From 32d9e212c5d7b255b2883757213acb7883116be9 Mon Sep 17 00:00:00 2001 From: =?utf8?q?J=C4=99drzej=20Boczar?= Date: Wed, 22 Jul 2020 15:02:42 +0200 Subject: [PATCH] soc/interconnect/axi: improve Timeout module and test it with shared interconnect --- litex/soc/interconnect/axi.py | 86 +++++++++++++++++++---------------- test/test_axi.py | 20 ++++++-- 2 files changed, 63 insertions(+), 43 deletions(-) diff --git a/litex/soc/interconnect/axi.py b/litex/soc/interconnect/axi.py index 71040ac7..6d00ca64 100644 --- a/litex/soc/interconnect/axi.py +++ b/litex/soc/interconnect/axi.py @@ -893,48 +893,58 @@ class AXILiteTimeout(Module): """Protect master against slave timeouts (master _has_ to respond correctly)""" def __init__(self, master, cycles): self.error = Signal() + wr_error = Signal() + rd_error = Signal() # # # - timer = WaitTimer(int(cycles)) - self.submodules += timer - is_write = Signal() - is_read = Signal() - - self.submodules.fsm = fsm = FSM() - fsm.act("WAIT", - is_write.eq((master.aw.valid & ~master.aw.ready) | (master.w.valid & ~master.w.ready)), - is_read.eq(master.ar.valid & ~master.ar.ready), - timer.wait.eq(is_write | is_read), - # done is updated in `sync`, so we must make sure that `ready` has not been issued - # by slave during that single cycle, by checking `timer.wait` - If(timer.done & timer.wait, - self.error.eq(1), - If(is_write, - NextState("RESPOND-WRITE") - ).Else( - NextState("RESPOND-READ") + self.comb += self.error.eq(wr_error | rd_error) + + wr_timer = WaitTimer(int(cycles)) + rd_timer = WaitTimer(int(cycles)) + self.submodules += wr_timer, rd_timer + + def channel_fsm(timer, wait_cond, error, response): + fsm = FSM(reset_state="WAIT") + fsm.act("WAIT", + timer.wait.eq(wait_cond), + # done is updated in `sync`, so we must make sure that `ready` has not been issued + # by slave during that single cycle, by checking `timer.wait` + If(timer.done & timer.wait, + error.eq(1), + NextState("RESPOND") ) ) - ) - fsm.act("RESPOND-WRITE", - master.aw.ready.eq(master.aw.valid), - master.w.ready.eq(master.w.valid), - master.b.valid.eq(~master.aw.valid & ~master.w.valid), - master.b.resp.eq(RESP_SLVERR), - If(master.b.valid & master.b.ready, - NextState("WAIT") - ) - ) - fsm.act("RESPOND-READ", - master.ar.ready.eq(master.ar.valid), - master.r.valid.eq(~master.ar.valid), - master.r.resp.eq(RESP_SLVERR), - master.r.data.eq(2**len(master.r.data) - 1), - If(master.r.valid & master.r.ready, - NextState("WAIT") - ) - ) + fsm.act("RESPOND", *response) + return fsm + + self.submodules.wr_fsm = channel_fsm( + timer = wr_timer, + wait_cond = (master.aw.valid & ~master.aw.ready) | (master.w.valid & ~master.w.ready), + error = wr_error, + response = [ + master.aw.ready.eq(master.aw.valid), + master.w.ready.eq(master.w.valid), + master.b.valid.eq(~master.aw.valid & ~master.w.valid), + master.b.resp.eq(RESP_SLVERR), + If(master.b.valid & master.b.ready, + NextState("WAIT") + ) + ]) + + self.submodules.rd_fsm = channel_fsm( + timer = rd_timer, + wait_cond = master.ar.valid & ~master.ar.ready, + error = rd_error, + response = [ + master.ar.ready.eq(master.ar.valid), + master.r.valid.eq(~master.ar.valid), + master.r.resp.eq(RESP_SLVERR), + master.r.data.eq(2**len(master.r.data) - 1), + If(master.r.valid & master.r.ready, + NextState("WAIT") + ) + ]) # AXILite Interconnect ----------------------------------------------------------------------------- @@ -1051,8 +1061,6 @@ class AXILiteDecoder(Module): slave_sel = new_slave_sel() # we need to hold the slave selected until all responses come back - # TODO: check if this will break Timeout if a slave does not respond? - # should probably work correctly as it uses master signals # TODO: we could reuse arbiter counters locks = { "write": AXILiteRequestCounter( diff --git a/test/test_axi.py b/test/test_axi.py index f76e48b0..70ff2f0c 100644 --- a/test/test_axi.py +++ b/test/test_axi.py @@ -974,10 +974,12 @@ class TestAXILiteInterconnect(unittest.TestCase): def interconnect_shared_test(self, master_patterns, slave_decoders, master_delay=0, slave_ready_latency=0, slave_response_latency=0, - timeout=300, **kwargs): + disconnected_slaves=None, timeout=300, **kwargs): # number of masters/slaves is defined by the number of patterns/decoders # master_patterns: list of patterns per master, pattern = list(tuple(rw, addr, data)) # slave_decoders: list of address decoders per slave + # delay/latency: control the speed of masters/slaves + # disconnected_slaves: list of slave numbers that shouldn't respond to any transactions class DUT(Module): def __init__(self, n_masters, decoders, **kwargs): self.masters = [AXILiteInterface(name="master") for _ in range(n_masters)] @@ -1013,9 +1015,11 @@ class TestAXILiteInterconnect(unittest.TestCase): # run simulator generators = [gen.handler() for gen in pattern_generators] - generators += [checker.handler(slave) for (slave, checker) in zip(dut.slaves, checkers)] + generators += [checker.handler(slave) + for i, (slave, checker) in enumerate(zip(dut.slaves, checkers)) + if i not in (disconnected_slaves or [])] generators += [timeout_generator(timeout)] - run_simulation(dut, generators) + run_simulation(dut, generators, vcd_name='sim.vcd') return pattern_generators, checkers @@ -1075,7 +1079,10 @@ class TestAXILiteInterconnect(unittest.TestCase): read_errors = [" 0x{:08x} vs 0x{:08x}".format(v, ref) for v, ref in gen.read_errors] msg = "\ngen.resp_errors = {}\ngen.read_errors = \n{}".format( gen.resp_errors, "\n".join(read_errors)) - self.assertEqual(gen.errors, 0, msg=msg) + if not kwargs.get("disconnected_slaves", None): + self.assertEqual(gen.errors, 0, msg=msg) + else: # when some slaves are disconnected we should have some errors + self.assertNotEqual(gen.errors, 0, msg=msg) # make sure all the accesses at slave side are in correct address region for i_slave, (checker, decoder) in enumerate(zip(checkers, slave_decoders_py)): @@ -1104,3 +1111,8 @@ class TestAXILiteInterconnect(unittest.TestCase): master_delay=rand, slave_ready_latency=rand, slave_response_latency=rand) + + def test_interconnect_shared_stress_timeout(self): + self.interconnect_shared_stress_test(timeout=4000, + disconnected_slaves=[1], + timeout_cycles=50) -- 2.30.2