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)
  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         if name is not None:
  33             # convention: give the name in the format "name_number"
  34             self.idx = int(name.split("_")[-1])
  35         else:
  36             self.idx = 0
  37             name = "spi_0"
  38         self.granularity = 8
  39         self.data_width = data_width
  40         self.dsize = log2_int(self.data_width//self.granularity)
  41
  42         # set up the wishbone busses
  43         if features is None:
  44             features = frozenset()
  45         if bus is None:
  46             bus = Interface(addr_width=spi_region_addr_width,
  47                             data_width=data_width,
  48                             features=features,
  49                             granularity=8,
  50                             name=name+"_wb_%d_0" % self.idx)
  51         if cfg_bus is None:
  52             cfg_bus = Interface(addr_width=6,
  53                             data_width=data_width,
  54                             features=features,
  55                             granularity=8,
  56                             name=name+"_wb_%d_1" % self.idx)
  57         self.bus = bus
  58         assert len(self.bus.dat_r) == data_width, \
  59                         "bus width must be %d" % data_width
  60         self.cfg_bus = cfg_bus
  61         assert len(self.cfg_bus.dat_r) == data_width, \
  62                         "bus width must be %d" % data_width
  63
  64         mmap = MemoryMap(addr_width=spi_region_addr_width+self.dsize,
  65                         data_width=self.granularity)
  66         cfg_mmap = MemoryMap(addr_width=6+self.dsize,
  67                         data_width=self.granularity)
  68
  69         self.bus.memory_map = mmap
  70         self.cfg_bus.memory_map = cfg_mmap
  71
  72         # QSPI signals
  73         self.dq_out = Signal(4)       # Data
  74         self.dq_direction = Signal(4)
  75         self.dq_in = Signal(4)
  76         self.cs_n_out = Signal()      # Slave select
  77         self.spi_clk = Signal()       # Clock
  78
  79         # pins resource
  80         self.pins = pins
  81
  82     @classmethod
  83     def add_verilog_source(cls, verilog_src_dir, platform):
  84         # add each of the verilog sources, needed for when doing platform.build
  85         for fname in ['wishbone_spi_master.v', 'phy.v']:
  86             # prepend the src directory to each filename, add its contents
  87             fullname = os.path.join(verilog_src_dir, fname)
  88             with open(fullname) as f:
  89                 platform.add_file(fullname, f)
  90
  91     def elaborate(self, platform):
  92         m = Module()
  93         comb = m.d.comb
  94
  95         # Calculate SPI flash address
  96         spi_bus_adr = Signal(30)
  97         # wb address is in words, offset is in bytes
  98         comb += spi_bus_adr.eq(bus.adr - (adr_offset >> 2))
  99
 100         # create definition of external verilog Tercel code here, so that
 101         # nmigen understands I/O directions (defined by i_ and o_ prefixes)
 102         idx, bus = self.idx, self.bus
 103         tercel = Instance("tercel_core",
 104                             # System parameters
 105                             i_sys_clk_freq = clk_freq,
 106
 107                             # Clock/reset (use DomainRenamer if needed)
 108                             i_peripheral_clock=ClockSignal(),
 109                             i_peripheral_reset=ResetSignal(),
 110
 111                             # SPI region Wishbone bus signals
 112                             i_wishbone_adr_i=spi_bus_adr,
 113                             i_wishbone_dat_i=bus.dat_w,
 114                             i_wishbone_sel_i=bus.sel,
 115                             o_wishbone_dat_o=bus.dat_r,
 116                             i_wishbone_we_i=bus.we,
 117                             i_wishbone_stb_i=bus.stb,
 118                             i_wishbone_cyc_i=bus.cyc,
 119                             o_wishbone_ack_o=bus.ack,
 120
 121                             # Configuration region Wishbone bus signals
 122                             i_cfg_wishbone_adr_i=cfg_bus.adr,
 123                             i_cfg_wishbone_dat_i=cfg_bus.dat_w,
 124                             i_cfg_wishbone_sel_i=cfg_bus.sel,
 125                             o_cfg_wishbone_dat_o=cfg_bus.dat_r,
 126                             i_cfg_wishbone_we_i=cfg_bus.we,
 127                             i_cfg_wishbone_stb_i=cfg_bus.stb,
 128                             i_cfg_wishbone_cyc_i=cfg_bus.cyc,
 129                             o_cfg_wishbone_ack_o=cfg_bus.ack,
 130
 131                             # QSPI signals
 132                             o_spi_d_out=self.dq_out,
 133                             o_spi_d_direction=self.dq_direction,
 134                             i_spi_d_in=self.dq_in,
 135                             o_spi_ss_n=self.cs_n_out,
 136                             o_spi_clock=self.spi_clk
 137                             );
 138
 139         m.submodules['tercel_%d' % self.idx] = uart
 140
 141         if self.pins is not None:
 142             comb += self.pins.dq.o.eq(self.dq_out)
 143             comb += self.pins.dq.oe.eq(self.dq_direction)
 144             comb += self.pins.dq.oe.eq(self.dq_direction)
 145             comb += self.pins.dq.o_clk.eq(ClockSignal())
 146             comb += self.dq_in.eq(self.pins.dq.i)
 147             comb += self.pins.dq.i_clk.eq(ClockSignal())
 148             comb += self.pins.cs_n.eq(self.cs_n_out)
 149             # ECP5 needs special handling for the SPI clock, sigh.
 150             if lattice_ecp5_usrmclk:
 151                 self.specials += Instance("USRMCLK",
 152                     i_USRMCLKI  = self.spi_clk,
 153                     i_USRMCLKTS = 0
 154                 )
 155             else:
 156                 comb += pads.clk.eq(self.spi_clk)
 157
 158         return m
 159
 160
 161 def create_ilang(dut, ports, test_name):
 162     vl = rtlil.convert(dut, name=test_name, ports=ports)
 163     with open("%s.il" % test_name, "w") as f:
 164         f.write(vl)
 165
 166 def create_verilog(dut, ports, test_name):
 167     vl = verilog.convert(dut, name=test_name, ports=ports)
 168     with open("%s.v" % test_name, "w") as f:
 169         f.write(vl)
 170
 171
 172 if __name__ == "__main__":
 173     tercel = Tercel(name="spi_0", data_width=32)
 174     create_ilang(tercel, [tercel.bus.cyc, tercel.bus.stb, tercel.bus.ack,
 175                         tercel.bus.dat_r, tercel.bus.dat_w, tercel.bus.adr,
 176                         tercel.bus.we, tercel.bus.sel,
 177                         tercel.cfg_bus.cyc, tercel.cfg_bus.stb,
 178                         tercel.cfg_bus.ack,
 179                         tercel.cfg_bus.dat_r, tercel.cfg_bus.dat_w,
 180                         tercel.cfg_bus.adr,
 181                         tercel.cfg_bus.we, tercel.cfg_bus.sel,
 182                         tercel.dq_out, tercel.dq_direction, tercel.dq_in,
 183                         tercel.cs_n_out, tercel.spi_clk
 184                        ], "spi_0")
 185