From: Robin Murphy <robin.murphy@arm.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Nipun Gupta <nipun.gupta@nxp.com>,
will.deacon@arm.com, mark.rutland@arm.com,
catalin.marinas@arm.com, iommu@lists.linux-foundation.org,
robh+dt@kernel.org, m.szyprowski@samsung.com,
gregkh@linuxfoundation.org, joro@8bytes.org, leoyang.li@nxp.com,
shawnguo@kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linuxppc-dev@lists.ozlabs.org, bharat.bhushan@nxp.com,
stuyoder@gmail.com, laurentiu.tudor@nxp.com
Subject: Re: [PATCH 5/6] dma-mapping: support fsl-mc bus
Date: Mon, 5 Mar 2018 18:51:56 +0000 [thread overview]
Message-ID: <1729ae21-d08c-b413-51a3-f22c394b388d@arm.com> (raw)
In-Reply-To: <20180305183938.GB20086@lst.de>
On 05/03/18 18:39, Christoph Hellwig wrote:
> On Mon, Mar 05, 2018 at 03:48:32PM +0000, Robin Murphy wrote:
>> Unfortunately for us, fsl-mc is conceptually rather like PCI in that it's
>> software-discoverable and the only thing described in DT is the bus "host",
>> thus we need the same sort of thing as for PCI to map from the child
>> devices back to the bus root in order to find the appropriate firmware
>> node. Worse than PCI, though, we wouldn't even have the option of
>> describing child devices statically in firmware at all, since it's actually
>> one of these runtime-configurable "build your own network accelerator"
>> hardware pools where userspace gets to create and destroy "devices" as it
>> likes.
>
> I really hate the PCI special case just as much. Maybe we just
> need a dma_configure method on the bus, and move PCI as well as fsl-mc
> to it.
Hmm, on reflection, 100% ack to that idea. It would neatly supersede
bus->force_dma *and* mean that we don't have to effectively pull pci.h
into everything, which I've never liked. In hindsight dma_configure()
does feel like it's grown into this odd choke point where we munge
everything in just for it to awkwardly unpick things again.
Robin.
next prev parent reply other threads:[~2018-03-05 18:51 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-05 14:29 [PATCH 0/6] Support for fsl-mc bus and its devices in SMMU Nipun Gupta
2018-03-05 14:29 ` [PATCH 1/6] Docs: dt: add fsl-mc iommu-parent device-tree binding Nipun Gupta
2018-03-05 14:53 ` Robin Murphy
2018-03-05 15:00 ` Nipun Gupta
2018-03-05 15:37 ` Robin Murphy
2018-03-05 15:54 ` Nipun Gupta
2018-03-07 22:40 ` Rob Herring
2018-03-08 12:32 ` Nipun Gupta
2018-03-05 14:29 ` [PATCH 2/6] iommu: support iommu configuration for fsl-mc devices Nipun Gupta
2018-03-05 14:29 ` [PATCH 3/6] iommu: arm-smmu: Add support for the fsl-mc bus Nipun Gupta
2018-03-05 14:29 ` [PATCH 4/6] bus: fsl-mc: remove dma ops setup from driver Nipun Gupta
2018-03-05 14:29 ` [PATCH 5/6] dma-mapping: support fsl-mc bus Nipun Gupta
2018-03-05 15:08 ` Christoph Hellwig
2018-03-05 15:48 ` Robin Murphy
2018-03-05 18:39 ` Christoph Hellwig
2018-03-05 18:51 ` Robin Murphy [this message]
2018-03-06 4:41 ` Nipun Gupta
2018-03-08 7:41 ` Christoph Hellwig
2018-03-09 18:29 ` Nipun Gupta
2018-03-09 18:50 ` Robin Murphy
2018-03-05 14:29 ` [PATCH 6/6] dts: fsl-ls208x: updated DT with SMMU support for fsl-mc Nipun Gupta
2018-04-17 10:21 ` [PATCH 0/6 v2] Support for fsl-mc bus and its devices in SMMU Nipun Gupta
2018-04-17 10:21 ` [PATCH 1/6 v2] Docs: dt: add fsl-mc iommu-map device-tree binding Nipun Gupta
2018-04-17 10:21 ` [PATCH 2/6 v2] iommu: of: make of_pci_map_rid() available for other devices too Nipun Gupta
2018-04-17 16:52 ` Robin Murphy
2018-04-18 5:09 ` Bharat Bhushan
2018-04-18 6:21 ` Nipun Gupta
2018-04-17 10:21 ` [PATCH 3/6 v2] iommu: support iommu configuration for fsl-mc devices Nipun Gupta
2018-04-17 10:21 ` [PATCH 4/6 v2] iommu: arm-smmu: Add support for the fsl-mc bus Nipun Gupta
2018-04-17 10:21 ` [PATCH 5/6 v2] bus: fsl-mc: supoprt dma configure for devices on " Nipun Gupta
2018-04-26 0:00 ` kbuild test robot
2018-04-17 10:21 ` [PATCH 6/6 v2] arm64: dts: ls208xa: comply with the iommu map binding for fsl_mc Nipun Gupta
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