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=-5.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 0BC1BC282CA for ; Wed, 13 Feb 2019 17:46:23 +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 D6ACB222B1 for ; Wed, 13 Feb 2019 17:46:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Vzay73LC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D6ACB222B1 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-riscv-bounces+infradead-linux-riscv=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=qkOc3ZtO3Ri3hPO2CjfOmIZlEOOu+ZVxXO5BuyIkHtM=; b=Vzay73LC4Ifapj q0FmFzlFqU6vdJ9gUyfFRCY07DO8L96A4Q0oyPbUh6uqu3mDG4kDdSg8BrWaSj4fIxV+E8w4TL/V9 yYNl9dFdJv09kLhwJtdc5N4UkTHA3xZGeTguhKEMpLIqmyRfMh9Uj3/L1sdWO6lGKr5e9EidMps5x 9Q9WFOsnFA2tyXz4McqL3h2yt1EWMPtk3sI+Areb+fDDthK7GdXWRvalLClyLGoMnHuwASEB8mO3Z 220xsS4y2kqZ5wiw1T3dQhXCO2wzQSKkiIoW9I/MhZJXp1s4QxVKCmkTOx4vNaISmd+PYJTCQ2GdC OpOaFfrM+oUQo7rgEfYg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gtyc1-0006Xs-MS; Wed, 13 Feb 2019 17:46:21 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gtybz-0006XR-6i for linux-riscv@lists.infradead.org; Wed, 13 Feb 2019 17:46:20 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CCBFFA78; Wed, 13 Feb 2019 09:46:18 -0800 (PST) Received: from fuggles.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 522783F675; Wed, 13 Feb 2019 09:46:17 -0800 (PST) Date: Wed, 13 Feb 2019 17:46:08 +0000 From: Will Deacon To: Arnd Bergmann Subject: Re: [PATCH 1/2] asm-generic/io: Pass result on inX() accessor to __io_par() Message-ID: <20190213174608.GA29100@fuggles.cambridge.arm.com> References: <20190211174544.4302-1-will.deacon@arm.com> <20190211174544.4302-2-will.deacon@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.1+86 (6f28e57d73f2) () X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190213_094619_249415_CA455A84 X-CRM114-Status: GOOD ( 19.82 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch , Albert Ou , Catalin Marinas , Palmer Dabbelt , Linux Kernel Mailing List , andrew.murray@arm.com, linux-riscv@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+infradead-linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, Feb 12, 2019 at 12:55:17PM +0100, Arnd Bergmann wrote: > On Mon, Feb 11, 2019 at 6:45 PM Will Deacon wrote: > > > > The inX() I/O accessors must enforce ordering against subsequent calls > > to the delay() routines, so that a read-back from a device can be used > > to postpone a subsequent write to the same device. > > > > On some architectures, including arm64, this ordering can only be > > achieved by creating a dependency on the value returned by the inX() > > operation, so we need to pass the value we read to the __io_par() > > macro in this case. > > > > Reported-by: Andrew Murray > > Signed-off-by: Will Deacon > > --- > > include/asm-generic/io.h | 8 ++++---- > > For changing the asm-generic file in the arm64 tree, > > Acked-by: Arnd Bergmann Thanks, Arnd. > For all I can see, this should not conflict with the usage of the > same macros on RISC-V, though it does make add a significant > difference, so I'd like to see an Ack from the RISC-V folks as > well (added to Cc), or possibly a change to arch/riscv/include/asm/io.h > to do a corresponding change. There's already a comment in that header which says that the accesses are ordered wrt timer reads, so I don't think anything needs to change there. For consistency with the macro arguments, I could augment their __io_par to take the read value as an unused argument, if that's what you mean? Will _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv