From: Christoph Hellwig <hch@lst.de>
To: dillon min <dillon.minfei@gmail.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
Vladimir Murzin <vladimir.murzin@arm.com>,
Alexandre Torgue <alexandre.torgue@st.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux@armlinux.org.uk, linux-stm32@st-md-mailman.stormreply.com,
Rob Herring <robh+dt@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
tglx@linutronix.de, info@metux.net, hch@lst.de,
allison@lohutok.net
Subject: Re: [PATCH 2/2] arm-nommu: Add use_reserved_mem() to check if device support reserved memory
Date: Tue, 9 Jun 2020 17:36:46 +0200 [thread overview]
Message-ID: <20200609153646.GA17969@lst.de> (raw)
In-Reply-To: <CAL9mu0+__0Z3R3TcSrj9-kPxsyQHKS9WqK1u58P0dEZ+Jd-wbQ@mail.gmail.com>
On Tue, Jun 09, 2020 at 11:22:24PM +0800, dillon min wrote:
> Hi Vladimir,
>
> Thanks for reviewing.
>
> Hi Christoph Hellwig,
>
> I just want to know if kernel dma mapping/direct is focused on
> platforms with MMU.
> leave arch code to handle dma coherent memory management themself for
> no-MMU platform.
No, I'd really like to consolidate everything that isn't overly
arch specific eventually.
>
> so, you just return error code in kernel/dma/mapping.c,direct.c
> without CONFIG_MMU defined ?
> which means dma-direct mapping doesn't support !CONFIG_MMU is not a
> bug, but design as it's.
> or, just return error code currently, will add dma direct mapping
> support for !CONFIG_MMU in the
> future?
>
> As Vladimir Murzin's suggestion has changes in kernel code, I need
> your input to get
> the design goal about dma-direct mapping, thanks.
Can someone repost the whole patch?
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WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: dillon min <dillon.minfei@gmail.com>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>,
hch@lst.de, Rob Herring <robh+dt@kernel.org>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre Torgue <alexandre.torgue@st.com>,
linux@armlinux.org.uk,
Kate Stewart <kstewart@linuxfoundation.org>,
allison@lohutok.net, info@metux.net, tglx@linutronix.de,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
linux-stm32@st-md-mailman.stormreply.com,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] arm-nommu: Add use_reserved_mem() to check if device support reserved memory
Date: Tue, 9 Jun 2020 17:36:46 +0200 [thread overview]
Message-ID: <20200609153646.GA17969@lst.de> (raw)
In-Reply-To: <CAL9mu0+__0Z3R3TcSrj9-kPxsyQHKS9WqK1u58P0dEZ+Jd-wbQ@mail.gmail.com>
On Tue, Jun 09, 2020 at 11:22:24PM +0800, dillon min wrote:
> Hi Vladimir,
>
> Thanks for reviewing.
>
> Hi Christoph Hellwig,
>
> I just want to know if kernel dma mapping/direct is focused on
> platforms with MMU.
> leave arch code to handle dma coherent memory management themself for
> no-MMU platform.
No, I'd really like to consolidate everything that isn't overly
arch specific eventually.
>
> so, you just return error code in kernel/dma/mapping.c,direct.c
> without CONFIG_MMU defined ?
> which means dma-direct mapping doesn't support !CONFIG_MMU is not a
> bug, but design as it's.
> or, just return error code currently, will add dma direct mapping
> support for !CONFIG_MMU in the
> future?
>
> As Vladimir Murzin's suggestion has changes in kernel code, I need
> your input to get
> the design goal about dma-direct mapping, thanks.
Can someone repost the whole patch?
next prev parent reply other threads:[~2020-06-09 15:37 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-08 8:30 [PATCH 0/2] Use 'arm_nommu_dma_ops' to handle dma memroy if device offer consistent dma memory region dillon.minfei
2020-06-08 8:30 ` dillon.minfei
2020-06-08 8:30 ` [PATCH 1/2] ARM: dts: stm32: Setup 4M bytes reserved memory for mmap dillon.minfei
2020-06-08 8:30 ` dillon.minfei
2020-06-09 15:58 ` dillon min
2020-06-09 15:58 ` dillon min
2020-06-08 8:30 ` [PATCH 2/2] arm-nommu: Add use_reserved_mem() to check if device support reserved memory dillon.minfei
2020-06-08 8:30 ` dillon.minfei
2020-06-09 14:08 ` Vladimir Murzin
2020-06-09 14:08 ` Vladimir Murzin
2020-06-09 15:22 ` dillon min
2020-06-09 15:22 ` dillon min
2020-06-09 15:36 ` Christoph Hellwig [this message]
2020-06-09 15:36 ` Christoph Hellwig
2020-06-09 15:43 ` Vladimir Murzin
2020-06-09 15:43 ` Vladimir Murzin
2020-06-09 16:25 ` Vladimir Murzin
2020-06-09 16:25 ` Vladimir Murzin
2020-06-09 17:34 ` Christoph Hellwig
2020-06-09 17:34 ` Christoph Hellwig
2020-06-10 2:24 ` dillon min
2020-06-10 2:24 ` dillon min
2020-06-10 7:24 ` Christoph Hellwig
2020-06-10 7:24 ` Christoph Hellwig
2020-06-10 8:19 ` Vladimir Murzin
2020-06-10 8:19 ` Vladimir Murzin
2020-06-11 15:45 ` Vladimir Murzin
2020-06-11 15:45 ` Vladimir Murzin
2020-06-12 2:15 ` dillon min
2020-06-12 2:15 ` dillon min
2020-06-09 15:58 ` [PATCH 0/2] Use 'arm_nommu_dma_ops' to handle dma memroy if device offer consistent dma memory region dillon min
2020-06-09 15:58 ` dillon min
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