--- /dev/null
+"""DCache
+
+based on Anton Blanchard microwatt dcache.vhdl
+
+note that the microwatt dcache wishbone interface expects "stall".
+for simplicity at the moment this is hard-coded to cyc & ~ack.
+see WB4 spec, p84, section 5.2.1
+
+IMPORTANT: for store, the data is sampled the cycle AFTER the "valid"
+is raised. sigh
+
+Links:
+
+* https://libre-soc.org/3d_gpu/architecture/set_associative_cache.jpg
+* https://bugs.libre-soc.org/show_bug.cgi?id=469
+
+"""
+
+import sys
+
+from nmutil.gtkw import write_gtkw
+
+sys.setrecursionlimit(1000000)
+
+from enum import Enum, unique
+
+from nmigen import Module, Signal, Elaboratable, Cat, Repl, Array, Const
+
+from copy import deepcopy
+from random import randint, seed
+
+from soc.experiment.cache_ram import CacheRam
+
+# for test
+from soc.bus.sram import SRAM
+from nmigen import Memory
+from nmigen.cli import rtlil
+
+# NOTE: to use cxxsim, export NMIGEN_SIM_MODE=cxxsim from the shell
+# Also, check out the cxxsim nmigen branch, and latest yosys from git
+from nmutil.sim_tmp_alternative import Simulator
+
+from nmutil.util import wrap
+
+from soc.experiment.dcache import DCache
+
+
+def dcache_load_m(dut, addr, nc=0):
+ REF = 1<<8
+ CHG = 1<<7
+ NC = 1<<5
+ PRIV = 1<<3
+ RD = 1<<2
+ WR = 1<<1
+ pte = RD | WR | REF | PRIV
+ yield dut.m_in.pte.eq(pte)
+ yield dut.m_in.addr.eq(addr)
+ yield dut.m_in.valid.eq(1)
+ yield
+ yield dut.m_in.valid.eq(0)
+ while not (yield dut.m_out.done):
+ yield
+ # yield # data is valid one cycle AFTER valid goes hi? (no it isn't)
+ data = yield dut.m_out.data
+ return data
+
+
+def dcache_load(dut, addr, nc=0):
+ yield dut.d_in.load.eq(1)
+ yield dut.d_in.nc.eq(nc)
+ yield dut.d_in.addr.eq(addr)
+ yield dut.d_in.byte_sel.eq(~0)
+ yield dut.d_in.valid.eq(1)
+ yield
+ yield dut.d_in.valid.eq(0)
+ yield dut.d_in.byte_sel.eq(0)
+ while not (yield dut.d_out.valid):
+ yield
+ # yield # data is valid one cycle AFTER valid goes hi? (no it isn't)
+ data = yield dut.d_out.data
+ return data
+
+
+def dcache_store(dut, addr, data, nc=0):
+ yield dut.d_in.load.eq(0)
+ yield dut.d_in.nc.eq(nc)
+ yield dut.d_in.byte_sel.eq(~0)
+ yield dut.d_in.addr.eq(addr)
+ yield dut.d_in.valid.eq(1)
+ yield
+ yield dut.d_in.data.eq(data) # leave set, but the cycle AFTER
+ yield dut.d_in.valid.eq(0)
+ yield dut.d_in.byte_sel.eq(0)
+ while not (yield dut.d_out.valid):
+ yield
+
+
+def dcache_random_sim(dut, mem, nc=0):
+
+ # start copy of mem
+ sim_mem = deepcopy(mem)
+ memsize = len(sim_mem)
+ print ("mem len", memsize)
+
+ # clear stuff
+ yield dut.d_in.valid.eq(0)
+ yield dut.d_in.load.eq(0)
+ yield dut.d_in.priv_mode.eq(1)
+ yield dut.d_in.nc.eq(0)
+ yield dut.d_in.addr.eq(0)
+ yield dut.d_in.data.eq(0)
+ yield dut.m_in.valid.eq(0)
+ yield dut.m_in.addr.eq(0)
+ yield dut.m_in.pte.eq(0)
+ # wait 4 * clk_period
+ yield
+ yield
+ yield
+ yield
+
+ print ()
+
+ #for i in range(1024):
+ # sim_mem[i] = i
+
+ for i in range(1024):
+ addr = randint(0, memsize-1)
+ data = randint(0, (1<<64)-1)
+ sim_mem[addr] = data
+ row = addr
+ addr *= 8
+
+ print ("random testing %d 0x%x row %d data 0x%x" % (i, addr, row, data))
+
+ yield from dcache_load(dut, addr, nc)
+ yield from dcache_store(dut, addr, data, nc)
+
+ addr = randint(0, memsize-1)
+ sim_data = sim_mem[addr]
+ row = addr
+ addr *= 8
+
+ print (" load 0x%x row %d expect data 0x%x" % (addr, row, sim_data))
+ data = yield from dcache_load(dut, addr, nc)
+ assert data == sim_data, \
+ "check addr 0x%x row %d data %x != %x" % (addr, row, data, sim_data)
+
+ for addr in range(memsize):
+ data = yield from dcache_load(dut, addr*8, nc)
+ assert data == sim_mem[addr], \
+ "final check %x data %x != %x" % (addr*8, data, sim_mem[addr])
+
+
+def dcache_regression_sim(dut, mem, nc=0):
+
+ # start copy of mem
+ sim_mem = deepcopy(mem)
+ memsize = len(sim_mem)
+ print ("mem len", memsize)
+
+ # clear stuff
+ yield dut.d_in.valid.eq(0)
+ yield dut.d_in.load.eq(0)
+ yield dut.d_in.priv_mode.eq(1)
+ yield dut.d_in.nc.eq(0)
+ yield dut.d_in.addr.eq(0)
+ yield dut.d_in.data.eq(0)
+ yield dut.m_in.valid.eq(0)
+ yield dut.m_in.addr.eq(0)
+ yield dut.m_in.pte.eq(0)
+ # wait 4 * clk_period
+ yield
+ yield
+ yield
+ yield
+
+ addr = 0
+ row = addr
+ addr *= 8
+
+ print ("random testing %d 0x%x row %d" % (i, addr, row))
+
+ yield from dcache_load(dut, addr, nc)
+
+ addr = 2
+ sim_data = sim_mem[addr]
+ row = addr
+ addr *= 8
+
+ print (" load 0x%x row %d expect data 0x%x" % (addr, row, sim_data))
+ data = yield from dcache_load(dut, addr, nc)
+ assert data == sim_data, \
+ "check addr 0x%x row %d data %x != %x" % (addr, row, data, sim_data)
+
+
+
+def dcache_sim(dut, mem):
+ # clear stuff
+ yield dut.d_in.valid.eq(0)
+ yield dut.d_in.load.eq(0)
+ yield dut.d_in.priv_mode.eq(1)
+ yield dut.d_in.nc.eq(0)
+ yield dut.d_in.addr.eq(0)
+ yield dut.d_in.data.eq(0)
+ yield dut.m_in.valid.eq(0)
+ yield dut.m_in.addr.eq(0)
+ yield dut.m_in.pte.eq(0)
+ # wait 4 * clk_period
+ yield
+ yield
+ yield
+ yield
+
+ # Cacheable read of address 4
+ data = yield from dcache_load_m(dut, 0x58)
+ addr = yield dut.d_in.addr
+ print ("dcache m_load 0x58", addr)
+ yield
+ yield
+
+ return
+
+ assert data == 0x0000001700000016, \
+ f"data @%x=%x expected 0x0000001700000016" % (addr, data)
+
+ # Cacheable read of address 20
+ data = yield from dcache_load(dut, 0x20)
+ addr = yield dut.d_in.addr
+ assert data == 0x0000000900000008, \
+ f"data @%x=%x expected 0x0000000900000008" % (addr, data)
+
+ # Cacheable read of address 30
+ data = yield from dcache_load(dut, 0x530)
+ addr = yield dut.d_in.addr
+ assert data == 0x0000014D0000014C, \
+ f"data @%x=%x expected 0000014D0000014C" % (addr, data)
+
+ # 2nd Cacheable read of address 30
+ data = yield from dcache_load(dut, 0x530)
+ addr = yield dut.d_in.addr
+ assert data == 0x0000014D0000014C, \
+ f"data @%x=%x expected 0000014D0000014C" % (addr, data)
+
+ # Non-cacheable read of address 100
+ data = yield from dcache_load(dut, 0x100, nc=1)
+ addr = yield dut.d_in.addr
+ assert data == 0x0000004100000040, \
+ f"data @%x=%x expected 0000004100000040" % (addr, data)
+
+ # Store at address 530
+ yield from dcache_store(dut, 0x530, 0x121)
+
+ # Store at address 30
+ yield from dcache_store(dut, 0x530, 0x12345678)
+
+ # 3nd Cacheable read of address 530
+ data = yield from dcache_load(dut, 0x530)
+ addr = yield dut.d_in.addr
+ assert data == 0x12345678, \
+ f"data @%x=%x expected 0x12345678" % (addr, data)
+
+ # 4th Cacheable read of address 20
+ data = yield from dcache_load(dut, 0x20)
+ addr = yield dut.d_in.addr
+ assert data == 0x0000000900000008, \
+ f"data @%x=%x expected 0x0000000900000008" % (addr, data)
+
+ yield
+ yield
+ yield
+ yield
+
+
+def test_dcache(mem, test_fn, test_name):
+ dut = DCache()
+
+ memory = Memory(width=64, depth=len(mem), init=mem, simulate=True)
+ sram = SRAM(memory=memory, granularity=8)
+
+ m = Module()
+ m.submodules.dcache = dut
+ m.submodules.sram = sram
+
+ m.d.comb += sram.bus.cyc.eq(dut.wb_out.cyc)
+ m.d.comb += sram.bus.stb.eq(dut.wb_out.stb)
+ m.d.comb += sram.bus.we.eq(dut.wb_out.we)
+ m.d.comb += sram.bus.sel.eq(dut.wb_out.sel)
+ m.d.comb += sram.bus.adr.eq(dut.wb_out.adr)
+ m.d.comb += sram.bus.dat_w.eq(dut.wb_out.dat)
+
+ m.d.comb += dut.wb_in.ack.eq(sram.bus.ack)
+ m.d.comb += dut.wb_in.dat.eq(sram.bus.dat_r)
+
+ dcache_write_gtkw(test_name)
+
+ # nmigen Simulation
+ sim = Simulator(m)
+ sim.add_clock(1e-6)
+
+ sim.add_sync_process(wrap(test_fn(dut, mem)))
+ with sim.write_vcd('test_dcache_m%s.vcd' % test_name):
+ sim.run()
+
+
+def dcache_write_gtkw(test_name):
+ traces = [
+ 'clk',
+ ('m_in', [
+ 'm_in_doall', 'm_in_addr[63:0]', 'm_in_pte[63:0]',
+ 'm_in_tlbie', 'm_in_tlbid', 'm_in_valid'
+ ]),
+ ('m_out', [
+ 'm_out_done', 'm_out_data[63:0]', 'm_out_err', 'm_out_stall'
+ ]),
+ ('d_in', [
+ 'd_in_load', 'd_in_nc', 'd_in_addr[63:0]', 'd_in_data[63:0]',
+ 'd_in_byte_sel[7:0]', 'd_in_valid'
+ ]),
+ ('d_out', [
+ 'd_out_valid', 'd_out_data[63:0]'
+ ]),
+ ('wb_out', [
+ 'wb_out_cyc', 'wb_out_stb', 'wb_out_we',
+ 'wb_out_adr[31:0]', 'wb_out_sel[7:0]', 'wb_out_dat[63:0]'
+ ]),
+ ('wb_in', [
+ 'wb_in_stall', 'wb_in_ack', 'wb_in_dat[63:0]'
+ ])
+ ]
+ write_gtkw('test_dcache_m%s.gtkw' % test_name,
+ 'test_dcache_m%s.vcd' % test_name,
+ traces, module='top.dcache')
+
+
+if __name__ == '__main__':
+ seed(0)
+ dut = DCache()
+ vl = rtlil.convert(dut, ports=[])
+ with open("test_dcache.il", "w") as f:
+ f.write(vl)
+
+ if False:
+ mem = []
+ memsize = 16
+ for i in range(memsize):
+ mem.append(i)
+
+ test_dcache(mem, dcache_regression_sim, "simpleregression")
+
+ mem = []
+ memsize = 256
+ for i in range(memsize):
+ mem.append(i)
+
+ test_dcache(mem, dcache_random_sim, "random")
+
+ mem = []
+ for i in range(1024):
+ mem.append((i*2)| ((i*2+1)<<32))
+
+ test_dcache(mem, dcache_sim, "")
+
projects / soc.git / commitdiff