From patchwork Mon Jan 10 01:50:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Marek_Beh=C3=BAn?= X-Patchwork-Id: 12708091 X-Patchwork-Delegate: lorenzo.pieralisi@arm.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3894AC433EF for ; Mon, 10 Jan 2022 01:51:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238011AbiAJBvO (ORCPT ); Sun, 9 Jan 2022 20:51:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238026AbiAJBvK (ORCPT ); Sun, 9 Jan 2022 20:51:10 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0999DC061748 for ; Sun, 9 Jan 2022 17:51:10 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9507C60DC9 for ; Mon, 10 Jan 2022 01:51:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D275C36AEF; Mon, 10 Jan 2022 01:51:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1641779468; bh=KV7Ev/+vKumsneQrWXEMHP1+QXgo9I55XQRdzbJR9Gk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tDGmslbciBZK6YBatPSCm3gqZ8oIsGRAJEJ5UULGjU3QWMMzKwuxck6B1FvIw8Of5 wHnrYdEh27ejd71+mbElkc4uUfixv2n5wPzQe3M5av2SnpqsHMGTlSIMj6UALbS9Sb UnSCyn++6a8dh+5zLjPKw/eLxQWkqgGDRsUB4wktpA1DTQhKzZtLAYP0X+7hRsqrUT ajq616PqL/2eKD3axZKupsT5XHgJ6bPOJCb39Bm+1mAKl1mOxvGHrLkWtox8ZpwvYK l0OeASi+WSbrYHcUgjSehS9ZbfbAeCQ7z3Ut7MbQ68jv6S6o1WdB/+BrNtsWq2R2y1 ynJ2jXJDWElXw== From: =?utf-8?q?Marek_Beh=C3=BAn?= To: Marc Zyngier , Lorenzo Pieralisi , Bjorn Helgaas Cc: pali@kernel.org, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, =?utf-8?q?Marek_Beh=C3=BAn?= Subject: [PATCH v2 22/23] PCI: aardvark: Update comment about link going down after link-up Date: Mon, 10 Jan 2022 02:50:17 +0100 Message-Id: <20220110015018.26359-23-kabel@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220110015018.26359-1-kabel@kernel.org> References: <20220110015018.26359-1-kabel@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Update the comment about what happens when link goes down after we have checked for link-up. If a PIO request is done while link-down, we have a serious problem. Signed-off-by: Marek Behún --- drivers/pci/controller/pci-aardvark.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index 360e2e3b3aa6..2c5cc929b94f 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -1007,8 +1007,12 @@ static bool advk_pcie_valid_device(struct advk_pcie *pcie, struct pci_bus *bus, return false; /* - * If the link goes down after we check for link-up, nothing bad - * happens but the config access times out. + * If the link goes down after we check for link-up, we have a problem: + * if a PIO request is executed while link-down, the whole controller + * gets stuck in a non-functional state, and even after link comes up + * again, PIO requests won't work anymore, and a reset of the whole PCIe + * controller is needed. Therefore we need to prevent sending PIO + * requests while the link is down. */ if (!pci_is_root_bus(bus) && !advk_pcie_link_up(pcie)) return false;