cxgb4: parse and configure TC-MQPRIO offload

Add logic for validation and configuration of TC-MQPRIO Qdisc
offload. Also, add support to manage EOSW_TXQ, which have 1-to-1
mapping with EOTIDs, and expose them to network stack.

Move common skb validation in Tx path to a separate function and
add minimal Tx path for ETHOFLD. Update Tx queue selection to return
normal NIC Txq to send traffic pattern that can't go through ETHOFLD
Tx path.

Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: chelsiocudbg

drivers/net/ethernet/chelsio/cxgb4/Makefile

@@ -8,7 +8,7 @@ obj-$(CONFIG_CHELSIO_T4) += cxgb4.o
 cxgb4-objs := cxgb4_main.o l2t.o smt.o t4_hw.o sge.o clip_tbl.o cxgb4_ethtool.o \
 	      cxgb4_uld.o srq.o sched.o cxgb4_filter.o cxgb4_tc_u32.o \
 	      cxgb4_ptp.o cxgb4_tc_flower.o cxgb4_cudbg.o cxgb4_mps.o \
-	      cudbg_common.o cudbg_lib.o cudbg_zlib.o
+	      cudbg_common.o cudbg_lib.o cudbg_zlib.o cxgb4_tc_mqprio.o
 cxgb4-$(CONFIG_CHELSIO_T4_DCB) +=  cxgb4_dcb.o
 cxgb4-$(CONFIG_CHELSIO_T4_FCOE) +=  cxgb4_fcoe.o
 cxgb4-$(CONFIG_DEBUG_FS) += cxgb4_debugfs.o

drivers/net/ethernet/chelsio/cxgb4/cxgb4.h

@@ -803,6 +803,38 @@ struct sge_uld_txq_info {
 	u16 ntxq;		/* # of egress uld queues */
 };
 
+enum sge_eosw_state {
+	CXGB4_EO_STATE_CLOSED = 0, /* Not ready to accept traffic */
+};
+
+struct sge_eosw_desc {
+	struct sk_buff *skb; /* SKB to free after getting completion */
+	dma_addr_t addr[MAX_SKB_FRAGS + 1]; /* DMA mapped addresses */
+};
+
+struct sge_eosw_txq {
+	spinlock_t lock; /* Per queue lock to synchronize completions */
+	enum sge_eosw_state state; /* Current ETHOFLD State */
+	struct sge_eosw_desc *desc; /* Descriptor ring to hold packets */
+	u32 ndesc; /* Number of descriptors */
+	u32 pidx; /* Current Producer Index */
+	u32 last_pidx; /* Last successfully transmitted Producer Index */
+	u32 cidx; /* Current Consumer Index */
+	u32 last_cidx; /* Last successfully reclaimed Consumer Index */
+	u32 inuse; /* Number of packets held in ring */
+
+	u32 cred; /* Current available credits */
+	u32 ncompl; /* # of completions posted */
+	u32 last_compl; /* # of credits consumed since last completion req */
+
+	u32 eotid; /* Index into EOTID table in software */
+	u32 hwtid; /* Hardware EOTID index */
+
+	u32 hwqid; /* Underlying hardware queue index */
+	struct net_device *netdev; /* Pointer to netdevice */
+	struct tasklet_struct qresume_tsk; /* Restarts the queue */
+};
+
 struct sge {
 	struct sge_eth_txq ethtxq[MAX_ETH_QSETS];
 	struct sge_eth_txq ptptxq;
@@ -1044,6 +1076,9 @@ struct adapter {
 #if IS_ENABLED(CONFIG_THERMAL)
 	struct ch_thermal ch_thermal;
 #endif
+
+	/* TC MQPRIO offload */
+	struct cxgb4_tc_mqprio *tc_mqprio;
 };
 
 /* Support for "sched-class" command to allow a TX Scheduling Class to be
@@ -1895,6 +1930,9 @@ int t4_i2c_rd(struct adapter *adap, unsigned int mbox, int port,
 void free_rspq_fl(struct adapter *adap, struct sge_rspq *rq, struct sge_fl *fl);
 void free_tx_desc(struct adapter *adap, struct sge_txq *q,
 		  unsigned int n, bool unmap);
+void cxgb4_eosw_txq_free_desc(struct adapter *adap, struct sge_eosw_txq *txq,
+			      u32 ndesc);
+void cxgb4_ethofld_restart(unsigned long data);
 void free_txq(struct adapter *adap, struct sge_txq *q);
 void cxgb4_reclaim_completed_tx(struct adapter *adap,
 				struct sge_txq *q, bool unmap);
@@ -1955,4 +1993,6 @@ int cxgb4_update_mac_filt(struct port_info *pi, unsigned int viid,
 			  bool persistent, u8 *smt_idx);
 int cxgb4_get_msix_idx_from_bmap(struct adapter *adap);
 void cxgb4_free_msix_idx_in_bmap(struct adapter *adap, u32 msix_idx);
+int cxgb_open(struct net_device *dev);
+int cxgb_close(struct net_device *dev);
 #endif /* __CXGB4_H__ */

drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c

@@ -65,6 +65,7 @@
 #include <linux/uaccess.h>
 #include <linux/crash_dump.h>
 #include <net/udp_tunnel.h>
+#include <net/xfrm.h>
 
 #include "cxgb4.h"
 #include "cxgb4_filter.h"
@@ -82,6 +83,7 @@
 #include "sched.h"
 #include "cxgb4_tc_u32.h"
 #include "cxgb4_tc_flower.h"
+#include "cxgb4_tc_mqprio.h"
 #include "cxgb4_ptp.h"
 #include "cxgb4_cudbg.h"
 
@@ -1117,6 +1119,18 @@ static u16 cxgb_select_queue(struct net_device *dev, struct sk_buff *skb,
 	}
 #endif /* CONFIG_CHELSIO_T4_DCB */
 
+	if (dev->num_tc) {
+		struct port_info *pi = netdev2pinfo(dev);
+
+		/* Send unsupported traffic pattern to normal NIC queues. */
+		txq = netdev_pick_tx(dev, skb, sb_dev);
+		if (xfrm_offload(skb) || is_ptp_enabled(skb, dev) ||
+		    ip_hdr(skb)->protocol != IPPROTO_TCP)
+			txq = txq % pi->nqsets;
+
+		return txq;
+	}
+
 	if (select_queue) {
 		txq = (skb_rx_queue_recorded(skb)
 			? skb_get_rx_queue(skb)
@@ -2472,11 +2486,11 @@ static void cxgb_down(struct adapter *adapter)
 /*
  * net_device operations
  */
-static int cxgb_open(struct net_device *dev)
+int cxgb_open(struct net_device *dev)
 {
-	int err;
 	struct port_info *pi = netdev_priv(dev);
 	struct adapter *adapter = pi->adapter;
+	int err;
 
 	netif_carrier_off(dev);
 
@@ -2499,7 +2513,7 @@ static int cxgb_open(struct net_device *dev)
 	return err;
 }
 
-static int cxgb_close(struct net_device *dev)
+int cxgb_close(struct net_device *dev)
 {
 	struct port_info *pi = netdev_priv(dev);
 	struct adapter *adapter = pi->adapter;
@@ -3233,6 +3247,17 @@ static int cxgb_setup_tc_block_cb(enum tc_setup_type type, void *type_data,
 	}
 }
 
+static int cxgb_setup_tc_mqprio(struct net_device *dev,
+				struct tc_mqprio_qopt_offload *mqprio)
+{
+	struct adapter *adap = netdev2adap(dev);
+
+	if (!is_ethofld(adap) || !adap->tc_mqprio)
+		return -ENOMEM;
+
+	return cxgb4_setup_tc_mqprio(dev, mqprio);
+}
+
 static LIST_HEAD(cxgb_block_cb_list);
 
 static int cxgb_setup_tc(struct net_device *dev, enum tc_setup_type type,
@@ -3241,6 +3266,8 @@ static int cxgb_setup_tc(struct net_device *dev, enum tc_setup_type type,
 	struct port_info *pi = netdev2pinfo(dev);
 
 	switch (type) {
+	case TC_SETUP_QDISC_MQPRIO:
+		return cxgb_setup_tc_mqprio(dev, type_data);
 	case TC_SETUP_BLOCK:
 		return flow_block_cb_setup_simple(type_data,
 						  &cxgb_block_cb_list,
@@ -5668,6 +5695,7 @@ static void free_some_resources(struct adapter *adapter)
 	kvfree(adapter->srq);
 	t4_cleanup_sched(adapter);
 	kvfree(adapter->tids.tid_tab);
+	cxgb4_cleanup_tc_mqprio(adapter);
 	cxgb4_cleanup_tc_flower(adapter);
 	cxgb4_cleanup_tc_u32(adapter);
 	kfree(adapter->sge.egr_map);
@@ -6237,6 +6265,10 @@ static int init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 		if (cxgb4_init_tc_flower(adapter))
 			dev_warn(&pdev->dev,
 				 "could not offload tc flower, continuing\n");
+
+		if (cxgb4_init_tc_mqprio(adapter))
+			dev_warn(&pdev->dev,
+				 "could not offload tc mqprio, continuing\n");
 	}
 
 	if (is_offload(adapter) || is_hashfilter(adapter)) {