From: Will Deacon <will.deacon@arm.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Marek Vasut <marek.vasut@gmail.com>,
Arnd Bergmann <arnd@arndb.de>,
linux-pci <linux-pci@vger.kernel.org>,
Phil Edworthy <phil.edworthy@renesas.com>,
Marek Vasut <marek.vasut+renesas@gmail.com>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Simon Horman <horms+renesas@verge.net.au>,
Wolfram Sang <wsa@the-dreams.de>,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
Nikita Yushchenko <nikita.yoush@cogentembedded.com>,
Catalin Marinas <catalin.marinas@arm.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH][RFC] PCI: rcar: Add bus notifier so we can limit the DMA range
Date: Wed, 6 Jun 2018 16:45:06 +0100 [thread overview]
Message-ID: <20180606154505.GJ6631@arm.com> (raw)
In-Reply-To: <20180604223048.GC30381@bhelgaas-glaptop.roam.corp.google.com>
On Mon, Jun 04, 2018 at 05:30:48PM -0500, Bjorn Helgaas wrote:
> [+cc ARM64 folks, linux-kernel]
>
> The original patch under discussion is:
> https://lkml.kernel.org/r/20180521220514.30256-1-marek.vasut+renesas@gmail.com
>
> On Tue, May 22, 2018 at 11:52:21AM +0200, Marek Vasut wrote:
> > On 05/22/2018 10:10 AM, Arnd Bergmann wrote:
> > > On Tue, May 22, 2018 at 12:05 AM, Marek Vasut <marek.vasut@gmail.com> wrote:
> > >> From: Phil Edworthy <phil.edworthy@renesas.com>
> > >>
> > >> The PCIe DMA controller on RCar Gen2 and earlier is on 32bit bus,
> > >> so limit the DMA range to 32bit.
> > >>
> > >> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
> > >> Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
> > >> Cc: Arnd Bergmann <arnd@arndb.de>
> > >> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
> > >> Cc: Phil Edworthy <phil.edworthy@renesas.com>
> > >> Cc: Simon Horman <horms+renesas@verge.net.au>
> > >> Cc: Wolfram Sang <wsa@the-dreams.de>
> > >> Cc: linux-renesas-soc@vger.kernel.org
> > >> To: linux-pci@vger.kernel.org
> > >> ---
> > >> NOTE: I'm aware of https://patchwork.kernel.org/patch/9495895/ , but the
> > >> discussion seems to have gone way off, so I'm sending this as a
> > >> RFC. Any feedback on how to do this limiting properly would be nice.
> > >
> > > Doing it in the driver is clearly not appropriate, we must do this in
> > > common code. If I remember correctly, it's specifically ARM64 that is
> > > broken here, it incorrectly allows setting a DMA mask to 64 bit
> > > when that is not available.
> >
> > Yep, that's correct. ARM64 with devices mapping tremendous amounts of
> > memory. So did anything change since that discussion references in the NOTE?
Is it specifically arm64 that's broken here? If so, why and how do other
archs (e.g. riscv) handle this? I thought all of this behaviour was driven
by the DMA ops, and we're just using generic code for that afaict.
Will
WARNING: multiple messages have this Message-ID (diff)
From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH][RFC] PCI: rcar: Add bus notifier so we can limit the DMA range
Date: Wed, 6 Jun 2018 16:45:06 +0100 [thread overview]
Message-ID: <20180606154505.GJ6631@arm.com> (raw)
In-Reply-To: <20180604223048.GC30381@bhelgaas-glaptop.roam.corp.google.com>
On Mon, Jun 04, 2018 at 05:30:48PM -0500, Bjorn Helgaas wrote:
> [+cc ARM64 folks, linux-kernel]
>
> The original patch under discussion is:
> https://lkml.kernel.org/r/20180521220514.30256-1-marek.vasut+renesas at gmail.com
>
> On Tue, May 22, 2018 at 11:52:21AM +0200, Marek Vasut wrote:
> > On 05/22/2018 10:10 AM, Arnd Bergmann wrote:
> > > On Tue, May 22, 2018 at 12:05 AM, Marek Vasut <marek.vasut@gmail.com> wrote:
> > >> From: Phil Edworthy <phil.edworthy@renesas.com>
> > >>
> > >> The PCIe DMA controller on RCar Gen2 and earlier is on 32bit bus,
> > >> so limit the DMA range to 32bit.
> > >>
> > >> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
> > >> Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
> > >> Cc: Arnd Bergmann <arnd@arndb.de>
> > >> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
> > >> Cc: Phil Edworthy <phil.edworthy@renesas.com>
> > >> Cc: Simon Horman <horms+renesas@verge.net.au>
> > >> Cc: Wolfram Sang <wsa@the-dreams.de>
> > >> Cc: linux-renesas-soc at vger.kernel.org
> > >> To: linux-pci at vger.kernel.org
> > >> ---
> > >> NOTE: I'm aware of https://patchwork.kernel.org/patch/9495895/ , but the
> > >> discussion seems to have gone way off, so I'm sending this as a
> > >> RFC. Any feedback on how to do this limiting properly would be nice.
> > >
> > > Doing it in the driver is clearly not appropriate, we must do this in
> > > common code. If I remember correctly, it's specifically ARM64 that is
> > > broken here, it incorrectly allows setting a DMA mask to 64 bit
> > > when that is not available.
> >
> > Yep, that's correct. ARM64 with devices mapping tremendous amounts of
> > memory. So did anything change since that discussion references in the NOTE?
Is it specifically arm64 that's broken here? If so, why and how do other
archs (e.g. riscv) handle this? I thought all of this behaviour was driven
by the DMA ops, and we're just using generic code for that afaict.
Will
next prev parent reply other threads:[~2018-06-06 15:45 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-21 22:05 [PATCH][RFC] PCI: rcar: Add bus notifier so we can limit the DMA range Marek Vasut
2018-05-22 8:10 ` Arnd Bergmann
2018-05-22 9:52 ` Marek Vasut
2018-06-04 21:09 ` Marek Vasut
2018-06-04 22:30 ` Bjorn Helgaas
2018-06-04 22:30 ` Bjorn Helgaas
2018-06-04 22:30 ` Bjorn Helgaas
2018-06-06 15:45 ` Will Deacon [this message]
2018-06-06 15:45 ` Will Deacon
2018-09-18 10:15 ` Lorenzo Pieralisi
2018-09-18 10:51 ` Wolfram Sang
2018-09-22 17:06 ` Marek Vasut
2018-10-01 22:44 ` Marek Vasut
2019-03-03 17:48 ` Marek Vasut
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