Add Chip ID Pin and Port

docs/Generators/TestChipIP.rst

@@ -92,3 +92,15 @@ The SPI flash model is a device that models a simple SPI flash device. It curren
 only supports single read, quad read, single write, and quad write instructions. The
 memory is backed by a file which is provided using ``+spiflash#=<NAME_OF_FILE>``,
 where ``#`` is the SPI flash ID (usually ``0``).
+
+Chip ID Pin
+---------------
+
+The chip ID pin sets the chip ID for the chip it is added to. This is most useful in 
+multi-chip configs. The pin value is driven by the chip ID value set in the harness 
+binder and the chip ID value can be read through MMIO at the address ``0x2000`` by default.
+
+The pin can be added to a system with the ``testchipip.soc.WithChipIdPin`` config. The pin
+width and MMIO address are parameterizable and can be set by passing ``ChipIdPinParams`` as an 
+argument to the config. The width can additionally be set using the ``testchipip.soc.WithChipIdPinWidth``
+config. 

generators/chipyard/src/main/scala/DigitalTop.scala

@@ -20,6 +20,7 @@ class DigitalTop(implicit p: Parameters) extends ChipyardSystem
   with testchipip.soc.CanHaveBankedScratchpad // Enables optionally adding a banked scratchpad
   with testchipip.iceblk.CanHavePeripheryBlockDevice // Enables optionally adding the block device
   with testchipip.serdes.CanHavePeripheryTLSerial // Enables optionally adding the backing memory and serial adapter
+  with testchipip.soc.CanHavePeripheryChipIdPin // Enables optional pin to set chip id for multi-chip configs
   with sifive.blocks.devices.i2c.HasPeripheryI2C // Enables optionally adding the sifive I2C
   with sifive.blocks.devices.pwm.HasPeripheryPWM // Enables optionally adding the sifive PWM
   with sifive.blocks.devices.uart.HasPeripheryUART // Enables optionally adding the sifive UART

generators/chipyard/src/main/scala/config/AbstractConfig.scala

@@ -23,6 +23,7 @@ class AbstractConfig extends Config(
   new chipyard.harness.WithTieOffInterrupts ++                     // tie-off interrupt ports, if present
   new chipyard.harness.WithTieOffL2FBusAXI ++                      // tie-off external AXI4 master, if present
   new chipyard.harness.WithCustomBootPinPlusArg ++                 // drive custom-boot pin with a plusarg, if custom-boot-pin is present
+  new chipyard.harness.WithDriveChipIdPin ++                       // drive chip id pin from harness binder, if chip id pin is present
   new chipyard.harness.WithSimUARTToUARTTSI ++                     // connect a SimUART to the UART-TSI port
   new chipyard.harness.WithClockFromHarness ++                     // all Clock I/O in ChipTop should be driven by harnessClockInstantiator
   new chipyard.harness.WithResetFromHarness ++                     // reset controlled by harness
@@ -36,6 +37,7 @@ class AbstractConfig extends Config(
   new chipyard.iobinders.WithGPIOCells ++
   new chipyard.iobinders.WithSPIFlashIOCells ++
   new chipyard.iobinders.WithExtInterruptIOCells ++
+  new chipyard.iobinders.WithChipIdIOCells ++
   new chipyard.iobinders.WithCustomBootPin ++
   // The "punchthrough" IOBInders below don't generate IOCells, as these interfaces shouldn't really be mapped to ASIC IO
   // Instead, they directly pass through the DigitalTop ports to ports in the ChipTop

generators/chipyard/src/main/scala/config/ChipletConfigs.scala

@@ -11,6 +11,7 @@ import testchipip.soc.{OBUS}
 
 // Simple design which exposes a second serial-tl port that can connect to another instance of itself
 class SymmetricChipletRocketConfig extends Config(
+  new testchipip.soc.WithChipIdPin ++                               // Add pin to identify chips
   new chipyard.harness.WithSerialTLTiedOff(tieoffs=Some(Seq(1))) ++ // Tie-off the chip-to-chip link in single-chip sims
   new testchipip.serdes.WithSerialTL(Seq(
     testchipip.serdes.SerialTLParams(                               // 0th serial-tl is chip-to-bringup-fpga

generators/chipyard/src/main/scala/harness/HarnessBinders.scala

@@ -252,6 +252,13 @@ class WithSimTSIOverSerialTL extends HarnessBinder({
   }
 })
 
+class WithDriveChipIdPin extends HarnessBinder({
+  case (th: HasHarnessInstantiators, port: ChipIdPort, chipId: Int) => {
+    require(chipId < math.pow(2, port.io.getWidth), "ID Pin is not wide enough")
+    port.io := chipId.U
+  }
+})
+
 class WithSimUARTToUARTTSI extends HarnessBinder({
   case (th: HasHarnessInstantiators, port: UARTPort, chipId: Int) => {
     UARTAdapter.connect(Seq(port.io),

generators/chipyard/src/main/scala/iobinders/IOBinders.scala

@@ -27,6 +27,7 @@ import barstools.iocell.chisel._
 import testchipip.serdes.{CanHavePeripheryTLSerial, SerialTLKey}
 import testchipip.spi.{SPIChipIO}
 import testchipip.boot.{CanHavePeripheryCustomBootPin}
+import testchipip.soc.{CanHavePeripheryChipIdPin}
 import testchipip.util.{ClockedIO}
 import testchipip.iceblk.{CanHavePeripheryBlockDevice, BlockDeviceKey, BlockDeviceIO}
 import testchipip.cosim.{CanHaveTraceIO, TraceOutputTop, SpikeCosimConfig}
@@ -355,6 +356,14 @@ class WithSerialTLIOCells extends OverrideIOBinder({
   }
 })
 
+class WithChipIdIOCells extends OverrideIOBinder({
+  (system: CanHavePeripheryChipIdPin) => system.chip_id_pin.map({ p =>
+    val sys = system.asInstanceOf[BaseSubsystem]
+    val (port, cells) = IOCell.generateIOFromSignal(p.getWrappedValue, s"chip_id", sys.p(IOCellKey), abstractResetAsAsync = true)
+    (Seq(ChipIdPort(() => port)), cells)
+  }).getOrElse(Nil, Nil)
+})
+
 class WithSerialTLPunchthrough extends OverrideIOBinder({
   (system: CanHavePeripheryTLSerial) => {
     val (ports, cells) = system.serial_tls.zipWithIndex.map({ case (s, id) =>

generators/chipyard/src/main/scala/iobinders/Ports.scala

@@ -76,6 +76,9 @@ case class JTAGPort        (val getIO: () => JTAGChipIO)
 case class SerialTLPort    (val getIO: () => Data, val params: SerialTLParams, val serdesser: TLSerdesser, val portId: Int)
     extends Port[Data]
 
+case class ChipIdPort      (val getIO: () => UInt)
+    extends Port[UInt]
+
 case class UARTTSIPort     (val getIO: () => UARTTSIIO)
     extends Port[UARTTSIIO]