-#!/bin/env python3
+#!/usr/bin/env python3
import os, textwrap
+from enum import Enum, auto
-from nmigen import *
-from nmigen.build import *
-from nmigen.lib.io import *
-from nmigen.hdl.rec import Direction
+from nmigen import (Elaboratable, Signal, Module, ClockDomain, Cat, Record,
+ Const, Mux)
+from nmigen.hdl.rec import Direction, Layout
from nmigen.tracer import get_var_name
from nmigen_soc.wishbone import Interface as WishboneInterface
from .bus import Interface
__all__ = [
- "TAP", "ShiftReg",
+ "TAP", "ShiftReg", "IOType", "IOConn",
]
+class _FSM(Elaboratable):
+ """TAP subblock for the FSM"""
+ def __init__(self, *, bus):
+ self.isir = Signal()
+ self.isdr = Signal()
+ self.capture = Signal()
+ self.shift = Signal()
+ self.update = Signal()
+
+ # JTAG uses both edges of the incoming clock (TCK). set them up here
+ self.posjtag = ClockDomain("posjtag", local=True)
+ self.negjtag = ClockDomain("negjtag", local=True, clk_edge="neg")
+
+ self._bus = bus
+
+ def elaborate(self, platform):
+ m = Module()
+
+ rst = Signal()
+ m.d.comb += [
+ self.posjtag.clk.eq(self._bus.tck),
+ self.posjtag.rst.eq(rst),
+ self.negjtag.clk.eq(self._bus.tck),
+ self.negjtag.rst.eq(rst),
+ ]
+
+ # Make local clock domain optionally using trst of JTAG bus as reset
+ if hasattr(self._bus, "trst"):
+ m.domains.local = local = ClockDomain(local=True)
+ m.d.comb += local.rst.eq(self._bus.trst)
+ else:
+ m.domains.local = local = ClockDomain(local=True, reset_less=True)
+ m.d.comb += local.clk.eq(self._bus.tck)
+
+ with m.FSM(domain="local") as fsm:
+ with m.State("TestLogicReset"):
+ # Be sure to reset isir, isdr
+ m.d.local += [
+ self.isir.eq(0),
+ self.isdr.eq(0),
+ ]
+ with m.If(self._bus.tms == 0):
+ m.next = "RunTestIdle"
+ with m.State("RunTestIdle"):
+ # Be sure to reset isir, isdr
+ m.d.local += [
+ self.isir.eq(0),
+ self.isdr.eq(0),
+ ]
+ with m.If(self._bus.tms == 1):
+ m.next = "SelectDRScan"
+ with m.State("SelectDRScan"):
+ with m.If(self._bus.tms == 0):
+ m.d.local += self.isdr.eq(1)
+ m.next = "CaptureState"
+ with m.Else():
+ m.next = "SelectIRScan"
+ with m.State("SelectIRScan"):
+ with m.If(self._bus.tms == 0):
+ m.d.local += self.isir.eq(1)
+ m.next = "CaptureState"
+ with m.Else():
+ m.next = "TestLogicReset"
+ with m.State("CaptureState"):
+ with m.If(self._bus.tms == 0):
+ m.next = "ShiftState"
+ with m.Else():
+ m.next = "Exit1"
+ with m.State("ShiftState"):
+ with m.If(self._bus.tms == 1):
+ m.next = "Exit1"
+ with m.State("Exit1"):
+ with m.If(self._bus.tms == 0):
+ m.next = "Pause"
+ with m.Else():
+ m.next = "UpdateState"
+ with m.State("Pause"):
+ with m.If(self._bus.tms == 1):
+ m.next = "Exit2"
+ with m.State("Exit2"):
+ with m.If(self._bus.tms == 0):
+ m.next = "ShiftState"
+ with m.Else():
+ m.next = "UpdateState"
+ with m.State("UpdateState"):
+ m.d.local += [
+ self.isir.eq(0),
+ self.isdr.eq(0),
+ ]
+ with m.If(self._bus.tms == 0):
+ m.next = "RunTestIdle"
+ with m.Else():
+ m.next = "SelectDRScan"
+
+ m.d.comb += [
+ rst.eq(fsm.ongoing("TestLogicReset")),
+ self.capture.eq(fsm.ongoing("CaptureState")),
+ self.shift.eq(fsm.ongoing("ShiftState")),
+ self.update.eq(fsm.ongoing("UpdateState")),
+ ]
+
+ return m
+
+
+class _IRBlock(Elaboratable):
+ """TAP subblock for handling the IR shift register"""
+ def __init__(self, *, ir_width, cmd_idcode,
+ tdi, capture, shift, update,
+ name):
+ self.name = name
+ self.ir = Signal(ir_width, reset=cmd_idcode)
+ self.tdo = Signal()
+
+ self._tdi = tdi
+ self._capture = capture
+ self._shift = shift
+ self._update = update
+
+ def elaborate(self, platform):
+ m = Module()
+
+ shift_ir = Signal(len(self.ir), reset_less=True)
+
+ m.d.comb += self.tdo.eq(self.ir[0])
+ with m.If(self._capture):
+ m.d.posjtag += shift_ir.eq(self.ir)
+ with m.Elif(self._shift):
+ m.d.posjtag += shift_ir.eq(Cat(shift_ir[1:], self._tdi))
+ with m.Elif(self._update):
+ # For ir we only update it on the rising edge of clock
+ # to avoid that we already have the new ir value when still in
+ # Update state
+ m.d.posjtag += self.ir.eq(shift_ir)
+
+ return m
+
+
+class IOType(Enum):
+ In = auto()
+ Out = auto()
+ TriOut = auto()
+ InTriOut = auto()
+
+
+class IOConn(Record):
+ """TAP subblock representing the interface for an JTAG IO cell.
+ It contains signal to connect to the core and to the pad
+
+ This object is normally only allocated and returned from ``TAP.add_io``
+ It is a Record subclass.
+
+ Attributes
+ ----------
+ core: subrecord with signals for the core
+ i: Signal(1), present only for IOType.In and IOType.InTriOut.
+ Signal input to core with pad input value.
+ o: Signal(1), present only for IOType.Out, IOType.TriOut and
+ IOType.InTriOut.
+ Signal output from core with the pad output value.
+ oe: Signal(1), present only for IOType.TriOut and IOType.InTriOut.
+ Signal output from core with the pad output enable value.
+ pad: subrecord with for the pad
+ i: Signal(1), present only for IOType.In and IOType.InTriOut
+ Output from pad with pad input value for core.
+ o: Signal(1), present only for IOType.Out, IOType.TriOut and
+ IOType.InTriOut.
+ Input to pad with pad output value.
+ oe: Signal(1), present only for IOType.TriOut and IOType.InTriOut.
+ Input to pad with pad output enable value.
+ """
+ @staticmethod
+ def layout(iotype):
+ sigs = []
+ if iotype in (IOType.In, IOType.InTriOut):
+ sigs.append(("i", 1))
+ if iotype in (IOType.Out, IOType.TriOut, IOType.InTriOut):
+ sigs.append(("o", 1))
+ if iotype in (IOType.TriOut, IOType.InTriOut):
+ sigs.append(("oe", 1))
+
+ return Layout((("core", sigs), ("pad", sigs)))
+
+ def __init__(self, *, iotype, name=None, src_loc_at=0):
+ super().__init__(self.__class__.layout(iotype), name=name,
+ src_loc_at=src_loc_at+1)
+
+ self._iotype = iotype
+
+
+class _IDBypassBlock(Elaboratable):
+ """TAP subblock for the ID shift register"""
+ def __init__(self, *, manufacturer_id, part_number, version,
+ tdi, capture, shift, update, bypass,
+ name):
+ self.name = name
+ if (not isinstance(manufacturer_id, Const) and
+ len(manufacturer_id) != 11):
+ raise ValueError("manufacturer_id has to be Const of length 11")
+ if not isinstance(part_number, Const) and len(manufacturer_id) != 16:
+ raise ValueError("part_number has to be Const of length 16")
+ if not isinstance(version, Const) and len(version) != 4:
+ raise ValueError("version has to be Const of length 4")
+ self._id = Cat(Const(1,1), manufacturer_id, part_number, version)
+
+ self.tdo = Signal(name=name+"_tdo")
+
+ self._tdi = tdi
+ self._capture = capture
+ self._shift = shift
+ self._update = update
+ self._bypass = bypass
+
+ def elaborate(self, platform):
+ m = Module()
+
+ sr = Signal(32, reset_less=True, name=self.name+"_sr")
+
+ # Local signals for the module
+ _tdi = Signal()
+ _capture = Signal()
+ _shift = Signal()
+ _update = Signal()
+ _bypass = Signal()
+
+ m.d.comb += [
+ _tdi.eq(self._tdi),
+ _capture.eq(self._capture),
+ _shift.eq(self._shift),
+ _update.eq(self._update),
+ _bypass.eq(self._bypass),
+ self.tdo.eq(sr[0]),
+ ]
+
+ with m.If(_capture):
+ m.d.posjtag += sr.eq(self._id)
+ with m.Elif(_shift):
+ with m.If(_bypass):
+ m.d.posjtag += sr[0].eq(_tdi)
+ with m.Else():
+ m.d.posjtag += sr.eq(Cat(sr[1:], _tdi))
+
+ return m
+
+
class ShiftReg(Record):
"""Object with interface for extra shift registers on a TAP.
o: length=sr_length, FANOUT
The value of the shift register.
oe: length=cmds, FANOUT
- Indicates that output needs to be sampled downstream because
- JTAG TAP in in the Update state. The bit indicated the corresponding
+ Indicates that output is stable and can be sampled downstream because
+ JTAG TAP is in the Update state. The bit indicates the corresponding
instruction. The bit is only kept high for one clock cycle.
"""
def __init__(self, *, sr_length, cmds=1, name=None, src_loc_at=0):
class TAP(Elaboratable):
#TODO: Document TAP
- @staticmethod
- def _add_files(platform, prefix):
- d = os.path.realpath("{dir}{sep}{par}{sep}{par}{sep}vhdl{sep}jtag".format(
- dir=os.path.dirname(__file__), sep=os.path.sep, par=os.path.pardir
- )) + os.path.sep
- for fname in [
- "c4m_jtag_pkg.vhdl",
- "c4m_jtag_idblock.vhdl",
- "c4m_jtag_iocell.vhdl",
- "c4m_jtag_ioblock.vhdl",
- "c4m_jtag_irblock.vhdl",
- "c4m_jtag_tap_fsm.vhdl",
- "c4m_jtag_tap_controller.vhdl",
- ]:
- f = open(d + fname, "r")
- platform.add_file(prefix + fname, f)
- f.close()
-
- _controller_templ = textwrap.dedent(r"""
- library ieee;
- use ieee.std_logic_1164.ALL;
-
- use work.c4m_jtag.ALL;
-
- entity {name} is
- port (
- -- The TAP signals
- TCK: in std_logic;
- TMS: in std_logic;
- TDI: in std_logic;
- TDO: out std_logic;
- TRST_N: in std_logic;
-
- -- The FSM state indicators
- RESET: out std_logic;
- CAPTURE: out std_logic;
- SHIFT: out std_logic;
- UPDATE: out std_logic;
-
- -- The Instruction Register
- IR: out std_logic_vector({ir_width}-1 downto 0);
-
- -- The I/O access ports
- CORE_IN: out std_logic_vector({ios}-1 downto 0);
- CORE_EN: in std_logic_vector({ios}-1 downto 0);
- CORE_OUT: in std_logic_vector({ios}-1 downto 0);
-
- -- The pad connections
- PAD_IN: in std_logic_vector({ios}-1 downto 0);
- PAD_EN: out std_logic_vector({ios}-1 downto 0);
- PAD_OUT: out std_logic_vector({ios}-1 downto 0)
- );
- end {name};
-
- architecture rtl of {name} is
- begin
- jtag : c4m_jtag_tap_controller
- generic map(
- DEBUG => FALSE,
- IR_WIDTH => {ir_width},
- IOS => {ios},
- MANUFACTURER => "{manufacturer:011b}",
- PART_NUMBER => "{part:016b}",
- VERSION => "{version:04b}"
- )
- port map(
- TCK => TCK,
- TMS => TMS,
- TDI => TDI,
- TDO => TDO,
- TRST_N => TRST_N,
- RESET => RESET,
- CAPTURE => CAPTURE,
- SHIFT => SHIFT,
- UPDATE => UPDATE,
- IR => IR,
- CORE_IN => CORE_IN,
- CORE_EN => CORE_EN,
- CORE_OUT => CORE_OUT,
- PAD_IN => PAD_IN,
- PAD_EN => PAD_EN,
- PAD_OUT => PAD_OUT
- );
- end architecture rtl;
- """)
- _cell_inst = 0
- @classmethod
- def _add_instance(cls, platform, prefix, *, ir_width, ios, manufacturer, part, version):
- name = "jtag_controller_i{}".format(cls._cell_inst)
- cls._cell_inst += 1
-
- platform.add_file(
- "{}{}.vhdl".format(prefix, name),
- cls._controller_templ.format(
- name=name, ir_width=ir_width, ios=ios,
- manufacturer=manufacturer, part=part, version=version,
- )
- )
-
- return name
-
-
def __init__(
- self, io_count, *, with_reset=False, ir_width=None,
+ self, *, with_reset=False, ir_width=None,
manufacturer_id=Const(0b10001111111, 11), part_number=Const(1, 16),
version=Const(0, 4),
name=None, src_loc_at=0
):
- assert(isinstance(io_count, int) and io_count > 0)
- assert((ir_width is None) or (isinstance(ir_width, int) and ir_width >= 2))
+ assert((ir_width is None) or (isinstance(ir_width, int) and
+ ir_width >= 2))
assert(len(version) == 4)
if name is None:
self.bus = Interface(with_reset=with_reset, name=self.name+"_bus",
src_loc_at=src_loc_at+1)
- # TODO: Handle IOs with different directions
- self.core = Array(
- Pin(1, "io", name=name+"_coreio"+str(i), src_loc_at=src_loc_at+1)
- for i in range(io_count)
- ) # Signals to use for core
- self.pad = Array(
- Pin(1, "io", name=name+"_padio"+str(i), src_loc_at=src_loc_at+1)
- for i in range(io_count)
- ) # Signals going to IO pads
-
##
- self._io_count = io_count
self._ir_width = ir_width
self._manufacturer_id = manufacturer_id
self._part_number = part_number
self._version = version
- self._ircodes = [0, 1, 2] # Already taken codes, all ones added at the end
- self._srs = []
+ self._ircodes = [0, 1, 2] # Already taken codes, all ones added at end
+ self._ios = []
+ self._srs = []
self._wbs = []
-
def elaborate(self, platform):
- self.__class__._add_files(platform, "jtag" + os.path.sep)
-
m = Module()
# Determine ir_width if not fixed.
ir_max = max(self._ircodes) + 1 # One extra code needed with all ones
ir_width = len("{:b}".format(ir_max))
if self._ir_width is not None:
- assert self._ir_width >= ir_width, "Specified JTAG IR width not big enough for allocated shiift registers"
+ assert self._ir_width >= ir_width, "Specified JTAG IR width " \
+ "not big enough for allocated shiift registers"
ir_width = self._ir_width
- cell = self.__class__._add_instance(
- platform, "jtag" + os.path.sep, ir_width=ir_width, ios=self._io_count,
- manufacturer=self._manufacturer_id.value, part=self._part_number.value,
- version=self._version.value,
+ # TODO: Make commands numbers configurable
+ cmd_extest = 0
+ cmd_intest = 0
+ cmd_idcode = 1
+ cmd_sample = 2
+ cmd_preload = 2
+ cmd_bypass = 2**ir_width - 1 # All ones
+
+ m.submodules._fsm = fsm = _FSM(bus=self.bus)
+ m.domains.posjtag = fsm.posjtag
+ m.domains.negjtag = fsm.negjtag
+
+ # IR block
+ select_ir = fsm.isir
+ m.submodules._irblock = irblock = _IRBlock(
+ ir_width=ir_width, cmd_idcode=cmd_idcode, tdi=self.bus.tdi,
+ capture=(fsm.isir & fsm.capture),
+ shift=(fsm.isir & fsm.shift),
+ update=(fsm.isir & fsm.update),
+ name=self.name+"_ir",
)
-
- sigs = Record([
- ("capture", 1),
- ("shift", 1),
- ("update", 1),
- ("ir", ir_width),
- ("tdo_jtag", 1),
- ])
-
- reset = Signal()
-
- trst_n = Signal()
- m.d.comb += trst_n.eq(~self.bus.trst if hasattr(self.bus, "trst") else Const(1))
-
- core_i = Cat(pin.i for pin in self.core)
- core_o = Cat(pin.o for pin in self.core)
- core_oe = Cat(pin.oe for pin in self.core)
- pad_i = Cat(pin.i for pin in self.pad)
- pad_o = Cat(pin.o for pin in self.pad)
- pad_oe = Cat(pin.oe for pin in self.pad)
-
- m.submodules.tap = Instance(cell,
- i_TCK=self.bus.tck,
- i_TMS=self.bus.tms,
- i_TDI=self.bus.tdi,
- o_TDO=sigs.tdo_jtag,
- i_TRST_N=trst_n,
- o_RESET=reset,
- o_CAPTURE=sigs.capture,
- o_SHIFT=sigs.shift,
- o_UPDATE=sigs.update,
- o_IR=sigs.ir,
- o_CORE_IN=core_i,
- i_CORE_OUT=core_o,
- i_CORE_EN=core_oe,
- i_PAD_IN=pad_i,
- o_PAD_OUT=pad_o,
- o_PAD_EN=pad_oe,
+ ir = irblock.ir
+
+ # ID block
+ select_id = fsm.isdr & ((ir == cmd_idcode) | (ir == cmd_bypass))
+ m.submodules._idblock = idblock = _IDBypassBlock(
+ manufacturer_id=self._manufacturer_id,
+ part_number=self._part_number,
+ version=self._version, tdi=self.bus.tdi,
+ capture=(select_id & fsm.capture),
+ shift=(select_id & fsm.shift),
+ update=(select_id & fsm.update),
+ bypass=(ir == cmd_bypass),
+ name=self.name+"_id",
)
- # Own clock domain using TCK as clock signal
- m.domains.jtag = jtag_cd = ClockDomain(name="jtag", local=True)
+ # IO (Boundary scan) block
+ io_capture = Signal()
+ io_shift = Signal()
+ io_update = Signal()
+ io_bd2io = Signal()
+ io_bd2core = Signal()
+ sample = (ir == cmd_extest) | (ir == cmd_sample)
+ preload = (ir == cmd_preload)
+ select_io = fsm.isdr & (sample | preload)
m.d.comb += [
- jtag_cd.clk.eq(self.bus.tck),
- jtag_cd.rst.eq(reset),
+ io_capture.eq(sample & fsm.capture), # Don't capture if not sample
+ # (like for PRELOAD)
+ io_shift.eq(select_io & fsm.shift),
+ io_update.eq(select_io & fsm.update),
+ io_bd2io.eq(ir == cmd_extest),
+ io_bd2core.eq(ir == cmd_intest),
]
+ io_tdo = self._elaborate_ios(
+ m=m,
+ capture=io_capture, shift=io_shift, update=io_update,
+ bd2io=io_bd2io, bd2core=io_bd2core,
+ )
- self._elaborate_shiftregs(m, sigs)
+ # chain tdo: select as appropriate, to go into into shiftregs
+ tdo = Signal(name=self.name+"_tdo")
+ with m.If(select_ir):
+ m.d.comb += tdo.eq(irblock.tdo)
+ with m.Elif(select_id):
+ m.d.comb += tdo.eq(idblock.tdo)
+ with m.Elif(select_io):
+ m.d.comb += tdo.eq(io_tdo)
+
+ # shiftregs block
+ self._elaborate_shiftregs(
+ m, capture=fsm.capture, shift=fsm.shift, update=fsm.update,
+ ir=irblock.ir, tdo_jtag=tdo
+ )
+
+ # wishbone
self._elaborate_wishbones(m)
return m
- def add_shiftreg(self, ircode, length, domain="sync", name=None, src_loc_at=0):
+ def add_io(self, *, iotype, name=None, src_loc_at=0):
+ """Add a io cell to the boundary scan chain
+
+ Parameters:
+ - iotype: :class:`IOType` enum.
+
+ Returns:
+ - :class:`IOConn`
+ """
+ if name is None:
+ name = "ioconn" + str(len(self._ios))
+
+ ioconn = IOConn(iotype=iotype, name=name, src_loc_at=src_loc_at+1)
+ self._ios.append(ioconn)
+ return ioconn
+
+ def _elaborate_ios(self, *, m, capture, shift, update, bd2io, bd2core):
+ connlength = {
+ IOType.In: 1,
+ IOType.Out: 1,
+ IOType.TriOut: 2,
+ IOType.InTriOut: 3,
+ }
+ length = sum(connlength[conn._iotype] for conn in self._ios)
+ if length == 0:
+ return self.bus.tdi
+
+ io_sr = Signal(length)
+ io_bd = Signal(length)
+
+ # Boundary scan "capture" mode. makes I/O status available via SR
+ with m.If(capture):
+ idx = 0
+ for conn in self._ios:
+ if conn._iotype == IOType.In:
+ m.d.posjtag += io_sr[idx].eq(conn.pad.i)
+ idx += 1
+ elif conn._iotype == IOType.Out:
+ m.d.posjtag += io_sr[idx].eq(conn.core.o)
+ idx += 1
+ elif conn._iotype == IOType.TriOut:
+ m.d.posjtag += [
+ io_sr[idx].eq(conn.core.o),
+ io_sr[idx+1].eq(conn.core.oe),
+ ]
+ idx += 2
+ elif conn._iotype == IOType.InTriOut:
+ m.d.posjtag += [
+ io_sr[idx].eq(conn.pad.i),
+ io_sr[idx+1].eq(conn.core.o),
+ io_sr[idx+2].eq(conn.core.oe),
+ ]
+ idx += 3
+ else:
+ raise("Internal error")
+ assert idx == length, "Internal error"
+
+ # "Shift" mode (sends out captured data on tdo, sets incoming from tdi)
+ with m.Elif(shift):
+ m.d.posjtag += io_sr.eq(Cat(self.bus.tdi, io_sr[:-1]))
+
+ # "Update" mode
+ with m.Elif(update):
+ m.d.negjtag += io_bd.eq(io_sr)
+
+ # sets up IO (pad<->core) or in testing mode depending on requested
+ # mode, via Muxes controlled by bd2core and bd2io
+ idx = 0
+ for conn in self._ios:
+ if conn._iotype == IOType.In:
+ m.d.comb += conn.core.i.eq(Mux(bd2core, io_bd[idx], conn.pad.i))
+ idx += 1
+ elif conn._iotype == IOType.Out:
+ m.d.comb += conn.pad.o.eq(Mux(bd2io, io_bd[idx], conn.core.o))
+ idx += 1
+ elif conn._iotype == IOType.TriOut:
+ m.d.comb += [
+ conn.pad.o.eq(Mux(bd2io, io_bd[idx], conn.core.o)),
+ conn.pad.oe.eq(Mux(bd2io, io_bd[idx+1], conn.core.oe)),
+ ]
+ idx += 2
+ elif conn._iotype == IOType.InTriOut:
+ m.d.comb += [
+ conn.core.i.eq(Mux(bd2core, io_bd[idx], conn.pad.i)),
+ conn.pad.o.eq(Mux(bd2io, io_bd[idx+1], conn.core.o)),
+ conn.pad.oe.eq(Mux(bd2io, io_bd[idx+2], conn.core.oe)),
+ ]
+ idx += 3
+ else:
+ raise("Internal error")
+ assert idx == length, "Internal error"
+
+ return io_sr[-1]
+
+ def add_shiftreg(self, *, ircode, length, domain="sync", name=None,
+ src_loc_at=0):
"""Add a shift register to the JTAG interface
Parameters:
- - ircode: code(s) for the IR; int or sequence of ints. In the latter case this
- shiftreg is shared between different IR codes.
+ - ircode: code(s) for the IR; int or sequence of ints. In the latter
+ case this shiftreg is shared between different IR codes.
- length: the length of the shift register
- domain: the domain on which the signal will be used"""
ir_it = ircodes = (ircode,)
for _ircode in ir_it:
if not isinstance(_ircode, int) or _ircode <= 0:
- raise ValueError("IR code '{}' is not an int greater than 0".format(_ircode))
+ raise ValueError("IR code '{}' is not an int "
+ "greater than 0".format(_ircode))
if _ircode in self._ircodes:
raise ValueError("IR code '{}' already taken".format(_ircode))
self._ircodes.extend(ircodes)
if name is None:
- name = self.name + "_sr{}".format(len(self._srs))
- sr = ShiftReg(sr_length=length, cmds=len(ircodes), name=name, src_loc_at=src_loc_at+1)
+ name = "sr{}".format(len(self._srs))
+ sr = ShiftReg(sr_length=length, cmds=len(ircodes), name=name,
+ src_loc_at=src_loc_at+1)
self._srs.append((ircodes, domain, sr))
return sr
- def _elaborate_shiftregs(self, m, sigs):
+ def _elaborate_shiftregs(self, m, capture, shift, update, ir, tdo_jtag):
# tdos is tuple of (tdo, tdo_en) for each shiftreg
tdos = []
for ircodes, domain, sr in self._srs:
m.d.comb += sr.o.eq(reg)
isir = Signal(len(ircodes), name=sr.name+"_isir")
- capture = Signal(name=sr.name+"_capture")
- shift = Signal(name=sr.name+"_shift")
- update = Signal(name=sr.name+"_update")
+ sr_capture = Signal(name=sr.name+"_capture")
+ sr_shift = Signal(name=sr.name+"_shift")
+ sr_update = Signal(name=sr.name+"_update")
m.d.comb += [
- isir.eq(Cat(sigs.ir == ircode for ircode in ircodes)),
- capture.eq((isir != 0) & sigs.capture),
- shift.eq((isir != 0) & sigs.shift),
- update.eq((isir != 0) & sigs.update),
+ isir.eq(Cat(ir == ircode for ircode in ircodes)),
+ sr_capture.eq((isir != 0) & capture),
+ sr_shift.eq((isir != 0) & shift),
+ sr_update.eq((isir != 0) & update),
]
- # update signal is on the JTAG clockdomain, sr.oe is on `domain` clockdomain
- # latch update in `domain` clockdomain and see when it has falling edge.
+ # update signal is on the JTAG clockdomain, sr.oe is on `domain`
+ # clockdomain latch update in `domain` clockdomain and see when
+ # it has falling edge.
# At that edge put isir in sr.oe for one `domain` clockdomain
+ # Using this custom sync <> JTAG domain synchronization avoids
+ # the use of more generic but also higher latency CDC solutions
+ # like FFSynchronizer.
update_core = Signal(name=sr.name+"_update_core")
update_core_prev = Signal(name=sr.name+"_update_core_prev")
m.d[domain] += [
- update_core.eq(update), # This is CDC from JTAG domain to given domain
+ update_core.eq(sr_update), # This is CDC from JTAG domain
+ # to given domain
update_core_prev.eq(update_core)
]
- with m.If(update_core_prev & ~update_core == 0):
+ with m.If(update_core_prev & ~update_core):
# Falling edge of update
m.d[domain] += sr.oe.eq(isir)
with m.Else():
m.d[domain] += sr.oe.eq(0)
- with m.If(shift):
- m.d.jtag += reg.eq(Cat(reg[1:], self.bus.tdi))
- with m.If(capture):
- m.d.jtag += reg.eq(sr.i)
+ with m.If(sr_shift):
+ m.d.posjtag += reg.eq(Cat(reg[1:], self.bus.tdi))
+ with m.If(sr_capture):
+ m.d.posjtag += reg.eq(sr.i)
# tdo = reg[0], tdo_en = shift
- tdos.append((reg[0], shift))
+ tdos.append((reg[0], sr_shift))
+
+ # Assign the right tdo to the bus tdo
for i, (tdo, tdo_en) in enumerate(tdos):
if i == 0:
- with m.If(shift):
+ with m.If(tdo_en):
m.d.comb += self.bus.tdo.eq(tdo)
else:
- with m.Elif(shift):
+ with m.Elif(tdo_en):
m.d.comb += self.bus.tdo.eq(tdo)
if len(tdos) > 0:
with m.Else():
- m.d.comb += self.bus.tdo.eq(sigs.tdo_jtag)
+ m.d.comb += self.bus.tdo.eq(tdo_jtag)
else:
- # Always connect tdo_jtag to
- m.d.comb += self.bus.tdo.eq(sigs.tdo_jtag)
+ # Always connect tdo_jtag to
+ m.d.comb += self.bus.tdo.eq(tdo_jtag)
- def add_wishbone(self, *, ircodes, address_width, data_width, granularity=None, domain="sync"):
+ def add_wishbone(self, *, ircodes, address_width, data_width,
+ granularity=None, domain="sync",
+ name=None, src_loc_at=0):
"""Add a wishbone interface
- In order to allow high JTAG clock speed, data will be cached. This means that if data is
- output the value of the next address will be read automatically.
+ In order to allow high JTAG clock speed, data will be cached.
+ This means that if data is output the value of the next address
+ will be read automatically.
Parameters:
-----------
if len(ircodes) != 3:
raise ValueError("3 IR Codes have to be provided")
- sr_addr = self.add_shiftreg(ircodes[0], address_width, domain=domain)
- sr_data = self.add_shiftreg(ircodes[1:], data_width, domain=domain)
+ if name is None:
+ name = "wb" + str(len(self._wbs))
+ sr_addr = self.add_shiftreg(
+ ircode=ircodes[0], length=address_width, domain=domain,
+ name=name+"_addrsr"
+ )
+ sr_data = self.add_shiftreg(
+ ircode=ircodes[1:], length=data_width, domain=domain,
+ name=name+"_datasr"
+ )
wb = WishboneInterface(data_width=data_width, addr_width=address_width,
- granularity=granularity, features={"stall", "lock", "err", "rty"})
+ granularity=granularity,
+ features={"stall", "lock", "err", "rty"},
+ name=name, src_loc_at=src_loc_at+1)
self._wbs.append((sr_addr, sr_data, wb, domain))
def _elaborate_wishbones(self, m):
for sr_addr, sr_data, wb, domain in self._wbs:
+ m.d.comb += sr_addr.i.eq(wb.adr)
+
if hasattr(wb, "sel"):
# Always selected
m.d.comb += [s.eq(1) for s in wb.sel]
m.next = "READACK"
with m.State("READACK"):
with m.If(wb.ack):
- # Store read data in sr_data.i and keep it there til next read
+ # Store read data in sr_data.i
+ # and keep it there til next read.
+ # This is enough to synchronize between sync and JTAG
+ # clock domain and no higher latency solutions like
+ # FFSynchronizer is needed.
m.d[domain] += sr_data.i.eq(wb.dat_r)
m.next = "IDLE"
with m.State("WRITEREAD"):
projects / c4m-jtag.git / blobdiff