Re: [PATCH 2/6] dp8393x: don't force 32-bit register access

[Finn Thain]

On Sat, 3 Jul 2021, Philippe Mathieu-Daudé wrote:

> From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> 
> Commit 3fe9a838ec "dp8393x: Always use 32-bit accesses" assumed that all 
> accesses
> to the registers were 32-bit but this is actually not the case. The access 
> size is
> determined by the CPU instruction used and not the number of physical address 
> lines.
> 
> The big_endian workaround applied to the register read/writes was actually 
> caused
> by forcing the access size to 32-bit when the guest OS was using a 16-bit 
> access.
> Since the registers are 16-bit then we can simply set .impl.min_access to 2 
> and
> then the memory API will automatically do the right thing for both 16-bit 
> accesses
> used by Linux and 32-bit accesses used by the MacOS toolbox ROM.
> 
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> Fixes: 3fe9a838ec ("dp8393x: Always use 32-bit accesses")
> Tested-by: Finn Thain <fthain@linux-m68k.org>

I have to retract that tested-by tag for this new version. It breaks my 
Linux/mipsel guest. The jazzsonic driver now says,

SONIC ethernet controller not found (0x40004)

> Message-Id: <20210625065401.30170-9-mark.cave-ayland@ilande.co.uk>
> [PMD: dp8393x_ops.impl.max_access_size 4 -> 2]
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>