USB4NET protocol allows the networking drivers to take advantage of end-to-end flow control supported by the USB4 host interface. This should prevent the receiving side from dropping network packets. In adddition add a module parameter that can be used to turn this off just in case it causes problems. Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> --- drivers/net/thunderbolt.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-) diff --git a/drivers/net/thunderbolt.c b/drivers/net/thunderbolt.c index ab3f04562980..8e272d2a61e5 100644 --- a/drivers/net/thunderbolt.c +++ b/drivers/net/thunderbolt.c @@ -30,6 +30,7 @@ #define TBNET_RING_SIZE 256 #define TBNET_LOGIN_RETRIES 60 #define TBNET_LOGOUT_RETRIES 10 +#define TBNET_E2E BIT(0) #define TBNET_MATCH_FRAGS_ID BIT(1) #define TBNET_64K_FRAMES BIT(2) #define TBNET_MAX_MTU SZ_64K @@ -209,6 +210,10 @@ static const uuid_t tbnet_svc_uuid = static struct tb_property_dir *tbnet_dir; +static bool tbnet_e2e = true; +module_param_named(e2e, tbnet_e2e, bool, 0444); +MODULE_PARM_DESC(e2e, "USB4NET full end-to-end flow control (default: true)"); + static void tbnet_fill_header(struct thunderbolt_ip_header *hdr, u64 route, u8 sequence, const uuid_t *initiator_uuid, const uuid_t *target_uuid, enum thunderbolt_ip_type type, size_t size, u32 command_id) @@ -873,6 +878,7 @@ static int tbnet_open(struct net_device *dev) struct tb_xdomain *xd = net->xd; u16 sof_mask, eof_mask; struct tb_ring *ring; + unsigned int flags; int hopid; netif_carrier_off(dev); @@ -897,9 +903,14 @@ static int tbnet_open(struct net_device *dev) sof_mask = BIT(TBIP_PDF_FRAME_START); eof_mask = BIT(TBIP_PDF_FRAME_END); - ring = tb_ring_alloc_rx(xd->tb->nhi, -1, TBNET_RING_SIZE, - RING_FLAG_FRAME, 0, sof_mask, eof_mask, - tbnet_start_poll, net); + flags = RING_FLAG_FRAME; + /* Only enable full E2E if the other end supports it too */ + if (tbnet_e2e && net->svc->prtcstns & TBNET_E2E) + flags |= RING_FLAG_E2E; + + ring = tb_ring_alloc_rx(xd->tb->nhi, -1, TBNET_RING_SIZE, flags, + net->tx_ring.ring->hop, sof_mask, + eof_mask, tbnet_start_poll, net); if (!ring) { netdev_err(dev, "failed to allocate Rx ring\n"); tb_ring_free(net->tx_ring.ring); @@ -1362,6 +1373,7 @@ static struct tb_service_driver tbnet_driver = { static int __init tbnet_init(void) { + unsigned int flags; int ret; tbnet_dir = tb_property_create_dir(&tbnet_dir_uuid); @@ -1371,12 +1383,11 @@ static int __init tbnet_init(void) tb_property_add_immediate(tbnet_dir, "prtcid", 1); tb_property_add_immediate(tbnet_dir, "prtcvers", 1); tb_property_add_immediate(tbnet_dir, "prtcrevs", 1); - /* Currently only announce support for match frags ID (bit 1). Bit 0 - * is reserved for full E2E flow control which we do not support at - * the moment. - */ - tb_property_add_immediate(tbnet_dir, "prtcstns", - TBNET_MATCH_FRAGS_ID | TBNET_64K_FRAMES); + + flags = TBNET_MATCH_FRAGS_ID | TBNET_64K_FRAMES; + if (tbnet_e2e) + flags |= TBNET_E2E; + tb_property_add_immediate(tbnet_dir, "prtcstns", flags); ret = tb_register_property_dir("network", tbnet_dir); if (ret) { -- 2.35.1