[OpenBIOS] Solaris 8: ESP device enumeration issue

[Blue Swirl]

On Sat, Feb 26, 2011 at 6:52 PM, Mark Cave-Ayland
<mark.cave-ayland at siriusit.co.uk> wrote:
> On 26/02/11 16:36, Blue Swirl wrote:
>
>>> A flush should be the removal of an entry, so I would guess that Solaris
>>> flushes the relevant entries and then adds them back into its IOMMU page
>>> table manually?
>>
>> The flush would just affect an internal TLB, which is not implemented
>> in QEMU, so the flush has no effect.
>
> Right. So I added some extra code to QEMU again to get it to print the
> current translation for 0xfc000000 every time the IOMMU is accessed, and
> that looks like this:
>
> Jumping to entry point 00004000 for type 00000005...
> switching to new context:
> Size: 259040+54154+47486 Bytes
> SunOS Release 5.8 Version Generic_108528-09 32-bit
> Copyright 1983-2001 Sun Microsystems, Inc.  All rights reserved.
> Ethernet address = 52:54:0:12:34:56
> Using default device instance data
> vac: enabled in write through mode
> mem = 131072K (0x8000000)
> avail mem = 110419968
> ### Writing to iommu addr: 1, value 6bc000   0
> --- Current translation for 0xfc000000 is 7fba06
> ### Setting IOMMU base addr: 6bc000
> ### Writing to iommu addr: 0, value 9   0
> --- Current translation for 0xfc000000 is 0
> ### Writing to iommu addr: 5, value 0   0
> --- Current translation for 0xfc000000 is 0
> ### IOMMU TLB flush 0
> root nexus = SUNW,SPARCstation-5
> iommu0 at root: obio 0x10000000
> sbus0 at iommu0: obio 0x10001000
> dma0 at sbus0: SBus slot 5 0x8400000
> dma0 is /iommu at 0,10000000/sbus at 0,10001000/espdma at 5,8400000
> ### Writing to iommu addr: 6, value fc000000   0
> --- Current translation for 0xfc000000 is 0
> ### IOMMU page flush fc000000
> /iommu at 0,10000000/sbus at 0,10001000/espdma at 5,8400000/esp at 5,8800000 (esp0):
>        esp-options=0x46
> esp0 at dma0: SBus slot 5 0x8800000 sparc ipl 4
> esp0 is /iommu at 0,10000000/sbus at 0,10001000/espdma at 5,8400000/esp at 5,8800000
> ### Writing to iommu addr: 6, value fc001000   0
> --- Current translation for 0xfc000000 is 0
> ### IOMMU page flush fc001000
> qemu: fatal: Trap 0x29 while interrupts disabled, Error state
>
> So the existing translation put in place by OpenBIOS is fine until the the
> IOMMU page table is switched, at which point we die because it doesn't get
> replaced.
>
> The fact that it is the 0xc2 (DMA enabled) command which is issued rather
> than the 0x42 non-DMA version is making this seem more of a QEMU bug as
> opposed to an OpenBIOS bug. Surely a kernel must set up its DMA buffers
> first before attempting a DMA command?
>
> Artyom: can you definitely boot Solaris 8 under OBP? And in fact, can you
> boot any of your other test images using OpenBIOS SVN trunk?
>
> Blue: what debugging do I need to add to prove that this is the DMA bug you
> mentioned before?

Tracepoint logs with all points from both sparc32_dma.c and
sun4m_iommu.c enabled?