From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 2/5] spi: pl022: use generic DMA slave configuration if possible
Date: Thu, 7 Feb 2013 19:42:54 +0000 [thread overview]
Message-ID: <201302071942.54642.arnd@arndb.de> (raw)
In-Reply-To: <CACRpkdZNpCJwp-uaH6feTcaPesNouwpHt-hO-M9v52G=Ux+Hqw@mail.gmail.com>
On Thursday 07 February 2013, Linus Walleij wrote:
> On Tue, Jan 29, 2013 at 2:13 PM, Arnd Bergmann <arnd@arndb•de> wrote:
> > On Tuesday 29 January 2013, Andy Shevchenko wrote:
>
> >> > + pl022->dummypage = kmalloc(PAGE_SIZE, GFP_KERNEL);
> >>
> >> Where this memory will be freed?
> >> In dependence of the answer could you consider to use
> >> devm_kmalloc or __get_free_page?
> >
> > There is another function like this called pl022_dma_probe()
> > that has the same allocation, and it gets freed in the same place.
> >
> > It's probably worth changing this into something different, but
> > I felt that it didn't belong into this patch. I was also not
> > sure if the best option would be dmam_alloc_coherent, dev_kzalloc,
> > or __get_free_page.
>
> Actually I once read about a feature where the kernel provides
> a static page full of zeroes or something like this, that would be
> ideal to use in cases like this, then all of this dummy page
> allocation and freeing can be deleted.
You mean empty_zero_page? That only works if this page is
read-only from the perspective of the DMA controller, but
then it would be a good fit, yes.
Arnd
next prev parent reply other threads:[~2013-02-07 19:42 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1359395857-1235-1-git-send-email-arnd@arndb.de>
2013-01-28 21:58 ` [PATCH v2 0/5] dmaengine: convert dw_dmac/spear13xx to generic binding Arnd Bergmann
2013-01-28 21:58 ` [PATCH 1/5] dmaengine: dw_dmac: move to generic DMA binding Arnd Bergmann
2013-01-29 7:24 ` Viresh Kumar
2013-01-29 10:35 ` Arnd Bergmann
2013-01-29 10:49 ` Viresh Kumar
2013-01-29 10:54 ` Andy Shevchenko
2013-01-29 10:57 ` Viresh Kumar
2013-01-29 11:14 ` Andy Shevchenko
2013-01-29 13:31 ` Arnd Bergmann
2013-01-29 13:45 ` Andy Shevchenko
2013-01-29 14:26 ` Russell King - ARM Linux
2013-01-29 15:28 ` Arnd Bergmann
2013-01-29 15:17 ` Viresh Kumar
2013-01-29 16:21 ` Arnd Bergmann
2013-01-30 2:04 ` Viresh Kumar
2013-01-30 9:41 ` Arnd Bergmann
2013-01-30 9:48 ` Viresh Kumar
2013-01-30 10:08 ` Arnd Bergmann
2013-01-30 10:32 ` Viresh Kumar
[not found] ` <1359445171.31148.30.camel@smile>
2013-01-29 10:50 ` Arnd Bergmann
2013-01-29 11:18 ` Russell King - ARM Linux
2013-01-29 13:44 ` Arnd Bergmann
2013-01-29 14:24 ` Russell King - ARM Linux
2013-01-29 14:55 ` Arnd Bergmann
2013-01-29 15:44 ` Russell King - ARM Linux
2013-01-29 16:36 ` Arnd Bergmann
2013-01-29 17:45 ` Russell King - ARM Linux
2013-01-29 20:40 ` Arnd Bergmann
2013-01-29 21:59 ` Linus Walleij
2013-02-15 8:50 ` Andy Shevchenko
2013-02-15 11:17 ` Arnd Bergmann
2013-01-28 21:58 ` [PATCH 2/5] spi: pl022: use generic DMA slave configuration if possible Arnd Bergmann
2013-01-29 2:41 ` Mark Brown
2013-01-29 7:49 ` Andy Shevchenko
2013-01-29 13:13 ` Arnd Bergmann
2013-02-07 18:29 ` Linus Walleij
2013-02-07 19:42 ` Arnd Bergmann [this message]
2013-02-07 20:19 ` Linus Walleij
2013-02-07 21:15 ` Arnd Bergmann
2013-02-08 16:22 ` Russell King - ARM Linux
2013-02-08 16:28 ` Arnd Bergmann
2013-02-08 22:10 ` Linus Walleij
2013-02-08 16:20 ` Russell King - ARM Linux
2013-01-28 21:58 ` [PATCH 3/5] serial: pl011: " Arnd Bergmann
2013-01-30 4:38 ` Greg Kroah-Hartman
2013-01-28 21:58 ` [PATCH 4/5] ata: arasan: remove the need for platform_data Arnd Bergmann
2013-01-29 8:18 ` Viresh Kumar
2013-01-28 21:58 ` [PATCH 5/5] ARM: SPEAr13xx: Pass generic DW DMAC platform data from DT Arnd Bergmann
2013-01-29 8:16 ` Viresh Kumar
2013-01-29 13:21 ` Arnd Bergmann
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=201302071942.54642.arnd@arndb.de \
--to=arnd@arndb$(echo .)de \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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