From: Manjeet Pawar <manjeet.p@samsung.com>
To: Stefano Stabellini <sstabellini@kernel.org>,
"konrad@darnok.org" <konrad@darnok.org>
Cc: PANKAJ MISHRA <pankaj.m@samsung.com>,
AJEET YADAV <ajeet.y@samsung.com>,
Rohit Thapliyal <r.thapliyal@samsung.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux@arm.linux.org.uk" <linux@arm.linux.org.uk>
Subject: Re: Re: [PATCH] arm:swiotlb:keep disabled in default configuration
Date: Mon, 27 Jun 2016 04:20:59 +0000 (GMT) [thread overview]
Message-ID: <560602875.24151467001258274.JavaMail.weblogic@epmlwas09d> (raw)
>> >
>> > From: Rohit Thapliyal
>> >
>> > swiotlb implementation not required to be enabled in arm and
>> > disabling it reduces uImage size by 16KB.
>> >
>>
>> How so? There are no DMA operations on ARM?
>Xen actively uses the swiotlb on ARM, see
>arch/arm64/include/asm/dma-mapping.h:get_dma_ops
>arch/arm/xen/mm.c:xen_swiotlb_dma_ops
Sorry, my last reply didn't go through so sending it again.
If XEN is enabled, it shall eventually enable SWIOTLB through SWIOTLB_XEN. So, there is no need to keep it enabled otherwise.
------- Original Message -------
Sender : Stefano Stabellini
Date : Jun 24, 2016 01:00 (GMT+09:00)
Title : Re: [PATCH] arm:swiotlb:keep disabled in default configuration
On Thu, 23 Jun 2016, Stefano Stabellini wrote:
> On Jun 23, 2016 8:27 AM, "Manjeet Pawar" wrote:
> >
> > From: Rohit Thapliyal
> >
> > swiotlb implementation not required to be enabled in arm and
> > disabling it reduces uImage size by 16KB.
> >
>
> How so? There are no DMA operations on ARM?
Xen actively uses the swiotlb on ARM, see
arch/arm64/include/asm/dma-mapping.h:get_dma_ops
arch/arm/xen/mm.c:xen_swiotlb_dma_ops
> > Signed-off-by: Rohit Thapliyal
> > Signed-off-by: Ajeet Kumar Yadav
> > ---
> > arch/arm/Kconfig | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index 90542db..ae65f29 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -1754,7 +1754,7 @@ config SECCOMP
> > defined by each seccomp mode.
> >
> > config SWIOTLB
> > - def_bool y
> > + def_bool n
> >
> > config IOMMU_HELPER
> > def_bool SWIOTLB
> > --
> > 1.7.9.5
> >
>
next reply other threads:[~2016-06-27 4:21 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-27 4:20 Manjeet Pawar [this message]
-- strict thread matches above, loose matches on Subject: below --
2016-06-24 6:58 Re: [PATCH] arm:swiotlb:keep disabled in default configuration Manjeet Pawar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=560602875.24151467001258274.JavaMail.weblogic@epmlwas09d \
--to=manjeet.p@samsung.com \
--cc=ajeet.y@samsung.com \
--cc=konrad@darnok.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@arm.linux.org.uk \
--cc=pankaj.m@samsung.com \
--cc=r.thapliyal@samsung.com \
--cc=sstabellini@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).