(cc'ing linux-scsi) Hello, On Fri, Jan 14, 2011 at 06:37:59PM +0100, Herbert Poetzl wrote: > Fair enough, let's start with a bunch of simple questions > I got from looking at the code (which I did just recently, > so don't expect deep understanding of the inner workings, > or even intelligent questions FWIW :) > > - libata is used in the kernel for ata, sata and to some > extend for scsi (via (s)ata), as a helper library. The (s) there is Serial not SCSI, but yes some SAS drivers use libata to drive SATA devices attached to SAS controllers. > is there any counterpart in userspace to communicate > with (s)ata host/devices or how are the interfaces to > userspace designed to work? SG_IO is the standard way to issue custom commands. You need to wrap ATA command inside a SCSI SCSI-ATA passthrough command. Take a look at hdparm, smartctl or any other tool which issues direct commands. > - the SiI3726 supports SAF-TE and SES protocols for the > SEMB/SEP and the EMCs are sent through the SATA interface > (according to the docu, SEP_ATTN in the command register > and SEP command code in the features register) > > + how would I send such a command and retrieve the result > (if there is one) from within the kernel (maybe with > libata or from the ahci layer)? If it's a proper command SAT passthrough via SG_IO should work but I'm not sure whether it is. Is it? > - the SiI3726 supports GPIO pins, which can be reached via > the General Status and Control Register [130] and accoring > to the docu, the Read/Write Port Multiplier command can > be used to read/write that register. > > + how would I go about issuing such a command and where > should it be done? i.e. what about interference with > other commands? what about retrieving return values? The problem is that the PMP device itself is currently not allocated a userland visible device, so it doesn't have any /dev/* node. Hmmm... > > There also was something added to ahci which is exported through > > sysfs. > > I saw that the ahci driver uses *em_message* which I > think might be related to sending activity messages and > it also lists capabilities (which include 'ems') on > host adapters, but I'm not entirely sure this is SEMB > related (yet) The message sent there can be of any format and that's why it was added as a separate sysfs node. ISTR there's a SCSI enclosure management driver. Maybe SCSI people have better clues about how enclosure management should be done? Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
