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AHBToTL: finally get the error signal right? (#594)

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This commit is contained in:
Wesley W. Terpstra 2017-03-18 22:24:20 -07:00 committed by GitHub
parent d4272db067
commit a4ca424a22
1 changed files with 19 additions and 16 deletions
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31
src/main/scala/uncore/ahb/ToTL.scala
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@ -50,14 +50,15 @@ class AHBToTL()(implicit p: Parameters) extends LazyModule
val d_send = RegInit(Bool(false))
val d_recv = RegInit(Bool(false))
val d_pause = RegInit(Bool(true))
val d_error = RegInit(Bool(false))
val d_pause = RegInit(Bool(false))
val d_write = RegInit(Bool(false))
val d_addr = Reg(in.haddr)
val d_size = Reg(in.hsize)
when (out.d.valid) { d_recv := Bool(false) }
when (out.a.ready) { d_send := Bool(false) }
when (in.hresp) { d_pause := Bool(false) }
val a_count = RegInit(UInt(0, width = 4))
val a_first = a_count === UInt(0)
@ -85,16 +86,6 @@ class AHBToTL()(implicit p: Parameters) extends LazyModule
val a_access = in.htrans === AHBParameters.TRANS_NONSEQ || in.htrans === AHBParameters.TRANS_SEQ
val a_accept = in.hready && in.hsel && a_access
// Make the error persistent
d_error :=
((d_error || (out.d.valid && out.d.bits.error)) // OR in a new error report
&& !(a_first && in.hready)) // clear error when a new beat starts
(a_accept && !a_legal) // error if the address requested is illegal
// When we report an error, we need to be hreadyout LOW for one cycle
val inject_error = d_last && (d_error || (out.d.valid && out.d.bits.error))
when (inject_error) { d_pause := Bool(true) }
when (a_accept) {
a_count := a_count - UInt(1)
when ( in.hwrite) { d_send := Bool(true) }
@ -103,7 +94,7 @@ class AHBToTL()(implicit p: Parameters) extends LazyModule
a_count := Mux(a_burst_ok, a_burst_mask >> log2Ceil(beatBytes), UInt(0))
d_send := a_legal
d_recv := a_legal
d_pause := Bool(false)
d_pause := Bool(true)
d_write := in.hwrite
d_addr := in.haddr
d_size := Mux(a_burst_ok, a_burst_size, in.hsize)
@ -118,10 +109,22 @@ class AHBToTL()(implicit p: Parameters) extends LazyModule
out.a.bits.address := d_addr
out.a.bits.data := in.hwdata
out.a.bits.mask := maskGen(d_addr, d_size, beatBytes)
out.d.ready := d_recv // backpressure AccessAckData arriving faster than AHB beats
in.hrdata := out.d.bits.data
in.hresp := inject_error
in.hreadyout := (!inject_error || d_pause) && Mux(d_write, (!d_send || out.a.ready) && (!d_last || !d_recv || out.d.valid), out.d.valid || !d_recv)
// In a perfect world, we'd use these signals
val hresp = d_error || (out.d.valid && out.d.bits.error)
val hreadyout = Mux(d_write, (!d_send || out.a.ready) && (!d_last || !d_recv || out.d.valid), out.d.valid || !d_recv)
// Make the error persistent (and defer it to the last beat--otherwise AHB can cancel the burst!)
d_error :=
(hresp && !(a_first && in.hready)) || // clear error when a new beat starts
(a_accept && !a_legal) // error if the address requested is illegal
// When we report an error, we need to be hreadyout LOW for one cycle
in.hresp := hreadyout && (hresp && d_last)
in.hreadyout := hreadyout && !(hresp && d_last && d_pause)
// Unused channels
out.b.ready := Bool(true)