src/soc/bus/tercel.py

   1 #!/usr/bin/env python3
   2 #
   3 # SPDX-License-Identifier: LGPLv3+
   4 # Copyright (C) 2020-2022 Raptor Engineering LLC <support@raptorengineering.com>
   5 # Copyright (C) 2022 Luke Kenneth Casson Leighton <lkcl@lkcl.net>
   6 # Sponsored by NLnet and NGI POINTER under EU Grants 871528 and 957073
   7 # Part of the Libre-SOC Project.
   8 #
   9 # this is a wrapper around the opencores verilog tercel module
  10
  11 from nmigen import (Elaboratable, Cat, Module, Signal, ClockSignal, Instance,
  12                     ResetSignal, Const)
  13
  14 from nmigen_soc.wishbone.bus import Interface
  15 from nmigen_soc.memory import MemoryMap
  16 from nmigen.utils import log2_int
  17 from nmigen.cli import rtlil, verilog
  18 import os
  19
  20 __all__ = ["Tercel"]
  21
  22
  23 class Tercel(Elaboratable):
  24     """Tercel SPI controller from Raptor Engineering, nmigen wrapper.
  25     remember to call Tercel.add_verilog_source
  26     """
  27
  28     def __init__(self, bus=None, cfg_bus=None, features=None, name=None,
  29                        data_width=32, spi_region_addr_width=28, pins=None,
  30                        clk_freq=None,
  31                        lattice_ecp5_usrmclk=False,
  32                        adr_offset=0): # address offset (bytes)
  33         if name is not None:
  34             # convention: give the name in the format "name_number"
  35             self.idx = int(name.split("_")[-1])
  36         else:
  37             self.idx = 0
  38             name = "spi_0"
  39         self.granularity = 8
  40         self.data_width = data_width
  41         self.dsize = log2_int(self.data_width//self.granularity)
  42         self.adr_offset = adr_offset
  43         self.lattice_ecp5_usrmclk = lattice_ecp5_usrmclk
  44
  45         # TODO, sort this out.
  46         assert clk_freq is not None
  47         clk_freq = round(clk_freq)
  48         self.clk_freq = Const(clk_freq, clk_freq.bit_length())
  49
  50         # set up the wishbone busses
  51         if features is None:
  52             features = frozenset()
  53         if bus is None:
  54             bus = Interface(addr_width=spi_region_addr_width,
  55                             data_width=data_width,
  56                             features=features,
  57                             granularity=8,
  58                             name=name+"_wb_%d_0" % self.idx)
  59         if cfg_bus is None:
  60             cfg_bus = Interface(addr_width=6,
  61                             data_width=data_width,
  62                             features=features,
  63                             granularity=8,
  64                             name=name+"_wb_%d_1" % self.idx)
  65         self.bus = bus
  66         assert len(self.bus.dat_r) == data_width, \
  67                         "bus width must be %d" % data_width
  68         self.cfg_bus = cfg_bus
  69         assert len(self.cfg_bus.dat_r) == data_width, \
  70                         "bus width must be %d" % data_width
  71
  72         mmap = MemoryMap(addr_width=spi_region_addr_width+self.dsize,
  73                         data_width=self.granularity)
  74         cfg_mmap = MemoryMap(addr_width=6+self.dsize,
  75                         data_width=self.granularity)
  76
  77         self.bus.memory_map = mmap
  78         self.cfg_bus.memory_map = cfg_mmap
  79
  80         # QSPI signals
  81         self.dq_out = Signal(4)       # Data
  82         self.dq_direction = Signal(4)
  83         self.dq_in = Signal(4)
  84         self.cs_n_out = Signal()      # Slave select
  85         self.spi_clk = Signal()       # Clock
  86
  87         # pins resource
  88         self.pins = pins
  89
  90     @classmethod
  91     def add_verilog_source(cls, verilog_src_dir, platform):
  92         # add each of the verilog sources, needed for when doing platform.build
  93         for fname in ['wishbone_spi_master.v', 'phy.v']:
  94             # prepend the src directory to each filename, add its contents
  95             fullname = os.path.join(verilog_src_dir, fname)
  96             with open(fullname) as f:
  97                 platform.add_file(fullname, f)
  98
  99     def elaborate(self, platform):
 100         m = Module()
 101         comb = m.d.comb
 102         pins, bus, cfg_bus = self.pins, self.bus, self.cfg_bus
 103
 104         # Calculate SPI flash address
 105         spi_bus_adr = Signal(30)
 106         # wb address is in words, offset is in bytes
 107         comb += spi_bus_adr.eq(bus.adr - (self.adr_offset >> 2))
 108
 109         # create definition of external verilog Tercel code here, so that
 110         # nmigen understands I/O directions (defined by i_ and o_ prefixes)
 111         idx, bus = self.idx, self.bus
 112         tercel = Instance("tercel_core",
 113                             # System parameters
 114                             i_sys_clk_freq = self.clk_freq,
 115
 116                             # Clock/reset (use DomainRenamer if needed)
 117                             i_peripheral_clock=ClockSignal(),
 118                             i_peripheral_reset=ResetSignal(),
 119
 120                             # SPI region Wishbone bus signals
 121                             i_wishbone_adr_i=spi_bus_adr,
 122                             i_wishbone_dat_i=bus.dat_w,
 123                             i_wishbone_sel_i=bus.sel,
 124                             o_wishbone_dat_o=bus.dat_r,
 125                             i_wishbone_we_i=bus.we,
 126                             i_wishbone_stb_i=bus.stb,
 127                             i_wishbone_cyc_i=bus.cyc,
 128                             o_wishbone_ack_o=bus.ack,
 129
 130                             # Configuration region Wishbone bus signals
 131                             i_cfg_wishbone_adr_i=cfg_bus.adr,
 132                             i_cfg_wishbone_dat_i=cfg_bus.dat_w,
 133                             i_cfg_wishbone_sel_i=cfg_bus.sel,
 134                             o_cfg_wishbone_dat_o=cfg_bus.dat_r,
 135                             i_cfg_wishbone_we_i=cfg_bus.we,
 136                             i_cfg_wishbone_stb_i=cfg_bus.stb,
 137                             i_cfg_wishbone_cyc_i=cfg_bus.cyc,
 138                             o_cfg_wishbone_ack_o=cfg_bus.ack,
 139
 140                             # QSPI signals
 141                             o_spi_d_out=self.dq_out,
 142                             o_spi_d_direction=self.dq_direction,
 143                             i_spi_d_in=self.dq_in,
 144                             o_spi_ss_n=self.cs_n_out,
 145                             o_spi_clock=self.spi_clk
 146                             );
 147
 148         m.submodules['tercel_%d' % self.idx] = tercel
 149
 150         if pins is not None:
 151             comb += pins.dq.o.eq(self.dq_out)
 152             comb += pins.dq.oe.eq(self.dq_direction)
 153             comb += pins.dq.oe.eq(self.dq_direction)
 154             comb += pins.dq.o_clk.eq(ClockSignal())
 155             comb += self.dq_in.eq(pins.dq.i)
 156             comb += pins.dq.i_clk.eq(ClockSignal())
 157             # XXX invert handled by SPIFlashResource
 158             comb += pins.cs.eq(~self.cs_n_out)
 159             # ECP5 needs special handling for the SPI clock, sigh.
 160             if self.lattice_ecp5_usrmclk:
 161                 self.specials += Instance("USRMCLK",
 162                     i_USRMCLKI  = self.spi_clk,
 163                     i_USRMCLKTS = 0
 164                 )
 165             else:
 166                 comb += pins.clk.eq(self.spi_clk)
 167
 168         return m
 169
 170
 171 def create_ilang(dut, ports, test_name):
 172     vl = rtlil.convert(dut, name=test_name, ports=ports)
 173     with open("%s.il" % test_name, "w") as f:
 174         f.write(vl)
 175
 176 def create_verilog(dut, ports, test_name):
 177     vl = verilog.convert(dut, name=test_name, ports=ports)
 178     with open("%s.v" % test_name, "w") as f:
 179         f.write(vl)
 180
 181
 182 if __name__ == "__main__":
 183     tercel = Tercel(name="spi_0", data_width=32, clk_freq=100e6)
 184     create_ilang(tercel, [tercel.bus.cyc, tercel.bus.stb, tercel.bus.ack,
 185                         tercel.bus.dat_r, tercel.bus.dat_w, tercel.bus.adr,
 186                         tercel.bus.we, tercel.bus.sel,
 187                         tercel.cfg_bus.cyc, tercel.cfg_bus.stb,
 188                         tercel.cfg_bus.ack,
 189                         tercel.cfg_bus.dat_r, tercel.cfg_bus.dat_w,
 190                         tercel.cfg_bus.adr,
 191                         tercel.cfg_bus.we, tercel.cfg_bus.sel,
 192                         tercel.dq_out, tercel.dq_direction, tercel.dq_in,
 193                         tercel.cs_n_out, tercel.spi_clk
 194                        ], "spi_0")
 195