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Re: [PATCH 2/6] dp8393x: don't force 32-bit register access
From: |
Finn Thain |
Subject: |
Re: [PATCH 2/6] dp8393x: don't force 32-bit register access |
Date: |
Sun, 4 Jul 2021 12:06:02 +1000 (AEST) |
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>
[PATCH 5/6] dp8393x: Replace address_space_rw(is_write=1) by address_space_write(), Philippe Mathieu-Daudé, 2021/07/03