litex/top.py

from fractions import Fraction
from math import ceil

from migen.fhdl.structure import *
from migen.fhdl import verilog, autofragment
from migen.bus import wishbone, wishbone2asmi, csr, wishbone2csr, dfi

from milkymist import m1crg, lm32, norflash, uart, sram, s6ddrphy, dfii, asmicon, identifier, timer, minimac3
from cmacros import get_macros
from constraints import Constraints

MHz = 1000000
clk_freq = (83 + Fraction(1, 3))*MHz
sram_size = 4096 # in bytes
l2_size = 8192 # in bytes

clk_period_ns = 1000000000/clk_freq
def ns(t, margin=True):
	if margin:
		t += clk_period_ns/2
	return ceil(t/clk_period_ns)

sdram_phy = asmicon.PhySettings(
	dfi_d=64, 
	nphases=2,
	rdphase=0,
	wrphase=1
)
sdram_geom = asmicon.GeomSettings(
	bank_a=2,
	row_a=13,
	col_a=10
)
sdram_timing = asmicon.TimingSettings(
	tRP=ns(15),
	tRCD=ns(15),
	tWR=ns(15),
	tREFI=ns(7800, False),
	tRFC=ns(70),
	
	CL=3,
	rd_delay=4,

	slot_time=16,
	read_time=32,
	write_time=16
)

def ddrphy_clocking(crg, phy):
	names = [
		"clk2x_270",
		"clk4x_wr",
		"clk4x_wr_strb",
		"clk4x_rd",
		"clk4x_rd_strb"
	]
	comb = [getattr(phy, name).eq(getattr(crg, name)) for name in names]
	return Fragment(comb)

csr_macros = get_macros("common/csrbase.h")
def csr_offset(name):
	base = int(csr_macros[name + "_BASE"], 0)
	assert((base >= 0xe0000000) and (base <= 0xe0010000))
	return (base - 0xe0000000)//0x800

interrupt_macros = get_macros("common/interrupt.h")
def interrupt_n(name):
	return int(interrupt_macros[name + "_INTERRUPT"], 0)

version = get_macros("common/version.h")["VERSION"][1:-1]

def get():
	#
	# ASMI
	#
	asmicon0 = asmicon.ASMIcon(sdram_phy, sdram_geom, sdram_timing)
	asmiport_wb = asmicon0.hub.get_port()
	asmicon0.finalize()
	
	#
	# DFI
	#
	ddrphy0 = s6ddrphy.S6DDRPHY(sdram_geom.mux_a, sdram_geom.bank_a, sdram_phy.dfi_d)
	dfii0 = dfii.DFIInjector(csr_offset("DFII"),
		sdram_geom.mux_a, sdram_geom.bank_a, sdram_phy.dfi_d, sdram_phy.nphases)
	dficon0 = dfi.Interconnect(dfii0.master, ddrphy0.dfi)
	dficon1 = dfi.Interconnect(asmicon0.dfi, dfii0.slave)

	#
	# WISHBONE
	#
	cpu0 = lm32.LM32()
	norflash0 = norflash.NorFlash(25, 12)
	sram0 = sram.SRAM(sram_size//4)
	minimac0 = minimac3.MiniMAC(csr_offset("MINIMAC"))
	wishbone2asmi0 = wishbone2asmi.WB2ASMI(l2_size//4, asmiport_wb)
	wishbone2csr0 = wishbone2csr.WB2CSR()
	
	# norflash     0x00000000 (shadow @0x80000000)
	# SRAM/debug   0x10000000 (shadow @0x90000000)
	# USB          0x20000000 (shadow @0xa0000000)
	# Ethernet     0x30000000 (shadow @0xb0000000)
	# SDRAM        0x40000000 (shadow @0xc0000000)
	# CSR bridge   0x60000000 (shadow @0xe0000000)
	wishbonecon0 = wishbone.InterconnectShared(
		[
			cpu0.ibus,
			cpu0.dbus
		], [
			(binc("000"), norflash0.bus),
			(binc("001"), sram0.bus),
			(binc("011"), minimac0.membus),
			(binc("10"), wishbone2asmi0.wishbone),
			(binc("11"), wishbone2csr0.wishbone)
		],
		register=True,
		offset=1)
	
	#
	# CSR
	#
	uart0 = uart.UART(csr_offset("UART"), clk_freq, baud=115200)
	identifier0 = identifier.Identifier(csr_offset("ID"), 0x4D31, version)
	timer0 = timer.Timer(csr_offset("TIMER0"))
	csrcon0 = csr.Interconnect(wishbone2csr0.csr, [
		uart0.bank.interface,
		dfii0.bank.interface,
		identifier0.bank.interface,
		timer0.bank.interface,
		minimac0.bank.interface
	])
	
	#
	# Interrupts
	#
	interrupts = Fragment([
		cpu0.interrupt[interrupt_n("UART")].eq(uart0.events.irq),
		cpu0.interrupt[interrupt_n("TIMER0")].eq(timer0.events.irq),
		cpu0.interrupt[interrupt_n("MINIMAC")].eq(minimac0.events.irq)
	])
	
	#
	# Housekeeping
	#
	crg0 = m1crg.M1CRG(50*MHz, clk_freq)
	
	frag = autofragment.from_local() + interrupts + ddrphy_clocking(crg0, ddrphy0)
	cst = Constraints(crg0, norflash0, uart0, ddrphy0, minimac0)
	src_verilog, vns = verilog.convert(frag,
		cst.get_ios(),
		name="soc",
		clk_signal=crg0.sys_clk,
		rst_signal=crg0.sys_rst,
		return_ns=True)
	src_ucf = cst.get_ucf(vns)
	return (src_verilog, src_ucf)