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 28459C433EF for ; Wed, 23 Feb 2022 18:32:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236524AbiBWScz (ORCPT ); Wed, 23 Feb 2022 13:32:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38614 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243936AbiBWScd (ORCPT ); Wed, 23 Feb 2022 13:32:33 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DDF79BC36; Wed, 23 Feb 2022 10:32:01 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id 8C635B8212D; Wed, 23 Feb 2022 18:32:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E49CC340E7; Wed, 23 Feb 2022 18:31:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645641119; bh=AkDY5SFZ//EjjzonkJWDtmO5oUw7EK4mfwf5idhETV4=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=rI8es7ID4IB366nvV/gM1u66kvmBnvSnp4QAzayAkT3VHBnUbYrVDFb2UGXUnRLPo 6vNnIBGyYYKQ5qOZseAjxqX5SvSVehoEYSqu4KbzLYFStIACex/PczjatZKLMQRq3O kPWvgI8QHfUo+BK35JPNidrRygOy54DwJFELi3Dol+U7suyeTtljArP7g3Dy6ajOij +eNVkQAAiLV14st+QPFl7dJUkH1K/gAQ4xY7SId/XRPMwUl26Nb7KqtBpi3L58zcub ONtz/OHx9YkURuPD5CORCe745V2Rx60IfuNmEvz/dql9xAc32+4yHlEnLcT1AczoXP L0qGU1LOl2NiQ== Date: Wed, 23 Feb 2022 12:31:57 -0600 From: Bjorn Helgaas To: Richard Zhu Cc: l.stach@pengutronix.de, bhelgaas@google.com, lorenzo.pieralisi@arm.com, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel@pengutronix.de, linux-imx@nxp.com Subject: Re: [PATCH] PCI: imx6: Override the CLKREQ low in the initialization Message-ID: <20220223183157.GA142509@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1645605513-7731-1-git-send-email-hongxing.zhu@nxp.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org In subject, maybe: PCI: imx6: Assert i.MX8MM CLKREQ# even if no device present On Wed, Feb 23, 2022 at 04:38:33PM +0800, Richard Zhu wrote: > The CLKREQ# signal is an open drain, active low signal that is driven > low by the remote Endpoint device. But it might not be driven low if no > Endpoint device is connected. > > On i.MX8MM PCIe, phy_init() would be failed and system boot hang if the > reference clock is not toggled. s/would be failed/may fail/ s/boot hang/boot may hang/ s/if the reference clock is not toggled/if no Endpoint is connected to assert CLKREQ#/ > Follow with i.MX8MQ PCIe, to make sure the reference clock on, override > the CLKREQ# low during initialization to fix this issue. Handle this as on i.MX8MQ, where we explicitly assert CLKREQ# so the PHY can be initialized. (I don't really understand the hardware here, so disregard if this doesn't say what it needs to.) > Fixes: 178e244cb6e2 ("PCI: imx: Add the imx8mm pcie support") > Signed-off-by: Richard Zhu > --- > drivers/pci/controller/dwc/pci-imx6.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c > index d7f0db01f3c3..a334341a1789 100644 > --- a/drivers/pci/controller/dwc/pci-imx6.c > +++ b/drivers/pci/controller/dwc/pci-imx6.c > @@ -447,10 +447,6 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie) > case IMX7D: > break; > case IMX8MM: > - ret = clk_prepare_enable(imx6_pcie->pcie_aux); > - if (ret) > - dev_err(dev, "unable to enable pcie_aux clock\n"); > - break; > case IMX8MQ: > ret = clk_prepare_enable(imx6_pcie->pcie_aux); > if (ret) { > -- > 2.25.1 >