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Date: Fri, 17 Dec 2010 14:36:11 -0600
From: Bob Breuer <breuerr@mc.net>
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Subject: Re: [Qemu-devel] [PATCH] sparc32_dma: separate ledma and espdma
References: <AANLkTim+QOaRxb41s0nOgGOcsNtTm6kCYq6Whu5suVV5@mail.gmail.com>
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To: Blue Swirl <blauwirbel@gmail.com>
Cc: qemu-devel <qemu-devel@nongnu.org>, Artyom Tarasenko <atar4qemu@gmail.com>

Blue Swirl wrote:
> ESP and Lance DMA controllers are not identical.
>
> Separate the controllers on VMState and instantiation level.
>
> NB: This change breaks savevm and migration compatibility.
>
> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
> ---
> Perhaps the compat properties could be used to retain compatibility.
> But if nobody cares (as I suspect), let's just break it.
>
> Further changes can either use s->is_ledma or make the state
> structures separate.
>
>  hw/sparc32_dma.c |   65 ++++++++++++++++++++++++++++++++++++++++++++---------
>  hw/sun4m.c       |   16 ++++++------
>  2 files changed, 62 insertions(+), 19 deletions(-)
>   

This change never made it in, and I found a case that may benefit from it.

The ledma seems to have an extra register that Solaris 9 reads, address
0x78400020 on SS-5, and the OBP properties of a SS-20 do indicate that
there could be up to 32 bytes of registers:
  ok cd /iommu/sbus/ledma
  ok .attributes
  burst-sizes              0000003f
  reg                      0000000f  00400010  00000020
  name                     ledma

As a hack, you can get Solaris 9 to boot single user by adding this one
line to sun4m_hw_init() in sun4m.c:
    empty_slot_init(hwdef->dma_base + 32ULL, 16);

Bob