Re: [PATCH 2/4 v2] i.MX31: Image Processing Unit DMA and IRQ drivers

From: Dmitry Krivoschekov
Date: Wed Dec 10 2008 - 08:26:57 EST


Hi,

Guennadi Liakhovetski wrote:
> From: Guennadi Liakhovetski <lg@xxxxxxx>
>
> 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@xxxxxxx>
> ---
> 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.


Dmitry



> 8 files changed, 2408 insertions(+), 2 deletions(-)
> create mode 100644 arch/arm/plat-mxc/include/mach/ipu.h
> create mode 100644 drivers/mfd/ipu/Makefile
> create mode 100644 drivers/mfd/ipu/ipu_idmac.c
> create mode 100644 drivers/mfd/ipu/ipu_intern.h
> create mode 100644 drivers/mfd/ipu/ipu_irq.c

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