From mboxrd@z Thu Jan 1 00:00:00 1970 From: Timur Tabi Subject: Re: [PATCH 4/4] ASoC: fsl: make fsl_ssi driver compilable on ARM/IMX Date: Thu, 23 Feb 2012 11:04:59 -0600 Message-ID: <4F4671BB.7060409@freescale.com> References: <1329979644-31046-1-git-send-email-shawn.guo@linaro.org> <1330008519-3584-1-git-send-email-shawn.guo@linaro.org> <1330008519-3584-5-git-send-email-shawn.guo@linaro.org> <4F465A33.3020208@ru.mvista.com> <4F465EE5.4010908@freescale.com> <20120223165242.GB22562@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from TX2EHSOBE007.bigfish.com (tx2ehsobe005.messaging.microsoft.com [65.55.88.15]) by alsa0.perex.cz (Postfix) with ESMTP id 04F7124411 for ; Thu, 23 Feb 2012 18:05:16 +0100 (CET) In-Reply-To: <20120223165242.GB22562@n2100.arm.linux.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Russell King - ARM Linux Cc: alsa-devel@alsa-project.org, Sergei Shtylyov , Sascha Hauer , Mark Brown , Shawn Guo , linux-arm-kernel@lists.infradead.org List-Id: alsa-devel@alsa-project.org Russell King - ARM Linux wrote: > Is your readl() or readl_be() unordered then? Yes. At least, it sure looks like it is. > Wouldn't that be buggy > between coherent DMA accesses and accessing, eg, a PCI peripheral to > enable or read DMA status? I think so. We almost never use readl. I see that it is used in some places, but honestly I can't see how it can be valid. For instance, the mpic driver uses it in mpic_startup_ht_interrupt(). I don't understand how that's valid, since there's nothing preventing the readl() from happening *before* the writeb. I'll have to ask around, because I'm sure I'm missing something. -- Timur Tabi Linux kernel developer at Freescale