riscv/rocket-chip
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add comments and small fixes for NASTI and SMI

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This commit is contained in:
Howard Mao 2015-09-10 17:33:48 -07:00
parent 8a8d52da4f
commit 6387d31c62
2 changed files with 21 additions and 4 deletions
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12
junctions/src/main/scala/nasti.scala
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@ -226,6 +226,7 @@ class MemIONASTISlaveIOConverter(cacheBlockOffsetBits: Int) extends MIFModule wi
io.mem.resp.ready := io.nasti.r.ready
}
/** Arbitrate among arbN masters requesting to a single slave */
class NASTIArbiter(val arbN: Int) extends NASTIModule {
val io = new Bundle {
val master = Vec.fill(arbN) { new NASTISlaveIO }
@ -292,7 +293,8 @@ class NASTIArbiter(val arbN: Int) extends NASTIModule {
} else { io.slave <> io.master.head }
}
// TODO: More efficient implementation a/la Chisel Stdlib
/** Locking RR arbiter for NASTI read data channel
* Arbiter locks until last message in channel is sent */
class NASTIReadDataArbiter(arbN: Int) extends NASTIModule {
val io = new Bundle {
val in = Vec.fill(arbN) { Decoupled(new NASTIReadDataChannel) }.flip
@ -363,6 +365,9 @@ class NASTIErrorSlave extends NASTIModule {
b_queue.io.deq.ready := io.b.ready && !draining
}
/** Take a single NASTI master and route its requests to various slaves
* @param addrmap a sequence of base address + memory size pairs,
* on for each slave interface */
class NASTIRouter(addrmap: Seq[(BigInt, BigInt)]) extends NASTIModule {
val nSlaves = addrmap.size
@ -437,6 +442,11 @@ class NASTIRouter(addrmap: Seq[(BigInt, BigInt)]) extends NASTIModule {
io.master.r <> r_arb.io.out
}
/** Crossbar between multiple NASTI masters and slaves
* @param nMasters the number of NASTI masters
* @param nSlaves the number of NASTI slaves
* @param addrmap a sequence of base - size pairs;
* size of addrmap should be nSlaves */
class NASTICrossbar(nMasters: Int, nSlaves: Int, addrmap: Seq[(BigInt, BigInt)])
extends NASTIModule {
val io = new Bundle {

13
junctions/src/main/scala/smi.scala
View File

@ -11,6 +11,9 @@ class SMIReq(val dataWidth: Int, val addrWidth: Int) extends Bundle {
new SMIReq(dataWidth, addrWidth).asInstanceOf[this.type]
}
/** Simple Memory Interface IO. Used to communicate with PCR and SCR
* @param dataWidth the width in bits of the data field
* @param addrWidth the width in bits of the addr field */
class SMIIO(val dataWidth: Int, val addrWidth: Int) extends Bundle {
val req = Decoupled(new SMIReq(dataWidth, addrWidth))
val resp = Decoupled(Bits(width = dataWidth)).flip
@ -26,6 +29,7 @@ abstract class SMIPeripheral extends Module {
lazy val io = new SMIIO(dataWidth, addrWidth).flip
}
/** A simple sequential memory accessed through SMI */
class SMIMem(val dataWidth: Int, val memDepth: Int) extends SMIPeripheral {
// override
val addrWidth = log2Up(memDepth)
@ -35,9 +39,6 @@ class SMIMem(val dataWidth: Int, val memDepth: Int) extends SMIPeripheral {
val ren = io.req.fire() && !io.req.bits.rw
val wen = io.req.fire() && io.req.bits.rw
io.resp.valid := Reg(next = ren)
io.resp.bits := mem.read(io.req.bits.addr, ren)
when (wen) { mem.write(io.req.bits.addr, io.req.bits.data) }
val resp_valid = Reg(init = Bool(false))
@ -46,9 +47,14 @@ class SMIMem(val dataWidth: Int, val memDepth: Int) extends SMIPeripheral {
when (io.req.fire()) { resp_valid := Bool(true) }
io.resp.valid := resp_valid
io.resp.bits := mem.read(io.req.bits.addr, ren)
io.req.ready := !resp_valid
}
/** Arbitrate among several SMI clients
* @param n the number of clients
* @param dataWidth SMI data width
* @param addrWidth SMI address width */
class SMIArbiter(val n: Int, val dataWidth: Int, val addrWidth: Int)
extends Module {
val io = new Bundle {
@ -243,6 +249,7 @@ class SMIIONASTIWriteIOConverter(val dataWidth: Int, val addrWidth: Int)
when (io.b.fire()) { state := s_idle }
}
/** Convert NASTI protocol to SMI protocol */
class SMIIONASTISlaveIOConverter(val dataWidth: Int, val addrWidth: Int)
extends NASTIModule {
val io = new Bundle {