riscv/rocket-chip
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support streaming DMA in DMA frontend

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This commit is contained in:
Howard Mao 2016-01-05 20:05:10 -08:00
parent dbe68056d9
commit 05b359d357
1 changed files with 56 additions and 37 deletions
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93
rocket/src/main/scala/dma.scala
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@ -8,7 +8,7 @@ import cde.Parameters
trait HasClientDmaParameters extends HasCoreParameters with HasDmaParameters {
val dmaAddrBits = coreMaxAddrBits
val dmaSizeBits = coreMaxAddrBits
val dmaSegmentSizeBits = coreMaxAddrBits
val dmaSegmentBits = 24
}
@ -21,10 +21,11 @@ class ClientDmaRequest(implicit p: Parameters) extends ClientDmaBundle()(p) {
val cmd = UInt(width = DMA_CMD_SZ)
val src_start = UInt(width = dmaAddrBits)
val dst_start = UInt(width = dmaAddrBits)
val src_stride = UInt(width = dmaSizeBits)
val dst_stride = UInt(width = dmaSizeBits)
val segment_size = UInt(width = dmaSizeBits)
val src_stride = UInt(width = dmaSegmentSizeBits)
val dst_stride = UInt(width = dmaSegmentSizeBits)
val segment_size = UInt(width = dmaSegmentSizeBits)
val nsegments = UInt(width = dmaSegmentBits)
val word_size = UInt(width = dmaWordSizeBits)
}
object ClientDmaRequest {
@ -34,7 +35,8 @@ object ClientDmaRequest {
segment_size: UInt,
nsegments: UInt = UInt(1),
src_stride: UInt = UInt(0),
dst_stride: UInt = UInt(0))
dst_stride: UInt = UInt(0),
word_size: UInt = UInt(0))
(implicit p: Parameters) = {
val req = Wire(new ClientDmaRequest)
req.cmd := cmd
@ -44,6 +46,7 @@ object ClientDmaRequest {
req.dst_stride := dst_stride
req.segment_size := segment_size
req.nsegments := nsegments
req.word_size := word_size
req
}
}
@ -83,10 +86,16 @@ class DmaFrontend(implicit val p: Parameters)
val vm_enabled = io.ptw.status.vm(3) && priv <= UInt(PRV_S)
val cmd = Reg(UInt(width = DMA_CMD_SZ))
val adv_ptr = MuxLookup(cmd, UInt("b11"), Seq(
DMA_CMD_PFR -> UInt("b10"),
DMA_CMD_PFW -> UInt("b10"),
DMA_CMD_SIN -> UInt("b10"),
DMA_CMD_SOUT -> UInt("b01")))
val segment_size = Reg(UInt(width = dmaSizeBits))
val bytes_left = Reg(UInt(width = dmaSizeBits))
val segment_size = Reg(UInt(width = dmaSegmentSizeBits))
val bytes_left = Reg(UInt(width = dmaSegmentSizeBits))
val segments_left = Reg(UInt(width = dmaSegmentBits))
val word_size = Reg(UInt(width = dmaWordSizeBits))
val src_vaddr = Reg(UInt(width = dmaAddrBits))
val dst_vaddr = Reg(UInt(width = dmaAddrBits))
@ -97,8 +106,8 @@ class DmaFrontend(implicit val p: Parameters)
val src_pglen = UInt(pgSize) - src_idx
val dst_pglen = UInt(pgSize) - dst_idx
val src_stride = Reg(UInt(width = dmaSizeBits))
val dst_stride = Reg(UInt(width = dmaSizeBits))
val src_stride = Reg(UInt(width = dmaSegmentSizeBits))
val dst_stride = Reg(UInt(width = dmaSegmentSizeBits))
val src_ppn = Reg(UInt(width = ppnBits))
val dst_ppn = Reg(UInt(width = ppnBits))
@ -145,8 +154,7 @@ class DmaFrontend(implicit val p: Parameters)
to_translate := to_translate & ~recv_choice
// getting the src translation
// if this is a prefetch, dst_ppn and src_ppn should be equal
when (recv_choice(0) || cmd(1)) {
when (recv_choice(0)) {
src_ppn := io.ptw.resp.bits.pte.ppn
} .otherwise {
dst_ppn := io.ptw.resp.bits.pte.ppn
@ -162,11 +170,13 @@ class DmaFrontend(implicit val p: Parameters)
cmd = cmd,
source = src_paddr,
dest = dst_paddr,
length = tx_len)
length = tx_len,
size = word_size)
io.dma.resp.ready := Bool(true)
when (io.cpu.req.fire()) {
val req = io.cpu.req.bits
val is_prefetch = req.cmd(2, 1) === UInt("b01")
cmd := req.cmd
src_vaddr := req.src_start
dst_vaddr := req.dst_start
@ -175,7 +185,8 @@ class DmaFrontend(implicit val p: Parameters)
segment_size := req.segment_size
segments_left := req.nsegments - UInt(1)
bytes_left := req.segment_size
to_translate := Mux(req.cmd(1), UInt("b10"), UInt("b11"))
word_size := req.word_size
to_translate := Mux(is_prefetch, UInt("b10"), UInt("b11"))
ptw_sent := UInt(0)
state := Mux(vm_enabled, s_translate, s_dma_req)
}
@ -184,16 +195,20 @@ class DmaFrontend(implicit val p: Parameters)
state := s_dma_req
}
when (io.dma.req.fire()) {
src_vaddr := src_vaddr + tx_len
dst_vaddr := dst_vaddr + tx_len
bytes_left := bytes_left - tx_len
dma_busy := dma_busy | UIntToOH(dma_xact_id)
state := s_dma_update
}
def setBusyOnSend(req: DecoupledIO[DmaRequest]): UInt =
Mux(req.fire(), UIntToOH(req.bits.client_xact_id), UInt(0))
when (io.dma.resp.fire()) {
dma_busy := dma_busy & ~UIntToOH(io.dma.resp.bits.client_xact_id)
def clearBusyOnRecv(resp: DecoupledIO[DmaResponse]): UInt =
~Mux(resp.fire(), UIntToOH(resp.bits.client_xact_id), UInt(0))
dma_busy := (dma_busy | setBusyOnSend(io.dma.req)) &
clearBusyOnRecv(io.dma.resp)
when (io.dma.req.fire()) {
src_vaddr := src_vaddr + Mux(adv_ptr(0), tx_len, UInt(0))
dst_vaddr := dst_vaddr + Mux(adv_ptr(1), tx_len, UInt(0))
bytes_left := bytes_left - tx_len
state := s_dma_update
}
when (state === s_dma_update) {
@ -211,16 +226,16 @@ class DmaFrontend(implicit val p: Parameters)
state := Mux(vm_enabled, s_prepare, s_dma_req)
}
} .otherwise {
to_translate := Cat(dst_idx === UInt(0), !cmd(1) && src_idx === UInt(0))
to_translate := adv_ptr & Cat(dst_idx === UInt(0), src_idx === UInt(0))
ptw_sent := UInt(0)
state := s_translate
}
}
when (state === s_prepare) {
to_translate := Cat(
to_translate := adv_ptr & Cat(
dst_vpn =/= last_dst_vpn,
src_vpn =/= last_src_vpn && !cmd(1))
src_vpn =/= last_src_vpn)
ptw_sent := UInt(0)
state := s_translate
}
@ -235,35 +250,38 @@ object DmaCtrlRegNumbers {
val DST_STRIDE = 1
val SEGMENT_SIZE = 2
val NSEGMENTS = 3
val RESP_STATUS = 4
val WORD_SIZE = 4
val RESP_STATUS = 5
}
import DmaCtrlRegNumbers._
class DmaCtrlRegFile(implicit p: Parameters) extends ClientDmaModule()(p) {
private val nWriteRegs = 4
private val nWriteRegs = 5
private val nReadRegs = 1
private val nRegs = nWriteRegs + nReadRegs
val io = new Bundle {
val wen = Bool(INPUT)
val addr = UInt(INPUT, log2Up(nRegs))
val wdata = UInt(INPUT, dmaSizeBits)
val rdata = UInt(OUTPUT, dmaSizeBits)
val wdata = UInt(INPUT, dmaSegmentSizeBits)
val rdata = UInt(OUTPUT, dmaSegmentSizeBits)
val src_stride = UInt(OUTPUT, dmaSizeBits)
val dst_stride = UInt(OUTPUT, dmaSizeBits)
val segment_size = UInt(OUTPUT, dmaSizeBits)
val src_stride = UInt(OUTPUT, dmaSegmentSizeBits)
val dst_stride = UInt(OUTPUT, dmaSegmentSizeBits)
val segment_size = UInt(OUTPUT, dmaSegmentSizeBits)
val nsegments = UInt(OUTPUT, dmaSegmentBits)
val word_size = UInt(OUTPUT, dmaWordSizeBits)
val status = UInt(INPUT, dmaStatusBits)
}
val regs = Reg(Vec(nWriteRegs, UInt(width = dmaSizeBits)))
val regs = Reg(Vec(nWriteRegs, UInt(width = dmaSegmentSizeBits)))
io.src_stride := regs(SRC_STRIDE)
io.dst_stride := regs(DST_STRIDE)
io.segment_size := regs(SEGMENT_SIZE)
io.nsegments := regs(NSEGMENTS)
io.word_size := regs(WORD_SIZE)
when (io.wen && io.addr < UInt(nWriteRegs)) {
regs.write(io.addr, io.wdata)
@ -283,9 +301,9 @@ class DmaController(implicit p: Parameters) extends RoCC()(p)
val cmd = Queue(io.cmd)
val inst = cmd.bits.inst
val is_transfer = inst.funct < UInt(4)
val is_cr_write = inst.funct === UInt(4)
val is_cr_read = inst.funct === UInt(5)
val is_transfer = inst.funct < UInt(8)
val is_cr_write = inst.funct === UInt(8)
val is_cr_read = inst.funct === UInt(9)
val is_cr_access = is_cr_write || is_cr_read
val resp_rd = Reg(io.resp.bits.rd)
@ -311,7 +329,8 @@ class DmaController(implicit p: Parameters) extends RoCC()(p)
src_stride = crfile.io.src_stride,
dst_stride = crfile.io.dst_stride,
segment_size = crfile.io.segment_size,
nsegments = crfile.io.nsegments)
nsegments = crfile.io.nsegments,
word_size = crfile.io.word_size)
cmd.ready := state === s_idle && (!is_transfer || frontend.io.cpu.req.ready)
io.resp.valid := state === s_resp