From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13A67C2BA83 for ; Sat, 15 Feb 2020 18:56:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D694B2083B for ; Sat, 15 Feb 2020 18:56:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="XUaaZYdu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726296AbgBOStj (ORCPT ); Sat, 15 Feb 2020 13:49:39 -0500 Received: from vps0.lunn.ch ([185.16.172.187]:47908 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726209AbgBOStj (ORCPT ); Sat, 15 Feb 2020 13:49:39 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=qScxe2MpGrfgcjlXIdk3h7jYPlni2oy8/z2manLMPRM=; b=XUaaZYduMmgedauYbwgwoS6Dd8 E9A6vUY8B6hrkLLqI1S7biw158+9FrsMjBnfcK122IGU1ZbsLe337mxsAbexuURQ34Dd8h3CQXddR whW4XyBEX7k8qcxCaennZlmEcJ2mqDN3jqXI8KApCIxpaSvo9O5F4N5qyXpZL0gLJKzw=; Received: from andrew by vps0.lunn.ch with local (Exim 4.93) (envelope-from ) id 1j32VQ-00058z-VG; Sat, 15 Feb 2020 19:49:32 +0100 Date: Sat, 15 Feb 2020 19:49:32 +0100 From: Andrew Lunn To: Russell King Cc: Florian Fainelli , Heiner Kallweit , "David S. Miller" , netdev@vger.kernel.org Subject: Re: [PATCH net-next 02/10] net: add helpers to resolve negotiated flow control Message-ID: <20200215184932.GS31084@lunn.ch> References: <20200215154839.GR25745@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sat, Feb 15, 2020 at 03:49:27PM +0000, Russell King wrote: > Add a couple of helpers to resolve negotiated flow control. Two helpers > are provided: > > - linkmode_resolve_pause() which takes the link partner and local > advertisements, and decodes whether we should enable TX or RX pause > at the MAC. This is useful outside of phylib, e.g. in phylink. > - phy_get_pause(), which returns the TX/RX enablement status for the > current negotiation results of the PHY. > > This allows us to centralise the flow control resolution, rather than > spreading it around. > > Signed-off-by: Russell King > --- > drivers/net/phy/Makefile | 3 ++- > drivers/net/phy/linkmode.c | 44 ++++++++++++++++++++++++++++++++++++ > drivers/net/phy/phy_device.c | 26 +++++++++++++++++++++ > include/linux/linkmode.h | 4 ++++ > include/linux/phy.h | 3 +++ > 5 files changed, 79 insertions(+), 1 deletion(-) > create mode 100644 drivers/net/phy/linkmode.c > > diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile > index fe5badf13b65..d523fd5670e4 100644 > --- a/drivers/net/phy/Makefile > +++ b/drivers/net/phy/Makefile > @@ -1,7 +1,8 @@ > # SPDX-License-Identifier: GPL-2.0 > # Makefile for Linux PHY drivers and MDIO bus drivers > > -libphy-y := phy.o phy-c45.o phy-core.o phy_device.o > +libphy-y := phy.o phy-c45.o phy-core.o phy_device.o \ > + linkmode.o > mdio-bus-y += mdio_bus.o mdio_device.o > > ifdef CONFIG_MDIO_DEVICE > diff --git a/drivers/net/phy/linkmode.c b/drivers/net/phy/linkmode.c > new file mode 100644 > index 000000000000..969918795228 > --- /dev/null > +++ b/drivers/net/phy/linkmode.c > @@ -0,0 +1,44 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +#include > + > +/** > + * linkmode_resolve_pause - resolve the allowable pause modes > + * @local_adv: local advertisement in ethtool format > + * @partner_adv: partner advertisement in ethtool format > + * @tx_pause: pointer to bool to indicate whether transmit pause should be > + * enabled. > + * @rx_pause: pointer to bool to indicate whether receive pause should be > + * enabled. > + * > + * Flow control is resolved according to our and the link partners > + * advertisements using the following drawn from the 802.3 specs: > + * Local device Link partner > + * Pause AsymDir Pause AsymDir Result > + * 0 X 0 X Disabled > + * 0 1 1 0 Disabled > + * 0 1 1 1 TX > + * 1 0 0 X Disabled > + * 1 X 1 X TX+RX > + * 1 1 0 1 RX > + */ > +void linkmode_resolve_pause(const unsigned long *local_adv, > + const unsigned long *partner_adv, > + bool *tx_pause, bool *rx_pause) > +{ > + __ETHTOOL_DECLARE_LINK_MODE_MASK(m); > + > + linkmode_and(m, local_adv, partner_adv); > + if (linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT, m)) { > + *tx_pause = true; > + *rx_pause = true; > + } else if (linkmode_test_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, m)) { > + *tx_pause = linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT, > + partner_adv); > + *rx_pause = linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT, > + local_adv); > + } else { > + *tx_pause = false; > + *rx_pause = false; > + } Hi Russell It took me a while to check this. Maybe it is the way my brain works, but to me, it is not obviously correct. I had to expand the table, and they try all 16 combinations. Maybe a lookup table would be more obvious? However, now i spent the time: Reviewed-by: Andrew Lunn Andrew