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soc/interconnect/avalon/AvalonMM: Do a first cosmetic cleanup pass. 

- Add separators.
- Use coding style similar to other modules.
- Replace the Mux with simpler If/Else constructs to improve understanding and readability.
This commit is contained in:
Florent Kermarrec 2023-05-08 09:14:35 +02:00
parent c5c7e86cca
commit 7071304b10
1 changed files with 61 additions and 32 deletions
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93
litex/soc/interconnect/avalon.py
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@ -12,6 +12,9 @@ from migen import *
from litex.soc.interconnect import stream
from litex.soc.interconnect import wishbone
# Avalon MM Layout ---------------------------------------------------------------------------------
_layout = [
("address", "adr_width", DIR_M_TO_S),
("writedata", "data_width", DIR_M_TO_S),
@ -21,11 +24,13 @@ _layout = [
("read", 1, DIR_M_TO_S),
("write", 1, DIR_M_TO_S),
("waitrequest", 1, DIR_S_TO_M),
("burstbegin", 1, DIR_M_TO_S), # this is optional
("burstbegin", 1, DIR_M_TO_S), # Optional.
("burstcount", 8, DIR_M_TO_S),
("chipselect", 1, DIR_M_TO_S), # this is optional
("chipselect", 1, DIR_M_TO_S), # Optional.
]
# Avalon MM Interface ------------------------------------------------------------------------------
class AvalonMMInterface(Record):
def __init__(self, data_width=32, adr_width=30, **kwargs):
self.data_width = data_width
@ -85,8 +90,7 @@ class AvalonMMInterface(Record):
while (yield self.waitrequest):
yield
yield self.read.eq(0)
# actually don't care outside of a transaction
# this makes the traces look neater
# Actually don't care outside of a transaction this makes the traces look neater.
yield self.byteenable.eq(0)
if burstcount != 1:
yield self.burstcount.eq(0)
@ -129,6 +133,8 @@ class AvalonMMInterface(Record):
if chipselect is not None:
yield self.chipselect.eq(0)
# Avalon MM <--> Wishbone Bridge -------------------------------------------------------------------
class AvalonMM2Wishbone(Module):
def __init__(self, data_width=32, address_width=32, wishbone_base_address=0x0, wishbone_extend_address_bits=0, avoid_combinatorial_loop=True):
word_width = data_width // 8
@ -156,8 +162,11 @@ class AvalonMM2Wishbone(Module):
# bus transaction
if avoid_combinatorial_loop:
self.sync += [
If (wb.ack | wb.err, read_access.eq(0)) \
.Elif(avl.read, read_access.eq(1)),
If(wb.ack | wb.err,
read_access.eq(0)
).Elif(avl.read,
read_access.eq(1)
),
readdata.eq(wb.dat_r),
readdatavalid.eq((wb.ack | wb.err) & read_access),
]
@ -177,40 +186,52 @@ class AvalonMM2Wishbone(Module):
# Avalon -> Wishbone
self.comb += [
# avalon is byte addresses, wishbone word addressed
wb.adr.eq(Mux(burst_cycle & last_burst_cycle,
burst_address, avl.address)[word_width_bits:]
+ Constant(wishbone_base_address, (wishbone_address_width, 0))),
# Avalon is byte addresses, Wishbone word addressed
If(burst_cycle & last_burst_cycle,
wb.adr.eq(burst_address[word_width_bits:] + wishbone_base_address)
).Else(
wb.adr.eq(avl.address[word_width_bits:] + wishbone_base_address)
),
wb.dat_w.eq(avl.writedata),
wb.we.eq(avl.write),
wb.cyc.eq(read_access | avl.write | burst_cycle),
wb.stb.eq(read_access | avl.write),
wb.bte.eq(Constant(0, 2)),
wb.bte.eq(0b00),
]
self.submodules.fsm = fsm = FSM(reset_state="NORMAL")
fsm.act("NORMAL",
self.submodules.fsm = fsm = FSM(reset_state="SINGLE")
fsm.act("SINGLE",
burst_cycle.eq(0),
wb.sel.eq(avl.byteenable),
wb.cti.eq(Mux(avl.burstcount > 1,
wishbone.CTI_BURST_INCREMENTING,
wishbone.CTI_BURST_NONE)),
If(avl.burstcount > 1,
wb.cti.eq(wishbone.CTI_BURST_INCREMENTING)
).Else(
wb.cti.eq(wishbone.CTI_BURST_NONE)
),
If(~avl.waitrequest & (avl.burstcount > 1),
burst_cycle.eq(1),
NextValue(burst_counter, avl.burstcount - 1),
NextValue(burst_address, avl.address + word_width),
NextValue(burst_sel, avl.byteenable),
If(avl.write, NextState("BURST_WRITE")),
If(avl.write,
NextState("BURST-WRITE")),
If(avl.read,
NextValue(burst_read, 1),
NextState("BURST_READ")))
NextState("BURST-READ"))
)
)
fsm.act("BURST_WRITE",
fsm.act("BURST-WRITE",
burst_cycle.eq(1),
wb.sel.eq(burst_sel),
wb.cti.eq(Mux(burst_counter > 1,
wishbone.CTI_BURST_INCREMENTING,
Mux(burst_counter == 1, wishbone.CTI_BURST_END, wishbone.CTI_BURST_NONE))),
If(burst_counter > 1,
wb.cti.eq(wishbone.CTI_BURST_INCREMENTING)
).Else(
If(burst_counter == 1,
wb.cti.eq(wishbone.CTI_BURST_END)
).Else(
wb.cti.eq(wishbone.CTI_BURST_NONE)
)
),
If(~avl.waitrequest,
NextValue(burst_address, burst_address + word_width),
NextValue(burst_counter, burst_counter - 1)),
@ -218,26 +239,34 @@ class AvalonMM2Wishbone(Module):
burst_cycle.eq(0),
wb.sel.eq(avl.byteenable),
NextValue(burst_sel, 0),
NextState("NORMAL"))
NextState("SINGLE")
)
)
fsm.act("BURST_READ", # TODO
fsm.act("BURST-READ", # TODO
burst_cycle.eq(1),
wb.stb.eq(1),
wb.sel.eq(burst_sel),
wb.cti.eq(Mux(burst_counter > 1,
wishbone.CTI_BURST_INCREMENTING,
Mux(burst_counter == 1, wishbone.CTI_BURST_END, wishbone.CTI_BURST_NONE))),
If (wb.ack,
If(burst_counter > 1,
wb.cti.eq(wishbone.CTI_BURST_INCREMENTING),
).Else(
If(burst_counter == 1,
wb.cti.eq(wishbone.CTI_BURST_END)
).Else(
wb.cti.eq(wishbone.CTI_BURST_NONE)
)
),
If(wb.ack,
avl.readdatavalid.eq(1),
NextValue(burst_address, burst_address + word_width),
NextValue(burst_counter, burst_counter - 1)),
If (burst_counter == 0,
NextValue(burst_counter, burst_counter - 1)
),
If(burst_counter == 0,
wb.cyc.eq(0),
wb.stb.eq(0),
wb.sel.eq(avl.byteenable),
NextValue(burst_sel, 0),
NextValue(burst_sel, 0),
NextValue(burst_read, 0),
NextState("NORMAL"))
NextState("SINGLE"))
)
# Avalon-ST to/from native LiteX's stream ----------------------------------------------------------