Re: [patch] kconfig: unify GENERIC_ISA_DMA and ISA_DMA_API
From: Russell King - ARM Linux
Date: Wed Jan 26 2011 - 15:12:22 EST
On Wed, Jan 26, 2011 at 12:00:08PM -0800, David Rientjes wrote:
> On Wed, 26 Jan 2011, Russell King - ARM Linux wrote:
> > On Tue, Jan 25, 2011 at 05:06:28PM -0800, David Rientjes wrote:
> > > CONFIG_GENERIC_ISA_DMA and CONFIG_ISA_DMA_API usually have dependencies
> > > on one another depending on the architecture and generic kernel code uses
> > > either to determine whether an ISA-style DMA API is configured.
> > Wrong.
> > GENERIC_ISA_DMA enables support for the standard ISA DMA allocator found
> > in kernel/dma.c
> > ISA_DMA_API says that a platform supports the ISA DMA interfaces.
> > An architecture can provide the ISA DMA interfaces, but not use the
> > standard ISA DMA allocator found in kernel/dma.c. Such as the one in
> > arch/arm/kernel/dma.c.
> > So on ARM, we have platforms where ISA_DMA_API=y but GENERIC_ISA_DMA=n.
> Ok, fair enough. Thanks for pointing that out. I'll work to resolve the
> existing dependency chain on x86 that cause build failures when one is
> disabled and another is not and add Kconfig dependencies on drivers that
> require GENERIC_ISA_DMA.
Drivers should depend on ISA_DMA_API as that indicates that the ISA DMA
API is present - in other words, when the following are available from
GENERIC_ISA_DMA should be set by an architecture/platform when ISA_DMA_API
has already been set -and- it wants to use kernel/dma.c. No drivers should
depend on GENERIC_ISA_DMA.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/