On Thu, 2008-06-26 at 07:46 -0700, Haavard Skinnemoen wrote:
> Adrian Bunk <[EMAIL PROTECTED]> wrote:
> > That discussion is mixing two different things I suggested besides other
> > things before the Kconfig file was added [1]:
> > - have DMA_ENGINE select'ed when a device gets enabled by the user,
> > and not be an independent option
> > - switch to menuconfig and don't offer an empty kconfig menu
> >
> > There seems to be no disagreement about the former (which could
> > otherwise easily lead to users mistakenly enabling NET_DMA).
> >
> > The latter is more a cosmetical kconfig UI thing, and I already said
> > back then that it "could be dropped if it would become a problem" [2].
>
> Ok, thanks for explaining. The menu does appear empty if I remove the
> architecture dependency without adding the driver...if that's a problem
> maybe we should do the HAVE_DMA_DEVICE thing...
>
> > So if you want to remove the architecture dependency from the DMADEVICES
> > menu that's OK with me.
>
> Ok, I'm gonna wait for Dan and others to respond. If it's fine with
> them, I'll post a patch removing the arch dependency.
I agree with removing the arch dependency, and I do not think we
necessarily need to add HAVE_DMA_ENGINE. Taking an example from libata
the SATA_FSL driver depends on FSL_SOC but the menuconfig for ATA does
not. We can use "depends on HAS_DMA" to make the menu disappear on
archs that will never have a dmaegine. So I propose the following:
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 6239c3d..e4dd006 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -4,13 +4,14 @@
menuconfig DMADEVICES
bool "DMA Engine support"
- depends on (PCI && X86) || ARCH_IOP32X || ARCH_IOP33X || ARCH_IOP13XX
|| PPC
- depends on !HIGHMEM64G
+ depends on !HIGHMEM64G && HAS_DMA
help
DMA engines can do asynchronous data transfers without
involving the host CPU. Currently, this framework can be
used to offload memory copies in the network stack and
- RAID operations in the MD driver.
+ RAID operations in the MD driver. This menu only presents
+ DMA Device drivers supported by the configured arch, it may
+ be empty in some cases.
if DMADEVICES
@@ -55,10 +56,12 @@ comment "DMA Clients"
config NET_DMA
bool "Network: TCP receive copy offload"
depends on DMA_ENGINE && NET
+ default (INTEL_IOATDMA || FSL_DMA)
help
This enables the use of DMA engines in the network stack to
offload receive copy-to-user operations, freeing CPU cycles.
- Since this is the main user of the DMA engine, it should be enabled;
- say Y here.
+
+ Say Y here if you enabled INTEL_IOATDMA or FSL_DMA, otherwise
+ say N.
endif
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