ATA_16 support on mptsas

["Krzysztof Błaszkowski" <kb@sysmikro.com.pl>]

Hello,

I found that any HDIO_DRIVE_CMD ioctl on sata drive connected through mpsas 
and backplane will fail. Basically the scsi_host_template structure is 
missing ioctl callback. after adding it and temporary tweaking domain_device 
structure associated to scsi_device (rphy only) i reached a point where 
ata_scsi_ioctl returns EIO and this why i need some clue on a way of adding 
such support similar way to aic94 where it has been done.

I found also that mptsas leaves domain_device rather uninitialized. the 
example is rphy but there more fields i don't know if they are revelant to 
proper processing of HDIO_DRIVE_CMD.
i need additional references on libata design, call flow and structures 
relationship.

probably it would be the best to design mptsas from scratch using libsas but 
this seems to me as huge work although if i was guided i would probably 
complete this.


I tried another approach where i used SG_IO ioctl and prepared ATA_16 cdb 
(just like libata does) but this failed on mptsas connected drives too 
altough this way works on drives connected to ICH6.

Regards,
Krzysztof Blaszkowski