From nobody Mon Apr 6 23:38:47 2026 Received: from smtpout-04.galae.net (smtpout-04.galae.net [185.171.202.116]) (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 B3A92248891 for ; Tue, 17 Mar 2026 16:19:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.171.202.116 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773764366; cv=none; b=GRoOlrJu0PUMxkC6JqnEcKSFjsZXQXrDmr7kjAcqmoFr7fBPnOmn4hbcYYI+EB4EhBXGjfQ0w1vfYUkqPAvKihHYAFfuwFyA5WUFOXSta2kr3QFcaF+E8L1UFdgARfDCJAQbgtbB5ddPubA3AY18jE/VaypzPoq/ph6TtweXPkM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773764366; c=relaxed/simple; bh=qigh43BKzsUOD2/4BjJhk4bZi9wLxWHIk6EvGfzEw64=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=I4ghc0baCh5VqYa0Zjh0y3rnWWNtaRS4K1lBsSrYRx85JFq0sf2uZCuSEgfKyKKBLg/JJ9cE2jIKeAaCLsipDJjhrTehLmWCFM1P470kILdrtmACRu3+is2WMhot3XbtUToFOjgsXYQTndedGZH8kKmYyDgeoIoMH5IPiYB7Tbc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=PsFlOdj6; arc=none smtp.client-ip=185.171.202.116 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="PsFlOdj6" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-04.galae.net (Postfix) with ESMTPS id A4499C5505E; Tue, 17 Mar 2026 16:19:45 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 8DD0B5FC9A; Tue, 17 Mar 2026 16:19:21 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 581A610450641; Tue, 17 Mar 2026 17:19:19 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1773764360; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=3e/0x+YhiV49h77QgHappcAYuSifhjt41F7k45+WPSs=; b=PsFlOdj6sccnnhPPUrfRF+xPZWlJ0dKEYOH6Xo8d+Q/MpjG8EpvhoBWdp/km8uDW7HJss9 QVcirU9OhdIc4QE3vYJfjGuxEkcSkR051FizfwSV3qtYWYGANJKX/VQu/lgimcDIAXFtTx evshHMTRBA6l0eFBN1Ugc9rIsd6HuTT2D4RhU6TGKyBAVEuw6269JJH8mEmIo9fiFduDiQ flsg6JZL0GoEjTPcjmATSj2DxzsnB86TGn4dExiHBJNAVyfEgBAK32l2YINZLC+xC0Z9ik kJVoVyoeu5eFcP2oOYlNOoEEmK8k4KCkDIXg116BzO0IvOk/LVRHjoZNkQuMKA== From: =?utf-8?q?Th=C3=A9o_Lebrun?= Date: Tue, 17 Mar 2026 17:19:08 +0100 Subject: [PATCH net-next v4 1/2] net: macb: implement ethtool_ops.get|set_channels() 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: <20260317-macb-set-channels-v4-1-1bd4f4ffcfca@bootlin.com> References: <20260317-macb-set-channels-v4-0-1bd4f4ffcfca@bootlin.com> In-Reply-To: <20260317-macb-set-channels-v4-0-1bd4f4ffcfca@bootlin.com> To: Nicolas Ferre , Claudiu Beznea , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Vladimir Kondratiev , Gregory CLEMENT , =?utf-8?q?Beno=C3=AEt_Monin?= , Tawfik Bayouk , Thomas Petazzoni , Paolo Valerio , =?utf-8?q?Th=C3=A9o_Lebrun?= X-Mailer: b4 0.15-dev X-Last-TLS-Session-Version: TLSv1.3 bp->num_queues is the total number of queues and is constant from probe. Introduce bp->max_num_queues which takes the current role of bp->num_queues and allow `0 < bp->num_queues <=3D bp->max_num_queues`. MACB/GEM does not know about rx/tx specific queues; it only has combined queues. .set_channels() is reserved to devices with MACB_CAPS_QUEUE_DISABLE. The tieoff workaround would not work as packets would still be routed into queues with a tieoff descriptor. Implement .set_channels() operation by refusing if netif_running(). The reason to implement .set_channels() is memory savings, we cannot preallocate and swap at runtime. Nit: fix an alignment issue inside gem_ethtool_ops which does not deserve its own patch. Signed-off-by: Th=C3=A9o Lebrun --- drivers/net/ethernet/cadence/macb.h | 1 + drivers/net/ethernet/cadence/macb_main.c | 100 ++++++++++++++++++++++++++-= ---- 2 files changed, 85 insertions(+), 16 deletions(-) diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cad= ence/macb.h index c69828b27dae..b08afe340996 100644 --- a/drivers/net/ethernet/cadence/macb.h +++ b/drivers/net/ethernet/cadence/macb.h @@ -1309,6 +1309,7 @@ struct macb { unsigned int tx_ring_size; =20 unsigned int num_queues; + unsigned int max_num_queues; struct macb_queue queues[MACB_MAX_QUEUES]; =20 spinlock_t lock; diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/etherne= t/cadence/macb_main.c index abd328428c94..dd066f481200 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -469,9 +469,26 @@ static void macb_init_buffers(struct macb *bp) upper_32_bits(bp->queues[0].tx_ring_dma)); } =20 - for (q =3D 0, queue =3D bp->queues; q < bp->num_queues; ++q, ++queue) { - queue_writel(queue, RBQP, lower_32_bits(queue->rx_ring_dma)); - queue_writel(queue, TBQP, lower_32_bits(queue->tx_ring_dma)); + for (q =3D 0, queue =3D bp->queues; q < bp->max_num_queues; ++q, ++queue)= { + if (q < bp->num_queues) { + queue_writel(queue, RBQP, + lower_32_bits(queue->rx_ring_dma)); + queue_writel(queue, TBQP, + lower_32_bits(queue->tx_ring_dma)); + } else { + /* + * macb_set_channels(), which is the only way of writing + * to bp->num_queues, is only allowed if + * MACB_CAPS_QUEUE_DISABLE. + */ + queue_writel(queue, RBQP, MACB_BIT(QUEUE_DISABLE)); + + /* Disable all interrupts */ + queue_writel(queue, IDR, -1); + queue_readl(queue, ISR); + if (bp->caps & MACB_CAPS_ISR_CLEAR_ON_WRITE) + queue_writel(queue, ISR, -1); + } } } =20 @@ -4121,8 +4138,8 @@ static int gem_set_rxnfc(struct net_device *netdev, s= truct ethtool_rxnfc *cmd) =20 switch (cmd->cmd) { case ETHTOOL_SRXCLSRLINS: - if ((cmd->fs.location >=3D bp->max_tuples) - || (cmd->fs.ring_cookie >=3D bp->num_queues)) { + if (cmd->fs.location >=3D bp->max_tuples || + cmd->fs.ring_cookie >=3D bp->max_num_queues) { ret =3D -EINVAL; break; } @@ -4140,6 +4157,51 @@ static int gem_set_rxnfc(struct net_device *netdev, = struct ethtool_rxnfc *cmd) return ret; } =20 +static void macb_get_channels(struct net_device *netdev, + struct ethtool_channels *ch) +{ + struct macb *bp =3D netdev_priv(netdev); + + ch->max_combined =3D bp->max_num_queues; + ch->combined_count =3D bp->num_queues; +} + +static int macb_set_channels(struct net_device *netdev, + struct ethtool_channels *ch) +{ + struct macb *bp =3D netdev_priv(netdev); + unsigned int old_count =3D bp->num_queues; + unsigned int count =3D ch->combined_count; + int ret; + + /* + * MACB_CAPS_QUEUE_DISABLE means that the field QUEUE_DISABLE/BIT0 in + * the per-queue RBQP register disables queue Rx. If we don't have that + * capability we can have multiple queues but we must always run with + * all enabled. + */ + if (!(bp->caps & MACB_CAPS_QUEUE_DISABLE)) + return -EOPNOTSUPP; + + /* + * An ideal .set_channels() implementation uses upfront allocated + * resources and swaps them in, bringing reliability under memory + * pressure. However, here we implement it for memory savings in + * setups with less than max number of queues active. + * + * Signal it by refusing .set_channels() once interface is opened. + */ + if (netif_running(bp->dev)) + return -EBUSY; + + ret =3D netif_set_real_num_queues(bp->dev, count, count); + if (ret) + return ret; + + bp->num_queues =3D count; + return 0; +} + static const struct ethtool_ops macb_ethtool_ops =3D { .get_regs_len =3D macb_get_regs_len, .get_regs =3D macb_get_regs, @@ -4155,6 +4217,8 @@ static const struct ethtool_ops macb_ethtool_ops =3D { .set_link_ksettings =3D macb_set_link_ksettings, .get_ringparam =3D macb_get_ringparam, .set_ringparam =3D macb_set_ringparam, + .get_channels =3D macb_get_channels, + .set_channels =3D macb_set_channels, }; =20 static int macb_get_eee(struct net_device *dev, struct ethtool_keee *eee) @@ -4189,12 +4253,14 @@ static const struct ethtool_ops gem_ethtool_ops =3D= { .set_link_ksettings =3D macb_set_link_ksettings, .get_ringparam =3D macb_get_ringparam, .set_ringparam =3D macb_set_ringparam, - .get_rxnfc =3D gem_get_rxnfc, - .set_rxnfc =3D gem_set_rxnfc, - .get_rx_ring_count =3D gem_get_rx_ring_count, - .nway_reset =3D phy_ethtool_nway_reset, + .get_rxnfc =3D gem_get_rxnfc, + .set_rxnfc =3D gem_set_rxnfc, + .get_rx_ring_count =3D gem_get_rx_ring_count, + .nway_reset =3D phy_ethtool_nway_reset, .get_eee =3D macb_get_eee, .set_eee =3D macb_set_eee, + .get_channels =3D macb_get_channels, + .set_channels =3D macb_set_channels, }; =20 static int macb_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) @@ -4335,9 +4401,9 @@ static int macb_taprio_setup_replace(struct net_devic= e *ndev, size_t i; int err; =20 - if (conf->num_entries > bp->num_queues) { + if (conf->num_entries > bp->max_num_queues) { netdev_err(ndev, "Too many TAPRIO entries: %zu > %d queues\n", - conf->num_entries, bp->num_queues); + conf->num_entries, bp->max_num_queues); return -EINVAL; } =20 @@ -4385,9 +4451,9 @@ static int macb_taprio_setup_replace(struct net_devic= e *ndev, =20 /* gate_mask must not select queues outside the valid queues */ queue_id =3D order_base_2(entry->gate_mask); - if (queue_id >=3D bp->num_queues) { + if (queue_id >=3D bp->max_num_queues) { netdev_err(ndev, "Entry %zu: gate_mask 0x%x exceeds queue range (max_qu= eues=3D%d)\n", - i, entry->gate_mask, bp->num_queues); + i, entry->gate_mask, bp->max_num_queues); err =3D -EINVAL; goto cleanup; } @@ -4447,7 +4513,7 @@ static int macb_taprio_setup_replace(struct net_devic= e *ndev, /* All validations passed - proceed with hardware configuration */ scoped_guard(spinlock_irqsave, &bp->lock) { /* Disable ENST queues if running before configuring */ - queue_mask =3D BIT_U32(bp->num_queues) - 1; + queue_mask =3D BIT_U32(bp->max_num_queues) - 1; gem_writel(bp, ENST_CONTROL, queue_mask << GEM_ENST_DISABLE_QUEUE_OFFSET); =20 @@ -4482,7 +4548,7 @@ static void macb_taprio_destroy(struct net_device *nd= ev) unsigned int q; =20 netdev_reset_tc(ndev); - queue_mask =3D BIT_U32(bp->num_queues) - 1; + queue_mask =3D BIT_U32(bp->max_num_queues) - 1; =20 scoped_guard(spinlock_irqsave, &bp->lock) { /* Single disable command for all queues */ @@ -4490,7 +4556,8 @@ static void macb_taprio_destroy(struct net_device *nd= ev) queue_mask << GEM_ENST_DISABLE_QUEUE_OFFSET); =20 /* Clear all queue ENST registers in batch */ - for (q =3D 0, queue =3D bp->queues; q < bp->num_queues; ++q, ++queue) { + for (q =3D 0, queue =3D bp->queues; q < bp->max_num_queues; + ++q, ++queue) { queue_writel(queue, ENST_START_TIME, 0); queue_writel(queue, ENST_ON_TIME, 0); queue_writel(queue, ENST_OFF_TIME, 0); @@ -5735,6 +5802,7 @@ static int macb_probe(struct platform_device *pdev) bp->macb_reg_writel =3D hw_writel; } bp->num_queues =3D num_queues; + bp->max_num_queues =3D num_queues; bp->dma_burst_length =3D macb_config->dma_burst_length; bp->pclk =3D pclk; bp->hclk =3D hclk; --=20 2.53.0