Jeff Garzik wrote: > Rather than sitting on this for far too long, I wanted to go ahead and > get this out there. I heard some chips might be trickling out into > public hands. > > This is a bare bones Broadcom 8603 SAS+SATA driver, attempting to use > the vaunted libsas. Notes: > > * A quick glance at the FIXMEs will tell you obviously doesn't work. > > * The hardware is quite simple and straightforward and easy to program > in an efficient way: each SAS port has a command queue (DMA ring) and > a response queue (DMA ring). Or if in SATA mode, just a command > queue. > > * The SAS/SATA negotiation is largely out of our hands. The silicon > does its thing, and then tells us what type of device connected. We > are then expected to switch the port to either SAS mode or SATA mode, > accordingly. > > * There is no firmware or anything. Just DMA and register bitbanging. > We have plenty of low-level control. > > * The state of SAS/SATA integration is perpetually pathetic. Updates > in this area are likely. There's a rumor Brian King @ IBM may look > into this area too. > > * This driver pretty much completely lacks exception handling. > > > As an aside, I am also writing a driver for Marvell chips that behave > quite similarly to this chip. It seems the future of storage might look > like these Broadcom and Marvell SAS+SATA DMA ring interfaces, in the > volume marketspace at least. Jeff, Is the lack of SMP support a driver limitation or is it the silicon? How about support for wide ports (i.e. when 2 or more HBA phys are attached to remote phys which have the same SAS addresses)? Last question: can the chip run in SCSI target mode? Doug Gilbert - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
