmission(priv, priv->ioaddr);

xsk_tx_metadata_to_compl(meta,
&tx_q->tx_skbuff_dma[entry].xsk_meta);

tx_q->cur_tx = STMMAC_GET_ENTRY(tx_q->cur_tx, priv->dma_conf.dma_tx_size);
entry = tx_q->cur_tx;
}
Expand Down Expand Up @@ -2620,8 +2671,18 @@ static int stmmac_tx_clean(struct stmmac_priv *priv, int budget, u32 queue,
} else {
tx_packets++;
}
if (skb)
if (skb) {
stmmac_get_tx_hwtstamp(priv, p, skb);
} else {
struct stmmac_xsk_tx_complete tx_compl = {
.priv = priv,
.desc = p,
};

xsk_tx_metadata_complete(&tx_q->tx_skbuff_dma[entry].xsk_meta,
&stmmac_xsk_tx_metadata_ops,
&tx_compl);
}
}

if (likely(tx_q->tx_skbuff_dma[entry].buf &&
Expand Down Expand Up @@ -7464,6 +7525,7 @@ int stmmac_dvr_probe(struct device *device,
ndev->netdev_ops = &stmmac_netdev_ops;

ndev->xdp_metadata_ops = &stmmac_xdp_metadata_ops;
ndev->xsk_tx_metadata_ops = &stmmac_xsk_tx_metadata_ops;

ndev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
NETIF_F_RXCSUM;
Expand Down

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