From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966818AbcCPO1c (ORCPT ); Wed, 16 Mar 2016 10:27:32 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:37419 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932846AbcCPO13 (ORCPT ); Wed, 16 Mar 2016 10:27:29 -0400 Subject: Re: [PATCH V2 2/3] vfio, platform: make reset driver a requirement To: Eric Auger , kvm@vger.kernel.org, timur@codeaurora.org, cov@codeaurora.org, jcm@redhat.com, Baptiste Reynal References: <1457715275-11925-1-git-send-email-okaya@codeaurora.org> <1457715275-11925-3-git-send-email-okaya@codeaurora.org> <56E5A271.6000408@codeaurora.org> <56E8E2CD.3020604@linaro.org> Cc: shankerd@codeaurora.org, vikrams@codeaurora.org, marc.zyngier@arm.com, mark.rutland@arm.com, devicetree@vger.kernel.org, vinod.koul@intel.com, agross@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Baptiste Reynal , Alex Williamson , linux-kernel@vger.kernel.org From: Sinan Kaya Message-ID: <56E96D4C.3080008@codeaurora.org> Date: Wed, 16 Mar 2016 10:27:24 -0400 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <56E8E2CD.3020604@linaro.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Baptiste, >> I couldn't see a reset function for AMBA devices. >> >> Is there anyway to write reset function for it? I have no experience with >> AMBA devices. > To my knowledge only the PL330 DMA controller (drivers/dma/pl330.c) was > passthrough'ed at some point, rather for development purpose than > production purpose. This was done by Virtual Open Systems (ask Baptiste > for more details). But I don't think this is really used. Are you OK with requiring reset driver for AMBA devices too? The PL330 driver won't work until a reset driver is submitted for it. >> >> Would you include a reset needed flag and just not require it for AMBA? >> (I honestly don't like this idea) >> > I think the requirement also makes sense for AMBA. > > Maybe an option would be to add a module parameter that would allow to > use the vfio platform/amba driver without reset module (with explicit > opt-in from the user). Maybe this can be done later on. I can see this flag useful for testing purposes but it should not be used in production. How about I add a module parameter which is not set by default? When set, I don't perform the reset requirement check. > > FYI I will not have access to my mailbox until the end of the week. OK, no rush. > > Best Regards > > Eric > -- Sinan Kaya Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project