litex/misoclib/mem/sdram/module.py

# SDRAM memory modules library
#
# This library avoid duplications of memory modules definitions in targets and
# ease SDRAM usage. (User can only select an already existing module or create
# one for its board and contribute to this library)
#
# TODO:
#   Try to share the maximum information we can between modules:
#    - ex: MT46V32M16 and MT46H32M16 are almost identical (V=DDR, H=LPDDR)
#    - Modules can have different configuration:
#        MT8JTF12864 (1GB), MT8JTF25664 (2GB)
#      but share all others informations, try to create an unique module for all
#      configurations.
#    - Modules can have different speedgrades, add support for it (and also add
#      a check to verify clk_freq is in the supported range)
#   Try to uniformize tREFI computations between modules

from math import ceil

from migen.fhdl.std import *
from misoclib.mem import sdram

class SDRAMModule:
	def __init__(self, clk_freq, memtype, geom_settings, timing_settings):
		self.clk_freq = clk_freq
		self.memtype = memtype
		self.geom_settings = sdram.GeomSettings(
			bankbits=log2_int(geom_settings["nbanks"]),
			rowbits=log2_int(geom_settings["nrows"]),
			colbits=log2_int(geom_settings["ncols"]),
		)
		self.timing_settings = sdram.TimingSettings(
			tRP=self.ns(timing_settings["tRP"]),
			tRCD=self.ns(timing_settings["tRCD"]),
			tWR=self.ns(timing_settings["tWR"]),
			tWTR=timing_settings["tWTR"],
			tREFI=self.ns(timing_settings["tREFI"], False),
			tRFC=self.ns(timing_settings["tRFC"])
		)

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

# SDR
class IS42S16160(SDRAMModule):
	geom_settings = {
		"nbanks": 	4,
		"nrows":	8192,
		"ncols":	512
	}
	# Note: timings for -7 speedgrade (add support for others speedgrades)
	timing_settings = {
		"tRP":		20,
		"tRCD":		20,
		"tWR":		20,
		"tWTR":		2,
		"tREFI":	7800,
		"tRFC":		70
	}
	def __init__(self, clk_freq):
		SDRAMModule.__init__(self, clk_freq,  "SDR", self.geom_settings,
			self.timing_settings)

class MT48LC4M16(SDRAMModule):
	geom_settings = {
		"nbanks":	4,
		"nrows":	4096,
		"ncols":	256
	}
	timing_settings = {
		"tRP":		15,
		"tRCD":		15,
		"tWR":		14,
		"tWTR":		2,
		"tREFI":	64*1000*1000/4096,
		"tRFC":		66
	}
	def __init__(self, clk_freq):
		SDRAMModule.__init__(self, clk_freq, "SDR", self.geom_settings,
			self.timing_settings)

class AS4C16M16(SDRAMModule):
	geom_settings = {
		"nbanks": 	4,
		"nrows":	8192,
		"ncols":	512
	}
	# Note: timings for -6 speedgrade (add support for others speedgrades)
	timing_settings = {
		"tRP":		18,
		"tRCD":		18,
		"tWR":		12,
		"tWTR":		2,
		"tREFI":	7800,
		"tRFC":		60
	}
	def __init__(self, clk_freq):
		SDRAMModule.__init__(self, clk_freq, "SDR", self.geom_settings,
			self.timing_settings)

# DDR
class MT46V32M16(SDRAMModule):
	geom_settings = {
		"nbanks":	4,
		"nrows":	8192,
		"ncols":	1024
	}
	timing_settings = {
		"tRP":		15,
		"tRCD":		15,
		"tWR":		15,
		"tWTR":		2,
		"tREFI":	7800,
		"tRFC":		70
	}
	def __init__(self, clk_freq):
		SDRAMModule.__init__(self, clk_freq, "DDR", self.geom_settings,
			self.timing_settings)

# LPDDR
class MT46H32M16(SDRAMModule):
	geom_settings = {
		"nbanks":	4,
		"nrows":	8192,
		"ncols":	1024
	}
	timing_settings = {
		"tRP":		15,
		"tRCD":		15,
		"tWR":		15,
		"tWTR":		2,
		"tREFI":	64*1000*1000/8192,
		"tRFC":		72
	}
	def __init__(self, clk_freq):
		SDRAMModule.__init__(self, clk_freq, "LPDDR", self.geom_settings,
			self.timing_settings)

# DDR2
class MT47H128M8(SDRAMModule):
	geom_settings = {
		"nbanks":	8,
		"nrows":	16384,
		"ncols":	1024
	}
	timing_settings = {
		"tRP":		15,
		"tRCD":		15,
		"tWR":		15,
		"tWTR":		2,
		"tREFI":	7800,
		"tRFC":		127.5
	}
	def __init__(self, clk_freq):
		SDRAMModule.__init__(self, clk_freq, "DDR2", self.geom_settings,
			self.timing_settings)

# DDR3
class MT8JTF12864(SDRAMModule):
	geom_settings = {
		"nbanks":	8,
		"nrows":	65536,
		"ncols":	1024
	}
	timing_settings = {
		"tRP":		15,
		"tRCD":		15,
		"tWR":		15,
		"tWTR":		2,
		"tREFI":	7800,
		"tRFC":		70
	}
	def __init__(self, clk_freq):
		SDRAMModule.__init__(self, clk_freq, "DDR3", self.geom_settings,
			self.timing_settings)