Re: Incomplete bus.h

[Radoslaw Kujawa <radoslaw.kujawa%c0ff33.net@localhost>]

Hello.

On 6 maj 2012, at 20:00, Izumi Tsutsui wrote:

> By the way, is there any plan to add support for PCI DMA bus master
> devices on amiga?

Yes, there is a plan to add it, but I don't own the required hardware. 

There are various PCI bridges for classic 68k amiga, but most of them do not 
support PCI DMA bus master on hardware level. The only bridge I know that 
really supports it is DCE G-REX.  Documentation for this device is unavailable 
and the hardware is very expensive (second hand only). I've added some 
preliminary support for G-REX in January thanks to a helpful tester on 
amibay[1]. This effort was based on reverse engineering and I don't know much 
about DMA implementation in G-REX yet.

The other bridge that _maybe_ has some kind of PCI DMA bus master support is 
Elbox Mediator 4000, but I don't have the hardware and the vendor is not 
willing to speak with me about programming documentation. 

All other PCI bridges on amiga are not bus master DMA capable.

> I think amiga can use m68k/bus_dma.c for most bus_dma(9) functions
> like mac68k, but I wonder if DMA implementation on amiga has some
> DMA xfer range restriction, like 24 bit address range of ISA
> (or x68k's intio) which require bounce buffer support.

There probably are some restrictions, the exact details would be dependent on 
used PCI bridge (and these details are not known...). 

[1] - http://www.amibay.com/showthread.php?t=18613

-- 
Best regards,
Radoslaw Kujawa