framebuffer: fake DMA for testing (WIP)

diff --git a/milkymist/framebuffer/__init__.py b/milkymist/framebuffer/__init__.py
index 704e08f07fb5555fde727a409f370dfc4552c412..cc02c4c27d0752e3f4336bfd0c35b9249ae00e63 100644 (file)
--- a/milkymist/framebuffer/__init__.py
+++ b/milkymist/framebuffer/__init__.py
@@ -201,6 +201,25 @@ class FIFO(Actor):
                ],
                instances=[asfifo])
 
+class FakeDMA(Actor):
+       def __init__(self, port):
+               self.port = port
+               super().__init__(
+                               ("address", Sink, [("a", BV(self.port.hub.aw))]),
+                               ("data", Source, [("d", BV(self.port.hub.dw))]))
+       
+       def get_fragment(self):
+               pixel = Signal(BV(32))
+               comb = [
+                       self.endpoints["address"].ack.eq(1),
+                       self.endpoints["data"].stb.eq(1),
+                       self.token("data").d.eq(Replicate(pixel, 4))
+               ]
+               sync = [
+                       If(self.endpoints["data"].ack, pixel.eq(pixel + 1))
+               ]
+               return Fragment(comb, sync)
+
 class Framebuffer:
        def __init__(self, address, asmiport):
                asmi_bits = asmiport.hub.aw
@@ -213,7 +232,8 @@ class Framebuffer:
                adrloop = ActorNode(misc.IntSequence(length_bits))
                adrbase = ActorNode(ala.Add(BV(asmi_bits)))
                adrbuffer = ActorNode(plumbing.Buffer)
-               dma = ActorNode(dma_asmi.SequentialReader(asmiport))
+               #dma = ActorNode(dma_asmi.SequentialReader(asmiport))
+               dma = ActorNode(FakeDMA(asmiport))
                cast = ActorNode(structuring.Cast(asmiport.hub.dw, packed_pixels))
                unpack = ActorNode(structuring.Unpack(pack_factor, _pixel_layout))
                vtg = ActorNode(VTG())