From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.tipi-net.de (mail.tipi-net.de [194.13.80.246]) (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 60FCD42EEBF; Fri, 27 Feb 2026 15:08:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=194.13.80.246 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772204929; cv=none; b=pmsp1q9YgNYaJeQvml21cxBwS+FI0CC4aXlSDMY4I971mrkj8oes6ZgxNZ+UtNrcA78DRAsGVVuwKJu1Grgn5Quy+EU4WmZloV/HbVHuDj1tdQiyCnrtfWZaxHjfTjOW1PsfzEJU2yULzuVTaM8EWDfpP/796Z67kYFgJ7/SVAI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772204929; c=relaxed/simple; bh=deKl210dEPTH61NE3uPje7uAdxuwszbBLhacecZfR2g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Xzb8pftl+SF2cGOWd8XM7iWrr0o7ab8AP4A4YZHAJD32dllhNmAePi4SOC8tWYzMBOZ/l2KIFa3018i6AEStyoBh9oIrjRpSBrfk2I6GMRbU5b3RZ6DMTRGKtqYlhm3L0UT9Ops3kcnbwIfT6NM3ID4W7xDKEH7cYsbf2KGfyN4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=tipi-net.de; spf=pass smtp.mailfrom=tipi-net.de; dkim=pass (2048-bit key) header.d=tipi-net.de header.i=@tipi-net.de header.b=i6Jlrp90; arc=none smtp.client-ip=194.13.80.246 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=tipi-net.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=tipi-net.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=tipi-net.de header.i=@tipi-net.de header.b="i6Jlrp90" Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id B361BA5004; Fri, 27 Feb 2026 16:08:43 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tipi-net.de; s=dkim; t=1772204924; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=8GC3kyRUMLQo0KzjbX6agpaPEYobEOwV6XjlkKdmHeE=; b=i6Jlrp90ugTYEzrEOuBnlICkLsEyot9xoladiMB+i+9XnLq7QHbvJnuuAJvYLfv26j86I7 Rn6vSo0XwrywloxUWF6oTtFgfAN2nvh9X4Zcfpp28C+Jgfy+/D/kuYO3ZLkn4z5fJoECC7 8WOVMvfPquFWxlHYIk174US3z82LhWRGk6SqvZ2KKMgB+xNZWU6NPf/owfF/AWdtI5sfLZ 3qQ+UFiVKeG8p4CrGHOtco2vm35+bIec+wgzuIWph+trc258TwkzDnGIV9fmUUUW/2sSgg Y6Npola12sEO3TDpN1ww2fxu+LvmHxh3t/j5Kx0i3tTO1dNGPld0TYUqc08S7g== From: Nicolai Buchwitz To: netdev@vger.kernel.org Cc: davem@davemloft.net, andrew+netdev@lunn.ch, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, linux@armlinux.org.uk, claudiu.beznea@tuxon.dev, nicolas.ferre@microchip.com, linux-kernel@vger.kernel.org, theo.lebrun@bootlin.com, phil@raspberrypi.com, Nicolai Buchwitz Subject: [PATCH net-next v5 2/5] net: cadence: macb: implement EEE TX LPI support Date: Fri, 27 Feb 2026 16:06:07 +0100 Message-ID: <20260227150610.242215-3-nb@tipi-net.de> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260227150610.242215-1-nb@tipi-net.de> References: <20260227150610.242215-1-nb@tipi-net.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Last-TLS-Session-Version: TLSv1.3 The GEM MAC has hardware LPI registers (NCR bit 19: TXLPIEN) but no built-in idle timer, so asserting TXLPIEN blocks all TX immediately with no automatic wake. A software idle timer is required, as noted in Microchip documentation (section 40.6.19): "It is best to use firmware to control LPI." Implement phylink managed EEE using the mac_enable_tx_lpi and mac_disable_tx_lpi callbacks: - macb_tx_lpi_set(): atomically sets or clears TXLPIEN under the existing bp->lock spinlock; returns bool indicating whether the register actually changed, avoiding redundant writes. - macb_tx_lpi_work_fn(): delayed_work handler that enters LPI if all TX queues are idle and EEE is still active. - macb_tx_lpi_schedule(): arms the work timer using the LPI timer value provided by phylink (default 250 ms). Called from macb_tx_complete() after each TX drain so the idle countdown restarts whenever the ring goes quiet. - macb_tx_lpi_wake(): called from macb_start_xmit() before TSTART. Clears TXLPIEN and applies a 50 us udelay for PHY wake (IEEE 802.3az Tw_sys_tx is 16.5 us for 1000BASE-T / 30 us for 100BASE-TX; GEM has no hardware enforcement). Only delays when TXLPIEN was actually set, avoiding overhead on the common path. The delay is placed after tx_head is advanced so the work_fn's queue-idle check sees a non-empty ring and cannot race back into LPI before the frame is transmitted. - mac_enable_tx_lpi: stores the timer and sets eee_active, then defers the first LPI entry by 1 second per IEEE 802.3az section 22.7a. - mac_disable_tx_lpi: clears eee_active, cancels the work, and deasserts TXLPIEN. Populate phylink_config lpi_interfaces (MII, GMII, RGMII variants) and lpi_capabilities (MAC_100FD | MAC_1000FD) so phylink can negotiate EEE with the PHY and call the callbacks appropriately. Set lpi_timer_default to 250000 us and eee_enabled_default to true. Reviewed-by: Théo Lebrun Signed-off-by: Nicolai Buchwitz --- drivers/net/ethernet/cadence/macb.h | 8 ++ drivers/net/ethernet/cadence/macb_main.c | 112 +++++++++++++++++++++++ 2 files changed, 120 insertions(+) diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h index 19aa98d01c8c..c69828b27dae 100644 --- a/drivers/net/ethernet/cadence/macb.h +++ b/drivers/net/ethernet/cadence/macb.h @@ -309,6 +309,8 @@ #define MACB_IRXFCS_SIZE 1 /* GEM specific NCR bitfields. */ +#define GEM_TXLPIEN_OFFSET 19 +#define GEM_TXLPIEN_SIZE 1 #define GEM_ENABLE_HS_MAC_OFFSET 31 #define GEM_ENABLE_HS_MAC_SIZE 1 @@ -783,6 +785,7 @@ #define MACB_CAPS_DMA_PTP BIT(22) #define MACB_CAPS_RSC BIT(23) #define MACB_CAPS_NO_LSO BIT(24) +#define MACB_CAPS_EEE BIT(25) /* LSO settings */ #define MACB_LSO_UFO_ENABLE 0x01 @@ -1369,6 +1372,11 @@ struct macb { struct work_struct hresp_err_bh_work; + /* EEE / LPI state */ + bool eee_active; + struct delayed_work tx_lpi_work; + u32 tx_lpi_timer; + int rx_bd_rd_prefetch; int tx_bd_rd_prefetch; diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index 02eab26fd98b..c23485f049d3 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -621,6 +622,94 @@ static const struct phylink_pcs_ops macb_phylink_pcs_ops = { .pcs_config = macb_pcs_config, }; +static bool macb_tx_lpi_set(struct macb *bp, bool enable) +{ + unsigned long flags; + u32 old, ncr; + + spin_lock_irqsave(&bp->lock, flags); + ncr = macb_readl(bp, NCR); + old = ncr; + if (enable) + ncr |= GEM_BIT(TXLPIEN); + else + ncr &= ~GEM_BIT(TXLPIEN); + if (old != ncr) + macb_writel(bp, NCR, ncr); + spin_unlock_irqrestore(&bp->lock, flags); + + return old != ncr; +} + +static bool macb_tx_all_queues_idle(struct macb *bp) +{ + unsigned int q; + + for (q = 0; q < bp->num_queues; q++) { + struct macb_queue *queue = &bp->queues[q]; + + if (queue->tx_head != queue->tx_tail) + return false; + } + return true; +} + +static void macb_tx_lpi_work_fn(struct work_struct *work) +{ + struct macb *bp = container_of(work, struct macb, tx_lpi_work.work); + + if (bp->eee_active && macb_tx_all_queues_idle(bp)) + macb_tx_lpi_set(bp, true); +} + +static void macb_tx_lpi_schedule(struct macb *bp) +{ + if (bp->eee_active) + mod_delayed_work(system_wq, &bp->tx_lpi_work, + usecs_to_jiffies(bp->tx_lpi_timer)); +} + +/* Wake from LPI before transmitting. The MAC must deassert TXLPIEN + * and wait for the PHY to exit LPI before any frame can be sent. + * IEEE 802.3az Tw_sys is ~17us for 1000BASE-T, ~30us for 100BASE-TX; + * we use a conservative 50us. + */ +static void macb_tx_lpi_wake(struct macb *bp) +{ + if (!macb_tx_lpi_set(bp, false)) + return; + + cancel_delayed_work(&bp->tx_lpi_work); + udelay(50); +} + +static void macb_mac_disable_tx_lpi(struct phylink_config *config) +{ + struct net_device *ndev = to_net_dev(config->dev); + struct macb *bp = netdev_priv(ndev); + + bp->eee_active = false; + cancel_delayed_work_sync(&bp->tx_lpi_work); + macb_tx_lpi_set(bp, false); +} + +static int macb_mac_enable_tx_lpi(struct phylink_config *config, u32 timer, + bool tx_clk_stop) +{ + struct net_device *ndev = to_net_dev(config->dev); + struct macb *bp = netdev_priv(ndev); + + bp->tx_lpi_timer = timer; + bp->eee_active = true; + + /* Defer initial LPI entry by 1 second after link-up per + * IEEE 802.3az section 22.7a. + */ + mod_delayed_work(system_wq, &bp->tx_lpi_work, msecs_to_jiffies(1000)); + + return 0; +} + static void macb_mac_config(struct phylink_config *config, unsigned int mode, const struct phylink_link_state *state) { @@ -769,6 +858,8 @@ static const struct phylink_mac_ops macb_phylink_ops = { .mac_config = macb_mac_config, .mac_link_down = macb_mac_link_down, .mac_link_up = macb_mac_link_up, + .mac_disable_tx_lpi = macb_mac_disable_tx_lpi, + .mac_enable_tx_lpi = macb_mac_enable_tx_lpi, }; static bool macb_phy_handle_exists(struct device_node *dn) @@ -864,6 +955,18 @@ static int macb_mii_probe(struct net_device *dev) } } + /* Configure EEE LPI if supported */ + if (bp->caps & MACB_CAPS_EEE) { + __set_bit(PHY_INTERFACE_MODE_MII, + bp->phylink_config.lpi_interfaces); + __set_bit(PHY_INTERFACE_MODE_GMII, + bp->phylink_config.lpi_interfaces); + phy_interface_set_rgmii(bp->phylink_config.lpi_interfaces); + bp->phylink_config.lpi_capabilities = MAC_100FD | MAC_1000FD; + bp->phylink_config.lpi_timer_default = 250000; + bp->phylink_config.eee_enabled_default = true; + } + bp->phylink = phylink_create(&bp->phylink_config, bp->pdev->dev.fwnode, bp->phy_interface, &macb_phylink_ops); if (IS_ERR(bp->phylink)) { @@ -1260,6 +1363,9 @@ static int macb_tx_complete(struct macb_queue *queue, int budget) netif_wake_subqueue(bp->dev, queue_index); spin_unlock_irqrestore(&queue->tx_ptr_lock, flags); + if (packets) + macb_tx_lpi_schedule(bp); + return packets; } @@ -2365,6 +2471,8 @@ static netdev_tx_t macb_start_xmit(struct sk_buff *skb, struct net_device *dev) netdev_tx_sent_queue(netdev_get_tx_queue(bp->dev, queue_index), skb->len); + macb_tx_lpi_wake(bp); + spin_lock(&bp->lock); macb_writel(bp, NCR, macb_readl(bp, NCR) | MACB_BIT(TSTART)); spin_unlock(&bp->lock); @@ -3026,6 +3134,8 @@ static int macb_close(struct net_device *dev) netdev_tx_reset_queue(netdev_get_tx_queue(dev, q)); } + cancel_delayed_work_sync(&bp->tx_lpi_work); + phylink_stop(bp->phylink); phylink_disconnect_phy(bp->phylink); @@ -5633,6 +5743,7 @@ static int macb_probe(struct platform_device *pdev) } INIT_WORK(&bp->hresp_err_bh_work, macb_hresp_error_task); + INIT_DELAYED_WORK(&bp->tx_lpi_work, macb_tx_lpi_work_fn); netdev_info(dev, "Cadence %s rev 0x%08x at 0x%08lx irq %d (%pM)\n", macb_is_gem(bp) ? "GEM" : "MACB", macb_readl(bp, MID), @@ -5676,6 +5787,7 @@ static void macb_remove(struct platform_device *pdev) mdiobus_free(bp->mii_bus); device_set_wakeup_enable(&bp->pdev->dev, 0); + cancel_delayed_work_sync(&bp->tx_lpi_work); cancel_work_sync(&bp->hresp_err_bh_work); pm_runtime_disable(&pdev->dev); pm_runtime_dont_use_autosuspend(&pdev->dev); -- 2.51.0