From: Robin Murphy <robin.murphy@arm.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Claire Chang <tientzu@chromium.org>
Cc: Rob Herring <robh+dt@kernel.org>,
mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org,
"list@263.net:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>,
Joerg Roedel <joro@8bytes.org>,
joro@8bytes.org, will@kernel.org,
Frank Rowand <frowand.list@gmail.com>,
boris.ostrovsky@oracle.com, jgross@suse.com,
sstabellini@kernel.org, Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>,
grant.likely@arm.com, xypron.glpk@gmx.de,
Thierry Reding <treding@nvidia.com>,
mingo@kernel.org, bauerman@linux.ibm.com, peterz@infradead.org,
Greg KH <gregkh@linuxfoundation.org>,
Saravana Kannan <saravanak@google.com>,
rafael.j.wysocki@intel.com, heikki.krogerus@linux.intel.com,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
rdunlap@infradead.org, dan.j.williams@intel.com,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
linux-devicetree <devicetree@vger.kernel.org>,
lkml <linux-kernel@vger.kernel.org>,
linuxppc-dev@lists.ozlabs.org,
"list@263.net:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>,
Joerg Roedel <joro@8bytes.org>,
iommu@lists.linux-foundation.org, xen-devel@lists.xenproject.org,
Tomasz Figa <tfiga@chromium.org>,
Nicolas Boichat <drinkcat@chromium.org>
Subject: Re: [RFC PATCH v3 2/6] swiotlb: Add restricted DMA pool
Date: Wed, 13 Jan 2021 01:53:02 +0000 [thread overview]
Message-ID: <41b466d0-0271-2d84-0623-4c877fcffe32@arm.com> (raw)
In-Reply-To: <20210107175740.GA16519@char.us.oracle.com>
On 2021-01-07 17:57, Konrad Rzeszutek Wilk wrote:
> On Fri, Jan 08, 2021 at 01:39:18AM +0800, Claire Chang wrote:
>> Hi Greg and Konrad,
>>
>> This change is intended to be non-arch specific. Any arch that lacks DMA access
>> control and has devices not behind an IOMMU can make use of it. Could you share
>> why you think this should be arch specific?
>
> The idea behind non-arch specific code is it to be generic. The devicetree
> is specific to PowerPC, Sparc, and ARM, and not to x86 - hence it should
> be in arch specific code.
Sorry, but that's an absurd argument. By the same token you'd equally
have to claim that bits of, say, the Broadcom WiFi driver (not to
mention dozens of others) should be split out into arch code, since not
all platforms use the devicetree parts, nor the ACPI parts, nor the PCI
parts...
There is nothing architecture-specific about using devicetree as a
system description - AFAIK there *are* a handful of x86 platforms that
use it, besides even more architectures than you've listed above. It has
long been the policy that devicetree-related code for a particular
subsystem should just live within that subsystem. Sometimes if there's
enough of it it gets collected together into its own file - e.g.
drivers/pci/of.c - otherwise it tends to just get #ifdef'ed - e.g.
of_spi_parse_dt(), or the other DMA reserved-memory consumers that
already exist as Florian points out.
Besides, there are far more platforms that enable CONFIG_OF than enable
CONFIG_SWIOTLB, so by that metric the whole of the SWIOTLB code itself
is even less "generic" than any DT parsing :P
Robin.
next prev parent reply other threads:[~2021-01-13 1:53 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-06 3:41 [RFC PATCH v3 0/6] Restricted DMA Claire Chang
2021-01-06 3:41 ` [RFC PATCH v3 1/6] swiotlb: Add io_tlb_mem struct Claire Chang
2021-01-13 11:50 ` Christoph Hellwig
2021-01-06 3:41 ` [RFC PATCH v3 2/6] swiotlb: Add restricted DMA pool Claire Chang
2021-01-06 7:50 ` Greg KH
2021-01-13 11:51 ` Christoph Hellwig
2021-01-13 12:29 ` Greg KH
2021-01-13 12:37 ` Christoph Hellwig
2021-01-06 18:52 ` Konrad Rzeszutek Wilk
2021-01-07 17:39 ` Claire Chang
2021-01-07 17:57 ` Konrad Rzeszutek Wilk
2021-01-07 18:09 ` Florian Fainelli
2021-01-07 21:19 ` Konrad Rzeszutek Wilk
2021-01-12 23:52 ` Florian Fainelli
2021-01-25 5:26 ` Jon Masters
2021-01-13 1:53 ` Robin Murphy [this message]
2021-01-13 0:03 ` Florian Fainelli
2021-01-13 13:59 ` Nicolas Saenz Julienne
2021-01-13 15:27 ` Robin Murphy
2021-01-13 17:43 ` Florian Fainelli
2021-01-13 18:03 ` Robin Murphy
2021-01-13 12:42 ` Christoph Hellwig
2021-01-14 9:06 ` Claire Chang
2021-01-06 3:41 ` [RFC PATCH v3 3/6] swiotlb: Use restricted DMA pool if available Claire Chang
2021-01-12 23:39 ` Florian Fainelli
2021-01-13 12:44 ` Christoph Hellwig
2021-01-06 3:41 ` [RFC PATCH v3 4/6] swiotlb: Add restricted DMA alloc/free support Claire Chang
2021-01-12 23:41 ` Florian Fainelli
2021-01-13 12:48 ` Christoph Hellwig
2021-01-13 18:27 ` Robin Murphy
2021-01-13 18:32 ` Christoph Hellwig
2021-01-06 3:41 ` [RFC PATCH v3 5/6] dt-bindings: of: Add restricted DMA pool Claire Chang
2021-01-06 18:57 ` Konrad Rzeszutek Wilk
2021-01-07 17:39 ` Claire Chang
2021-01-07 18:00 ` Konrad Rzeszutek Wilk
2021-01-07 18:14 ` Florian Fainelli
2021-01-12 7:47 ` Claire Chang
2021-01-20 16:53 ` Rob Herring
2021-01-20 17:30 ` Robin Murphy
2021-01-20 21:31 ` Rob Herring
2021-01-21 1:09 ` Robin Murphy
2021-01-21 15:48 ` Rob Herring
2021-01-21 17:29 ` Robin Murphy
2021-01-06 3:41 ` [RFC PATCH v3 6/6] of: Add plumbing for " Claire Chang
2021-01-12 23:48 ` Florian Fainelli
2021-01-14 9:08 ` Claire Chang
2021-01-14 18:52 ` Florian Fainelli
2021-01-15 3:46 ` Claire Chang
2021-01-06 18:48 ` [RFC PATCH v3 0/6] Restricted DMA Florian Fainelli
2021-01-07 17:38 ` Claire Chang
2021-01-07 17:42 ` Claire Chang
2021-01-07 17:59 ` Florian Fainelli
2021-01-12 7:48 ` Claire Chang
2021-01-12 18:01 ` Florian Fainelli
2021-01-13 2:29 ` Tomasz Figa
2021-01-13 3:56 ` Florian Fainelli
2021-01-13 4:25 ` Tomasz Figa
2021-01-13 4:41 ` Florian Fainelli
2021-02-09 6:27 ` Claire Chang
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