Add dma.py

dma.py

@@ -0,0 +1,63 @@
+import uctypes
+from uctypes import BF_POS, BF_LEN, BFUINT32
+
+DMA_CTRL_REG = {
+        "AHB_ERROR": 31     << BF_POS | 1 << BF_LEN | BFUINT32,
+        "READ_ERR": 30      << BF_POS | 1 << BF_LEN | BFUINT32,
+        "WRITE_ERR": 29     << BF_POS | 1 << BF_LEN | BFUINT32,
+        "Reserved": 25      << BF_POS | 4 << BF_LEN | BFUINT32,
+        "BUSY": 24          << BF_POS | 1 << BF_LEN | BFUINT32,
+        "SNIFF_EN": 23      << BF_POS | 1 << BF_LEN | BFUINT32,
+        "BSWAP": 22         << BF_POS | 1 << BF_LEN | BFUINT32,
+        "IRQ_QUIET": 21     << BF_POS | 1 << BF_LEN | BFUINT32,
+        "TREQ_SEL": 15      << BF_POS | 6 << BF_LEN | BFUINT32,
+        "CHAIN_TO": 11      << BF_POS | 4 << BF_LEN | BFUINT32,
+        "RING_SEL": 10      << BF_POS | 1 << BF_LEN | BFUINT32,
+        "RING_SIZE": 6      << BF_POS | 4 << BF_LEN | BFUINT32,
+        "INCR_WRITE": 5     << BF_POS | 1 << BF_LEN | BFUINT32,
+        "INCR_READ": 4      << BF_POS | 1 << BF_LEN | BFUINT32,
+        "DATA_SIZE": 2      << BF_POS | 2 << BF_LEN | BFUINT32,
+        "HIGH_PRIO": 1      << BF_POS | 1 << BF_LEN | BFUINT32,
+        "EN": 0             << BF_POS | 1 << BF_LEN | BFUINT32,
+}
+
+DMA_LAYOUT = {
+    "READ_ADDR": 0   | uctypes.UINT32,
+    "WRITE_ADDR": 4  | uctypes.UINT32,
+    "TRANS_COUNT": 8 | uctypes.UINT32,
+    "CTRL_TRIG": (12,  DMA_CTRL_REG),
+    "CTRL_TRIG_RAW": 12 | uctypes.UINT32, # for single update of all fields
+    "AL1_CTRL": 16   | uctypes.UINT32,
+}
+
+# create the DMA channel structs (0-11)
+CHANNELS = [uctypes.struct(0x50000000 + i * 0x40, DMA_LAYOUT) for i in range(0,12)]
+
+# init dma channels to some default values
+def init_channels():
+    for i, ch in enumerate(CHANNELS):
+        # no wraparound, sniff=0, swap_byte=0, irq_quiet=1
+        # unpaced transfers (=0x3f). high prio=0, data_size=word, incr_r/w = true
+        ch.CTRL_TRIG_RAW = 0x3f8030
+        # set chain to itself, to disable chaining
+        ch.CTRL_TRIG.CHAIN_TO = i
+
+# example function to show mem->mem transfer
+# dest, src can be bytearrays, size in bytes
+def memcopy(ch, dest, src, size, enable=1):
+    ch.CTRL_TRIG.EN = 0
+    ch.WRITE_ADDR = uctypes.addressof(dest)
+    ch.READ_ADDR = uctypes.addressof(src)
+    ch.TRANS_COUNT = size // (1 << ch.CTRL_TRIG.DATA_SIZE)
+    ch.CTRL_TRIG.EN = enable
+
+
+# can be used to temporary construct the necessary DMA CTRL values
+# then copy over to actual dma channel's CTRL value in one write
+# e.g. 
+# scratch.CHAIN_TO=2;
+# scratch.DATA_SIZE=2;
+# ...
+# CH0.CTRL_TRIG_RAW=scratch.CTRL_TRIG_RAW
+tmp = bytearray(uctypes.sizeof(DMA_LAYOUT))
+scratch_ctrl = uctypes.struct(uctypes.addressof(tmp), DMA_CTRL_REG)