On Mon, 2007-04-02 at 11:49 +0900, FUJITA Tomonori wrote:
> I started to work on SMP pass through via bsg as a non-SCSI command
> experimentation. I asked Doug to try the patch but it seems to take
> some time to make Doug's hardware work with the mainline aic94xxx
> driver.
If you post the code, others who also have the hardware can try it
too ...
> How should a user-space tool (like Doug's smp_utils) send a request
> and get the response via bsg?
Basic frame in/frame out ... this is why we need the block layer
bidirectional support
> -- each SAS object (host, device, expander, etc) has the own bsg
> device
I think so; probably attached via the transport class.
> A user-space tool opens a bsg device for a sas object that it wants to
> send a request to.
>
> -- one bsg device handles multiple SAS objects
>
> Some options: one bsg device in the whole system; one bsg device per
> SAS driver; one bsg device per SAS host; etc.
>
> With this approach, we need to invent a header incluing routing
> information.
>
> My hacky patch creates one bsg device per SAS host and invents:
>
> struct smp_passthrough_hdr {
> __u64 sas_address;
> __u8 phy_identifier;
> };
I'd really rather not go this route unless the one device per object
approach becomes untenable.
> a user-space tool sends this header instead of scb via bsg and put a
> SMP request at dout_xfer and a buffer response at din_xfer (note that
> now I do bidi transfer in a hacky way).
>
>
> - SAS implementation details
>
> As I said, the patch is too hacky. I just tried to implement a
> smp_portal alternative by using bsg.
>
> The patch adds a hook into sas transport class. sas_host_setup calls
> bsg_register_queue. Then, the request_fn calls smp_execute_task to
> send a smp request and get the response. It doesn't look good to link
> the sas transport class with libsas. In addition, the mpt driver
> handles smp request/response in a very different way.
>
> Any suggestion to bind SMP pass through via bsg to aic94xx and mpt
> cleanly?
bind in the transport class, not the driver ...
James
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