kopia lustrzana https://github.com/peterhinch/micropython_eeprom
48 wiersze
1.9 KiB
Python
48 wiersze
1.9 KiB
Python
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# bdevice.py Hardware-agnostic base class for block devices.
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# Released under the MIT License (MIT). See LICENSE.
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# Copyright (c) 2019 Peter Hinch
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# Hardware-independent class implementing the uos.AbstractBlockDev protocol with
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# simple and extended interface. It should therefore support littlefs.
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# http://docs.micropython.org/en/latest/reference/filesystem.html#custom-block-devices
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# The subclass must implement .readwrite which can read or write arbitrary amounts
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# of data to arbitrary addresses. IOW .readwrite handles physical block structure
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# while ioctl supports a virtual block size.
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class BlockDevice:
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def __init__(self, nbits, nchips, chip_size):
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self._c_bytes = chip_size # Size of chip in bytes
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self._a_bytes = chip_size * nchips # Size of array
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self._nbits = nbits # Block size in bits
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self._block_size = 2**nbits
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def __len__(self):
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return self._a_bytes
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# Handle special cases of a slice. Always return a pair of positive indices.
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def do_slice(self, addr):
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if not (addr.step is None or addr.step == 1):
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raise NotImplementedError('only slices with step=1 (aka None) are supported')
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start = addr.start if addr.start is not None else 0
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stop = addr.stop if addr.stop is not None else self._a_bytes
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start = start if start >= 0 else self._a_bytes + start
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stop = stop if stop >= 0 else self._a_bytes + stop
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return start, stop
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# IOCTL protocol.
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def readblocks(self, blocknum, buf, offset=0):
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return self.readwrite(offset + (blocknum << self._nbits), buf, True)
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def writeblocks(self, blocknum, buf, offset=0):
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self.readwrite(offset + (blocknum << self._nbits), buf, False)
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def ioctl(self, op, arg):
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#print("ioctl(%d, %r)" % (op, arg))
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if op == 4: # BP_IOCTL_SEC_COUNT
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return self._a_bytes >> self._nbits
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if op == 5: # BP_IOCTL_SEC_SIZE
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return self._block_size
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