From: viresh kumar <viresh.kumar@st.com>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>,
Dan Williams <dan.j.williams@intel.com>,
"Koul, Vinod" <vinod.koul@intel.com>
Cc: Pratyush ANAND <pratyush.anand@st.com>,
Rajeev KUMAR <rajeev-dlh.kumar@st.com>,
Bhavna YADAV <bhavna.yadav@st.com>,
Bhupesh SHARMA <bhupesh.sharma@st.com>,
Armando VISCONTI <armando.visconti@st.com>,
"linus.walleij@linaro.org" <linus.walleij@linaro.org>,
"jassisinghbrar@gmail.com" <jassisinghbrar@gmail.com>,
Vipin KUMAR <vipin.kumar@st.com>,
"grant.likely@secretlab.ca" <grant.likely@secretlab.ca>,
Shiraz HASHIM <shiraz.hashim@st.com>,
Amit VIRDI <Amit.VIRDI@st.com>,
Vipul Kumar SAMAR <vipulkumar.samar@st.com>,
"viresh.linux@gmail.com" <viresh.linux@gmail.com>,
Deepak SIKRI <deepak.sikri@st.com>,
"spi-devel-general@lists.sourceforge.net"
<spi-devel-general@lists.sourceforge.net>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH V2 6/6] spi/spi-pl022: Request/free DMA channels as and when required.
Date: Wed, 10 Aug 2011 14:59:31 +0530 [thread overview]
Message-ID: <4E424F7B.2000800@st.com> (raw)
In-Reply-To: <20110810090042.GE1831@n2100.arm.linux.org.uk>
On 08/10/2011 02:30 PM, Russell King - ARM Linux wrote:
>> > They must be allocated when they are required and must be freed after we are
>> > done with transfers. So that they can be used by other users.
> Which DMA engine driver requires this?
>
dw_dmac.c
> Normally, when we have DMA engine drivers with multiple request signals,
> the slave peripheral side publishes several virtual channels which are
> claimed by the peripheral drivers. This (amongst other things) allows
> the peripheral drivers to hold claim to one of the virtual channels
> all the time that it's required.
If users of DMA expect DMA engine drivers to work this way, then we should
have this mentioned clearly in DMA slave documentation.
@Dan/Vinod: What do you say?
--
viresh
WARNING: multiple messages have this Message-ID (diff)
From: viresh.kumar@st.com (viresh kumar)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V2 6/6] spi/spi-pl022: Request/free DMA channels as and when required.
Date: Wed, 10 Aug 2011 14:59:31 +0530 [thread overview]
Message-ID: <4E424F7B.2000800@st.com> (raw)
In-Reply-To: <20110810090042.GE1831@n2100.arm.linux.org.uk>
On 08/10/2011 02:30 PM, Russell King - ARM Linux wrote:
>> > They must be allocated when they are required and must be freed after we are
>> > done with transfers. So that they can be used by other users.
> Which DMA engine driver requires this?
>
dw_dmac.c
> Normally, when we have DMA engine drivers with multiple request signals,
> the slave peripheral side publishes several virtual channels which are
> claimed by the peripheral drivers. This (amongst other things) allows
> the peripheral drivers to hold claim to one of the virtual channels
> all the time that it's required.
If users of DMA expect DMA engine drivers to work this way, then we should
have this mentioned clearly in DMA slave documentation.
@Dan/Vinod: What do you say?
--
viresh
next prev parent reply other threads:[~2011-08-10 9:29 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-10 8:50 [PATCH V2 0/6] spi/spi-pl022 fixes Viresh Kumar
2011-08-10 8:50 ` Viresh Kumar
2011-08-10 8:50 ` [PATCH V2 1/6] spi/spi-pl022: Resolve formatting issues Viresh Kumar
2011-08-10 8:50 ` Viresh Kumar
2011-09-20 17:17 ` Grant Likely
2011-09-20 17:17 ` Grant Likely
[not found] ` <cover.1312965741.git.viresh.kumar-qxv4g6HH51o@public.gmane.org>
2011-08-10 8:50 ` [PATCH V2 2/6] spi/spi-pl022: Use GFP_ATOMIC for allocation from tasklet Viresh Kumar
2011-08-10 8:50 ` Viresh Kumar
2011-08-10 8:50 ` [PATCH V2 3/6] spi/spi-pl022: Don't allocate more sg than required Viresh Kumar
2011-08-10 8:50 ` Viresh Kumar
2011-08-10 8:54 ` Russell King - ARM Linux
2011-08-10 8:54 ` Russell King - ARM Linux
2011-08-10 9:05 ` viresh kumar
2011-08-10 9:05 ` viresh kumar
2011-08-10 11:42 ` Sergei Shtylyov
2011-08-10 11:42 ` Sergei Shtylyov
2011-08-10 11:46 ` viresh kumar
2011-08-10 11:46 ` viresh kumar
2011-08-10 8:50 ` [PATCH V2 4/6] spi/spi-pl022: calculate_effective_freq() must set rate <= requested rate Viresh Kumar
2011-08-10 8:50 ` Viresh Kumar
2011-08-10 8:50 ` [PATCH V2 5/6] spi/spi-pl022: Call pl022_dma_remove(pl022) only if enable_dma is true Viresh Kumar
2011-08-10 8:50 ` Viresh Kumar
2011-08-10 8:50 ` [PATCH V2 6/6] spi/spi-pl022: Request/free DMA channels as and when required Viresh Kumar
2011-08-10 8:50 ` Viresh Kumar
2011-08-10 9:00 ` Russell King - ARM Linux
2011-08-10 9:00 ` Russell King - ARM Linux
2011-08-10 9:29 ` viresh kumar [this message]
2011-08-10 9:29 ` viresh kumar
2011-08-10 10:01 ` Koul, Vinod
2011-08-10 10:01 ` Koul, Vinod
[not found] ` <438BB0150E931F4B9CE701519A4463010871804A15-qq4HA3s+46oFyVwBAnZdSLfspsVTdybXVpNB7YpNyf8@public.gmane.org>
2011-08-10 10:14 ` viresh kumar
2011-08-10 10:14 ` viresh kumar
2011-08-10 10:32 ` Russell King - ARM Linux
2011-08-10 10:32 ` Russell King - ARM Linux
2011-08-10 16:53 ` Koul, Vinod
2011-08-10 16:53 ` Koul, Vinod
2011-08-10 10:29 ` Russell King - ARM Linux
2011-08-10 10:29 ` Russell King - ARM Linux
2011-08-10 10:31 ` Jassi Brar
2011-08-10 10:31 ` Jassi Brar
2011-08-10 10:40 ` Russell King - ARM Linux
2011-08-10 10:40 ` Russell King - ARM Linux
2011-08-10 11:24 ` Jassi Brar
2011-08-10 11:24 ` Jassi Brar
2011-08-10 11:54 ` Linus Walleij
2011-08-10 11:54 ` Linus Walleij
2011-08-10 13:16 ` Jassi Brar
2011-08-10 13:16 ` Jassi Brar
2011-08-10 20:58 ` Vinod Koul
2011-08-10 20:58 ` Vinod Koul
2011-08-10 18:59 ` Jassi Brar
2011-08-10 18:59 ` Jassi Brar
2011-08-16 11:55 ` Koul, Vinod
2011-08-16 11:55 ` Koul, Vinod
2011-08-16 14:51 ` Jassi Brar
2011-08-16 14:51 ` Jassi Brar
2011-08-19 13:49 ` Koul, Vinod
2011-08-19 13:49 ` Koul, Vinod
2011-08-11 12:55 ` Linus Walleij
2011-08-11 12:55 ` Linus Walleij
2011-08-11 14:22 ` Jassi Brar
2011-08-11 14:22 ` Jassi Brar
2011-08-11 14:48 ` Linus Walleij
2011-08-11 14:48 ` Linus Walleij
[not found] ` <CAKnu2MptC8HWCNo6W+X9rawn6MCwAe3DB3B5UcHD1tCD9tA2cg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2011-08-11 17:05 ` Jassi Brar
2011-08-11 17:05 ` Jassi Brar
2011-08-11 22:35 ` Koul, Vinod
2011-08-11 22:35 ` Koul, Vinod
2011-08-10 10:09 ` Jassi Brar
2011-08-10 10:09 ` Jassi Brar
[not found] ` <CABb+yY0Qvuhrn+FUhWDHMwUjv=nR4MOfLeDfTzG17HXEuu2pmA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2011-08-10 10:30 ` Russell King - ARM Linux
2011-08-10 10:30 ` Russell King - ARM Linux
2011-08-10 10:48 ` Jassi Brar
2011-08-10 10:48 ` Jassi Brar
2011-08-10 11:42 ` [PATCH V3 3/6] spi/spi-pl022: Don't allocate more sg than required Viresh Kumar
2011-08-10 11:42 ` Viresh Kumar
2011-09-01 10:04 ` [PATCH V2 0/6] spi/spi-pl022 fixes Viresh Kumar
2011-09-01 10:04 ` Viresh Kumar
2011-09-01 10:56 ` Linus Walleij
2011-09-01 10:56 ` Linus Walleij
[not found] ` <CACRpkdYeq9in+U_tyvb=yVuX2t5TnkUSsO+BozUGVJwZVh+4Ag-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2011-09-20 11:16 ` Viresh Kumar
2011-09-20 11:16 ` Viresh Kumar
2011-09-20 17:23 ` Grant Likely
2011-09-20 17:23 ` Grant Likely
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=4E424F7B.2000800@st.com \
--to=viresh.kumar@st.com \
--cc=Amit.VIRDI@st.com \
--cc=armando.visconti@st.com \
--cc=bhavna.yadav@st.com \
--cc=bhupesh.sharma@st.com \
--cc=dan.j.williams@intel.com \
--cc=deepak.sikri@st.com \
--cc=grant.likely@secretlab.ca \
--cc=jassisinghbrar@gmail.com \
--cc=linus.walleij@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux@arm.linux.org.uk \
--cc=pratyush.anand@st.com \
--cc=rajeev-dlh.kumar@st.com \
--cc=shiraz.hashim@st.com \
--cc=spi-devel-general@lists.sourceforge.net \
--cc=vinod.koul@intel.com \
--cc=vipin.kumar@st.com \
--cc=vipulkumar.samar@st.com \
--cc=viresh.linux@gmail.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.