Section 4.9 in ARM IHI 0050E.c mentions the below
RetToSrc is inapplicable and must be set to zero in:
• SnpQuery and Stash snoops
• SnpCleanShared, SnpCleanInvalid, and SnpMakeInvalid
• SnpOnceFwd and SnpUniqueFwd
RetToSrc is applicable and can take any value in all other snoops except SnpDVMOp. Also Table 4 - 53 shows different values of RetToSrc applicable for SnpCleanFwd, SnpNotSharedDirtyFwd
But table A-10 in the appendix mentions the value of RetToSrc to be 0 always which is contradicting
Hi Nachiket,
This is incorrect in the Appendix tables for Issue E.c and was fixed in Issue F.b of the CHI Specification - RetToSrc can be non-zero for these snoop types . The latest release is issue G - developer.arm.com/.../
Thanks Christopher Tory for the clarification!