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=-8.3 required=3.0 tests=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 06A75C3A5A9 for ; Mon, 4 May 2020 09:10:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF50D2054F for ; Mon, 4 May 2020 09:10:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728215AbgEDJKs (ORCPT ); Mon, 4 May 2020 05:10:48 -0400 Received: from mx2.suse.de ([195.135.220.15]:38692 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726467AbgEDJKr (ORCPT ); Mon, 4 May 2020 05:10:47 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id D8EDFAC7D; Mon, 4 May 2020 09:10:46 +0000 (UTC) Received: by lion.mk-sys.cz (Postfix, from userid 1000) id 43276604EE; Mon, 4 May 2020 11:10:44 +0200 (CEST) Date: Mon, 4 May 2020 11:10:44 +0200 From: Michal Kubecek To: netdev@vger.kernel.org Cc: Oleksij Rempel , Andrew Lunn , "David S. Miller" , Florian Fainelli , Heiner Kallweit , Jakub Kicinski , Jonathan Corbet , David Jander , kernel@pengutronix.de, linux-kernel@vger.kernel.org, Russell King , mkl@pengutronix.de, Marek Vasut , Christian Herber Subject: Re: [PATCH v5 1/2] ethtool: provide UAPI for PHY master/slave configuration. Message-ID: <20200504091044.GA8237@lion.mk-sys.cz> References: <20200504071214.5890-1-o.rempel@pengutronix.de> <20200504071214.5890-2-o.rempel@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200504071214.5890-2-o.rempel@pengutronix.de> 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 Mon, May 04, 2020 at 09:12:13AM +0200, Oleksij Rempel wrote: > This UAPI is needed for BroadR-Reach 100BASE-T1 devices. Due to lack of > auto-negotiation support, we needed to be able to configure the > MASTER-SLAVE role of the port manually or from an application in user > space. > > The same UAPI can be used for 1000BASE-T or MultiGBASE-T devices to > force MASTER or SLAVE role. See IEEE 802.3-2018: > 22.2.4.3.7 MASTER-SLAVE control register (Register 9) > 22.2.4.3.8 MASTER-SLAVE status register (Register 10) > 40.5.2 MASTER-SLAVE configuration resolution > 45.2.1.185.1 MASTER-SLAVE config value (1.2100.14) > 45.2.7.10 MultiGBASE-T AN control 1 register (Register 7.32) > > The MASTER-SLAVE role affects the clock configuration: > > ------------------------------------------------------------------------------- > When the PHY is configured as MASTER, the PMA Transmit function shall > source TX_TCLK from a local clock source. When configured as SLAVE, the > PMA Transmit function shall source TX_TCLK from the clock recovered from > data stream provided by MASTER. > > iMX6Q KSZ9031 XXX > ------\ /-----------\ /------------\ > | | | | | > MAC |<----RGMII----->| PHY Slave |<------>| PHY Master | > |<--- 125 MHz ---+-<------/ | | \ | > ------/ \-----------/ \------------/ > ^ > \-TX_TCLK > > ------------------------------------------------------------------------------- > > Since some clock or link related issues are only reproducible in a > specific MASTER-SLAVE-role, MAC and PHY configuration, it is beneficial > to provide generic (not 100BASE-T1 specific) interface to the user space > for configuration flexibility and trouble shooting. > > Signed-off-by: Oleksij Rempel > --- > diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c > index ac2784192472f..42dda9d2082ee 100644 > --- a/drivers/net/phy/phy_device.c > +++ b/drivers/net/phy/phy_device.c > @@ -1768,6 +1768,90 @@ int genphy_setup_forced(struct phy_device *phydev) > } > EXPORT_SYMBOL(genphy_setup_forced); > > +static int genphy_setup_master_slave(struct phy_device *phydev) > +{ > + u16 ctl = 0; > + > + if (!phydev->is_gigabit_capable) > + return 0; Why did you revert to silently ignoring requests in this case? On the other hand, we might rather want to do a more generic check which would handle all drivers not supporting the feature, see below. [...] > @@ -287,14 +308,37 @@ static bool ethnl_auto_linkmodes(struct ethtool_link_ksettings *ksettings, > __ETHTOOL_LINK_MODE_MASK_NBITS); > } > > +static int ethnl_validate_master_slave_cfg(u8 cfg) > +{ > + switch (cfg) { > + case MASTER_SLAVE_CFG_MASTER_PREFERRED: > + case MASTER_SLAVE_CFG_SLAVE_PREFERRED: > + case MASTER_SLAVE_CFG_MASTER_FORCE: > + case MASTER_SLAVE_CFG_SLAVE_FORCE: > + return 1; > + } > + > + return 0; > +} Nitpick: bool would be more appropriate as return value. > + > static int ethnl_update_linkmodes(struct genl_info *info, struct nlattr **tb, > struct ethtool_link_ksettings *ksettings, > bool *mod) > { > struct ethtool_link_settings *lsettings = &ksettings->base; > bool req_speed, req_duplex; > + const struct nlattr *master_slave_cfg; > int ret; > > + master_slave_cfg = tb[ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG]; > + if (master_slave_cfg) { > + u8 cfg = nla_get_u8(master_slave_cfg); > + if (!ethnl_validate_master_slave_cfg(cfg)) { > + GENL_SET_ERR_MSG(info, "LINKMODES_MASTER_SLAVE_CFG contains not valid value"); > + return -EOPNOTSUPP; > + } > + } Please set also the "bad attribute" in extack, it may help non-interactive clients. Also, it would be nice to report error if client wants to set master/slave but driver does not support it. How about this? if (master_slave_cfg) { u8 cfg = nla_get_u8(master_slave_cfg); if (lsettings->master_slave_cfg == MASTER_SLAVE_CFG_UNSUPPORTED) { NL_SET_ERR_MSG_ATTR(info->extack, master_slave_cfg, "master/slave configuration not supported by device"); return -EOPNOTSUPP; } if (!ethnl_validate_master_slave_cfg(cfg)) { NL_SET_ERR_MSG_ATTR(info->extack, master_slave_cfg, "master/slave value is invalid"); return -EOPNOTSUPP; } } Do you plan to allow handling master/slave also via ioctl()? If yes, we should also add the sanity checks to ioctl code path. If not, we should prevent passing non-zero values from userspace to driver. Other than this, the patch looks good to me. Michal > *mod = false; > req_speed = tb[ETHTOOL_A_LINKMODES_SPEED]; > req_duplex = tb[ETHTOOL_A_LINKMODES_DUPLEX]; > @@ -311,6 +355,7 @@ static int ethnl_update_linkmodes(struct genl_info *info, struct nlattr **tb, > mod); > ethnl_update_u8(&lsettings->duplex, tb[ETHTOOL_A_LINKMODES_DUPLEX], > mod); > + ethnl_update_u8(&lsettings->master_slave_cfg, master_slave_cfg, mod); > > if (!tb[ETHTOOL_A_LINKMODES_OURS] && lsettings->autoneg && > (req_speed || req_duplex) && > -- > 2.26.2 >