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=-7.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 8BF1CC43332 for ; Mon, 18 Jan 2021 10:44:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 65792229C7 for ; Mon, 18 Jan 2021 10:44:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389367AbhARKns (ORCPT ); Mon, 18 Jan 2021 05:43:48 -0500 Received: from mail.kernel.org ([198.145.29.99]:34978 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388113AbhARJjs (ORCPT ); Mon, 18 Jan 2021 04:39:48 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9FF6D22240; Mon, 18 Jan 2021 09:38:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610962714; bh=xf7ovFx31ZaLY2y+UGO3bswHVltAepIKbcx0CwbTAEg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UY4vGCbCUKTB+npbtB/jKRlKWTC6P5XvBXcjOoYgiio15MuRseJApjhfxdgJO9ly8 id4SDmLDrClxMcJAbF6VT5xFe/cPOY+oO7BH5Lg+Oc16+gl/ZZAtNkwoZl83Fejm7U W4bYKPeUzLxm+UbDagch3HWUvtgPka8UtA4kQef/lya5Bkd3XoKVxKStZqhR7Q3o/q EERRdPH9sJRmu2Wp1d4ETwDwx216RVqjQ6OIpSncU53tKO+Tn5Kaig314p6aZps9YB bPPRkk6IfFsu3YZjoMHmWZdwkFmtQV1wKg8cwKw/Q3AlqMdt+ZFaN0r2vYxoXpRuug A8594HAduFLHQ== Received: by pali.im (Postfix) id 8B680889; Mon, 18 Jan 2021 10:38:32 +0100 (CET) Date: Mon, 18 Jan 2021 10:38:32 +0100 From: Pali =?utf-8?B?Um9ow6Fy?= To: Russell King - ARM Linux admin Cc: Marek =?utf-8?B?QmVow7pu?= , netdev@vger.kernel.org, Andrew Lunn , Jakub Kicinski , davem@davemloft.net Subject: Re: [PATCH net-next v5 4/5] net: sfp: create/destroy I2C mdiobus before PHY probe/after PHY release Message-ID: <20210118093832.kcbciojnjlcuetb2@pali> References: <20210114044331.5073-1-kabel@kernel.org> <20210114044331.5073-5-kabel@kernel.org> <20210114160719.GV1551@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210114160719.GV1551@shell.armlinux.org.uk> User-Agent: NeoMutt/20180716 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thursday 14 January 2021 16:07:19 Russell King - ARM Linux admin wrote: > On Thu, Jan 14, 2021 at 05:43:30AM +0100, Marek Behún wrote: > > Instead of configuring the I2C mdiobus when SFP driver is probed, > > create/destroy the mdiobus before the PHY is probed for/after it is > > released. > > > > This way we can tell the mdio-i2c code which protocol to use for each > > SFP transceiver. > > I've been thinking a bit more about this. It looks like it will > allocate and free the MDIO bus each time any module is inserted or > removed, even a fiber module that wouldn't ever have a PHY. This adds > unnecessary noise to the kernel message log. > > We only probe for a PHY if one of: > > - id.base.extended_cc is SFF8024_ECC_10GBASE_T_SFI, > SFF8024_ECC_10GBASE_T_SR, SFF8024_ECC_5GBASE_T, or > SFF8024_ECC_2_5GBASE_T. > - id.base.e1000_base_t is set. > > So, we only need the MDIO bus to be registered if one of those is true. > > As you are introducing "enum mdio_i2c_proto", I'm wondering whether > that should include "MDIO_I2C_NONE", and we should only register the > bus and probe for a PHY if it is not MDIO_I2C_NONE. > > Maybe we should have: > > enum mdio_i2c_proto { > MDIO_I2C_NONE, > MDIO_I2C_MARVELL_C22, > MDIO_I2C_C45, > MDIO_I2C_ROLLBALL, > ... > }; > > with: > > sfp->mdio_protocol = MDIO_I2C_NONE; > if (((!memcmp(id.base.vendor_name, "OEM ", 16) || > !memcmp(id.base.vendor_name, "Turris ", 16)) && > (!memcmp(id.base.vendor_pn, "SFP-10G-T ", 16) || > !memcmp(id.base.vendor_pn, "RTSFP-10", 8)))) { > sfp->mdio_protocol = MDIO_I2C_ROLLBALL; > sfp->module_t_wait = T_WAIT_ROLLBALL; > } else { > switch (id.base.extended_cc) { > ... > } > } > > static int sfp_sm_add_mdio_bus(struct sfp *sfp) > { > int err = 0; > > if (sfp->mdio_protocol != MDIO_I2C_NONE) > err = sfp_i2c_mdiobus_create(sfp); > > return err; > } > > called from the place you call sfp_i2c_mdiobus_create(), and > sfp_sm_probe_for_phy() becomes: > > static int sfp_sm_probe_for_phy(struct sfp *sfp) > { > int err = 0; > > switch (sfp->mdio_protocol) { > case MDIO_I2C_NONE: > break; > > case MDIO_I2C_MARVELL_C22: > err = sfp_sm_probe_phy(sfp, SFP_PHY_ADDR, false); > break; > > case MDIO_I2C_C45: > err = sfp_sm_probe_phy(sfp, SFP_PHY_ADDR, true); > break; > > case MDIO_I2C_ROLLBALL: > err = sfp_sm_probe_phy(sfp, SFP_PHY_ADDR_ROLLBALL, true); > break; > } > > return err; > } > > This avoids having to add the PHY address, as well as fudge around with > id.base.extended_cc to get the PHY probed. > > Thoughts? Hello Russell! For me this solution looks more cleaner. As all those MDIO access protocols are vendor dependent, kernel code should not detect them only from the standard (non-vendor) extended_cc property.