Bus.md

Rocket/tilelink/Bus

Generic TileLink bus implementation.

---

trait TLBusParams

Specifies widths of various attachement points in the SoC

trait TLBusParams {
  val beatBytes: Int
  val blockBytes: Int
  val masterBuffering: BufferParams
  val slaveBuffering: BufferParams
}

• beatBytes Int number of bytes per beat.
• blockBytes Int number of bytes per burst.
• masterBuffering BufferParams buffer depth on the master (inner) side.
• slaveBuffering BufferParams buffer depth on the slave (outer) side.
• beatBits () => Int get the bit size of a beat.
• blockBits () => Int get the bit size of a burst.
• blockBeats () => Int get the number of beats in a burst.
• blockOffset () => Int get the width of byte index inside a burst.

abstract class TLBusWrapper

Wrap a TLXbar into a bus.

abstract class TLBusWrapper(params: TLBusParams)(implicit p: Parameters) extends TLBusParams

• xbar TLXbar (private) the internal crossbar.
• master_buffer TLBuffer (private) buffer on the master side.
• slave_buffer TLBuffer (private) buffer on the slave side.
• slave_frag TLFragmenter (private) fragmenter, tune the size of bursts.
• slave_ww TLWidthWidget (private) fix bus width mismatch between client and manager.
• outwardNode () => TLOutwardNode (protected) get the crossbar output.
• outwardBufNode () => TLOutwardNode (protected) get the outer buffer output.
• outwardFragNode () => TLOutwardNode (protected) get the fragmenter output.
• outwardWWNode () => TLOutwardNode (protected) get the width fixer output.
• inwardNode () => TLInwardNode (protected) get the crossbar input.
• inwardBufNode () => TLInwardNode (protected) get the inner buffer input.
• bufferFromMasters () => TLInwardNode get the inner buffer input.
• bufferToSlaves () => TLOutwardNode get the outer buffer output.
• toAsyncSlaves (Int) => TLAsyncOutwardNode get the crossbar output with an asynchronous synchronizer.
• toRationalSlaves (Int) => TLRationalOutwardNode get the crossbar output with a rational synchronizer.
• toVariableWidthSlaves () => TLOutwardNode get the fragmenter output.
• toAsyncVariableWidthSlaves () => TLAsyncOutwardNode get the fragmenter output with an asynchronous synchronizer.
• toRationalVariableWidthSlaves () => TLRationalOutwardNode get the fragmenter output with a rational synchronizer.
• toFixedWidthSlaves () => TLOutwardNode get the width fixer output.
• toAsyncFixedWidthSlaves () => TLAsyncOutwardNode get the width fixer output with an asynchronous synchronizer.
• toRationalFixedWidthSlaves () => TLRationalOutwardNode get the width fixer output with a rational synchronizer.

The internal connections:

master_buffer      xbar      slave_buffer       slave_ww
------------- *==> ---- ==>* ------------ ==>* -----------
     Buffer        Xbar         Buffer   |     WidthWidget
                                         |
                                         |      slave_frage
                                         \===>* -----------
                                                Fragmenter

_{Last updated: 11/08/2017
CC BY-NC-SA 4.0, © (2017) Wei Song
Apache 2.0, © (2016-2017) SiFive, Inc
BSD, © (2012-2014, 2016) The Regents of the University of California (Regents)}