litex/targets/pipistrello.py

from fractions import Fraction

from migen.fhdl.std import *
from migen.genlib.resetsync import AsyncResetSynchronizer

from misoclib.mem import sdram
from misoclib.mem.sdram.phy import gensdrphy
from misoclib.mem.flash import SpiFlash
from misoclib.gensoc import SDRAMSoC

class _CRG(Module):
	def __init__(self, platform, clk_freq):
		self.clock_domains.cd_sys = ClockDomain()
		self.clock_domains.cd_sys_ps = ClockDomain()

		f0 = 50*1000*1000
		clk50 = platform.request("clk50")
		clk50a = Signal()
		self.specials += Instance("IBUFG", i_I=clk50, o_O=clk50a)
		clk50b = Signal()
		self.specials += Instance("BUFIO2", p_DIVIDE=1,
			p_DIVIDE_BYPASS="TRUE", p_I_INVERT="FALSE",
			i_I=clk50a, o_DIVCLK=clk50b)
		f = Fraction(int(clk_freq), int(f0))
		n, m, p = f.denominator, f.numerator, 8
		assert f0/n*m == clk_freq
		pll_lckd = Signal()
		pll_fb = Signal()
		pll = Signal(6)
		self.specials.pll = Instance("PLL_ADV", p_SIM_DEVICE="SPARTAN6",
			p_BANDWIDTH="OPTIMIZED", p_COMPENSATION="INTERNAL",
			p_REF_JITTER=.01, p_CLK_FEEDBACK="CLKFBOUT",
			i_DADDR=0, i_DCLK=0, i_DEN=0, i_DI=0, i_DWE=0, i_RST=0, i_REL=0,
			p_DIVCLK_DIVIDE=1, p_CLKFBOUT_MULT=m*p//n, p_CLKFBOUT_PHASE=0.,
			i_CLKIN1=clk50b, i_CLKIN2=0, i_CLKINSEL=1,
			p_CLKIN1_PERIOD=1/f0, p_CLKIN2_PERIOD=0.,
			i_CLKFBIN=pll_fb, o_CLKFBOUT=pll_fb, o_LOCKED=pll_lckd,
			o_CLKOUT0=pll[0], p_CLKOUT0_DUTY_CYCLE=.5,
			o_CLKOUT1=pll[1], p_CLKOUT1_DUTY_CYCLE=.5,
			o_CLKOUT2=pll[2], p_CLKOUT2_DUTY_CYCLE=.5,
			o_CLKOUT3=pll[3], p_CLKOUT3_DUTY_CYCLE=.5,
			o_CLKOUT4=pll[4], p_CLKOUT4_DUTY_CYCLE=.5,
			o_CLKOUT5=pll[5], p_CLKOUT5_DUTY_CYCLE=.5,
			p_CLKOUT0_PHASE=0., p_CLKOUT0_DIVIDE=p//1,
			p_CLKOUT1_PHASE=0., p_CLKOUT1_DIVIDE=p//1,
			p_CLKOUT2_PHASE=0., p_CLKOUT2_DIVIDE=p//1,
			p_CLKOUT3_PHASE=0., p_CLKOUT3_DIVIDE=p//1,
			p_CLKOUT4_PHASE=0., p_CLKOUT4_DIVIDE=p//1, # sys
			p_CLKOUT5_PHASE=270., p_CLKOUT5_DIVIDE=p//1, # sys_ps
		)
		self.specials += Instance("BUFG", i_I=pll[4], o_O=self.cd_sys.clk)
		self.specials += Instance("BUFG", i_I=pll[5], o_O=self.cd_sys_ps.clk)
		self.specials += AsyncResetSynchronizer(self.cd_sys, ~pll_lckd)

		clk = platform.request("sdram_clock")
		self.specials += Instance("ODDR2", p_DDR_ALIGNMENT="NONE",
			p_INIT=0, p_SRTYPE="SYNC",
			i_D0=0, i_D1=1, i_S=0, i_R=0, i_CE=1,
			i_C0=self.cd_sys.clk, i_C1=~self.cd_sys.clk,
			o_Q=clk.p)
		self.specials += Instance("ODDR2", p_DDR_ALIGNMENT="NONE",
			p_INIT=0, p_SRTYPE="SYNC",
			i_D0=1, i_D1=0, i_S=0, i_R=0, i_CE=1,
			i_C0=self.cd_sys.clk, i_C1=~self.cd_sys.clk,
			o_Q=clk.n)

class BaseSoC(SDRAMSoC):
	default_platform = "pipistrello"

	csr_map = {
		"spiflash":	16,
	}
	csr_map.update(SDRAMSoC.csr_map)

	def __init__(self, platform, **kwargs):
		clk_freq = 80*1000*1000
		SDRAMSoC.__init__(self, platform, clk_freq,
			cpu_reset_address=0x60000, **kwargs)

		self.submodules.crg = _CRG(platform, clk_freq)

		sdram_geom = sdram.GeomSettings(
			bank_a=2,
			row_a=12,
			col_a=8
		)
		sdram_timing = sdram.TimingSettings(
			tRP=self.ns(15),
			tRCD=self.ns(15),
			tWR=self.ns(15),
			tWTR=2,
			tREFI=self.ns(64*1000*1000/4096, False),
			tRFC=self.ns(72),
			req_queue_size=8,
			read_time=32,
			write_time=16
		)
		self.submodules.sdrphy = gensdrphy.GENSDRPHY(platform.request("sdram"))
		self.register_sdram_phy(self.sdrphy.dfi, self.sdrphy.phy_settings, sdram_geom, sdram_timing)

		# If not in ROM, BIOS is in SPI flash
		if not self.with_rom:
			self.submodules.spiflash = spiflash.SpiFlash(platform.request("spiflash2x"), dummy=4, div=6)
			self.flash_boot_address = 0x70000
			self.register_rom(self.spiflash.bus)

default_subtarget = BaseSoC