71 lines
1.9 KiB
Python
71 lines
1.9 KiB
Python
# (c) Copyright 2021 by Coinkite Inc. This file is covered by license found in COPYING-CC.
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#
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# psram.py -- access PSRAM chip on Mk4
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#
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import version, uctypes
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# already started and memory mapped by bootrom.
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class PSRAMWrapper:
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base = 0x9000_0000 # OCTOSPI1
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length = 0x40_0000 # 4 meg (lower half)
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def __init__(self):
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self._wr = uctypes.bytearray_at(self.base, self.length)
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def read_at(self, offset, ln):
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# one-copy byte-wise access
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return uctypes.bytes_at(self.base+offset, ln)
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def write_at(self, offset, ln):
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# word-aligned writes only
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assert offset % 4 == 0, offset
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assert ln % 4 == 0, ln
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assert offset + ln <= self.length, (offset+ln)
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return memoryview(self._wr)[offset:offset+ln]
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def is_at(self, ptr, offset):
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# is bytes() object really one we created at read_at
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return uctypes.addressof(ptr) == self.base+offset
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# Be compatible with SPIFlash class...
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def read(self, address, buf, cmd=None):
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buf[:] = self.read_at(address, len(buf))
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def write(self, address, buf):
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ln = len(buf)
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if ln % 4:
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assert address % 4 == 0, address
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runt = ln % 4
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tb = buf + bytes(4-runt)
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self.write_at(address, len(tb))[:] = tb
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else:
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self.write_at(address, ln)[:] = buf
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def is_busy(self):
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return False
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def wait_done(self):
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return
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# we are not flash
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def chip_erase(self):
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return
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def sector_erase(self, address):
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return
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def block_erase(self, address):
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return
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def wipe_all(self):
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# works, but code in bootrom is much faster and better (rng values used)
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from glob import dis
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z = bytes(16384)
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for pos in range(0, self.length, len(z)):
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self.write_at(pos, len(z))[:] = z
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dis.progress_bar_show(pos / self.length)
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# EOF
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