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Re: dynamic dma interface

To: dagum@xxxxxxxxxxxxxxxxxxx (Leo Dagum)
Subject: Re: dynamic dma interface
From: kanoj@xxxxxxxxxxxxxxxxxxx (Kanoj Sarcar)
Date: Wed, 2 Feb 2000 12:58:57 -0800 (PST)
Cc: linux-origin@xxxxxxxxxxx
In-reply-to: <200002020735.XAA16262@xxxxxxxxxxxxxxxxxxx> from "Leo Dagum" at Feb 01, 2000 11:35:03 PM
Sender: owner-linux-origin@xxxxxxxxxxx
> 
> Issues
> ------
> 1. Assumes that resources are only required for 32-bit devices doing
>    dma's into a .gt. 32-bit paddr space.  On mips64 we need to allocate
>    resources for all dma's (i.e. RRB's on the bridge are required for
>    any dma, and in addition ATE's are required for 32-bit dma's).
>    How do we distinguish between 32bit dma's and 64bit dma's with this
>    interface?  Jakub states outright in one of his postings that 
>    the "whole interface is currently for SAC".

As you mention later on, we probably need to pass a 32/64 bit flag down
to the pci/dma layers (most efficient). Alternately, we might need to come 
up with a way of tying some information to each device number, similar to 
the irix hwgraph, from which this information can be looked up.

Agree with all your comments.

Kanoj

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