Date: Tue, 22 Feb 2000 16:00:18 +0530 From: Nanda Kumar <nanda@procsys.com> To: "Kenneth D. Merry" <ken@kdm.org> Cc: freebsd-scsi@FreeBSD.ORG Subject: Re: Help to write a SCSI block driver Message-ID: <38B2653A.41C5@procsys.com> References: <38B22C09.2B7A@procsys.com> <20000221235253.A16855@panzer.kdm.org>
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Hi, The card that i am using is a RAID adapter and the RAID functionality is implemented in the firmware running on the adapter. Hence it can be treated as a normal SCSI adapter as far as the driver is concerned. So i think i can write the device driver as SCSI block device driver. Is there any documentation available on how the SCSI block device driver interacts with the system ? Thanks a lot Regards, Nandan >Kenneth D. Merry wrote: > > On Tue, Feb 22, 2000 at 11:56:17 +0530, Nanda Kumar wrote: > > > > I have to write a SCSI block device driver for one RAID controller we > > have designed. Can anyone tell me how to go about it ? We have already > > one Windows miniport driver working for the same card. Please tell me a > > good sample driver to go through and if any document is available > > regarding how to write a SCSI block device driver and how it interacts > > with the system. I am quite new to the unix world. > > Well, the device model you use will really depend on what sort of interface > your RAID controller presents. > > There are two basic categories that other RAID controllers fall into right > now: > > - controllers that can function as a standard SCSI controller, as well as > a RAID controller. (e.g. you could put a CDROM drive on the controller, > and access it with standard SCSI commands) The DPT cards fall into this > category. > > - controllers that function primarily as a RAID controller, and don't > allow direct SCSI acess to devices on their busses. The AMI, Mylex, and > Compaq SmartRAID controllers fall into this category. > > Controllers that fall into the first category would probably be best > written as HBA drivers under the CAM SCSI layer. General documentation on > CAM is located here: > > http://www.t10.org/drafts.htm#SWLAY > > Controllers that fall into the second category should probably written as > block device drivers, like the AMI, Mylex, and Compaq drivers. > > The other RAID drivers are located in the following places in the FreeBSD > source tree: > > DPT: src/sys/dev/dpt > AMI: src/sys/dev/amr > Mylex: src/sys/dev/mlx > Compaq: src/sys/dev/ida > > If you want to look at plain SCSI card drivers, there are plenty to choose > from as well. Here are a few samples: > > Adaptec AIC 7xxx chips: src/sys/dev/aic7xxx > Advansys chips: src/sys/dev/advansys > Symbios/LSI chips: src/sys/dev/sym > Adaptec 154x-type boards: src/sys/dev/aha > > Ken > -- > Kenneth Merry > ken@kdm.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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