CRC Generation Module

src/main/scala/d2dadapter/CRC16Lookup8Bit.scala

@@ -0,0 +1,271 @@
+package edu.berkeley.cs.ucie.digital.d2dadapter
+
+import chisel3._
+
+class CRC16Lookup {
+
+  /** Lookup table for CRC-16 (0x8005) polynomial. Consumes message from MSB
+    * Byte to LSB Byte and results in CRC[15:0] in unreversed format as detailed
+    * in UCIe1.1 spec.
+    */
+
+  val table = VecInit(
+    0x0000.U,
+    0x8005.U,
+    0x800f.U,
+    0x000a.U,
+    0x801b.U,
+    0x001e.U,
+    0x0014.U,
+    0x8011.U,
+    0x8033.U,
+    0x0036.U,
+    0x003c.U,
+    0x8039.U,
+    0x0028.U,
+    0x802d.U,
+    0x8027.U,
+    0x0022.U,
+    0x8063.U,
+    0x0066.U,
+    0x006c.U,
+    0x8069.U,
+    0x0078.U,
+    0x807d.U,
+    0x8077.U,
+    0x0072.U,
+    0x0050.U,
+    0x8055.U,
+    0x805f.U,
+    0x005a.U,
+    0x804b.U,
+    0x004e.U,
+    0x0044.U,
+    0x8041.U,
+    0x80c3.U,
+    0x00c6.U,
+    0x00cc.U,
+    0x80c9.U,
+    0x00d8.U,
+    0x80dd.U,
+    0x80d7.U,
+    0x00d2.U,
+    0x00f0.U,
+    0x80f5.U,
+    0x80ff.U,
+    0x00fa.U,
+    0x80eb.U,
+    0x00ee.U,
+    0x00e4.U,
+    0x80e1.U,
+    0x00a0.U,
+    0x80a5.U,
+    0x80af.U,
+    0x00aa.U,
+    0x80bb.U,
+    0x00be.U,
+    0x00b4.U,
+    0x80b1.U,
+    0x8093.U,
+    0x0096.U,
+    0x009c.U,
+    0x8099.U,
+    0x0088.U,
+    0x808d.U,
+    0x8087.U,
+    0x0082.U,
+    0x8183.U,
+    0x0186.U,
+    0x018c.U,
+    0x8189.U,
+    0x0198.U,
+    0x819d.U,
+    0x8197.U,
+    0x0192.U,
+    0x01b0.U,
+    0x81b5.U,
+    0x81bf.U,
+    0x01ba.U,
+    0x81ab.U,
+    0x01ae.U,
+    0x01a4.U,
+    0x81a1.U,
+    0x01e0.U,
+    0x81e5.U,
+    0x81ef.U,
+    0x01ea.U,
+    0x81fb.U,
+    0x01fe.U,
+    0x01f4.U,
+    0x81f1.U,
+    0x81d3.U,
+    0x01d6.U,
+    0x01dc.U,
+    0x81d9.U,
+    0x01c8.U,
+    0x81cd.U,
+    0x81c7.U,
+    0x01c2.U,
+    0x0140.U,
+    0x8145.U,
+    0x814f.U,
+    0x014a.U,
+    0x815b.U,
+    0x015e.U,
+    0x0154.U,
+    0x8151.U,
+    0x8173.U,
+    0x0176.U,
+    0x017c.U,
+    0x8179.U,
+    0x0168.U,
+    0x816d.U,
+    0x8167.U,
+    0x0162.U,
+    0x8123.U,
+    0x0126.U,
+    0x012c.U,
+    0x8129.U,
+    0x0138.U,
+    0x813d.U,
+    0x8137.U,
+    0x0132.U,
+    0x0110.U,
+    0x8115.U,
+    0x811f.U,
+    0x011a.U,
+    0x810b.U,
+    0x010e.U,
+    0x0104.U,
+    0x8101.U,
+    0x8303.U,
+    0x0306.U,
+    0x030c.U,
+    0x8309.U,
+    0x0318.U,
+    0x831d.U,
+    0x8317.U,
+    0x0312.U,
+    0x0330.U,
+    0x8335.U,
+    0x833f.U,
+    0x033a.U,
+    0x832b.U,
+    0x032e.U,
+    0x0324.U,
+    0x8321.U,
+    0x0360.U,
+    0x8365.U,
+    0x836f.U,
+    0x036a.U,
+    0x837b.U,
+    0x037e.U,
+    0x0374.U,
+    0x8371.U,
+    0x8353.U,
+    0x0356.U,
+    0x035c.U,
+    0x8359.U,
+    0x0348.U,
+    0x834d.U,
+    0x8347.U,
+    0x0342.U,
+    0x03c0.U,
+    0x83c5.U,
+    0x83cf.U,
+    0x03ca.U,
+    0x83db.U,
+    0x03de.U,
+    0x03d4.U,
+    0x83d1.U,
+    0x83f3.U,
+    0x03f6.U,
+    0x03fc.U,
+    0x83f9.U,
+    0x03e8.U,
+    0x83ed.U,
+    0x83e7.U,
+    0x03e2.U,
+    0x83a3.U,
+    0x03a6.U,
+    0x03ac.U,
+    0x83a9.U,
+    0x03b8.U,
+    0x83bd.U,
+    0x83b7.U,
+    0x03b2.U,
+    0x0390.U,
+    0x8395.U,
+    0x839f.U,
+    0x039a.U,
+    0x838b.U,
+    0x038e.U,
+    0x0384.U,
+    0x8381.U,
+    0x0280.U,
+    0x8285.U,
+    0x828f.U,
+    0x028a.U,
+    0x829b.U,
+    0x029e.U,
+    0x0294.U,
+    0x8291.U,
+    0x82b3.U,
+    0x02b6.U,
+    0x02bc.U,
+    0x82b9.U,
+    0x02a8.U,
+    0x82ad.U,
+    0x82a7.U,
+    0x02a2.U,
+    0x82e3.U,
+    0x02e6.U,
+    0x02ec.U,
+    0x82e9.U,
+    0x02f8.U,
+    0x82fd.U,
+    0x82f7.U,
+    0x02f2.U,
+    0x02d0.U,
+    0x82d5.U,
+    0x82df.U,
+    0x02da.U,
+    0x82cb.U,
+    0x02ce.U,
+    0x02c4.U,
+    0x82c1.U,
+    0x8243.U,
+    0x0246.U,
+    0x024c.U,
+    0x8249.U,
+    0x0258.U,
+    0x825d.U,
+    0x8257.U,
+    0x0252.U,
+    0x0270.U,
+    0x8275.U,
+    0x827f.U,
+    0x027a.U,
+    0x826b.U,
+    0x026e.U,
+    0x0264.U,
+    0x8261.U,
+    0x0220.U,
+    0x8225.U,
+    0x822f.U,
+    0x022a.U,
+    0x823b.U,
+    0x023e.U,
+    0x0234.U,
+    0x8231.U,
+    0x8213.U,
+    0x0216.U,
+    0x021c.U,
+    0x8219.U,
+    0x0208.U,
+    0x820d.U,
+    0x8207.U,
+    0x0202.U,
+  )
+
+}

src/main/scala/d2dadapter/CRCGenerator.scala

@@ -0,0 +1,109 @@
+package edu.berkeley.cs.ucie.digital.d2dadapter
+
+import chisel3._
+import chisel3.util._
+
+/** Generates the CRC of data using the polynomial x^16 + x^15 + x^2 + 1. The
+  * message must be formatted according to the UCIe1.1 spec, and the message
+  * will be consumed one byte per clock cycle, starting from the MSB to the LSB.
+  * The calculated 2 byte CRC will be available on the crc ReadyValid3IO
+  * interface in the raw, un-reversed format as indicated in the UCIe1.1 spec
+  * (i.e. CRC[15] is the MSB of the crc interface's data bits).
+  * @param width
+  *   The message size in bits (must be whole number of bytes). UCIe1.1 spec
+  *   will use 1024-bit messages, with shorter messages padded with 0s in MSB
+  *   side.
+  * @groupdesc Signals
+  *   The input and output controls of the CRCGenerator module
+  */
+
+class CRCGenerator(width: Int) extends Module {
+  assert(width % 8 == 0)
+  val io = IO(new Bundle {
+
+    /** ReadyValidIO interface to allow consumer to transfer message bits to the
+      * CRCGenerator. Message bits are latched when message ready and message
+      * valid are high for the same clock cycle, and then the CRCGenerator is
+      * locked into the calculation loop.
+      *
+      * The CRCGenerator will not accept new messages during the calculation
+      * loop, nor reflect any changes that occur to the message data bits after
+      * the message was latched on the ready/valid transfer.
+      *
+      * The CRCGenerator will only accept a new message after the CRC data has
+      * been transfered through the CRC ReadyValid3IO interface.
+      * @group Signals
+      */
+    val message = Flipped(Decoupled(Bits(width.W)))
+
+    /** ReadyValidIO interface to allow CRCGenerator to transfer crc bits to the
+      * consumer. CRC will be cleared to 0 and invalid on reset.
+      *
+      * Once message bits have been transfered, the CRCGenerator will enter the
+      * calculation loop, consuming the message data one byte each clock cycle
+      * until all bytes have been consumed. The CRC data bits on the interface
+      * willl then become valid with the crc valid signal set high.
+      *
+      * The CRC data will remain valid and the CRCGenerator will remain in an
+      * idle state until the consumer initiates a transfer of the CRC data by
+      * signaling CRC ready high. After this transfer, the CRC data will become
+      * invalid and the CRC Generator will signal message ready to accept a new
+      * message.
+      * @group Signals
+      */
+    val crc = Decoupled(Bits(16.W))
+  })
+
+  // Output data registers
+  val crc0 = RegInit(Bits(8.W), 0.U)
+  val crc1 = RegInit(Bits(8.W), 0.U)
+
+  // Output signal registers
+  val message_ready = RegInit(Bool(), true.B)
+  val crc_valid = RegInit(Bool(), false.B)
+
+  // CRC calculating registers
+  // Store number of bytes in width bits
+  val step = RegInit(0.U(log2Ceil(width / 8 + 1).W))
+  // Latches full message when message_ready and data_val
+  val message_bits = RegInit(Bits(width.W), 0.U)
+
+  // CRC calculating table
+  val lookup = new CRC16Lookup
+
+  // Propogate output data register
+  io.crc.bits := Cat(crc1, crc0)
+
+  // Propogate crc valid and message ready signal
+  io.crc.valid := crc_valid
+  io.message.ready := message_ready
+
+  // Latch data on message_ready and data_val
+  when(io.message.fire) {
+    // Reset logic
+    crc0 := 0.U
+    crc1 := 0.U
+    crc_valid := false.B
+
+    step := (width / 8).U // Set step to number of bytes in word
+    message_bits := io.message.bits
+    message_ready := false.B
+  }
+
+  // Computation not finished when step is not 0
+  when(step > 0.U) {
+    crc1 := crc0 ^ lookup
+      .table(crc1 ^ message_bits(width - 1, width - 8))(15, 8)
+    crc0 := lookup.table(crc1 ^ message_bits(width - 1, width - 8))(7, 0)
+    message_bits := message_bits << 8
+    step := step - 1.U
+    crc_valid := step === 1.U // If next step will be 0, CRC is now valid
+  }
+
+  /* Idle with crc output valid until consumer initiates transfer of CRC with
+   * io.crc.ready */
+  when(io.crc.fire) {
+    crc_valid := false.B
+    message_ready := true.B
+  }
+}