Subject: Re: netbooting an OF 1.0.5 macppc with SUNW,hme on PCI
To: None <mrg@eterna.com.au>
From: Izumi Tsutsui <tsutsui@ceres.dti.ne.jp>
List: port-macppc
Date: 04/05/2000 20:58:54
In <6806.954915188@eterna.com.au>
mrg@eterna.com.au wrote:

>    Does PCI isp SCSI support DMA with big endian hosts?
>    If no, some byte-swap macros are needed in /sys/dev/isp.c
>    for DMA transfers, but they would break SBUS isp code.
>    I think hme_pci might have the same problem.
> 
> UltraSPARC PCI already does various dances to get accesses
> performed in the correct manner...

Well, then does the PCI-host bridge on sparc64 do byte-swapping
even when the PCI bus-master accesses memory on its host via DMA?
Other PCI drivers which contain byte-swapping code would not
work on sparc64?

BTW, it seems that /sys/dev/ic/hme.c has bus_dmamem_alloc() and
bus_dmamem_map() but no bus_dmamap_load() nor bus_dmamap_sync()...
Anyway, does hme pass non byte-stream (like u_int32_t) data via DMA?
if no, no byte-swapping code is needed even on other big endian archs.
---
Izumi Tsutsui
tsutsui@ceres.dti.ne.jp