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axi4 Fragmenter: confirm correct handling of last

This commit is contained in:
Wesley W. Terpstra 2016-10-13 13:49:47 -07:00
parent 1c79a23a8b
commit 84be93f9f3
1 changed files with 6 additions and 4 deletions
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10
src/main/scala/uncore/axi4/Fragmenter.scala
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@ -53,10 +53,10 @@ class AXI4Fragmenter(lite: Boolean = false, maxInFlight: Int = 32, combinational
* FIXED => each beat is a new request
* WRAP/INCR => take xfr up to next power of two, capped by max size of target
*
* On AR and AW, we fragment the requests
* On W we insert 'last' to match
* On R we surpress 'last'
* On B we surpress 'valid'
* On AR and AW, we fragment one request into many
* On W we set 'last' on beats which are fragment boundaries
* On R we clear 'last' on the fragments being reassembled
* On B we clear 'valid' on the responses for the injected fragments
*
* AR=>R and AW+W=>B are completely independent state machines.
*/
@ -208,6 +208,8 @@ class AXI4Fragmenter(lite: Boolean = false, maxInFlight: Int = 32, combinational
in_w.ready := out_w.ready && (!wbeats_ready || wbeats_valid)
out_w.bits := in_w.bits
out_w.bits.last := w_last
// We should also recreate the last last
assert (!out_w.valid || !in_w.bits.last || w_last)
// R flow control
val r_last = out_r.bits.last