From patchwork Thu Apr 30 08:06:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Pali_Roh=C3=A1r?= X-Patchwork-Id: 1280036 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=default header.b=TtcL8ObD; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49CSfd5xLCz9sSk for ; Thu, 30 Apr 2020 18:07:37 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727115AbgD3IHa (ORCPT ); Thu, 30 Apr 2020 04:07:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:50848 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726871AbgD3IGn (ORCPT ); Thu, 30 Apr 2020 04:06:43 -0400 Received: from pali.im (pali.im [31.31.79.79]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E7E032192A; Thu, 30 Apr 2020 08:06:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588234003; bh=7Q6yx7BAcNGphXyMJ64Hizlmq02sPIkiGXe5IfpE7Z8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TtcL8ObD9ZShKGhTyCFi7x9xii5PxTKPG28YjJWpUDfsSnzJR2XRsB+IuWynuwZ5s FVggj8KBUEpbTwrAOvO0TrscLr5TJOODGSjQ8wfYnUasQD+lssLZCNSAjD00ONAR87 LuwCzjE1oAbDDpLUvris+w/1Bl6QBWsByjAMKaz8= Received: by pali.im (Postfix) id EF9F8AC9; Thu, 30 Apr 2020 10:06:40 +0200 (CEST) From: =?utf-8?q?Pali_Roh=C3=A1r?= To: Jason Cooper , Andrew Lunn , Gregory Clement , Sebastian Hesselbarth , Rob Herring , Thomas Petazzoni , Lorenzo Pieralisi , Andrew Murray , Bjorn Helgaas , Remi Pommarel , =?utf-8?q?Marek_Beh=C3=BAn?= , Tomasz Maciej Nowak , Xogium Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: [PATCH v4 02/12] PCI: aardvark: Don't blindly enable ASPM L0s and don't write to read-only register Date: Thu, 30 Apr 2020 10:06:15 +0200 Message-Id: <20200430080625.26070-3-pali@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200430080625.26070-1-pali@kernel.org> References: <20200430080625.26070-1-pali@kernel.org> MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Trying to change Link Status register does not have any effect as this is a read-only register. Trying to overwrite bits for Negotiated Link Width does not make sense. In future proper change of link width can be done via Lane Count Select bits in PCIe Control 0 register. Trying to unconditionally enable ASPM L0s via ASPM Control bits in Link Control register is wrong. There should be at least some detection if endpoint supports L0s as isn't mandatory. Moreover ASPM Control bits in Link Control register are controlled by pcie/aspm.c code which sets it according to system ASPM settings, immediately after aardvark driver probes. So setting these bits by aardvark driver has no long running effect. Remove code which touches ASPM L0s bits from this driver and let kernel's ASPM implementation to set ASPM state properly. Some users are reporting issues that this code is problematic for some Intel wifi cards and removing it fixes them, see e.g.: https://bugzilla.kernel.org/show_bug.cgi?id=196339 If problems with Intel wifi cards occur even after this commit, then pcie/aspm.c code could be modified / hooked to not enable ASPM L0s state for affected problematic cards. Signed-off-by: Pali Rohár Acked-by: Rob Herring --- drivers/pci/controller/pci-aardvark.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index f9955b494267..74b90940a9d4 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -356,10 +356,6 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie) advk_pcie_wait_for_link(pcie); - reg = PCIE_CORE_LINK_L0S_ENTRY | - (1 << PCIE_CORE_LINK_WIDTH_SHIFT); - advk_writel(pcie, reg, PCIE_CORE_LINK_CTRL_STAT_REG); - reg = advk_readl(pcie, PCIE_CORE_CMD_STATUS_REG); reg |= PCIE_CORE_CMD_MEM_ACCESS_EN | PCIE_CORE_CMD_IO_ACCESS_EN |