SAS - primitive after SOF

Sriram Srinivasan srirams at lsil.com
Tue Jun 11 08:48:20 PDT 2002


* From the T10 Reflector (t10 at t10.org), posted by:
* Sriram Srinivasan <srirams at lsil.com>
*
Rob:

  I understand that primitives are allowed in an SSP frame.  My question was 
specifically aimed at those immediately before or after an EOF or SOF 
respectively.  If it is NOT an error why mandate: [SOF DWORD .... DWORD EOF] 
?!? i.e. why disallow primitives before EOF or after SOF during 
transmission?
  
  So if I get [SOF DWORD1 ... DWORDN RRDY EOF]  how do I know that DWORDN 
was CRC for the frame?!?  What if I get 5 RRDYs between the CRC and the 
EOF?!?  How do I recognize the CRC?  I guess that is why the primitives are 
disallowed in those spots.  So if they are not allowed and I DO get a 
primitive in those positions what do I do?

  Should clause 7.13.6.3.1 "SSP_RF1:Frame_rcv state description" also 
describe this case (just as it describes receiving two SOF primitives 
without an intervening EOF primitive) as a protocol violation condition?
  
  thank you,
  \Sriram\
  
~ 
~ * From the T10 Reflector (t10 at t10.org), posted by:
~ * "Elliott, Robert (Server Storage)" <Elliott at hp.com>
~ *
~ 
~ > -----Original Message-----
~ > From: Sriram Srinivasan [mailto:srirams at lsil.com] 
~ > Sent: Monday, June 10, 2002 4:36 PM
~ > Subject: SAS - primitive after SOF
~ >
~ > In sas-r00a.pdf clause 7.13.6.7.1 SSP_T1:Transmit state 
~ > description states:
~ >   
~ > "On an indication that a SOF/frame/EOF is to be transmitted 
~ > the transmit state shall transmit an SOF in the dword before 
~ > the first dword of the frame and an EOF in first dword after 
~ > the last dword of the frame. 
~ > If during the transmission of a frame an indication that a 
~ > primitive is to be transmitted occurs the transmit state may 
~ > transmit the indicated primitive by inserting 
~ > the primitive between the frames  dwords."
~ >   
~ > If the receiving device gets a primitive immediately after 
~ > an SOF or immediately before an EOF, is it supposed to 
~ > indicate a protocol error to the port layer?  
~ 
~ No error - primitives are allowed inside SSP frames.  This is
~ mainly for ALIGN, RRDY, ACK, and NAK.
~ 
~ The SSP_RF states are the ones that receive frames (there are
~ some typos where SSP_FR is used, but they're the same).
~ 
~ > Or should the primitive(s) just be processed as usual and 
~ > the frame accepted?
~ 
~ Yes.
~ 
~ >  Sriram Srinivasan                       Sriram.Srinivasan at lsil.com
~ >  ASIC Design Engineer, LSI Logic,
~ >  2001 Danfield Ct., 				Phone: 970-206-5847
~ >  Fort Collins, CO 80525				FAX  : 
~ > 970-206-5244
~ 
~ --
~ Rob Elliott, elliott at hp.com
~ Industry Standard Server Storage Advanced Technology
~ Hewlett-Packard
~ 
~ *
~ * For T10 Reflector information, send a message with
~ * 'info t10' (no quotes) in the message body to majordomo at t10.org



----------------------------------------------------------------------
	"FORGET NOT THAT THE EARTH DELIGHTS TO FEEL YOUR BARE FEET,
               AND THE WINDS LONG TO PLAY WITH YOUR HAIR"
                                          -Khalil Gibran

 Sriram Srinivasan                       Sriram.Srinivasan at lsil.com
 ASIC Design Engineer, LSI Logic,
 2001 Danfield Ct., 				Phone: 970-206-5847
 Fort Collins, CO 80525				FAX  : 970-206-5244
----------------------------------------------------------------------

*
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