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=-8.1 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,USER_AGENT_SANE_1 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 DCC97C0044D for ; Mon, 16 Mar 2020 09:12:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8DD3520663 for ; Mon, 16 Mar 2020 09:12:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="XpfltrYj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730280AbgCPJMV (ORCPT ); Mon, 16 Mar 2020 05:12:21 -0400 Received: from pandora.armlinux.org.uk ([78.32.30.218]:48278 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730076AbgCPJMV (ORCPT ); Mon, 16 Mar 2020 05:12:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: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=0cMCib0i4x5DglbDKqSEEANoz7bkgkVr0BxGXGd1PLo=; b=XpfltrYjsibMAdkZpJcHWHgrY 3UAvseg3hAlxC5Qqguzj6CQ/ctv1hpwQI0j4NaWs4kaiadfwop2lq29vVLti03hKrZGsMpNW8gtBs rtAZutYtZyBDQWIwpLBarWzEDcklNUaeUETkTZEv+pirKhE8x6dnvFM9zorN2XvI2tFqY5LENULyj 8vFVGBtyRNg7w/JXfdNkRBoFLlq1tehpuGorDciIvAd1Dw9JqQVQK1QHu2STskuii4dp/vGM51jmN LRgZjDEDJ5XmjjlDxRzZN9jYQzXtYLmKxH1PBItANFc00irljt3Fv8iY5ZPl9n4iSGi+7QkyDd4uA gZGoRS0Lg==; Received: from shell.armlinux.org.uk ([2002:4e20:1eda:1:5054:ff:fe00:4ec]:33002) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jDln8-0008Vi-0b; Mon, 16 Mar 2020 09:12:10 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1jDln5-0001hn-LP; Mon, 16 Mar 2020 09:12:07 +0000 Date: Mon, 16 Mar 2020 09:12:07 +0000 From: Russell King - ARM Linux admin To: Andrew Lunn Cc: Florian Fainelli , Heiner Kallweit , "David S. Miller" , netdev@vger.kernel.org Subject: Re: [PATCH net-next 1/3] net: mdiobus: add APIs for modifying a MDIO device register Message-ID: <20200316091207.GM25745@shell.armlinux.org.uk> References: <20200314103102.GJ25745@shell.armlinux.org.uk> <20200314215728.GG8622@lunn.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200314215728.GG8622@lunn.ch> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sat, Mar 14, 2020 at 10:57:28PM +0100, Andrew Lunn wrote: > On Sat, Mar 14, 2020 at 10:31:24AM +0000, Russell King wrote: > > Add APIs for modifying a MDIO device register, similar to the existing > > phy_modify() group of functions, but at mdiobus level instead. Adapt > > __phy_modify_changed() to use the new mdiobus level helper. > > > > Signed-off-by: Russell King > > --- > > drivers/net/phy/mdio_bus.c | 55 ++++++++++++++++++++++++++++++++++++++ > > drivers/net/phy/phy-core.c | 31 --------------------- > > include/linux/mdio.h | 4 +++ > > include/linux/phy.h | 19 +++++++++++++ > > 4 files changed, 78 insertions(+), 31 deletions(-) > > > > diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c > > index 3ab9ca7614d1..b33d1e793686 100644 > > --- a/drivers/net/phy/mdio_bus.c > > +++ b/drivers/net/phy/mdio_bus.c > > @@ -824,6 +824,38 @@ int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val) > > } > > EXPORT_SYMBOL(__mdiobus_write); > > > > +/** > > + * __mdiobus_modify_changed - Unlocked version of the mdiobus_modify function > > + * @bus: the mii_bus struct > > + * @addr: the phy address > > + * @regnum: register number to modify > > + * @mask: bit mask of bits to clear > > + * @set: bit mask of bits to set > > + * > > + * Read, modify, and if any change, write the register value back to the > > + * device. Any error returns a negative number. > > + * > > + * NOTE: MUST NOT be called from interrupt context. > > + */ > > +int __mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum, > > + u16 mask, u16 set) > > +{ > > + int new, ret; > > + > > + ret = __mdiobus_read(bus, addr, regnum); > > + if (ret < 0) > > + return ret; > > + > > + new = (ret & ~mask) | set; > > + if (new == ret) > > + return 0; > > + > > + ret = __mdiobus_write(bus, addr, regnum, new); > > + > > + return ret < 0 ? ret : 1; > > +} > > +EXPORT_SYMBOL_GPL(__mdiobus_modify_changed); > > + > > /** > > * mdiobus_read_nested - Nested version of the mdiobus_read function > > * @bus: the mii_bus struct > > @@ -928,6 +960,29 @@ int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val) > > } > > EXPORT_SYMBOL(mdiobus_write); > > > > +/** > > + * mdiobus_modify - Convenience function for modifying a given mdio device > > + * register > > + * @bus: the mii_bus struct > > + * @addr: the phy address > > + * @regnum: register number to write > > + * @mask: bit mask of bits to clear > > + * @set: bit mask of bits to set > > + */ > > +int mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask, u16 set) > > +{ > > + int err; > > + > > + BUG_ON(in_interrupt()); > > Hi Russell > > There seems to be growing push back on using BUG_ON and its > variants. If should only be used if the system is so badly messed up, > going further would only cause more damage. What really happens here > if it is called in interrupt context? The mutex lock probably won't > work, and we might corrupt the state of the PCS. That is not the end > of the world. So i would suggest a WARN_ON here. Do we even need these checks? (phylib has them scattered throughout on the bus accessors.) Aren't the might_sleep() checks that are already in the locking functions already sufficient? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 10.2Mbps down 587kbps up