5.4-stable review patch. If anyone has any objections, please let me know.
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From: Jonas Rebmann jre@pengutronix.de
[ Upstream commit b7ad21258f9e9a7f58b19595d5ceed2cde3bed68 ]
In the current implementation, IP coalescing is always enabled and cannot be disabled.
As setting maximum frames to 0 or 1, or setting delay to zero implies immediate delivery of single packets/IRQs, disable coalescing in hardware in these cases.
This also guarantees that coalescing is never enabled with ICFT or ICTT set to zero, a configuration that could lead to unpredictable behaviour according to i.MX8MP reference manual.
Signed-off-by: Jonas Rebmann jre@pengutronix.de Reviewed-by: Wei Fang wei.fang@nxp.com Link: https://patch.msgid.link/20250626-fec_deactivate_coalescing-v2-1-0b217f2e80d... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/freescale/fec_main.c | 34 +++++++++++------------ 1 file changed, 16 insertions(+), 18 deletions(-)
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index fd7c504b44f2..f8a096633280 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -2590,27 +2590,25 @@ static int fec_enet_us_to_itr_clock(struct net_device *ndev, int us) static void fec_enet_itr_coal_set(struct net_device *ndev) { struct fec_enet_private *fep = netdev_priv(ndev); - int rx_itr, tx_itr; + u32 rx_itr = 0, tx_itr = 0; + int rx_ictt, tx_ictt;
- /* Must be greater than zero to avoid unpredictable behavior */ - if (!fep->rx_time_itr || !fep->rx_pkts_itr || - !fep->tx_time_itr || !fep->tx_pkts_itr) - return; - - /* Select enet system clock as Interrupt Coalescing - * timer Clock Source - */ - rx_itr = FEC_ITR_CLK_SEL; - tx_itr = FEC_ITR_CLK_SEL; + rx_ictt = fec_enet_us_to_itr_clock(ndev, fep->rx_time_itr); + tx_ictt = fec_enet_us_to_itr_clock(ndev, fep->tx_time_itr);
- /* set ICFT and ICTT */ - rx_itr |= FEC_ITR_ICFT(fep->rx_pkts_itr); - rx_itr |= FEC_ITR_ICTT(fec_enet_us_to_itr_clock(ndev, fep->rx_time_itr)); - tx_itr |= FEC_ITR_ICFT(fep->tx_pkts_itr); - tx_itr |= FEC_ITR_ICTT(fec_enet_us_to_itr_clock(ndev, fep->tx_time_itr)); + if (rx_ictt > 0 && fep->rx_pkts_itr > 1) { + /* Enable with enet system clock as Interrupt Coalescing timer Clock Source */ + rx_itr = FEC_ITR_EN | FEC_ITR_CLK_SEL; + rx_itr |= FEC_ITR_ICFT(fep->rx_pkts_itr); + rx_itr |= FEC_ITR_ICTT(rx_ictt); + }
- rx_itr |= FEC_ITR_EN; - tx_itr |= FEC_ITR_EN; + if (tx_ictt > 0 && fep->tx_pkts_itr > 1) { + /* Enable with enet system clock as Interrupt Coalescing timer Clock Source */ + tx_itr = FEC_ITR_EN | FEC_ITR_CLK_SEL; + tx_itr |= FEC_ITR_ICFT(fep->tx_pkts_itr); + tx_itr |= FEC_ITR_ICTT(tx_ictt); + }
writel(tx_itr, fep->hwp + FEC_TXIC0); writel(rx_itr, fep->hwp + FEC_RXIC0);