From: linux@arm.linux.org.uk (Russell King - ARM Linux)
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 11:32:25 +0100 [thread overview]
Message-ID: <20110810103225.GJ1831@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <4E4259F5.8060402@st.com>
On Wed, Aug 10, 2011 at 03:44:13PM +0530, viresh kumar wrote:
> On 08/10/2011 03:31 PM, Koul, Vinod wrote:
> > And on your patch, are you able to dynamically assign the channels for
> > platform? What is the intended usage? (as Russell articulated it is bad
> > to dynamically assign channel for something like uart)
>
> Are you talking about channels or DMA request lines? For channels yes,
> we can always allocate channels as they are independent of peripherals.
> About request lines, they are muxed in our case between several
> peripherals, but support for that has to be added in dw_dmac.
Right, and when you do, you'll probably have to go to a virtual channel
implementation, which solves the problem of keeping a channel allocated
and makes this patch redundant.
I assert that any DMA engine implementation where request signals can
be assigned dynamically to DMA channels should be using a virtual channel
implementation.
next prev parent reply other threads:[~2011-08-10 10:32 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
2011-08-10 10:01 ` Koul, Vinod
2011-08-10 10:14 ` viresh kumar
2011-08-10 10:32 ` Russell King - ARM Linux [this message]
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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