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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 29732C433E0 for ; Mon, 8 Feb 2021 15:14:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD40C64E8B for ; Mon, 8 Feb 2021 15:14:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229698AbhBHPOR (ORCPT ); Mon, 8 Feb 2021 10:14:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:56506 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233321AbhBHPLx (ORCPT ); Mon, 8 Feb 2021 10:11:53 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0152264EF1; Mon, 8 Feb 2021 15:08:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612796937; bh=zr67fEzWLuZ0vHNgTkhUhsiy6lnPQycTC6X3B6BIgTw=; h=Date:From:To:Cc:Subject:From; b=KG9DLRMwXqOHMYY+ga1h0Apw2Mn54243THb94HdFenpPUIxwhi/CYbPWji9oSXoMy CRfKw0e2CuCAEyZfjn6AUwtz0y7mWkxh760emTmYcS6ShN2rFS6uZ/e294HCx2blOr v8976cCgrwgaso/01bpWD1JtNEnfc3dFStiDekcj+bemHkDmXQsUtAvIjp0DxAfShv LqkvJHTLUI2xpPW0b4ze0fyJIPL6MjrBAF8n5QN0+QnZmrq0viCgtbbCNJVjIJlc7t KQ1KQ0u0cJ8F/dCfLzQFX8rqxXc37YlJVok+EzAwwlHFq7Jl3xhmQF5quuIee837Kt MfKvRI05aZW5A== Date: Mon, 8 Feb 2021 16:08:52 +0100 From: Marek =?UTF-8?B?QmVow7pu?= To: Thomas Petazzoni Cc: Stefan Roese , Phil Sutter , Mario Six , Pali =?UTF-8?B?Um9ow6Fy?= , Lorenzo Pieralisi , Bjorn Helgaas , linux-pci@vger.kernel.org Subject: pci mvebu issue (memory controller) Message-ID: <20210208160853.5559de99@kernel.org> X-Mailer: Claws Mail 3.17.7 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Hello Thomas, we have enountered an issue with pci-mvebu driver and would like your opinion, since you are the author of commit https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f4ac99011e542d06ea2bda10063502583c6d7991 After upgrading to new version of U-Boot on a Armada XP / 38x device, some WiFi cards stopped working in kernel. Ath10k driver, for example, could not load firmware into the card. We discovered that the issue is caused by U-Boot: - when U-Boot's pci_mvebu driver was converted to driver model API, U-Boot started to configure PCIe registers not only for the newtork adapter, but also for the Marvell Memory Controller (that you are mentioning in your commit). - Since pci-mvebu driver in Linux is ignoring the Marvell Memory Controller device, and U-Boot configures its registers (BARs and what not), after kernel boots, the registers of this device are incompatible with kernel, or something, and this causes problems for the real PCIe device. - Stefan Roese has temporarily solved this issue with U-Boot commit https://gitlab.denx.de/u-boot/custodians/u-boot-marvell/-/commit/6a2fa284aee2981be2c7661b3757ce112de8d528 which basically just masks the Memory Controller's existence. - in Linux commit f4ac99011e54 ("pci: mvebu: no longer fake the slot location of downstream devices") you mention that: * On slot 0, a "Marvell Memory controller", identical on all PCIe interfaces, and which isn't useful when the Marvell SoC is the PCIe root complex (i.e, the normal case when we run Linux on the Marvell SoC). What we are wondering is: - what does the Marvell Memory controller really do? Can it be used to configure something? It clearly does something, because if it is configured in U-Boot somehow but not in kernel, problems can occur. - is the best solution really just to ignore this device? - should U-Boot also start doing what commit f4ac99011e54 does? I.e. to make sure that the real device is in slot 0, and Marvell Memory Controller in slot 1. - why is Linux ignoring this device? It isn't even listed in lspci output. Thanks, Marek