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 BD0DAC43217 for ; Wed, 24 Nov 2021 22:50:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352193AbhKXWxT (ORCPT ); Wed, 24 Nov 2021 17:53:19 -0500 Received: from mail.kernel.org ([198.145.29.99]:47290 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352221AbhKXWxT (ORCPT ); Wed, 24 Nov 2021 17:53:19 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id A275F610A5; Wed, 24 Nov 2021 22:50:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637794208; bh=wy1zps5hF1c24DdsmUQj9vuQDJ/Tz0BODYkKPOpHmWA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WBGYV7nqo0lMe9h7rj0ZK38T6vgeU9s0P6yFEgHtPnYkUXygijmq6/WJTB/wPe2ID Hf78ntL6KOCuxj7x1wUony7ZE5ThwalcbwhUqz6eJxohH3vpvEC2n0D6Pu+KXFzAch xSQ+kWxaT4t452bXxlYNQTZWFn4jEp02Ej5BStQ5I/7i9Z37kBy5/LdhCGh16HtReh f9s/5vraL2vUwIGj068o/0VVHLxk2We9o7NfbOWyfQWwk9bdyJdEZ4kb5CfPMtKTM1 hAROsZP3k0v/1meMWl/iSMSzhYMlM1lbcm8h/Ppav2XRTr0SZlRl5CHAXlDs9yp+lQ f8V637o5kNWtg== 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 4.14 13/24] PCI: aardvark: Update comment about disabling link training Date: Wed, 24 Nov 2021 23:49:22 +0100 Message-Id: <20211124224933.24275-14-kabel@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211124224933.24275-1-kabel@kernel.org> References: <20211124224933.24275-1-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/host/pci-aardvark.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/pci/host/pci-aardvark.c b/drivers/pci/host/pci-aardvark.c index 68ab3aef0e12..66c4b9282420 100644 --- a/drivers/pci/host/pci-aardvark.c +++ b/drivers/pci/host/pci-aardvark.c @@ -275,7 +275,14 @@ 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