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=unavailable 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 4FDB8C433E0 for ; Mon, 25 May 2020 22:01:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2A8202071C for ; Mon, 25 May 2020 22:01:41 +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="iDCzlo91" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731384AbgEYWBh (ORCPT ); Mon, 25 May 2020 18:01:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33660 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726937AbgEYWBh (ORCPT ); Mon, 25 May 2020 18:01:37 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:3201:214:fdff:fe10:1be6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28DE0C061A0E; Mon, 25 May 2020 15:01:36 -0700 (PDT) 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=ZtM3sWNpPRIGai+yzN8mIIMz8cMvbCBA40vpGmubNyA=; b=iDCzlo91sx+/jAahLcRYfiRNl rG0a0LK7ANWpwKYgNvF15pRy+zSPT1EHazoZaptKo8/CSEVULht5VhnLe4iEe3LsteoQAFurcOqeT 4MR49l9wT4mizG2fw2wKM4yBIP0KxqlSgcUsnzjE2ltb5k29Lsf3yrlXFi9kwubqLoji+8OiisgKb EBixS5ZCbKDyPFLqqUoL7h4V0ea40WfJHT6d94RE6EecrvIH2QZlfrpkhBCN5Kp8SihObVkR/2U1B rhS+8P2PqTzq9zV46i4scx4Kr0N2fUJvmBT+XHWJCJrDpJNrMPjI+JbN8cI8YDr/QLlkC2Ymphs7F rhNjxE1hQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:36944) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jdLA1-000670-8F; Mon, 25 May 2020 23:01:29 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1jdL9z-0004hu-Et; Mon, 25 May 2020 23:01:27 +0100 Date: Mon, 25 May 2020 23:01:27 +0100 From: Russell King - ARM Linux admin To: Jeremy Linton Cc: netdev@vger.kernel.org, davem@davemloft.net, andrew@lunn.ch, f.fainelli@gmail.com, hkallweit1@gmail.com, madalin.bucur@oss.nxp.com, calvin.johnson@oss.nxp.com, linux-kernel@vger.kernel.org Subject: Re: [RFC 04/11] net: phy: Handle c22 regs presence better Message-ID: <20200525220127.GO1551@shell.armlinux.org.uk> References: <20200522213059.1535892-1-jeremy.linton@arm.com> <20200522213059.1535892-5-jeremy.linton@arm.com> <20200523183731.GZ1551@shell.armlinux.org.uk> <20200525100612.GM1551@shell.armlinux.org.uk> <63ca13e3-11ea-3ddf-e1c7-90597d4a5f8c@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <63ca13e3-11ea-3ddf-e1c7-90597d4a5f8c@arm.com> 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 Mon, May 25, 2020 at 04:51:16PM -0500, Jeremy Linton wrote: > Hi, > > On 5/25/20 5:06 AM, Russell King - ARM Linux admin wrote: > > On Sun, May 24, 2020 at 10:34:13PM -0500, Jeremy Linton wrote: > > > Hi, > > > > > > On 5/23/20 1:37 PM, Russell King - ARM Linux admin wrote: > > > > On Fri, May 22, 2020 at 04:30:52PM -0500, Jeremy Linton wrote: > > > > > Until this point, we have been sanitizing the c22 > > > > > regs presence bit out of all the MMD device lists. > > > > > This is incorrect as it causes the 0xFFFFFFFF checks > > > > > to incorrectly fail. Further, it turns out that we > > > > > want to utilize this flag to make a determination that > > > > > there is actually a phy at this location and we should > > > > > be accessing it using c22. > > > > > > > > > > Signed-off-by: Jeremy Linton > > > > > --- > > > > > drivers/net/phy/phy_device.c | 16 +++++++++++++--- > > > > > 1 file changed, 13 insertions(+), 3 deletions(-) > > > > > > > > > > diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c > > > > > index f0761fa5e40b..2d677490ecab 100644 > > > > > --- a/drivers/net/phy/phy_device.c > > > > > +++ b/drivers/net/phy/phy_device.c > > > > > @@ -689,9 +689,6 @@ static int get_phy_c45_devs_in_pkg(struct mii_bus *bus, int addr, int dev_addr, > > > > > return -EIO; > > > > > *devices_in_package |= phy_reg; > > > > > - /* Bit 0 doesn't represent a device, it indicates c22 regs presence */ > > > > > - *devices_in_package &= ~BIT(0); > > > > > - > > > > > return 0; > > > > > } > > > > > @@ -742,6 +739,8 @@ static int get_phy_c45_ids(struct mii_bus *bus, int addr, u32 *phy_id, > > > > > int i; > > > > > const int num_ids = ARRAY_SIZE(c45_ids->device_ids); > > > > > u32 *devs = &c45_ids->devices_in_package; > > > > > + bool c22_present = false; > > > > > + bool valid_id = false; > > > > > /* Find first non-zero Devices In package. Device zero is reserved > > > > > * for 802.3 c45 complied PHYs, so don't probe it at first. > > > > > @@ -770,6 +769,10 @@ static int get_phy_c45_ids(struct mii_bus *bus, int addr, u32 *phy_id, > > > > > return 0; > > > > > } > > > > > + /* Bit 0 doesn't represent a device, it indicates c22 regs presence */ > > > > > + c22_present = *devs & BIT(0); > > > > > + *devs &= ~BIT(0); > > > > > + > > > > > /* Now probe Device Identifiers for each device present. */ > > > > > for (i = 1; i < num_ids; i++) { > > > > > if (!(c45_ids->devices_in_package & (1 << i))) > > > > > @@ -778,6 +781,13 @@ static int get_phy_c45_ids(struct mii_bus *bus, int addr, u32 *phy_id, > > > > > ret = _get_phy_id(bus, addr, i, &c45_ids->device_ids[i], true); > > > > > if (ret < 0) > > > > > return ret; > > > > > + if (valid_phy_id(c45_ids->device_ids[i])) > > > > > + valid_id = true; > > > > > > > > Here you are using your "devices in package" validator to validate the > > > > PHY ID value. One of the things it does is mask this value with > > > > 0x1fffffff. That means you lose some of the vendor OUI. To me, this > > > > looks completely wrong. > > > > > > I think in this case I was just using it like the comment in > > > get_phy_device() "if the phy_id is mostly F's, there is no device here". > > > > > > My understanding is that the code is trying to avoid the 0xFFFFFFFF returns > > > that seem to indicate "bus ok, phy didn't respond". > > > > > > I just checked the OUI registration, and while there are a couple OUI's > > > registered that have a number of FFF's in them, none of those cases seems to > > > overlap sufficiently to cause this to throw them out. Plus a phy would also > > > have to have model+revision set to 'F's. So while might be possible, if > > > unlikely, at the moment I think the OUI registration keeps this from being a > > > problem. Particularly, if i'm reading the mapping correctly, the OUI mapping > > > guarantees that the field cannot be all '1's due to the OUI having X & M > > > bits cleared. It sort of looks like the mapping is trying to lose those > > > bits, by tossing bit 1 & 2, but the X & M are in the wrong octet (AFAIK, I > > > just read it three times cause it didn't make any sense). > > > > I should also note that we have at least one supported PHY where one > > of the MMDs returns 0xfffe for even numbered registers and 0x0000 for > > odd numbered registers in one of the vendor MMDs for addresses 0 > > through 0xefff - which has a bit set in the devices-in-package. > > > > It also returns 0x0082 for almost every register in MMD 2, but MMD 2's > > devices-in-package bit is clear in most of the valid MMDs, so we > > shouldn't touch it. > > > > These reveal the problem of randomly probing MMDs - they can return > > unexpected values and not be as well behaved as we would like them to > > be. Using register 8 to detect presence may be beneficial, but that > > may also introduce problems as we haven't used that before (and we > > don't know whether any PHY that wrong.) I know at least the 88x3310 > > gets it right for all except the vendor MMDs, where the low addresses > > appear non-confromant to the 802.3 specs. Both vendor MMDs are > > definitely implemented, just not with anything conforming to 802.3. > > Yes, we know even for the NXP reference hardware, one of the phy's doesn't > probe out correctly because it doesn't respond to the ieee defined > registers. I think at this point, there really isn't anything we can do > about that unless we involve the (ACPI) firmware in currently nonstandard > behaviors. > > So, my goals here have been to first, not break anything, and then do a > slightly better job finding phy's that are (mostly?) responding correctly to > the 802.3 spec. So we can say "if you hardware is ACPI conformant, and you > have IEEE conformant phy's you should be ok". So, for your example phy, I > guess the immediate answer is "use DT" or "find a conformant phy", or even > "abstract it in the firmware and use a mailbox interface". You haven't understood. The PHY does conform for most of the MMDs, but there are a number that do not conform. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC for 0.8m (est. 1762m) line in suburbia: sync at 13.1Mbps down 424kbps up