[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <Pine.LNX.4.64.0812101442110.4578@axis700.grange>
Date: Wed, 10 Dec 2008 14:49:18 +0100 (CET)
From: Guennadi Liakhovetski <g.liakhovetski@....de>
To: Dmitry Krivoschekov <dmitry.krivoschekov@...il.com>
cc: linux-kernel@...r.kernel.org,
linux-fbdev-devel@...ts.sourceforge.net, adaplas@...il.com,
Sascha Hauer <s.hauer@...gutronix.de>,
linux-arm-kernel@...ts.arm.linux.org.uk,
Dan Williams <dan.j.williams@...el.com>
Subject: Re: [PATCH 2/4 v2] i.MX31: Image Processing Unit DMA and IRQ drivers
On Wed, 10 Dec 2008, Dmitry Krivoschekov wrote:
> Hi,
>
> Guennadi Liakhovetski wrote:
> > From: Guennadi Liakhovetski <lg@...x.de>
> >
> > i.MX3x SoCs contain an Image Processing Unit, consisting of a Control
> > Module (CM), Display Interface (DI), Synchronous Display Controller (SDC),
> > Asynchronous Display Controller (ADC), Image Converter (IC), Post-Filter
> > (PF), Camera Sensor Interface (CSI), and an Image DMA Controller (IDMAC).
> > CM contains, among other blocks, an Interrupt Generator (IG) and a Clock
> > and Reset Control Unit (CRCU). This driver serves IDMAC and IG. They are
> > supported over dmaengine and irq-chip APIs respectively.
> >
> > IDMAC is a specialised DMA controller, its DMA channels cannot be used for
> > general-purpose operations, even though it might be possible to configure
> > a memory-to-memory channel for memcpy operation. This driver will not work
> > with generic dmaengine clients, clients, wishing to use it must use
> > respective wrapper structures, they also must specify which channels they
> > require, as channels are hard-wired to specific IPU functions.
> >
> > Signed-off-by: Guennadi Liakhovetski <lg@...x.de>
> > ---
> > arch/arm/plat-mxc/include/mach/ipu.h | 180 ++++
> > arch/arm/plat-mxc/include/mach/mx31.h | 139 +++-
> > drivers/mfd/Kconfig | 16 +
> > drivers/mfd/Makefile | 4 +-
> > drivers/mfd/ipu/Makefile | 5 +
> > drivers/mfd/ipu/ipu_idmac.c | 1617 +++++++++++++++++++++++++++++++++
> > drivers/mfd/ipu/ipu_intern.h | 172 ++++
> > drivers/mfd/ipu/ipu_irq.c | 277 ++++++
> why do you think drivers/mfd is an appropriate location for this driver?
> IPU is on-chip device, but it is not a separate multifunction device so
> it should not be placed in drivers/mfd.
>
> arch/arm/plat-mxc/ or drivers/video/ipu seem better places for this driver.
I am not sure drivers/mxc is the best place for it, but I am against both
arch/arm (well, mildly, it is now preferred to put arch-specific drivers
under drivers/) and drivers/video - I'm going to submit a camera driver
shortly, which goes under drivers/media/video and will use the ipu driver,
and should not depend on drivers/video. I was thinking about
drivers/media/ipu... But eventually decided for mfd as it is
multifunctional (no, it is not separate, is this a requirement?) - it is
currently providing an IRQ and a DMA driver. But I don't use the mfd API
atm. If we decide to keep it there, I can add it, if necessary / if it
provides any advantages for this case.
In general, I am open to ideas in this respect.
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists