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=-5.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 2D03EC388F9 for ; Fri, 23 Oct 2020 20:33:05 +0000 (UTC) Received: from mail02.groups.io (mail02.groups.io [66.175.222.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C324420BED for ; Fri, 23 Oct 2020 20:33:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=lists.cip-project.org header.i=@lists.cip-project.org header.b="YepPo0g9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C324420BED Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ucw.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=bounce+64572+5671+4520388+8129055@lists.cip-project.org X-Received: by 127.0.0.2 with SMTP id jEAyYY4521723xNc44gdkwz0; Fri, 23 Oct 2020 13:33:03 -0700 X-Received: from jabberwock.ucw.cz (jabberwock.ucw.cz [46.255.230.98]) by mx.groups.io with SMTP id smtpd.web12.2651.1603485180963861388 for ; Fri, 23 Oct 2020 13:33:01 -0700 X-Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id B02FA1C0B81; Fri, 23 Oct 2020 22:32:57 +0200 (CEST) Date: Fri, 23 Oct 2020 22:32:57 +0200 From: "Pavel Machek" To: cip-dev@lists.cip-project.org Cc: Pavel Machek , Nobuhiro Iwamatsu , Biju Das Subject: Re: [cip-dev] [PATCH 4.19.y-cip 1/6] PCI: rcar: Move shareable code to a common file Message-ID: <20201023203257.GA10156@duo.ucw.cz> References: <20201023165805.1910-1-prabhakar.mahadev-lad.rj@bp.renesas.com> <20201023165805.1910-2-prabhakar.mahadev-lad.rj@bp.renesas.com> <20201023194039.GB6002@duo.ucw.cz> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: Bulk List-Unsubscribe: Sender: cip-dev@lists.cip-project.org List-Id: Mailing-List: list cip-dev@lists.cip-project.org; contact cip-dev+owner@lists.cip-project.org Reply-To: cip-dev@lists.cip-project.org X-Gm-Message-State: x6WPVrlfVQlF42LHwVCSrgi0x4520388AA= Content-Type: multipart/mixed; boundary="aOePwXBS97bnMqNS8eyG" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=lists.cip-project.org; q=dns/txt; s=20140610; t=1603485183; bh=iK2X4lEmWbFmwRkuSmEO9qivfzSJO+PL6jcqU+kX//Q=; h=Cc:Content-Type:Date:From:Reply-To:Subject:To; b=YepPo0g9EIdZVlPqLnWa9EFPAOYCo49GFvfiOzQhdN397q2nkU15qbpJJzRY1VrUO2K DSDicLpJP/bLatlUH/8hivh38oYFHfzpC5cP2KBj2KPG+N89MAjzR7AXXkOEPrA2dyBZ8 f9oco2WrChOeScnVDgCxXzyIeqfzhFu4Bj0= --aOePwXBS97bnMqNS8eyG Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="vkogqOf2sHV7VnPd" Content-Disposition: inline --vkogqOf2sHV7VnPd Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > > > +int rcar_pcie_wait_for_dl(struct rcar_pcie *pcie) > > > +{ > > > + unsigned int timeout =3D 10000; > > > + > > > + while (timeout--) { > > > + if ((rcar_pci_read_reg(pcie, PCIETSTR) & DATA_LINK_ACTIVE)) > > > + return 0; > > > + > > > + udelay(5); > > > + cpu_relax(); > > > + } > > > + > > > + return -ETIMEDOUT; > > > +} > >=20 > > This has same problem. Plus, I don't believe cpu_relax() is good idea > > there. Relaxing CPU every 5usec will not change anything. > >=20 > Agreed (as above). wrt cpu_relax() I believe this was added to improve t= he performance of other HW threads. > Yes, but you'd need to call it in a loop. It will be effective if done inside udelay(), but not like this. Best regards, Pavel --=20 DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany --vkogqOf2sHV7VnPd Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABECAB0WIQRPfPO7r0eAhk010v0w5/Bqldv68gUCX5M9+QAKCRAw5/Bqldv6 8r/aAJ9UDlAW7CsiU2saxKBzQLuckTJblACfSSOVvBkUNmIC70dSAebCggqu7xI= =Psd8 -----END PGP SIGNATURE----- --vkogqOf2sHV7VnPd-- --aOePwXBS97bnMqNS8eyG Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline -=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D- Links: You receive all messages sent to this group. View/Reply Online (#5671): https://lists.cip-project.org/g/cip-dev/message= /5671 Mute This Topic: https://lists.cip-project.org/mt/77756293/4520388 Group Owner: cip-dev+owner@lists.cip-project.org Unsubscribe: https://lists.cip-project.org/g/cip-dev/leave/8129055/7279483= 98/xyzzy [cip-dev@archiver.kernel.org] -=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D- --aOePwXBS97bnMqNS8eyG--