fix read for case (bits <= 32 && !wholeBytes) || len <= 4))
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*/*spi.h Support for odd bit lengths in SPI, per discussion at micropython#5225
Before, each copy from SPI transaction buf to destination buf was overwriting all previously copied data, so always only the last $bytesPerChunk bytes were stored. Fix by shifting pointer within destination buf to actually append newly read data instead of overwriting.
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You might want to submit this to upstream MP repository ... |
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Thing is, upstream changed a lot (well, mainly ports/esp32/machine_hw_spi.c). So I wanted to get this PR working on for which version it was originally developed against, and then getting it rebased onto upstream/master. However due to the changes upstream meanwhile, my attempts of rebasing failed so far due to lacking some understanding of why certain things were done the way they are. |
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asan considers that memcmp(p, q, N) is permitted to access N bytes at each
of p and q, even for values of p and q that have a difference earlier.
Accessing additional values is frequently done in practice, reading 4 or
more bytes from each input at a time for efficiency, so when completing
"non_exist<TAB>" in the repl, this causes a diagnostic:
==16938==ERROR: AddressSanitizer: global-buffer-overflow on
address 0x555555cd8dc8 at pc 0x7ffff726457b bp 0x7fffffffda20 sp 0x7fff
READ of size 9 at 0x555555cd8dc8 thread T0
#0 0x7ffff726457a (/usr/lib/x86_64-linux-gnu/libasan.so.5+0xb857a)
#1 0x555555b0e82a in mp_repl_autocomplete ../../py/repl.c:301
#2 0x555555c89585 in readline_process_char ../../lib/mp-readline/re
micropython#3 0x555555c8ac6e in readline ../../lib/mp-readline/readline.c:513
micropython#4 0x555555b8dcbd in do_repl /home/jepler/src/micropython/ports/uni
micropython#5 0x555555b90859 in main_ /home/jepler/src/micropython/ports/unix/
micropython#6 0x555555b90a3a in main /home/jepler/src/micropython/ports/unix/m
micropython#7 0x7ffff619a09a in __libc_start_main ../csu/libc-start.c:308
micropython#8 0x55555595fd69 in _start (/home/jepler/src/micropython/ports/uni
0x555555cd8dc8 is located 0 bytes to the right of global variable
'import_str' defined in '../../py/repl.c:285:23' (0x555555cd8dc0) of
size 8
'import_str' is ascii string 'import '
Signed-off-by: Jeff Epler <jepler@gmail.com>
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Before, each copy from SPI transaction buf to destination buf was overwriting
all previously copied data, so always only the last $bytesPerChunk bytes were
stored.
Fix by shifting pointer within destination buf to actually append newly read
data instead of overwriting.