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Commit c363b658 authored by Fabrice Gasnier's avatar Fabrice Gasnier Committed by David S. Miller
Browse files

stmmac: optimize tx clean function 



This patch "inline" get_tx_owner and get_ls routines. It Results in a
unique read to tdes0, instead of three, to check TX_OWN and LS bits,
and other status bits.

It helps improve driver TX path by removing two uncached read/writes
inside TX clean loop for enhanced descriptors but not for normal ones
because the des1 must be read in any case.

Signed-off-by: default avatarFabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: default avatarGiuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: default avatarAlexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent be434d50

drivers/net/ethernet/stmicro/stmmac/common.h

+8 −0
Original line number Diff line number Diff line
@@ -245,6 +245,14 @@ enum rx_frame_status { 
	dma_own = 0x8,

};



/* Tx status */

enum tx_frame_status {

	tx_done = 0x0,

	tx_not_ls = 0x1,

	tx_err = 0x2,

	tx_dma_own = 0x4,

};



enum dma_irq_status {

	tx_hard_error = 0x1,

	tx_hard_error_bump_tc = 0x2,

drivers/net/ethernet/stmicro/stmmac/enh_desc.c

+10 −2
Original line number Diff line number Diff line
@@ -31,7 +31,15 @@ static int enh_desc_get_tx_status(void *data, struct stmmac_extra_stats *x, 
{

	struct net_device_stats *stats = (struct net_device_stats *)data;

	unsigned int tdes0 = p->des0;

	int ret = 0;

	int ret = tx_done;



	/* Get tx owner first */

	if (unlikely(tdes0 & ETDES0_OWN))

		return tx_dma_own;



	/* Verify tx error by looking at the last segment. */

	if (likely(!(tdes0 & ETDES0_LAST_SEGMENT)))

		return tx_not_ls;



	if (unlikely(tdes0 & ETDES0_ERROR_SUMMARY)) {

		if (unlikely(tdes0 & ETDES0_JABBER_TIMEOUT))
@@ -71,7 +79,7 @@ static int enh_desc_get_tx_status(void *data, struct stmmac_extra_stats *x, 
			dwmac_dma_flush_tx_fifo(ioaddr);

		}



		ret = -1;

		ret = tx_err;

	}



	if (unlikely(tdes0 & ETDES0_DEFERRED))

drivers/net/ethernet/stmicro/stmmac/norm_desc.c

+11 −2
Original line number Diff line number Diff line
@@ -31,7 +31,16 @@ static int ndesc_get_tx_status(void *data, struct stmmac_extra_stats *x, 
{

	struct net_device_stats *stats = (struct net_device_stats *)data;

	unsigned int tdes0 = p->des0;

	int ret = 0;

	unsigned int tdes1 = p->des1;

	int ret = tx_done;



	/* Get tx owner first */

	if (unlikely(tdes0 & TDES0_OWN))

		return tx_dma_own;



	/* Verify tx error by looking at the last segment. */

	if (likely(!(tdes1 & TDES1_LAST_SEGMENT)))

		return tx_not_ls;



	if (unlikely(tdes0 & TDES0_ERROR_SUMMARY)) {

		if (unlikely(tdes0 & TDES0_UNDERFLOW_ERROR)) {
@@ -54,7 +63,7 @@ static int ndesc_get_tx_status(void *data, struct stmmac_extra_stats *x, 
			collisions = (tdes0 & TDES0_COLLISION_COUNT_MASK) >> 3;

			stats->collisions += collisions;

		}

		ret = -1;

		ret = tx_err;

	}



	if (tdes0 & TDES0_VLAN_FRAME)

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

+13 −14
Original line number Diff line number Diff line
@@ -1313,32 +1313,31 @@ static void stmmac_tx_clean(struct stmmac_priv *priv) 
	priv->xstats.tx_clean++;



	while (entry != priv->cur_tx) {

		int last;

		struct sk_buff *skb = priv->tx_skbuff[entry];

		struct dma_desc *p;

		int status;



		if (priv->extend_desc)

			p = (struct dma_desc *)(priv->dma_etx + entry);

		else

			p = priv->dma_tx + entry;



		/* Check if the descriptor is owned by the DMA. */

		if (priv->hw->desc->get_tx_owner(p))

			break;



		/* Verify tx error by looking at the last segment. */

		last = priv->tx_skbuff_dma[entry].last_segment;

		if (likely(last)) {

			int tx_error =

			    priv->hw->desc->tx_status(&priv->dev->stats,

		status = priv->hw->desc->tx_status(&priv->dev->stats,

						      &priv->xstats, p,

						      priv->ioaddr);

			if (likely(tx_error == 0)) {

		/* Check if the descriptor is owned by the DMA */

		if (unlikely(status & tx_dma_own))

			break;



		/* Just consider the last segment and ...*/

		if (likely(!(status & tx_not_ls))) {

			/* ... verify the status error condition */

			if (unlikely(status & tx_err)) {

				priv->dev->stats.tx_errors++;

			} else {

				priv->dev->stats.tx_packets++;

				priv->xstats.tx_pkt_n++;

			} else

				priv->dev->stats.tx_errors++;



			}

			stmmac_get_tx_hwtstamp(priv, entry, skb);

		}

		if (netif_msg_tx_done(priv))