package sifive.blocks.devices.i2c
import Chisel._
-import config._
-import regmapper._
-import uncore.tilelink2._
-import util.{AsyncResetRegVec, Majority}
-import sifive.blocks.devices.gpio.{GPIOPinCtrl}
+import chisel3.experimental.MultiIOModule
+import freechips.rocketchip.config._
+import freechips.rocketchip.regmapper._
+import freechips.rocketchip.tilelink._
+import freechips.rocketchip.util.{AsyncResetRegVec, Majority}
case class I2CParams(address: BigInt)
val port = new I2CPort
}
-trait HasI2CModuleContents extends Module with HasRegMap {
+trait HasI2CModuleContents extends MultiIOModule with HasRegMap {
val io: HasI2CBundleContents
val params: I2CParams
// hack: b/c the same register offset is used to write cmd and read status
val nextCmd = Wire(UInt(8.W))
- nextCmd := cmd.asUInt
cmd := (new CommandBundle).fromBits(nextCmd)
+ nextCmd := cmd.asUInt & 0xFE.U // clear IRQ_ACK bit (essentially 1 cycle pulse b/c it is overwritten by regmap below)
+ // Note: This wins over the regmap update of nextCmd (even if something tries to write them to 1, these values take priority).
when (cmdAck || arbLost) {
cmd.start := false.B // clear command bits when done
cmd.stop := false.B // or when aribitration lost
cmd.read := false.B
cmd.write := false.B
}
- cmd.irqAck := false.B // clear IRQ_ACK bit (essentially 1 cycle pulse b/c it is overwritten by regmap below)
status.receivedAck := receivedAck
when (stopCond) {
status.arbLost := false.B
}
status.transferInProgress := cmd.read || cmd.write
- status.irqFlag := (cmdAck || arbLost || status.irqFlag) && !cmd.irqAck
+ status.irqFlag := (cmdAck || arbLost || status.irqFlag) && !cmd.irqAck // interrupt request flag is always generated
+ val statusReadReady = Reg(init = true.B)
+ when (cmdAck || arbLost) { // => cmd.read or cmd.write deassert 1 cycle later => transferInProgress deassert 2 cycles later
+ statusReadReady := false.B // do not allow status read if status.transferInProgress is going to change
+ }
+ .elsewhen (!statusReadReady) {
+ statusReadReady := true.B
+ }
+
+ // statusReadReady,
regmap(
I2CCtrlRegs.prescaler_lo -> Seq(RegField(8, prescaler.lo)),
I2CCtrlRegs.prescaler_hi -> Seq(RegField(8, prescaler.hi)),
I2CCtrlRegs.control -> control.elements.map{ case(name, e) => RegField(e.getWidth, e.asInstanceOf[UInt]) }.toSeq,
I2CCtrlRegs.data -> Seq(RegField(8, r = RegReadFn(receivedData), w = RegWriteFn(transmitData))),
- I2CCtrlRegs.cmd_status -> Seq(RegField(8, r = RegReadFn(status.asUInt), w = RegWriteFn(nextCmd)))
+ I2CCtrlRegs.cmd_status -> Seq(RegField(8, r = RegReadFn{ ready =>
+ (statusReadReady, status.asUInt)
+ },
+ w = RegWriteFn((valid, data) => {
+ when (valid) {
+ statusReadReady := false.B
+ nextCmd := data
+ }
+ true.B
+ }
+ )))
)
// tie off unused bits