litex/targets/pipistrello.py

from fractions import Fraction

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

from misoclib.mem.sdram.module import MT46H32M16
from misoclib.mem.sdram.phy import s6ddrphy
from misoclib.mem.sdram.core.lasmicon import LASMIconSettings
from misoclib.mem.flash import spiflash
from misoclib.soc.sdram import SDRAMSoC


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

        self.clk4x_wr_strb = Signal()
        self.clk4x_rd_strb = Signal()

        f0 = 50*1000000
        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 = f.denominator, f.numerator
        assert f0/n*m == clk_freq
        p = 8
        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=1000000000/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//4,  # sdram wr rd
                                     p_CLKOUT1_PHASE=0., p_CLKOUT1_DIVIDE=p//8,
                                     p_CLKOUT2_PHASE=270., p_CLKOUT2_DIVIDE=p//2,  # sdram dqs adr ctrl
                                     p_CLKOUT3_PHASE=250., p_CLKOUT3_DIVIDE=p//2,  # off-chip ddr
                                     p_CLKOUT4_PHASE=0., p_CLKOUT4_DIVIDE=p//1,
                                     p_CLKOUT5_PHASE=0., p_CLKOUT5_DIVIDE=p//1,  # sys
        )
        self.specials += Instance("BUFG", i_I=pll[5], o_O=self.cd_sys.clk)
        reset = platform.request("user_btn")
        self.clock_domains.cd_por = ClockDomain()
        por = Signal(max=1 << 11, reset=(1 << 11) - 1)
        self.sync.por += If(por != 0, por.eq(por - 1))
        self.comb += self.cd_por.clk.eq(self.cd_sys.clk)
        self.specials += AsyncResetSynchronizer(self.cd_por, reset)
        self.specials += AsyncResetSynchronizer(self.cd_sys, ~pll_lckd | (por > 0))
        self.specials += Instance("BUFG", i_I=pll[2], o_O=self.cd_sdram_half.clk)
        self.specials += Instance("BUFPLL", p_DIVIDE=4,
                                  i_PLLIN=pll[0], i_GCLK=self.cd_sys.clk,
                                  i_LOCKED=pll_lckd, o_IOCLK=self.cd_sdram_full_wr.clk,
                                  o_SERDESSTROBE=self.clk4x_wr_strb)
        self.comb += [
            self.cd_sdram_full_rd.clk.eq(self.cd_sdram_full_wr.clk),
            self.clk4x_rd_strb.eq(self.clk4x_wr_strb),
        ]
        clk_sdram_half_shifted = Signal()
        self.specials += Instance("BUFG", i_I=pll[3], o_O=clk_sdram_half_shifted)
        clk = platform.request("ddram_clock")
        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=clk_sdram_half_shifted, i_C1=~clk_sdram_half_shifted,
                                  o_Q=clk.p)
        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=clk_sdram_half_shifted, i_C1=~clk_sdram_half_shifted,
                                  o_Q=clk.n)


class BaseSoC(SDRAMSoC):
    default_platform = "pipistrello"

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

    def __init__(self, platform, sdram_controller_settings=LASMIconSettings(), **kwargs):
        clk_freq = 75*1000000
        SDRAMSoC.__init__(self, platform, clk_freq,
                          cpu_reset_address=0x170000,  # 1.5 MB
                          sdram_controller_settings=sdram_controller_settings,
                          **kwargs)

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

        if not self.integrated_main_ram_size:
            self.submodules.ddrphy = s6ddrphy.S6DDRPHY(platform.request("ddram"),
                                                       MT46H32M16(self.clk_freq),
                                                       rd_bitslip=1,
                                                       wr_bitslip=3,
                                                       dqs_ddr_alignment="C1")
            self.comb += [
                self.ddrphy.clk4x_wr_strb.eq(self.crg.clk4x_wr_strb),
                self.ddrphy.clk4x_rd_strb.eq(self.crg.clk4x_rd_strb),
            ]
            self.register_sdram_phy(self.ddrphy)

        if not self.integrated_rom_size:
            self.submodules.spiflash = spiflash.SpiFlash(platform.request("spiflash4x"),
                                                         dummy=10, div=4)
            self.add_constant("SPIFLASH_PAGE_SIZE", 256)
            self.add_constant("SPIFLASH_SECTOR_SIZE", 0x10000)
            self.flash_boot_address = 0x180000
            self.register_rom(self.spiflash.bus, 0x1000000)

default_subtarget = BaseSoC