[SLOF] [PATCH] board-qemu/slof/vio-vscsi: Scan up to 64 SCSI IDs

[Thomas Huth]

On 2018-12-06 12:07, Laurent Vivier wrote:
> On 06/12/2018 12:02, Thomas Huth wrote:
>> QEMU supports up the 64 SCSI IDs on the vscsi "bus", see the string
>> "max_target = 63" in the source file hw/scsi/spapr_vscsi.c of QEMU.
>> However, SLOF currently only checks the first 9 IDs on the vscsi adaptor,
>> so when you try to boot from a CD-ROM like this, the boot fails:
>>
>>  qemu-system-ppc64 ... -device spapr-vscsi,id=scsi0,reg=0x2000 \
>>     -drive file=/path/to/cdrom.iso,format=raw,if=none,id=dr1,readonly=on \
>>     -device scsi-cd,bus=scsi0.0,channel=0,scsi-id=63,lun=1,drive=dr1,id=scd1
>>
>> Thus let's change the amount of IDs that we scan in SLOF to 64, too, to
>> match the ID range that QEMU provides.
>>
>> Signed-off-by: Thomas Huth <thuth at redhat.com>
>> ---
>>  board-qemu/slof/vio-vscsi.fs | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/board-qemu/slof/vio-vscsi.fs b/board-qemu/slof/vio-vscsi.fs
>> index f2d4c6f..be11b69 100644
>> --- a/board-qemu/slof/vio-vscsi.fs
>> +++ b/board-qemu/slof/vio-vscsi.fs
>> @@ -507,9 +507,9 @@ TRUE VALUE first-time-init?
>>      10000 \ Larger value seem to have problems with some CDROMs
>>  ;
>>  
>> -8 CONSTANT #dev
>> +\ Report the amount of supported SCSI IDs - QEMU uses "max_target = 63"
>>  : dev-max-target ( -- #max-target )
>> -    #dev
>> +    40
>>  ;
>>  
>>  " scsi-probe-helpers.fs" included
>>
> 
> In SLOF, it seems the id is encoded on 3 bits, see:
> 
> \ We use SRP luns of the form 8000 | (bus << 8) | (id << 5) | lun
> \ in the top 16 bits of the 64-bit LUN
> : (set-target)
>     to current-target
> ;
> 
> : dev-generate-srplun ( target lun -- )
>     swap 8 << 8000 or or 30 <<
> ;

Let me write that in C code:

  srplun = ((target << 8) | 0x8000 | lun) << 0x30;

If I count correctly, we've got 7 bits here, not 3, so my patch should
be fine ...?

 Thomas