From patchwork Mon Dec 6 14:55:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 521549 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 52F0BC433FE for ; Mon, 6 Dec 2021 15:08:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348461AbhLFPL3 (ORCPT ); Mon, 6 Dec 2021 10:11:29 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:58226 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346087AbhLFPIv (ORCPT ); Mon, 6 Dec 2021 10:08:51 -0500 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 AD62C6130A; Mon, 6 Dec 2021 15:05:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95847C341C2; Mon, 6 Dec 2021 15:05:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1638803121; bh=MiuoqTWrq9Db1jYOXtpzds0tLQMjUDZabSMVXfphPyk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VT9BiJbOCvLTlrYLxYIc1rgwxkvtPHVCuFmTsujpGomLS0YNxTuscFb7qcILTujf0 CGu8PYyckqCR0mvsoesmpWncbBPnFxpSl9xqtm/EukTKFm/alJjISoanHd6EqEqgJ0 18UbpsRsoTygoSZTBOAMK+nRR5qz7ABIa56xfaWE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Remi Pommarel , Lorenzo Pieralisi , Thomas Petazzoni , =?utf-8?q?Marek_Beh=C3=BAn?= Subject: [PATCH 4.14 034/106] PCI: aardvark: Wait for endpoint to be ready before training link Date: Mon, 6 Dec 2021 15:55:42 +0100 Message-Id: <20211206145556.541978437@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211206145555.386095297@linuxfoundation.org> References: <20211206145555.386095297@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Remi Pommarel commit f4c7d053d7f77cd5c1a1ba7c7ce085ddba13d1d7 upstream. When configuring pcie reset pin from gpio (e.g. initially set by u-boot) to pcie function this pin goes low for a brief moment asserting the PERST# signal. Thus connected device enters fundamental reset process and link configuration can only begin after a minimal 100ms delay (see [1]). Because the pin configuration comes from the "default" pinctrl it is implicitly configured before the probe callback is called: driver_probe_device() really_probe() ... pinctrl_bind_pins() /* Here pin goes from gpio to PCIE reset function and PERST# is asserted */ ... drv->probe() [1] "PCI Express Base Specification", REV. 4.0 PCI Express, February 19 2014, 6.6.1 Conventional Reset Signed-off-by: Remi Pommarel Signed-off-by: Lorenzo Pieralisi Acked-by: Thomas Petazzoni Signed-off-by: Marek Behún Signed-off-by: Greg Kroah-Hartman --- drivers/pci/host/pci-aardvark.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/drivers/pci/host/pci-aardvark.c +++ b/drivers/pci/host/pci-aardvark.c @@ -362,6 +362,14 @@ static void advk_pcie_setup_hw(struct ad reg |= PIO_CTRL_ADDR_WIN_DISABLE; advk_writel(pcie, reg, PIO_CTRL); + /* + * PERST# signal could have been asserted by pinctrl subsystem before + * probe() callback has been called, making the endpoint going into + * fundamental reset. As required by PCI Express spec a delay for at + * least 100ms after such a reset before link training is needed. + */ + msleep(PCI_PM_D3COLD_WAIT); + /* Start link training */ reg = advk_readl(pcie, PCIE_CORE_LINK_CTRL_STAT_REG); reg |= PCIE_CORE_LINK_TRAINING;