net: bnxt: Add boilerplate GSO code

Add bnxt_gso.c and bnxt_gso.h with a stub bnxt_sw_udp_gso_xmit()
function, SW USO constants (BNXT_SW_USO_MAX_SEGS,
BNXT_SW_USO_MAX_DESCS), and the is_sw_gso field in bnxt_sw_tx_bd
with BNXT_SW_GSO_MID/LAST markers.

The full SW USO implementation will be added in a future commit.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Joe Damato <joe@dama.to>
Link: https://patch.msgid.link/20260408230607.2019402-7-joe@dama.to
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/broadcom/bnxt/Makefile b/drivers/net/ethernet/broadcom/bnxt/Makefile
index ba6c239d52fade2148eb33724fc99ebe65565853..debef78c8b6d64a684c4708bbaaad078608207a6 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/Makefile
+++ b/drivers/net/ethernet/broadcom/bnxt/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_BNXT) += bnxt_en.o
 
-bnxt_en-y := bnxt.o bnxt_hwrm.o bnxt_sriov.o bnxt_ethtool.o bnxt_dcb.o bnxt_ulp.o bnxt_xdp.o bnxt_ptp.o bnxt_vfr.o bnxt_devlink.o bnxt_dim.o bnxt_coredump.o
+bnxt_en-y := bnxt.o bnxt_hwrm.o bnxt_sriov.o bnxt_ethtool.o bnxt_dcb.o bnxt_ulp.o bnxt_xdp.o bnxt_ptp.o bnxt_vfr.o bnxt_devlink.o bnxt_dim.o bnxt_coredump.o bnxt_gso.o
 bnxt_en-$(CONFIG_BNXT_FLOWER_OFFLOAD) += bnxt_tc.o
 bnxt_en-$(CONFIG_DEBUG_FS) += bnxt_debugfs.o
 bnxt_en-$(CONFIG_BNXT_HWMON) += bnxt_hwmon.o

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index d98a58aa30f60398bc629d0b20c43200087a1418..6b38b84924e0965ad08f1509889719aa0ddd9480 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -892,6 +892,7 @@ struct bnxt_sw_tx_bd {
        struct page             *page;
        u8                      is_ts_pkt;
        u8                      is_push;
+       u8                      is_sw_gso;
        u8                      action;
        unsigned short          nr_frags;
        union {
@@ -900,6 +901,9 @@ struct bnxt_sw_tx_bd {
        };
 };
 
+#define BNXT_SW_GSO_MID                1
+#define BNXT_SW_GSO_LAST       2
+
 struct bnxt_sw_rx_bd {
        void                    *data;
        u8                      *data_ptr;

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_gso.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_gso.c
new file mode 100644 (file)
index 0000000..b296769
--- /dev/null
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_gso.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Broadcom NetXtreme-C/E network driver.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/pci.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/netdev_queues.h>
+#include <net/ip.h>
+#include <net/ipv6.h>
+#include <net/udp.h>
+#include <net/tso.h>
+#include <linux/bnxt/hsi.h>
+
+#include "bnxt.h"
+#include "bnxt_gso.h"
+
+netdev_tx_t bnxt_sw_udp_gso_xmit(struct bnxt *bp,
+                                struct bnxt_tx_ring_info *txr,
+                                struct netdev_queue *txq,
+                                struct sk_buff *skb)
+{
+       dev_kfree_skb_any(skb);
+       dev_core_stats_tx_dropped_inc(bp->dev);
+       return NETDEV_TX_OK;
+}

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_gso.h b/drivers/net/ethernet/broadcom/bnxt/bnxt_gso.h
new file mode 100644 (file)
index 0000000..f01e810
--- /dev/null
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_gso.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Broadcom NetXtreme-C/E network driver.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.
+ */
+
+#ifndef BNXT_GSO_H
+#define BNXT_GSO_H
+
+/* Maximum segments the stack may send in a single SW USO skb.
+ * This caps gso_max_segs for NICs without HW USO support.
+ */
+#define BNXT_SW_USO_MAX_SEGS   64
+
+/* Worst-case TX descriptors consumed by one SW USO packet:
+ * Each segment: 1 long BD + 1 ext BD + payload BDs.
+ * Total payload BDs across all segs <= num_segs + nr_frags (each frag
+ * boundary crossing adds at most 1 extra BD).
+ * So: 3 * max_segs + MAX_SKB_FRAGS + 1 = 3 * 64 + 17 + 1 = 210.
+ */
+#define BNXT_SW_USO_MAX_DESCS  (3 * BNXT_SW_USO_MAX_SEGS + MAX_SKB_FRAGS + 1)
+
+netdev_tx_t bnxt_sw_udp_gso_xmit(struct bnxt *bp,
+                                struct bnxt_tx_ring_info *txr,
+                                struct netdev_queue *txq,
+                                struct sk_buff *skb);
+
+#endif