From nobody Wed Oct 8 15:58:29 2025 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 75BDF2E7178 for ; Thu, 26 Jun 2025 13:44:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750945456; cv=none; b=A0ri6DaeaApKKsEnboC07+WyiFp01pFCD1tw5+0lImhntTKQcK6onP5am5ztA8Ng+cg7ihjQVcEmTT88yO0D0RkJXSA+aL+RtOM2zupExjnB7wpXUHsG1bYTZ7uijbRmEbbGdcZ7+nX9VeNpAY5oJ8GKPuC4+4r4FnWYk7nNgjk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750945456; c=relaxed/simple; bh=lOIhZPwjq2iRUH2/8/px4H6GSxHqp5XVL22e3XXy7z8=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=EItGdEjEP9QM4KOlmYnpTkL0E5At44s9U94jiqD/LKvGzReVBCROCy0/BNrJFatOC+zmr7QuJrDAwtr++1XwFFqcNXPmlI2kTkO3QtlpPOllAXuTqYyALfSPTTpQBJ65tMqlmsvH2HjrbUN6wgSbt5O/C3mxAMTk1zdLvRSNSE0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from dude04.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::ac]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1uUmte-0004GB-8X; Thu, 26 Jun 2025 15:44:10 +0200 From: Jonas Rebmann Date: Thu, 26 Jun 2025 15:44:02 +0200 Subject: [PATCH v2] net: fec: allow disable coalescing Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250626-fec_deactivate_coalescing-v2-1-0b217f2e80da@pengutronix.de> X-B4-Tracking: v=1; b=H4sIAKFOXWgC/42NQQrCMBBFr1JmbaSJTRRX3kNKGZJpOyBJSWKol N7d2BO4fA/++xskikwJ7s0GkQonDr6COjVgZ/QTCXaVQbVKt0ZpMZIdHKHNXDDTYAO+KFn2k7B mvDnZoXTGQN0vkUZej/azrzxzyiF+jqsif/afapFCCn1FSZ3ETrvLYyE/vXMMntezI+j3ff8CC mFWLMcAAAA= X-Change-ID: 20250625-fec_deactivate_coalescing-c6f8d14a1d66 To: Wei Fang , Shenwei Wang , Clark Wang , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: imx@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@pengutronix.de, Jonas Rebmann X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=3113; i=jre@pengutronix.de; h=from:subject:message-id; bh=lOIhZPwjq2iRUH2/8/px4H6GSxHqp5XVL22e3XXy7z8=; b=owGbwMvMwCF2ZcYT3onnbjcwnlZLYsiI9Vvx4OHE6n/nVJLubsl8WbztT/rihy+8LZfZnFnsV d+394WAU0cpC4MYB4OsmCJLrJqcgpCx/3WzSrtYmDmsTCBDGLg4BWAic40Y/vvq6XwWsDDStV++ aeWlK3EHNFpK2zeHhrqnbrV90dbjUc7w34GDW3TyRK0ic8GQ5Q+nHfUIsr28IufcJd6DzmVSn/Q t+AA= X-Developer-Key: i=jre@pengutronix.de; a=openpgp; fpr=0B7B750D5D3CD21B3B130DE8B61515E135CD49B5 X-SA-Exim-Connect-IP: 2a0a:edc0:0:1101:1d::ac X-SA-Exim-Mail-From: jre@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org 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 --- Changes in v2: - Adjust type of rx_itr, tx_itr (Thanks, Wei) - Set multiple FEC_ITR_ flags in one line for more compact code (Thanks, We= i) - Commit Message: mention ICFT/CTT fields constraints (Thanks, Andrew) - Link to v1: https://lore.kernel.org/r/20250625-fec_deactivate_coalescing-= v1-1-57a1e41a45d3@pengutronix.de --- 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/ethern= et/freescale/fec_main.c index 63dac42720453a8b8a847bdd1eec76ac072030bf..d4eed252ad4098a7962f615bce9= 8338bc3d12f5c 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -3121,27 +3121,25 @@ static int fec_enet_us_to_itr_clock(struct net_devi= ce *ndev, int us) static void fec_enet_itr_coal_set(struct net_device *ndev) { struct fec_enet_private *fep =3D netdev_priv(ndev); - int rx_itr, tx_itr; + u32 rx_itr =3D 0, tx_itr =3D 0; + int rx_ictt, tx_ictt; =20 - /* 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 =3D FEC_ITR_CLK_SEL; - tx_itr =3D FEC_ITR_CLK_SEL; + rx_ictt =3D fec_enet_us_to_itr_clock(ndev, fep->rx_time_itr); + tx_ictt =3D fec_enet_us_to_itr_clock(ndev, fep->tx_time_itr); =20 - /* set ICFT and ICTT */ - rx_itr |=3D FEC_ITR_ICFT(fep->rx_pkts_itr); - rx_itr |=3D FEC_ITR_ICTT(fec_enet_us_to_itr_clock(ndev, fep->rx_time_itr)= ); - tx_itr |=3D FEC_ITR_ICFT(fep->tx_pkts_itr); - tx_itr |=3D 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 Sou= rce */ + rx_itr =3D FEC_ITR_EN | FEC_ITR_CLK_SEL; + rx_itr |=3D FEC_ITR_ICFT(fep->rx_pkts_itr); + rx_itr |=3D FEC_ITR_ICTT(rx_ictt); + } =20 - rx_itr |=3D FEC_ITR_EN; - tx_itr |=3D FEC_ITR_EN; + if (tx_ictt > 0 && fep->tx_pkts_itr > 1) { + /* Enable with enet system clock as Interrupt Coalescing timer Clock Sou= rce */ + tx_itr =3D FEC_ITR_EN | FEC_ITR_CLK_SEL; + tx_itr |=3D FEC_ITR_ICFT(fep->tx_pkts_itr); + tx_itr |=3D FEC_ITR_ICTT(tx_ictt); + } =20 writel(tx_itr, fep->hwp + FEC_TXIC0); writel(rx_itr, fep->hwp + FEC_RXIC0); --- base-commit: 8dacfd92dbefee829ca555a860e86108fdd1d55b change-id: 20250625-fec_deactivate_coalescing-c6f8d14a1d66 Best regards, --=20 Jonas Rebmann