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 X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9CDAECE58E for ; Tue, 15 Oct 2019 09:54:13 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 87E0F21835 for ; Tue, 15 Oct 2019 09:54:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="elfeXP+b" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 87E0F21835 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=yQ7WCTWTNNEEZGxtGAaYgXIkHgvtXMc9PsOgH6NvKQI=; b=elfeXP+bF9Wdst ws6hYhtC20FQTt0o96ASazPHLVp7cc+1qXpcFoIYAJLZigIgJtBD8lvFPpVYMOtQwTd2nTlMVP8ym 7if9mU/qp5BEGBfds7OxgpMuM03R2qBtKzlHH+xBBpLurq5koHkRIYMRMNQfqH69bnFC73+ckmdDZ yUmLnFx34EzmOd0nLpoM1wsef7sSEOQTfxuJXz1tc9bflAgAt33VzfjoTu8Etql6x44azp98KA3rV kryPZNyIxlmI4UUliv9lpn6b7lVXZF3raNB9vQe8A0SLpBgXu3skmZpG37PUj5juLSTf7jpSSjnD8 /9boW++mLlKKkpARM6/g==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iKJWq-0008Ka-4j; Tue, 15 Oct 2019 09:54:08 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iKJWn-0008Ju-Bz for linux-arm-kernel@lists.infradead.org; Tue, 15 Oct 2019 09:54:06 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8074C28; Tue, 15 Oct 2019 02:54:04 -0700 (PDT) Received: from e121166-lin.cambridge.arm.com (unknown [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7C2BD3F68E; Tue, 15 Oct 2019 02:54:03 -0700 (PDT) Date: Tue, 15 Oct 2019 10:53:58 +0100 From: Lorenzo Pieralisi To: Remi Pommarel Subject: Re: [PATCH v2] PCI: aardvark: Wait for endpoint to be ready before training link Message-ID: <20191015095358.GA32431@e121166-lin.cambridge.arm.com> References: <20190522213351.21366-2-repk@triplefau.lt> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190522213351.21366-2-repk@triplefau.lt> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191015_025405_448050_49895128 X-CRM114-Status: GOOD ( 17.21 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ellie Reeves , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Bjorn Helgaas , Thomas Petazzoni , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, May 22, 2019 at 11:33:50PM +0200, Remi Pommarel wrote: > 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 > --- > Changes since v1: > - Add a comment about pinctrl implicit pin configuration > - Use more legible msleep > - Use PCI_PM_D3COLD_WAIT macro > > Please note that I will unlikely be able to answer any comments from May > 24th to June 10th. > --- > drivers/pci/controller/pci-aardvark.c | 8 ++++++++ > 1 file changed, 8 insertions(+) Applied to pci/aardvark, thanks. Lorenzo > diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c > index 134e0306ff00..d998c2b9cd04 100644 > --- a/drivers/pci/controller/pci-aardvark.c > +++ b/drivers/pci/controller/pci-aardvark.c > @@ -324,6 +324,14 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie) > 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; > -- > 2.20.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel