Merge branch 'mlxsw-move-tx-header-handling-to-pci-driver'

Petr Machata says:

====================
mlxsw: Move Tx header handling to PCI driver

Amit Cohen writes:

Tx header should be added to all packets transmitted from the CPU to
Spectrum ASICs. Historically, handling this header was added as a driver
function, as Tx header is different between Spectrum and Switch-X.

From May 2021, there is no support for SwitchX-2 ASIC, and all the relevant
code was removed.

For now, there is no justification to handle Tx header as part of
spectrum.c, we can handle this as part of PCI, in skb_transmit().

This change will also be useful when XDP support will be added to mlxsw,
as for XDP_TX and XDP_REDIRECT actions, Tx header should be added before
transmitting the packet.

Patch set overview:
Patches Rust-for-Linux#1-Rust-for-Linux#2 add structure to store Tx header info and initialize it
Patch Rust-for-Linux#3 moves definitions of Tx header fields to txheader.h
Patch Rust-for-Linux#4 moves Tx header handling to PCI driver
Patch Rust-for-Linux#5 removes unnecessary attribute
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: kuba-moo

drivers/net/ethernet/mellanox/mlxsw/core.c

@@ -35,6 +35,7 @@
 #include "reg.h"
 #include "resources.h"
 #include "../mlxfw/mlxfw.h"
+#include "txheader.h"
 
 static LIST_HEAD(mlxsw_core_driver_list);
 static DEFINE_SPINLOCK(mlxsw_core_driver_list_lock);
@@ -677,7 +678,7 @@ struct mlxsw_reg_trans {
 	struct list_head bulk_list;
 	struct mlxsw_core *core;
 	struct sk_buff *tx_skb;
-	struct mlxsw_tx_info tx_info;
+	struct mlxsw_txhdr_info txhdr_info;
 	struct delayed_work timeout_dw;
 	unsigned int retries;
 	u64 tid;
@@ -737,12 +738,11 @@ static int mlxsw_emad_transmit(struct mlxsw_core *mlxsw_core,
 	if (!skb)
 		return -ENOMEM;
 
-	trace_devlink_hwmsg(priv_to_devlink(mlxsw_core), false, 0,
-			    skb->data + mlxsw_core->driver->txhdr_len,
-			    skb->len - mlxsw_core->driver->txhdr_len);
+	trace_devlink_hwmsg(priv_to_devlink(mlxsw_core), false, 0, skb->data,
+			    skb->len);
 
 	atomic_set(&trans->active, 1);
-	err = mlxsw_core_skb_transmit(mlxsw_core, skb, &trans->tx_info);
+	err = mlxsw_core_skb_transmit(mlxsw_core, skb, &trans->txhdr_info);
 	if (err) {
 		dev_kfree_skb(skb);
 		return err;
@@ -944,7 +944,7 @@ static struct sk_buff *mlxsw_emad_alloc(const struct mlxsw_core *mlxsw_core,
 
 	emad_len = (reg_len + sizeof(u32) + MLXSW_EMAD_ETH_HDR_LEN +
 		    (MLXSW_EMAD_OP_TLV_LEN + MLXSW_EMAD_END_TLV_LEN) *
-		    sizeof(u32) + mlxsw_core->driver->txhdr_len);
+		    sizeof(u32) + MLXSW_TXHDR_LEN);
 	if (mlxsw_core->emad.enable_string_tlv)
 		emad_len += MLXSW_EMAD_STRING_TLV_LEN * sizeof(u32);
 	if (mlxsw_core->emad.enable_latency_tlv)
@@ -984,8 +984,8 @@ static int mlxsw_emad_reg_access(struct mlxsw_core *mlxsw_core,
 	list_add_tail(&trans->bulk_list, bulk_list);
 	trans->core = mlxsw_core;
 	trans->tx_skb = skb;
-	trans->tx_info.local_port = MLXSW_PORT_CPU_PORT;
-	trans->tx_info.is_emad = true;
+	trans->txhdr_info.tx_info.local_port = MLXSW_PORT_CPU_PORT;
+	trans->txhdr_info.tx_info.is_emad = true;
 	INIT_DELAYED_WORK(&trans->timeout_dw, mlxsw_emad_trans_timeout_work);
 	trans->tid = tid;
 	init_completion(&trans->completion);
@@ -995,7 +995,6 @@ static int mlxsw_emad_reg_access(struct mlxsw_core *mlxsw_core,
 	trans->type = type;
 
 	mlxsw_emad_construct(mlxsw_core, skb, reg, payload, type, trans->tid);
-	mlxsw_core->driver->txhdr_construct(skb, &trans->tx_info);
 
 	spin_lock_bh(&mlxsw_core->emad.trans_list_lock);
 	list_add_tail_rcu(&trans->list, &mlxsw_core->emad.trans_list);
@@ -2330,10 +2329,10 @@ bool mlxsw_core_skb_transmit_busy(struct mlxsw_core *mlxsw_core,
 EXPORT_SYMBOL(mlxsw_core_skb_transmit_busy);
 
 int mlxsw_core_skb_transmit(struct mlxsw_core *mlxsw_core, struct sk_buff *skb,
-			    const struct mlxsw_tx_info *tx_info)
+			    const struct mlxsw_txhdr_info *txhdr_info)
 {
 	return mlxsw_core->bus->skb_transmit(mlxsw_core->bus_priv, skb,
-					     tx_info);
+					     txhdr_info);
 }
 EXPORT_SYMBOL(mlxsw_core_skb_transmit);
 

drivers/net/ethernet/mellanox/mlxsw/core.h

@@ -72,6 +72,12 @@ struct mlxsw_tx_info {
 	bool is_emad;
 };
 
+struct mlxsw_txhdr_info {
+	struct mlxsw_tx_info tx_info;
+	bool data;
+	u16 max_fid; /* Used for PTP packets which are sent as data. */
+};
+
 struct mlxsw_rx_md_info {
 	struct napi_struct *napi;
 	u32 cookie_index;
@@ -95,7 +101,7 @@ struct mlxsw_rx_md_info {
 bool mlxsw_core_skb_transmit_busy(struct mlxsw_core *mlxsw_core,
 				  const struct mlxsw_tx_info *tx_info);
 int mlxsw_core_skb_transmit(struct mlxsw_core *mlxsw_core, struct sk_buff *skb,
-			    const struct mlxsw_tx_info *tx_info);
+			    const struct mlxsw_txhdr_info *txhdr_info);
 void mlxsw_core_ptp_transmitted(struct mlxsw_core *mlxsw_core,
 				struct sk_buff *skb, u16 local_port);
 
@@ -426,8 +432,6 @@ struct mlxsw_driver {
 	int (*trap_policer_counter_get)(struct mlxsw_core *mlxsw_core,
 					const struct devlink_trap_policer *policer,
 					u64 *p_drops);
-	void (*txhdr_construct)(struct sk_buff *skb,
-				const struct mlxsw_tx_info *tx_info);
 	int (*resources_register)(struct mlxsw_core *mlxsw_core);
 	int (*kvd_sizes_get)(struct mlxsw_core *mlxsw_core,
 			     const struct mlxsw_config_profile *profile,
@@ -440,7 +444,6 @@ struct mlxsw_driver {
 	void (*ptp_transmitted)(struct mlxsw_core *mlxsw_core,
 				struct sk_buff *skb, u16 local_port);
 
-	u8 txhdr_len;
 	const struct mlxsw_config_profile *profile;
 	bool sdq_supports_cqe_v2;
 };
@@ -487,7 +490,7 @@ struct mlxsw_bus {
 	bool (*skb_transmit_busy)(void *bus_priv,
 				  const struct mlxsw_tx_info *tx_info);
 	int (*skb_transmit)(void *bus_priv, struct sk_buff *skb,
-			    const struct mlxsw_tx_info *tx_info);
+			    const struct mlxsw_txhdr_info *txhdr_info);
 	int (*cmd_exec)(void *bus_priv, u16 opcode, u8 opcode_mod,
 			u32 in_mod, bool out_mbox_direct,
 			char *in_mbox, size_t in_mbox_size,

drivers/net/ethernet/mellanox/mlxsw/i2c.c

@@ -516,7 +516,7 @@ static bool mlxsw_i2c_skb_transmit_busy(void *bus_priv,
 }
 
 static int mlxsw_i2c_skb_transmit(void *bus_priv, struct sk_buff *skb,
-				  const struct mlxsw_tx_info *tx_info)
+				  const struct mlxsw_txhdr_info *txhdr_info)
 {
 	return 0;
 }

drivers/net/ethernet/mellanox/mlxsw/pci.c

@@ -21,6 +21,7 @@
 #include "cmd.h"
 #include "port.h"
 #include "resources.h"
+#include "txheader.h"
 
 #define mlxsw_pci_write32(mlxsw_pci, reg, val) \
 	iowrite32be(val, (mlxsw_pci)->hw_addr + (MLXSW_PCI_ ## reg))
@@ -2095,6 +2096,39 @@ static void mlxsw_pci_fini(void *bus_priv)
 	mlxsw_pci_free_irq_vectors(mlxsw_pci);
 }
 
+static int mlxsw_pci_txhdr_construct(struct sk_buff *skb,
+				     const struct mlxsw_txhdr_info *txhdr_info)
+{
+	const struct mlxsw_tx_info tx_info = txhdr_info->tx_info;
+	char *txhdr;
+
+	if (skb_cow_head(skb, MLXSW_TXHDR_LEN))
+		return -ENOMEM;
+
+	txhdr = skb_push(skb, MLXSW_TXHDR_LEN);
+	memset(txhdr, 0, MLXSW_TXHDR_LEN);
+
+	mlxsw_tx_hdr_version_set(txhdr, MLXSW_TXHDR_VERSION_1);
+	mlxsw_tx_hdr_proto_set(txhdr, MLXSW_TXHDR_PROTO_ETH);
+	mlxsw_tx_hdr_swid_set(txhdr, 0);
+
+	if (unlikely(txhdr_info->data)) {
+		u16 fid = txhdr_info->max_fid + tx_info.local_port - 1;
+
+		mlxsw_tx_hdr_rx_is_router_set(txhdr, true);
+		mlxsw_tx_hdr_fid_valid_set(txhdr, true);
+		mlxsw_tx_hdr_fid_set(txhdr, fid);
+		mlxsw_tx_hdr_type_set(txhdr, MLXSW_TXHDR_TYPE_DATA);
+	} else {
+		mlxsw_tx_hdr_ctl_set(txhdr, MLXSW_TXHDR_ETH_CTL);
+		mlxsw_tx_hdr_control_tclass_set(txhdr, 1);
+		mlxsw_tx_hdr_port_mid_set(txhdr, tx_info.local_port);
+		mlxsw_tx_hdr_type_set(txhdr, MLXSW_TXHDR_TYPE_CONTROL);
+	}
+
+	return 0;
+}
+
 static struct mlxsw_pci_queue *
 mlxsw_pci_sdq_pick(struct mlxsw_pci *mlxsw_pci,
 		   const struct mlxsw_tx_info *tx_info)
@@ -2122,7 +2156,7 @@ static bool mlxsw_pci_skb_transmit_busy(void *bus_priv,
 }
 
 static int mlxsw_pci_skb_transmit(void *bus_priv, struct sk_buff *skb,
-				  const struct mlxsw_tx_info *tx_info)
+				  const struct mlxsw_txhdr_info *txhdr_info)
 {
 	struct mlxsw_pci *mlxsw_pci = bus_priv;
 	struct mlxsw_pci_queue *q;
@@ -2131,21 +2165,25 @@ static int mlxsw_pci_skb_transmit(void *bus_priv, struct sk_buff *skb,
 	int i;
 	int err;
 
+	err = mlxsw_pci_txhdr_construct(skb, txhdr_info);
+	if (err)
+		return err;
+
 	if (skb_shinfo(skb)->nr_frags > MLXSW_PCI_WQE_SG_ENTRIES - 1) {
 		err = skb_linearize(skb);
 		if (err)
 			return err;
 	}
 
-	q = mlxsw_pci_sdq_pick(mlxsw_pci, tx_info);
+	q = mlxsw_pci_sdq_pick(mlxsw_pci, &txhdr_info->tx_info);
 	spin_lock_bh(&q->lock);
 	elem_info = mlxsw_pci_queue_elem_info_producer_get(q);
 	if (!elem_info) {
 		/* queue is full */
 		err = -EAGAIN;
 		goto unlock;
 	}
-	mlxsw_skb_cb(skb)->tx_info = *tx_info;
+	mlxsw_skb_cb(skb)->tx_info = txhdr_info->tx_info;
 	elem_info->sdq.skb = skb;
 
 	wqe = elem_info->elem;