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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66E99C43219 for ; Thu, 25 Nov 2021 00:31:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245525AbhKYAeK (ORCPT ); Wed, 24 Nov 2021 19:34:10 -0500 Received: from mail.kernel.org ([198.145.29.99]:46856 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346270AbhKYAbe (ORCPT ); Wed, 24 Nov 2021 19:31:34 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 861DD610D2; Thu, 25 Nov 2021 00:26:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637799998; bh=xwzeY9Vy3Srw4ZX1kVB0laTyjtoJTiriGfKTU1JEH6k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IZFzQDdxxVEoC9MEyg+Y5Z3fRiFJcjAy2S9+EpVZbS+IdDxKqhCnbVCd6fPnzABwV dxNUPbdcGdsqtQnoiLfcIva/YTtUjJwK1Yw0M2xXS40M6lk+gYMUNHYUnOagW+KZuj KOx1L+GOgpDuCq5km8+K93vGV1LOC9sCab2pooApK+dJXoxWYLqeTafNzq+dcWWB14 ZBRFkBP1bTFtcRq6aszJQmhKPjebG66yn++OhcGga+1a8i5sfaZugw7HfLf5G6Uyv5 44Dz3VyAWFoduNjEWFd10aw6YtKh+AcRtxN9qakpjjkF675adZn/H693eQSXWgQ34E w/PNTmRqTmGDw== From: =?UTF-8?q?Marek=20Beh=C3=BAn?= To: Greg Kroah-Hartman , Sasha Levin Cc: pali@kernel.org, stable@vger.kernel.org, Lorenzo Pieralisi , =?UTF-8?q?Marek=20Beh=C3=BAn?= Subject: [PATCH 5.4 10/22] PCI: aardvark: Update comment about disabling link training Date: Thu, 25 Nov 2021 01:26:04 +0100 Message-Id: <20211125002616.31363-11-kabel@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211125002616.31363-1-kabel@kernel.org> References: <20211125002616.31363-1-kabel@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Pali Rohár commit 1d1cd163d0de22a4041a6f1aeabcf78f80076539 upstream. According to PCI Express Base Specifications (rev 4.0, 6.6.1 "Conventional reset"), after fundamental reset a 100ms delay is needed prior to enabling link training. Update comment in code to reflect this requirement. Link: https://lore.kernel.org/r/20201202184659.3795-1-pali@kernel.org Signed-off-by: Pali Rohár Signed-off-by: Lorenzo Pieralisi Signed-off-by: Marek Behún --- drivers/pci/controller/pci-aardvark.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index c96343f0235c..f86466563ad9 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -339,7 +339,14 @@ static void advk_pcie_issue_perst(struct advk_pcie *pcie) if (!pcie->reset_gpio) return; - /* PERST does not work for some cards when link training is enabled */ + /* + * As required by PCI Express spec (PCI Express Base Specification, REV. + * 4.0 PCI Express, February 19 2014, 6.6.1 Conventional Reset) a delay + * for at least 100ms after de-asserting PERST# signal is needed before + * link training is enabled. So ensure that link training is disabled + * prior de-asserting PERST# signal to fulfill that PCI Express spec + * requirement. + */ reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG); reg &= ~LINK_TRAINING_EN; advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG); -- 2.32.0