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Commit 434c975a authored by Michael Chan's avatar Michael Chan Committed by David S. Miller
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bnxt_en: Optimize doorbell write operations for newer chips. 



Older chips require the doorbells to be written twice, but newer chips
do not.  Add a new common function bnxt_db_write() to write all
doorbells appropriately depending on the chip.  Eliminating the extra
doorbell on newer chips has a significant performance improvement
on pktgen.

Signed-off-by: default avatarMichael Chan <michael.chan@broadcom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3284f9e1

drivers/net/ethernet/broadcom/bnxt/bnxt.c

+12 −18
Original line number Diff line number Diff line
@@ -463,8 +463,7 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	prod = NEXT_TX(prod);

	txr->tx_prod = prod;



	writel(DB_KEY_TX | prod, txr->tx_doorbell);

	writel(DB_KEY_TX | prod, txr->tx_doorbell);

	bnxt_db_write(bp, txr->tx_doorbell, DB_KEY_TX | prod);



tx_done:
@@ -1779,8 +1778,7 @@ static int bnxt_poll_work(struct bnxt *bp, struct bnxt_napi *bnapi, int budget) 
		/* Sync BD data before updating doorbell */

		wmb();



		writel(DB_KEY_TX | prod, db);

		writel(DB_KEY_TX | prod, db);

		bnxt_db_write(bp, db, DB_KEY_TX | prod);

	}



	cpr->cp_raw_cons = raw_cons;
@@ -1796,14 +1794,10 @@ static int bnxt_poll_work(struct bnxt *bp, struct bnxt_napi *bnapi, int budget) 
	if (event & BNXT_RX_EVENT) {

		struct bnxt_rx_ring_info *rxr = bnapi->rx_ring;



		writel(DB_KEY_RX | rxr->rx_prod, rxr->rx_doorbell);

		writel(DB_KEY_RX | rxr->rx_prod, rxr->rx_doorbell);

		if (event & BNXT_AGG_EVENT) {

			writel(DB_KEY_RX | rxr->rx_agg_prod,

			       rxr->rx_agg_doorbell);

			writel(DB_KEY_RX | rxr->rx_agg_prod,

			       rxr->rx_agg_doorbell);

		}

		bnxt_db_write(bp, rxr->rx_doorbell, DB_KEY_RX | rxr->rx_prod);

		if (event & BNXT_AGG_EVENT)

			bnxt_db_write(bp, rxr->rx_agg_doorbell,

				      DB_KEY_RX | rxr->rx_agg_prod);

	}

	return rx_pkts;

}
@@ -1863,13 +1857,11 @@ static int bnxt_poll_nitroa0(struct napi_struct *napi, int budget) 


	cpr->cp_raw_cons = raw_cons;

	BNXT_CP_DB(cpr->cp_doorbell, cpr->cp_raw_cons);

	writel(DB_KEY_RX | rxr->rx_prod, rxr->rx_doorbell);

	writel(DB_KEY_RX | rxr->rx_prod, rxr->rx_doorbell);

	bnxt_db_write(bp, rxr->rx_doorbell, DB_KEY_RX | rxr->rx_prod);



	if (event & BNXT_AGG_EVENT) {

		writel(DB_KEY_RX | rxr->rx_agg_prod, rxr->rx_agg_doorbell);

		writel(DB_KEY_RX | rxr->rx_agg_prod, rxr->rx_agg_doorbell);

	}

	if (event & BNXT_AGG_EVENT)

		bnxt_db_write(bp, rxr->rx_agg_doorbell,

			      DB_KEY_RX | rxr->rx_agg_prod);



	if (!bnxt_has_work(bp, cpr) && rx_pkts < budget) {

		napi_complete_done(napi, rx_pkts);
@@ -7714,6 +7706,8 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) 
	bp->gro_func = bnxt_gro_func_5730x;

	if (BNXT_CHIP_P4_PLUS(bp))

		bp->gro_func = bnxt_gro_func_5731x;

	else

		bp->flags |= BNXT_FLAG_DOUBLE_DB;



	rc = bnxt_hwrm_func_drv_rgtr(bp);

	if (rc)

drivers/net/ethernet/broadcom/bnxt/bnxt.h

+9 −0
Original line number Diff line number Diff line
@@ -1022,6 +1022,7 @@ struct bnxt { 
	#define BNXT_FLAG_FW_LLDP_AGENT	0x80000

	#define BNXT_FLAG_MULTI_HOST	0x100000

	#define BNXT_FLAG_SHORT_CMD	0x200000

	#define BNXT_FLAG_DOUBLE_DB	0x400000

	#define BNXT_FLAG_CHIP_NITRO_A0	0x1000000



	#define BNXT_FLAG_ALL_CONFIG_FEATS (BNXT_FLAG_TPA |		\
@@ -1254,6 +1255,14 @@ static inline u32 bnxt_tx_avail(struct bnxt *bp, struct bnxt_tx_ring_info *txr) 
		((txr->tx_prod - txr->tx_cons) & bp->tx_ring_mask);

}



/* For TX and RX ring doorbells */

static inline void bnxt_db_write(struct bnxt *bp, void __iomem *db, u32 val)

{

	writel(val, db);

	if (bp->flags & BNXT_FLAG_DOUBLE_DB)

		writel(val, db);

}



extern const u16 bnxt_lhint_arr[];



int bnxt_alloc_rx_data(struct bnxt *bp, struct bnxt_rx_ring_info *rxr,

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

+1 −2
Original line number Diff line number Diff line
@@ -2376,8 +2376,7 @@ static int bnxt_run_loopback(struct bnxt *bp) 
	/* Sync BD data before updating doorbell */

	wmb();



	writel(DB_KEY_TX | txr->tx_prod, txr->tx_doorbell);

	writel(DB_KEY_TX | txr->tx_prod, txr->tx_doorbell);

	bnxt_db_write(bp, txr->tx_doorbell, DB_KEY_TX | txr->tx_prod);

	rc = bnxt_poll_loopback(bp, pkt_size);



	dma_unmap_single(&bp->pdev->dev, map, pkt_size, PCI_DMA_TODEVICE);

drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c

+1 −1
Original line number Diff line number Diff line
@@ -63,7 +63,7 @@ void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts) 
		tx_buf = &txr->tx_buf_ring[last_tx_cons];

		rx_prod = tx_buf->rx_prod;

	}

	writel(DB_KEY_RX | rx_prod, rxr->rx_doorbell);

	bnxt_db_write(bp, rxr->rx_doorbell, DB_KEY_RX | rx_prod);

}



/* returns the following: