from machine import Pin
from rp2 import PIO, StateMachine, asm_pio
from time import sleep
import array
import uctypes
from uctypes import BF_POS, BF_LEN, UINT32, BFUINT32, struct

PIO0_BASE       = 0x50200000
PIO1_BASE       = 0x50300000
DMA_BASE        = 0x50000000
DMA_CHAN_WIDTH  = 0x40
DMA_CHAN_COUNT  = 12

DMA_SIZE_BYTE = 0x0
DMA_SIZE_HALFWORD = 0x1
DMA_SIZE_WORD = 0x2

# DMA: RP2040 datasheet 2.5.7
DMA_CTRL_TRIG_FIELDS = {
    "AHB_ERROR":   31<<BF_POS | 1<<BF_LEN | BFUINT32,
    "READ_ERROR":  30<<BF_POS | 1<<BF_LEN | BFUINT32,
    "WRITE_ERROR": 29<<BF_POS | 1<<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_PRIORITY":1<<BF_POS | 1<<BF_LEN | BFUINT32,
    "EN":           0<<BF_POS | 1<<BF_LEN | BFUINT32
}
# Channel-specific DMA registers
DMA_CHAN_REGS = {
    "READ_ADDR_REG":       0x00|UINT32,
    "WRITE_ADDR_REG":      0x04|UINT32,
    "TRANS_COUNT_REG":     0x08|UINT32,
    "CTRL_TRIG_REG":       0x0c|UINT32,
    "CTRL_TRIG":          (0x0c,DMA_CTRL_TRIG_FIELDS)
}

# General DMA registers
DMA_REGS = {
    "INTR":               0x400|UINT32,
    "INTE0":              0x404|UINT32,
    "INTF0":              0x408|UINT32,
    "INTS0":              0x40c|UINT32,
    "INTE1":              0x414|UINT32,
    "INTF1":              0x418|UINT32,
    "INTS1":              0x41c|UINT32,
    "TIMER0":             0x420|UINT32,
    "TIMER1":             0x424|UINT32,
    "TIMER2":             0x428|UINT32,
    "TIMER3":             0x42c|UINT32,
    "MULTI_CHAN_TRIGGER": 0x430|UINT32,
    "SNIFF_CTRL":         0x434|UINT32,
    "SNIFF_DATA":         0x438|UINT32,
    "FIFO_LEVELS":        0x440|UINT32,
    "CHAN_ABORT":         0x444|UINT32
}

DMA_CHANS = [struct(DMA_BASE + n*DMA_CHAN_WIDTH, DMA_CHAN_REGS) for n in range(0,DMA_CHAN_COUNT)]
DMA_DEVICE = struct(DMA_BASE, DMA_REGS)

DMA_CH0_AL3_TRANS_COUNT = DMA_BASE + 0x38

class PIO_DMA_Transfer():
    def __init__(self, dma_channel, sm_num, block_size, transfer_count):
        self.dma_chan = DMA_CHANS[dma_channel]
        self.channel_number = dma_channel
       
        if (sm_num >= 0 and sm_num < 4):
            self.dma_chan.WRITE_ADDR_REG = PIO0_BASE + 0x10 + sm_num *4
            self.dma_chan.CTRL_TRIG.TREQ_SEL = sm_num
        elif (sm_num < 8):
            self.dma_chan.WRITE_ADDR_REG = PIO1_BASE + 0x10 + (sm_num-4) *4
            self.dma_chan.CTRL_TRIG.TREQ_SEL = sm_num + 4
        
        if (block_size == 8):
            self.dma_chan.CTRL_TRIG.DATA_SIZE = DMA_SIZE_BYTE
        if (block_size == 16):
            self.dma_chan.CTRL_TRIG.DATA_SIZE = DMA_SIZE_HALFWORD
        if (block_size == 32):
            self.dma_chan.CTRL_TRIG.DATA_SIZE = DMA_SIZE_WORD
            
        self.dma_chan.TRANS_COUNT_REG = transfer_count
        
        #Do I just always want these?
        self.dma_chan.CTRL_TRIG.INCR_WRITE = 0
        self.dma_chan.CTRL_TRIG.INCR_READ = 1
            
    def start_transfer(self, buffer):
        self.dma_chan.READ_ADDR_REG = uctypes.addressof(buffer)
        self.dma_chan.CTRL_TRIG.EN = 1

    def transfer_count(self):
        return self.dma_chan.TRANS_COUNT_REG
    
    def busy(self):
        if self.dma_chan.CTRL_TRIG.DATA_SIZE == 1:
            return True
        else:
            return False