litex/misoc/cores/dvi_sampler/dma.py

147 lines
5.2 KiB
Python

from migen import *
from migen.genlib.fsm import FSM, NextState
from misoc.interconnect.csr import *
from misoc.interconnect.csr_eventmanager import *
# TODO: rewrite dma_lasmi module
# TODO: use stream packets to resync DMA
#from misoc.mem.sdram.frontend import dma_lasmi
# Slot status: EMPTY=0 LOADED=1 PENDING=2
class _Slot(Module, AutoCSR):
def __init__(self, addr_bits, alignment_bits):
self.ev_source = EventSourceLevel()
self.address = Signal(addr_bits)
self.address_reached = Signal(addr_bits)
self.address_valid = Signal()
self.address_done = Signal()
self._status = CSRStorage(2, write_from_dev=True)
self._address = CSRStorage(addr_bits + alignment_bits, alignment_bits=alignment_bits, write_from_dev=True)
###
self.comb += [
self.address.eq(self._address.storage),
self.address_valid.eq(self._status.storage[0]),
self._status.dat_w.eq(2),
self._status.we.eq(self.address_done),
self._address.dat_w.eq(self.address_reached),
self._address.we.eq(self.address_done),
self.ev_source.trigger.eq(self._status.storage[1])
]
class _SlotArray(Module, AutoCSR):
def __init__(self, nslots, addr_bits, alignment_bits):
self.submodules.ev = EventManager()
self.address = Signal(addr_bits)
self.address_reached = Signal(addr_bits)
self.address_valid = Signal()
self.address_done = Signal()
###
slots = [_Slot(addr_bits, alignment_bits) for i in range(nslots)]
for n, slot in enumerate(slots):
setattr(self.submodules, "slot"+str(n), slot)
setattr(self.ev, "slot"+str(n), slot.ev_source)
self.ev.finalize()
change_slot = Signal()
current_slot = Signal(max=nslots)
self.sync += If(change_slot, [If(slot.address_valid, current_slot.eq(n)) for n, slot in reversed(list(enumerate(slots)))])
self.comb += change_slot.eq(~self.address_valid | self.address_done)
self.comb += [
self.address.eq(Array(slot.address for slot in slots)[current_slot]),
self.address_valid.eq(Array(slot.address_valid for slot in slots)[current_slot])
]
self.comb += [slot.address_reached.eq(self.address_reached) for slot in slots]
self.comb += [slot.address_done.eq(self.address_done & (current_slot == n)) for n, slot in enumerate(slots)]
class DMA(Module):
def __init__(self, lasmim, nslots):
bus_aw = lasmim.aw
bus_dw = lasmim.dw
alignment_bits = bits_for(bus_dw//8) - 1
fifo_word_width = 24*bus_dw//32
self.frame = Sink([("sof", 1), ("pixels", fifo_word_width)])
self._frame_size = CSRStorage(bus_aw + alignment_bits, alignment_bits=alignment_bits)
self.submodules._slot_array = _SlotArray(nslots, bus_aw, alignment_bits)
self.ev = self._slot_array.ev
###
# address generator + maximum memory word count to prevent DMA buffer overrun
reset_words = Signal()
count_word = Signal()
last_word = Signal()
current_address = Signal(bus_aw)
mwords_remaining = Signal(bus_aw)
self.comb += [
self._slot_array.address_reached.eq(current_address),
last_word.eq(mwords_remaining == 1)
]
self.sync += [
If(reset_words,
current_address.eq(self._slot_array.address),
mwords_remaining.eq(self._frame_size.storage)
).Elif(count_word,
current_address.eq(current_address + 1),
mwords_remaining.eq(mwords_remaining - 1)
)
]
# 24bpp -> 32bpp
memory_word = Signal(bus_dw)
pixbits = []
for i in range(bus_dw//32):
for j in range(3):
b = (i*3+j)*8
pixbits.append(self.frame.pixels[b+6:b+8])
pixbits.append(self.frame.pixels[b:b+8])
pixbits.append(0)
pixbits.append(0)
self.comb += memory_word.eq(Cat(*pixbits))
# bus accessor
self.submodules._bus_accessor = dma_lasmi.Writer(lasmim)
self.comb += [
self._bus_accessor.address_data.a.eq(current_address),
self._bus_accessor.address_data.d.eq(memory_word)
]
# control FSM
fsm = FSM()
self.submodules += fsm
fsm.act("WAIT_SOF",
reset_words.eq(1),
self.frame.ack.eq(~self._slot_array.address_valid | ~self.frame.sof),
If(self._slot_array.address_valid & self.frame.sof & self.frame.stb, NextState("TRANSFER_PIXELS"))
)
fsm.act("TRANSFER_PIXELS",
self.frame.ack.eq(self._bus_accessor.address_data.ack),
If(self.frame.stb,
self._bus_accessor.address_data.stb.eq(1),
If(self._bus_accessor.address_data.ack,
count_word.eq(1),
If(last_word, NextState("EOF"))
)
)
)
fsm.act("EOF",
If(~self._bus_accessor.busy,
self._slot_array.address_done.eq(1),
NextState("WAIT_SOF")
)
)
def get_csrs(self):
return [self._frame_size] + self._slot_array.get_csrs()