From: msalter@redhat.com (Mark Salter)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/3] define ARM-specific dma_coherent_write_sync
Date: Tue, 06 Sep 2011 10:37:15 -0400 [thread overview]
Message-ID: <1315319837.2313.1.camel@deneb.redhat.com> (raw)
In-Reply-To: <CAHkRjk7ZMDQh8sYf7N_4LLS12JU2ps8dkC34gNWNH+-Zp0p8Rg@mail.gmail.com>
On Tue, 2011-09-06 at 15:32 +0100, Catalin Marinas wrote:
> That's what mb() and wmb() do already, at least on ARM. Why do we need
> another API? IIRC from past discussions on linux-arch around barriers,
> the mb() should be sufficient in the case of DMA coherent buffers.
> That's why macros like writel() on ARM have the mb() added by default
> (for cases where you start the DMA transfer by writing to a device
> register).
For USB EHCI, the driver does not necessarily write to a register after
writing to DMA coherent memory. In some cases, the controller polls for
information written by the driver.
--Mark
next prev parent reply other threads:[~2011-09-06 14:37 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-31 21:30 [PATCH 0/3] RFC: addition to DMA API Mark Salter
2011-08-31 21:30 ` [PATCH 1/3] add dma_coherent_write_sync " Mark Salter
2011-09-01 2:59 ` Josh Cartwright
2011-09-01 9:57 ` Michał Mirosław
2011-09-01 12:36 ` Mark Salter
2011-09-06 14:30 ` Catalin Marinas
2011-08-31 21:30 ` [PATCH 2/3] define ARM-specific dma_coherent_write_sync Mark Salter
2011-09-06 14:32 ` Catalin Marinas
2011-09-06 14:37 ` Mark Salter [this message]
2011-09-06 14:48 ` Catalin Marinas
2011-09-06 15:02 ` Mark Salter
2011-10-03 1:40 ` Jon Masters
2011-10-03 8:44 ` Catalin Marinas
2011-10-03 9:24 ` Jon Masters
2011-08-31 21:30 ` [PATCH 3/3] add dma_coherent_write_sync calls to USB EHCI driver Mark Salter
2011-09-01 2:33 ` Ming Lei
2011-09-01 2:09 ` [PATCH 0/3] RFC: addition to DMA API Ming Lei
2011-09-01 3:09 ` Alan Stern
2011-09-01 3:41 ` Ming Lei
2011-09-01 8:45 ` Will Deacon
2011-09-01 9:14 ` Ming Lei
2011-09-01 15:42 ` Alan Stern
2011-09-01 16:04 ` Russell King - ARM Linux
2011-09-01 17:31 ` Will Deacon
2011-09-01 18:07 ` Russell King - ARM Linux
2011-09-01 19:14 ` Mark Salter
2011-09-01 15:22 ` Alan Stern
2011-09-01 15:56 ` Ming Lei
2011-09-01 16:48 ` Alan Stern
2011-09-02 0:59 ` Ming Lei
2011-09-02 13:53 ` Alan Stern
2011-09-01 9:11 ` Will Deacon
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=1315319837.2313.1.camel@deneb.redhat.com \
--to=msalter@redhat.com \
--cc=linux-arm-kernel@lists.infradead.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).