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SubjectRe: streaming data from linux host to devel board
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> I use another kernel buffer (from __get_dma_pages) in which the
> software on the mediaprocessor can write data and a linux user-space
> daemon can watch this buffer and parse dump it's contents. This is
> used for printf and basic file IO support for mediaprocessor software.

That is probably the most efficient approach. If its PCI you dont need to
pull DMA pages. You can also grab a chunk of pages if your board can do
scatter gather pulls from them.

Using mmap() means you can map the same memory into the address space of
the user app and the kernel. That is probably as good as you get for small
stuff.

> Basically, I'm looking for a fast way for software running on our
> mediaprocessor to stream in data from the host. The applications
> being audio/video/imaging codecs that are running on the
> mediaprocessor would get their input data from the linux host.

With 2.3.x you can use kiovecs and the routines with them to lock down user
pages and get a list of addresses. So you can

foo_write

get kiovec
lock pages
translate addresses and send message to media processor

returning irq
unlock pages
return done

Alan


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