Hi Horatiu, On Sat, Sep 26, 2020 at 01:20:02PM +0200, Horatiu Vultur wrote: > To be honest, I don't remember precisely. I will need to setup a board > and see exactly. But from what I remember: > - according to this[1] in chapter 3.8.6, table 71. It says that the full > entry of IS2 is 384. And this 384 represent a full entry. In this row, > can be also sub entries like: half entry and quater entries. And each > entry has 2 bits that describes the entry type. So if you have 2 bits > for each possible entry then you have 8 bits describing each type. One > observation is even if you have a full entry each pair of 2 bits > describing the type needs to be set that is a full entry. But if I have a single entry per row, I have a single Type-Group value, so I only need to subtract 2, no? > Maybe if you have a look at Figure 30, it would be a little bit more > clear. Even there is a register called VCAP_TG_DAT that information > is storred internally in the VCAP_ENTRY_DAT. See, this is what I don't understand. You're saying that the Type-Group is stored as part of the entry inside the TCAM, even if you're accessing it through a different set of cache registers? What else is stored in a TCAM row sub-word? The key + mask + Type-Group are stored in the same sub-word, I assume? > - so having those in mind, then VCAP_IS2_ENTRY_WIDTH is the full entry > length - 8 bits. 384 - 8 = 376. But there are 4 Type-Group (and therefore 4 entries per row) only if the entries are for quarter keys, am I not correct? And the IS2 code currently uses half keys. Does this variable need to be set differently according to the key size? > - then if I remember correctly then VCAP_CONST_ENTRY_WIDTH should be > 384? or 12 if it is counting the words. Yes, it is 384 and the VCAP core version is 0. > Does it make sense or am I completly off? So, in simple words, what is the physical significance of (VCAP_CONST_ENTRY_WIDTH - VCAP_CONST_ENTRY_TG_WIDTH * VCAP_CONST_ENTRY_SWCNT)? To my understanding, it means the size used by all key+mask entries within a TCAM row (therefore without the length of Type-Group fields) when that row contains 4 quarter keys. Divide this number by 2, you get the length of the key, or the length of the mask, for a single sub-word, BUT only assuming that quarter keys are used. So, why does this value have any significance to a driver that is not using quarter keys? Am _I_ completely off? This is so confusing. Thanks, -Vladimir
