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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 0795CC3815B for ; Wed, 15 Apr 2020 16:04:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF3942166E for ; Wed, 15 Apr 2020 16:04:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2410184AbgDOQEm (ORCPT ); Wed, 15 Apr 2020 12:04:42 -0400 Received: from foss.arm.com ([217.140.110.172]:47910 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2410177AbgDOQEe (ORCPT ); Wed, 15 Apr 2020 12:04:34 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id BD6FF1FB; Wed, 15 Apr 2020 09:04:33 -0700 (PDT) Received: from e121166-lin.cambridge.arm.com (e121166-lin.cambridge.arm.com [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 38A133F6C4; Wed, 15 Apr 2020 09:04:31 -0700 (PDT) Date: Wed, 15 Apr 2020 17:04:25 +0100 From: Lorenzo Pieralisi To: Laurentiu Tudor Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, robin.murphy@arm.com, ard.biesheuvel@linaro.org, ioana.ciornei@nxp.com, diana.craciun@oss.nxp.com, maz@kernel.org, jon@solid-run.com, pankaj.bansal@nxp.com, makarand.pawagi@nxp.com, calvin.johnson@nxp.com, V.Sethi@nxp.com, cristian.sovaiala@nxp.com, Stuart.Yoder@arm.com, jeremy.linton@arm.com, joro@8bytes.org, tglx@linutronix.de, jason@lakedaemon.net Subject: Re: [RFC PATCH 1/4] bus: fsl-mc: add custom .dma_configure implementation Message-ID: <20200415160425.GA6436@e121166-lin.cambridge.arm.com> References: <20200227100542.13819-1-laurentiu.tudor@nxp.com> <20200325125109.GA5430@red-moon.cambridge.arm.com> <499fbf9a-416f-d7c7-0655-881d92138a6c@nxp.com> <20200414143211.GA14905@red-moon.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Wed, Apr 15, 2020 at 06:44:37PM +0300, Laurentiu Tudor wrote: > > > On 4/14/2020 5:32 PM, Lorenzo Pieralisi wrote: > > On Wed, Mar 25, 2020 at 06:48:55PM +0200, Laurentiu Tudor wrote: > >> Hi Lorenzo, > >> > >> On 3/25/2020 2:51 PM, Lorenzo Pieralisi wrote: > >>> On Thu, Feb 27, 2020 at 12:05:39PM +0200, laurentiu.tudor@nxp.com wrote: > >>>> From: Laurentiu Tudor > >>>> > >>>> The devices on this bus are not discovered by way of device tree > >>>> but by queries to the firmware. It makes little sense to trick the > >>>> generic of layer into thinking that these devices are of related so > >>>> that we can get our dma configuration. Instead of doing that, add > >>>> our custom dma configuration implementation. > >>>> > >>>> Signed-off-by: Laurentiu Tudor > >>>> --- > >>>> drivers/bus/fsl-mc/fsl-mc-bus.c | 31 ++++++++++++++++++++++++++++++- > >>>> 1 file changed, 30 insertions(+), 1 deletion(-) > >>>> > >>>> diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c > >>>> index 36eb25f82c8e..eafaa0e0b906 100644 > >>>> --- a/drivers/bus/fsl-mc/fsl-mc-bus.c > >>>> +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c > >>>> @@ -132,11 +132,40 @@ static int fsl_mc_bus_uevent(struct device *dev, struct kobj_uevent_env *env) > >>>> static int fsl_mc_dma_configure(struct device *dev) > >>>> { > >>>> struct device *dma_dev = dev; > >>>> + struct iommu_fwspec *fwspec; > >>>> + const struct iommu_ops *iommu_ops; > >>>> + struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev); > >>>> + int ret; > >>>> + u32 icid; > >>>> > >>>> while (dev_is_fsl_mc(dma_dev)) > >>>> dma_dev = dma_dev->parent; > >>>> > >>>> - return of_dma_configure(dev, dma_dev->of_node, 0); > >>>> + fwspec = dev_iommu_fwspec_get(dma_dev); > >>>> + if (!fwspec) > >>>> + return -ENODEV; > >>>> + iommu_ops = iommu_ops_from_fwnode(fwspec->iommu_fwnode); > >>>> + if (!iommu_ops) > >>>> + return -ENODEV; > >>>> + > >>>> + ret = iommu_fwspec_init(dev, fwspec->iommu_fwnode, iommu_ops); > >>>> + if (ret) > >>>> + return ret; > >>>> + > >>>> + icid = mc_dev->icid; > >>>> + ret = iommu_fwspec_add_ids(dev, &icid, 1); > >>> > >>> I see. So with this patch we would use the MC named component only to > >>> retrieve the iommu_ops > >> > >> Right. I'd also add that the implementation tries to follow the existing > >> standard .dma_configure implementations, e.g. of_dma_configure + > >> of_iommu_configure. I'd also note that similarly to the ACPI case, this > >> MC FW device is probed as a platform device in the DT scenario, binding > >> here [1]. > >> A similar approach is used for the retrieval of the msi irq domain, see > >> following patch. > >> > >>> - the streamid are injected directly here bypassing OF/IORT bindings translations altogether. > >> > >> Actually I've submitted a v2 [2] that calls into .of_xlate() to allow > >> the smmu driver to do some processing on the raw streamid coming from > >> the firmware. I have not yet tested this with ACPI but expect it to > >> work, however, it's debatable how valid is this approach in the context > >> of ACPI. > > > > Actually, what I think you need is of_map_rid() (and an IORT > > equivalent, that I am going to write - generalizing iort_msi_map_rid()). > > > > Would that be enough to enable IORT "normal" mappings in the MC bus > > named components ? > > > > At a first glance, looks like this could very well fix the ACPI > scenario, but I have some unclarities on the approach: > * are we going to rely in DT and ACPI generic layers even if these > devices are not published / enumerated through DT or ACPI tables? > * the firmware manages and provides discrete streamids for the devices > it exposes so there's no translation involved. There's no > requestor_id / input_id involved but it seems that we would still do > some kind of translation relying for this on the DT/ACPI functions. > * MC firmware has its own stream_id (e.g. on some chips 0x4000, others > 0xf00, so outside the range of stream_ids used for the mc devices) > while for the devices on this bus, MC allocates stream_ids from a > range (e.g. 0x17 - 0x3f). Is it possible to describe this in the IORT table? > * Regarding the of_map_rid() use you mentioned, I was planning to > decouple the mc bus from the DT layer by dropping the use of > of_map_rid(), see patch 4. > I briefly glanced over the iort code and spotted this static function: > iort_iommu_xlate(). Wouldn't it also help, of course after making it public? Guys I have lost you honestly. I don't understand what you really need to do with DT and ACPI here. Are they needed to describe what you need or not ? If the MC dma configure function does not need any DT/ACPI bindings that's fine by me, I don't understand though why you are still asking how to represent MC in ACPI then, what for. Can you talk between *yourselves* please and decide what you need ? What's the problem ? Thanks, Lorenzo