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[73.241.114.122]) by smtp.gmail.com with ESMTPSA id q8sm16955436pfs.161.2020.03.01.04.22.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 01 Mar 2020 04:22:13 -0800 (PST) Date: Sun, 1 Mar 2020 04:22:11 -0800 From: Richard Cochran To: Michael Walle Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Andrew Lunn , Florian Fainelli , Heiner Kallweit , Russell King , "David S . Miller" Subject: Re: [RFC PATCH v2 2/2] net: phy: at803x: add PTP support for AR8031 Message-ID: <20200301122211.GA32253@localhost> References: <20200228180226.22986-1-michael@walle.cc> <20200228180226.22986-3-michael@walle.cc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200228180226.22986-3-michael@walle.cc> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 28, 2020 at 07:02:26PM +0100, Michael Walle wrote: > +static int at8031_rtc_adjust(struct phy_device *phydev, s64 delta) > +{ > + struct timespec64 ts = ns_to_timespec64(delta); > + int ret; Here the 'ts' is written in multiple steps, > + ret = phy_write_mmd(phydev, MDIO_MMD_PCS, > + AT8031_MMD3_RTC_OFFSET_SEC_2, > + (ts.tv_sec >> 32) & 0xffff); > + if (ret) > + return ret; > + > + ret = phy_write_mmd(phydev, MDIO_MMD_PCS, > + AT8031_MMD3_RTC_OFFSET_SEC_1, > + (ts.tv_sec >> 16) & 0xffff); > + if (ret) > + return ret; > + > + ret = phy_write_mmd(phydev, MDIO_MMD_PCS, > + AT8031_MMD3_RTC_OFFSET_SEC_0, > + ts.tv_sec & 0xffff); > + if (ret) > + return ret; > + > + ret = phy_write_mmd(phydev, MDIO_MMD_PCS, > + AT8031_MMD3_RTC_OFFSET_NSEC_1, > + (ts.tv_nsec >> 16) & 0xffff); > + if (ret) > + return ret; > + > + ret = phy_write_mmd(phydev, MDIO_MMD_PCS, > + AT8031_MMD3_RTC_OFFSET_NSEC_0, > + ts.tv_nsec & 0xffff); > + if (ret) > + return ret; > + > + return phy_write_mmd(phydev, MDIO_MMD_PCS, AT8031_MMD3_RTC_ADJUST, > + AT8031_RTC_ADJUST); > +} ... > +static int at8031_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta) > +{ > + struct at803x_priv *priv = > + container_of(ptp, struct at803x_priv, ptp_info); > + struct phy_device *phydev = priv->phydev; > + > + return at8031_rtc_adjust(phydev, delta); > +} ... and here there is no locking. You would need a mutex here and elsewhere to prevent multiple readers/writers from accessing the device registers asynchronously. (I know this is a just a RFC and that there are bigger problems with the HW, but just saying.) Thanks, Richard