Import ml507 mig TL implementation stub

2018-05-09 23:17:08 +02:00 · 2018-05-09 23:17:08 +02:00 · 3797385a8c
commit 3797385a8c
parent 79b53cf2ae
1 changed files with 104 additions and 0 deletions
--- a/src/main/scala/devices/xilinx/xilinxml507mig/XilinxML507MIG.scala
+++ b/src/main/scala/devices/xilinx/xilinxml507mig/XilinxML507MIG.scala
@ -0,0 +1,104 @@
+// See LICENSE.SiFive for license details.
+
+package sifive.fpgashells.devices.xilinx.xilinxml507mig
+
+import Chisel._
+import freechips.rocketchip.config.{Field, Parameters}
+import freechips.rocketchip.diplomacy._
+import freechips.rocketchip.subsystem.BaseSubsystem
+import freechips.rocketchip.tilelink._
+import freechips.rocketchip.util._
+
+case class MemoryML507Params(
+    address: Seq[AddressSet]
+)
+
+case object MemoryML507Key extends Field[MemoryML507Params]
+
+trait HasMemoryML507 { this: BaseSubsystem =>
+    val memory = LazyModule(new TLMemoryML507(p(MemoryML507Key)))
+
+    // The Fragmenter will not fragment messages <= 32 bytes, so all
+    // slaves have to support this size. 64 byte specifies the maximum
+    // supported transfer size that the slave side of the fragmenter supports
+    // against the master (here the main memory bus). Specifying alwaysMin as
+    // true results in all messages being fragmented to the minimal size
+    // (32 byte). In TL1 terms, slaves
+    // correspond roughly to managers and masters to clients (confusingly…).
+    val fragmenter = TLFragmenter(32, 64, alwaysMin=true)
+
+    // TODO: right TL/memory node chain?
+    memory.node := fragmenter := memBuses.head.toDRAMController(Some("ml507mig"))()
+}
+
+class TLMemoryML507(c: MemoryML507Params)(implicit p: Parameters) extends LazyModule {
+    // Corresponds to MIG interface with 64 bit width and a burst length of 4
+    val width = 256
+    val beatBytes = width/8 // 32 byte (half a cache-line, fragmented)
+
+    val device = new MemoryDevice
+    val node = TLManagerNode(
+        Seq(TLManagerPortParameters(
+            Seq(TLManagerParameters(
+                address         = c.address,
+                resources       = device.reg,
+                regionType      = RegionType.UNCACHED,
+                executable      = true,
+                supportsGet     = TransferSizes(1, beatBytes),
+                supportsPutFull = TransferSizes(1, beatBytes),
+                fifoId          = Some(0) // in-order
+            )),
+            beatBytes = beatBytes
+        ))
+    )
+    // We could possibly also support supportsPutPartial, as we need support
+    // for masks anyway because of the possibility of transfers smaller that
+    // the data width (size signal, see below).
+
+    lazy val module = new LazyModuleImp(this) {
+        // in: TLBundle, edge: TLEdgeIn
+        val (in, edge) = node.in(0)
+
+        // Due to the Fragmenter defined above, all messages are 32 bytes or
+        // smaller. The data signal of the TL channels is also 32 bytes, so
+        // all messages will be transfered in a single beat.
+        // Also, TL guarantees (see TL$4.6) that the payload of a data message
+        // is always aligned to the width of the beat, e.g. in case of a 32
+        // byte data signal, data[7:0] will always have address 0x***00000 and
+        // data[255:247] address 0x***11111. It is also guaranteed that the
+        // mask bits always correctly reflect the active bytes inside the beat
+        // with respect to the size and address.
+        // So we can directly forward the mask, (relative) address and possibly
+        // data to the MIG interface.
+        // Put requests can be acknowledged as soon as they are latched into
+        // the write fifo of the MIG (possibly combinatorily).
+        // For read requests, we have to store the source id and size in a
+        // queue for later acknowledgment.
+        // We are ready if both the MIG and the response data queue are not
+        // full.
+
+        // Widths of the A channel:
+        // addressBits: 32
+        // dataBits:    256
+        // sourceBits:  6
+        // sinkBits:    1
+        // sizeBits:    3
+
+        // source (from): in.a.bits.source
+        // adresse (to): edgeIn.address(in.a.bits)
+        // size: edgeIn.size(in.a.bits)
+        // isPut: edgeIn.hasData(in.a.bits)
+
+        // bits kommt von Decoupled: ready, valid + bits
+
+        println("a parameters: " + in.a.bits.params)
+
+        in.a.ready := Bool(false)
+        in.d.valid := Bool(false)
+
+        // Tie off unused channels
+        in.b.valid := Bool(false)
+        in.c.ready := Bool(true)
+        in.e.ready := Bool(true)
+    }
+}