Re: DMA with PCI

[Dave New <den@aisinc.com>]

roybier alexandre wrote:
> 
> 
>         I'd like to have some informations about the DMA with a PCI Bus.
> Does Smbdy knows a URL which can help me ? Or does smbd knows how it
> works ?
On most (all?) desktop platforms, you cannot use the system DMA
controller, since it usually embedded in the PCI-to-ISA bridge,
and used for doing DMA transfers between legacy ISA devices and
the host.

For PCI devices, you must have a device capable of busmastering,
or in PCI parlance, a PCI initiator.  There are source code
examples of how to do this in the Windows NT Device Driver Kit.
The NT DDK is available only as part of the Microsoft Development
Platform, by subscription from Microsoft.  Check out
http://www.microsoft.com/devonly

Bluewater Systems also vends a set of DDK classes, with sample
driver sources for DMA operations.  Check out
http://www.bluewatersystems.com

You didn't say what operating system you wanted to do this with.
The techniques are similar, but the details vary widely with
the operating system platform.  For examples of Unix-like drivers,
try the Linux kernel source code, available from a number of FTP
sites and CD-ROM releases.  Check out
http://www.infomagic.com

I'm not associated with any of these companies, but I do use the
NT DDK and the Infomagic Linux releases.

Good luck,

-- DaveN

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