where data will flow on *every* clock when the conditions are right.
input acceptance conditions are when:
- * incoming previous-stage strobe (i.p_stb) is HIGH
+ * incoming previous-stage strobe (i.p_valid) is HIGH
* outgoing previous-stage busy (o.p_busy) is LOW
output transmission conditions are when:
- * outgoing next-stage strobe (o.n_stb) is HIGH
+ * outgoing next-stage strobe (o.n_valid) is HIGH
* outgoing next-stage busy (i.n_busy) is LOW
the tricky bit is when the input has valid data and the output is not
class IOAckIn:
def __init__(self):
- self.p_stb = Signal() # >>in - comes in from PREVIOUS stage
+ self.p_valid = Signal() # >>in - comes in from PREVIOUS stage
self.n_busy = Signal() # in<< - comes in from the NEXT stage
class IOAckOut:
def __init__(self):
- self.n_stb = Signal() # out>> - goes out to the NEXT stage
+ self.n_valid = Signal() # out>> - goes out to the NEXT stage
self.p_busy = Signal() # <<out - goes out to the PREVIOUS stage
class BufferedPipeline:
""" buffered pipeline stage
- stage-1 i.p_stb >>in stage o.n_stb out>> stage+1
+ stage-1 i.p_valid >>in stage o.n_valid out>> stage+1
stage-1 o.p_busy <<out stage i.n_busy <<in stage+1
stage-1 i_data >>in stage o_data out>> stage+1
| |
def __init__(self):
# input: strobe comes in from previous stage, busy comes in from next
self.i = IOAckIn()
- #self.i.p_stb = Signal() # >>in - comes in from PREVIOUS stage
+ #self.i.p_valid = Signal() # >>in - comes in from PREVIOUS stage
#self.i.n_busy = Signal() # in<< - comes in from the NEXT stage
# output: strobe goes out to next stage, busy comes in from previous
self.o = IOAckOut()
- #self.o.n_stb = Signal() # out>> - goes out to the NEXT stage
+ #self.o.n_valid = Signal() # out>> - goes out to the NEXT stage
#self.o.p_busy = Signal() # <<out - goes out to the PREVIOUS stage
def elaborate(self, platform):
# establish some combinatorial temporaries
o_p_busyn = Signal(reset_less=True)
- o_n_stbn = Signal(reset_less=True)
+ o_n_validn = Signal(reset_less=True)
i_n_busyn = Signal(reset_less=True)
- i_p_stb_o_p_busyn = Signal(reset_less=True)
+ i_p_valid_o_p_busyn = Signal(reset_less=True)
m.d.comb += [i_n_busyn.eq(~self.i.n_busy),
- o_n_stbn.eq(~self.o.n_stb),
+ o_n_validn.eq(~self.o.n_valid),
o_p_busyn.eq(~self.o.p_busy),
- i_p_stb_o_p_busyn.eq(self.i.p_stb & o_p_busyn),
+ i_p_valid_o_p_busyn.eq(self.i.p_valid & o_p_busyn),
]
# store result of processing in combinatorial temporary
- with m.If(self.i.p_stb): # input is valid: process it
+ with m.If(self.i.p_valid): # input is valid: process it
m.d.comb += self.stage.process()
# if not in stall condition, update the temporary register
with m.If(o_p_busyn): # not stalled
m.d.sync += self.stage.update_buffer()
#with m.If(self.i.p_rst): # reset
- # m.d.sync += self.o.n_stb.eq(0)
+ # m.d.sync += self.o.n_valid.eq(0)
# m.d.sync += self.o.p_busy.eq(0)
with m.If(i_n_busyn): # next stage is not busy
with m.If(o_p_busyn): # not stalled
# nothing in buffer: send (processed) input direct to output
- m.d.sync += [self.o.n_stb.eq(self.i.p_stb),
+ m.d.sync += [self.o.n_valid.eq(self.i.p_valid),
self.stage.update_output(),
]
with m.Else(): # o.p_busy is true, and something is in our buffer.
# Flush the [already processed] buffer to the output port.
- m.d.sync += [self.o.n_stb.eq(1),
+ m.d.sync += [self.o.n_valid.eq(1),
self.stage.flush_buffer(),
# clear stall condition, declare register empty.
self.o.p_busy.eq(0),
# ignore input, since o.p_busy is also true.
# (i.n_busy) is true here: next stage is busy
- with m.Elif(o_n_stbn): # next stage being told "not busy"
- m.d.sync += [self.o.n_stb.eq(self.i.p_stb),
+ with m.Elif(o_n_validn): # next stage being told "not busy"
+ m.d.sync += [self.o.n_valid.eq(self.i.p_valid),
self.o.p_busy.eq(0), # Keep the buffer empty
# set the output data (from comb result)
self.stage.update_output(),
]
- # (i.n_busy) and (o.n_stb) both true:
- with m.Elif(i_p_stb_o_p_busyn):
+ # (i.n_busy) and (o.n_valid) both true:
+ with m.Elif(i_p_valid_o_p_busyn):
# If next stage *is* busy, and not stalled yet, accept input
- m.d.sync += self.o.p_busy.eq(self.i.p_stb & self.o.n_stb)
+ m.d.sync += self.o.p_busy.eq(self.i.p_valid & self.o.n_valid)
return m
def ports(self):
- return [self.i.p_stb, self.i.n_busy,
- self.o.n_stb, self.o.p_busy,
+ return [self.i.p_valid, self.i.n_busy,
+ self.o.n_valid, self.o.p_busy,
]
from random import randint
-def check_o_n_stb(dut, val):
- o_n_stb = yield dut.o.n_stb
- assert o_n_stb == val
+def check_o_n_valid(dut, val):
+ o_n_valid = yield dut.o.n_valid
+ assert o_n_valid == val
-def check_o_n_stb2(dut, val):
- o_n_stb = yield dut.o_n_stb
- assert o_n_stb == val
+def check_o_n_valid2(dut, val):
+ o_n_valid = yield dut.o_n_valid
+ assert o_n_valid == val
def testbench(dut):
#yield dut.i_p_rst.eq(0)
yield dut.i.n_busy.eq(0)
yield dut.stage.i_data.eq(5)
- yield dut.i.p_stb.eq(1)
+ yield dut.i.p_valid.eq(1)
yield
yield dut.stage.i_data.eq(7)
- yield from check_o_n_stb(dut, 0) # effects of i_p_stb delayed
+ yield from check_o_n_valid(dut, 0) # effects of i_p_valid delayed
yield
- yield from check_o_n_stb(dut, 1) # ok *now* i_p_stb effect is felt
+ yield from check_o_n_valid(dut, 1) # ok *now* i_p_valid effect is felt
yield dut.stage.i_data.eq(2)
yield
yield dut.i.n_busy.eq(1) # begin going into "stall" (next stage says busy)
yield dut.stage.i_data.eq(9)
yield
- yield dut.i.p_stb.eq(0)
+ yield dut.i.p_valid.eq(0)
yield dut.stage.i_data.eq(12)
yield
yield dut.stage.i_data.eq(32)
yield dut.i.n_busy.eq(0)
yield
- yield from check_o_n_stb(dut, 1) # buffer still needs to output
+ yield from check_o_n_valid(dut, 1) # buffer still needs to output
yield
- yield from check_o_n_stb(dut, 1) # buffer still needs to output
+ yield from check_o_n_valid(dut, 1) # buffer still needs to output
yield
- yield from check_o_n_stb(dut, 0) # buffer outputted, *now* we're done.
+ yield from check_o_n_valid(dut, 0) # buffer outputted, *now* we're done.
yield
#yield dut.i.p_rst.eq(0)
yield dut.i_n_busy.eq(0)
yield dut.i_data.eq(5)
- yield dut.i_p_stb.eq(1)
+ yield dut.i_p_valid.eq(1)
yield
yield dut.i_data.eq(7)
- yield from check_o_n_stb2(dut, 0) # effects of i_p_stb delayed 2 clocks
+ yield from check_o_n_valid2(dut, 0) # effects of i_p_valid delayed 2 clocks
yield
- yield from check_o_n_stb2(dut, 0) # effects of i_p_stb delayed 2 clocks
+ yield from check_o_n_valid2(dut, 0) # effects of i_p_valid delayed 2 clocks
yield dut.i_data.eq(2)
yield
- yield from check_o_n_stb2(dut, 1) # ok *now* i_p_stb effect is felt
+ yield from check_o_n_valid2(dut, 1) # ok *now* i_p_valid effect is felt
yield dut.i_n_busy.eq(1) # begin going into "stall" (next stage says busy)
yield dut.i_data.eq(9)
yield
- yield dut.i_p_stb.eq(0)
+ yield dut.i_p_valid.eq(0)
yield dut.i_data.eq(12)
yield
yield dut.i_data.eq(32)
yield dut.i_n_busy.eq(0)
yield
- yield from check_o_n_stb2(dut, 1) # buffer still needs to output
+ yield from check_o_n_valid2(dut, 1) # buffer still needs to output
yield
- yield from check_o_n_stb2(dut, 1) # buffer still needs to output
+ yield from check_o_n_valid2(dut, 1) # buffer still needs to output
yield
- yield from check_o_n_stb2(dut, 1) # buffer still needs to output
+ yield from check_o_n_valid2(dut, 1) # buffer still needs to output
yield
- yield from check_o_n_stb2(dut, 0) # buffer outputted, *now* we're done.
+ yield from check_o_n_valid2(dut, 0) # buffer outputted, *now* we're done.
yield
yield
yield
yield
continue
if send and self.i != len(self.data):
- yield self.dut.i.p_stb.eq(1)
+ yield self.dut.i.p_valid.eq(1)
yield self.dut.stage.i_data.eq(self.data[self.i])
self.i += 1
else:
- yield self.dut.i.p_stb.eq(0)
+ yield self.dut.i.p_valid.eq(0)
yield
def rcv(self):
stall = randint(0, stall_range) == 0
yield self.dut.i.n_busy.eq(stall)
yield
- o_n_stb = yield self.dut.o.n_stb
+ o_n_valid = yield self.dut.o.n_valid
i_n_busy = yield self.dut.i.n_busy
- if not o_n_stb or i_n_busy:
+ if not o_n_valid or i_n_busy:
continue
o_data = yield self.dut.stage.o_data
assert o_data == self.data[self.o] + 1, \
o_p_busy = yield dut.o_p_busy
if not o_p_busy:
if send and i != len(data):
- yield dut.i_p_stb.eq(1)
+ yield dut.i_p_valid.eq(1)
yield dut.i_data.eq(data[i])
i += 1
else:
- yield dut.i_p_stb.eq(0)
+ yield dut.i_p_valid.eq(0)
yield
- o_n_stb = yield dut.o_n_stb
+ o_n_valid = yield dut.o_n_valid
i_n_busy = yield dut.i_n_busy
- if o_n_stb and not i_n_busy:
+ if o_n_valid and not i_n_busy:
o_data = yield dut.o_data
assert o_data == data[o] + 2, "%d-%d data %x not match %x\n" \
% (i, o, o_data, data[o])
"""
connect these: ------|---------------|
v v
- i_p_stb >>in pipe1 o_n_stb out>> i_p_stb >>in pipe2
+ i_p_valid >>in pipe1 o_n_valid out>> i_p_valid >>in pipe2
o_p_busy <<out pipe1 i_n_busy <<in o_p_busy <<out pipe2
stage.i_data >>in pipe1 o_data out>> stage.i_data >>in pipe2
"""
self.pipe2 = BufPipe()
# input
- self.i_p_stb = Signal() # >>in - comes in from PREVIOUS stage
+ self.i_p_valid = Signal() # >>in - comes in from PREVIOUS stage
self.i_n_busy = Signal() # in<< - comes in from the NEXT stage
self.i_data = Signal(32) # >>in - comes in from the PREVIOUS stage
# output
- self.o_n_stb = Signal() # out>> - goes out to the NEXT stage
+ self.o_n_valid = Signal() # out>> - goes out to the NEXT stage
self.o_p_busy = Signal() # <<out - goes out to the PREVIOUS stage
self.o_data = Signal(32) # out>> - goes out to the NEXT stage
m.submodules.pipe1 = self.pipe1
m.submodules.pipe2 = self.pipe2
- # connect inter-pipe input/output stb/busy/data
- m.d.comb += self.pipe2.i.p_stb.eq(self.pipe1.o.n_stb)
+ # connect inter-pipe input/output valid/busy/data
+ m.d.comb += self.pipe2.i.p_valid.eq(self.pipe1.o.n_valid)
m.d.comb += self.pipe1.i.n_busy.eq(self.pipe2.o.p_busy)
m.d.comb += self.pipe2.stage.i_data.eq(self.pipe1.stage.o_data)
# inputs/outputs to the module: pipe1 connections here (LHS)
- m.d.comb += self.pipe1.i.p_stb.eq(self.i_p_stb)
+ m.d.comb += self.pipe1.i.p_valid.eq(self.i_p_valid)
m.d.comb += self.o_p_busy.eq(self.pipe1.o.p_busy)
m.d.comb += self.pipe1.stage.i_data.eq(self.i_data)
# now pipe2 connections (RHS)
- m.d.comb += self.o_n_stb.eq(self.pipe2.o.n_stb)
+ m.d.comb += self.o_n_valid.eq(self.pipe2.o.n_valid)
m.d.comb += self.pipe2.i.n_busy.eq(self.i_n_busy)
m.d.comb += self.o_data.eq(self.pipe2.stage.o_data)