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ahb: SRAM reports errors on illegal access

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This commit is contained in:
Wesley W. Terpstra
2017-07-07 19:39:03 -07:00
parent 19851a7c9e
commit f1fb3be603
1 changed files with 4 additions and 2 deletions
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6
src/main/scala/amba/ahb/SRAM.scala
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@@ -38,6 +38,7 @@ class AHBRAM(address: AddressSet, executable: Boolean = true, beatBytes: Int = 4
val a_mask = MaskGen(in.haddr, in.hsize, beatBytes)
val a_address = Cat((mask zip (in.haddr >> log2Ceil(beatBytes)).toBools).filter(_._1).map(_._2).reverse)
val a_write = in.hwrite
val a_legal = address.contains(in.haddr)
// The data phase signals
val d_wdata = Vec.tabulate(beatBytes) { i => in.hwdata(8*(i+1)-1, 8*i) }
@@ -67,6 +68,7 @@ class AHBRAM(address: AddressSet, executable: Boolean = true, beatBytes: Int = 4
val read = a_request && !a_write
// In case we choose to stall, we need to hold the read data
val d_rdata = mem.readAndHold(a_address, read)
val d_legal = RegEnable(a_legal, in.hreadyout)
// Whenever the port is not needed for reading, execute pending writes
when (!read && p_valid) {
p_valid := Bool(false)
@@ -75,7 +77,7 @@ class AHBRAM(address: AddressSet, executable: Boolean = true, beatBytes: Int = 4
// Record the request for later?
p_latch_d := a_request && a_write
when (a_request && a_write) {
when (a_request && a_write && a_legal) {
p_valid := Bool(true)
p_address := a_address
p_mask := a_mask
@@ -96,7 +98,7 @@ class AHBRAM(address: AddressSet, executable: Boolean = true, beatBytes: Int = 4
// Finally, the outputs
in.hreadyout := (if(fuzzHreadyout) { !d_request || LFSR16(Bool(true))(0) } else { Bool(true) })
in.hresp := AHBParameters.RESP_OKAY
in.hresp := Mux(d_legal || !in.hreadyout, AHBParameters.RESP_OKAY, AHBParameters.RESP_ERROR)
in.hrdata := Mux(in.hreadyout, muxdata.asUInt, UInt(0))
}
}