nrf52: SPI transfer failure and corruption #1777
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The current EasyDMA implementation will fail if a transfer of over 255 bytes is requested with no warning. Also we do not set the RX and TX transfer lengths to 0 if the buffer is NULL which can cause data to be written to the old address as well as cause unexpected transaction lenghts. Example: transfer 1: rx_len = 10 rx_buff != NULL tx_len = 10 tx_buff != NULL transfer 2: rx_len = 2 rx_buff != NULL tx_buff == NULL Total transaction length for the second would be 10 because it would still be using the old rx length of 10 and would corrupt data in the old rx buffer. Signed-off-by: Brennan Ashton <bashton@brennanashton.com>
protobits
approved these changes
Sep 14, 2020
raiden00pl
approved these changes
Sep 14, 2020
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Summary
The current EasyDMA implementation will fail if a transfer of over
255 bytes is requested with no warning.
Also we do not set the RX and TX transfer lengths to 0 if the
buffer is NULL which can cause data to be written to the old
address as well as cause unexpected transaction lengths.
Example:
transfer 1:
transfer 2:
Total transaction length for the second would be 10 because it would still be using the old tx length of 10 and would send the data in that buffer out.
Impact
SPI transactions should be safer. And warnings are given when transactions are too long.
Testing
Driving a SPI display.