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: 42+ 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 ` [PATCH V2 1/6] spi/spi-pl022: Resolve formatting issues Viresh Kumar
2011-09-20 17:17 ` Grant Likely
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 ` [PATCH V2 3/6] spi/spi-pl022: Don't allocate more sg than required Viresh Kumar
2011-08-10 8:54 ` Russell King - ARM Linux
2011-08-10 9:05 ` viresh kumar
2011-08-10 11:42 ` Sergei Shtylyov
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 ` [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 ` [PATCH V2 6/6] spi/spi-pl022: Request/free DMA channels as and when required Viresh Kumar
2011-08-10 9:00 ` Russell King - ARM Linux
2011-08-10 9:29 ` viresh kumar [this message]
2011-08-10 10:01 ` Koul, Vinod
2011-08-10 10:14 ` viresh kumar
2011-08-10 10:32 ` Russell King - ARM Linux
2011-08-10 16:53 ` Koul, Vinod
2011-08-10 10:29 ` Russell King - ARM Linux
2011-08-10 10:31 ` Jassi Brar
2011-08-10 10:40 ` Russell King - ARM Linux
2011-08-10 11:24 ` Jassi Brar
2011-08-10 11:54 ` Linus Walleij
2011-08-10 13:16 ` Jassi Brar
2011-08-10 20:58 ` Vinod Koul
2011-08-10 18:59 ` Jassi Brar
2011-08-16 11:55 ` Koul, Vinod
2011-08-16 14:51 ` Jassi Brar
2011-08-19 13:49 ` Koul, Vinod
2011-08-11 12:55 ` Linus Walleij
2011-08-11 14:22 ` Jassi Brar
2011-08-11 14:48 ` Linus Walleij
2011-08-11 17:05 ` Jassi Brar
2011-08-11 22:35 ` Koul, Vinod
2011-08-10 10:09 ` Jassi Brar
2011-08-10 10:30 ` Russell King - ARM Linux
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
2011-09-01 10:04 ` [PATCH V2 0/6] spi/spi-pl022 fixes Viresh Kumar
2011-09-01 10:56 ` Linus Walleij
2011-09-20 11:16 ` Viresh Kumar
2011-09-20 17:23 ` Grant Likely
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