zephyr-cp: size nvm and storage to a whole erase block on RP2040/RP2350 - #11272
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zephyr-cp: size nvm and storage to a whole erase block on RP2040/RP2350#11272lynt-smitka wants to merge 1 commit into
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Both partitions are 0x800 on the five RP2040 and RP2350 boards, but the erase block on those chips is 4096. common_hal_nvm_bytearray_set_bytes takes its page size from the flash device, so it asks flash_area_read for 4096 bytes out of a 2048-byte area; flash_area_read bounds-checks that and returns -EINVAL, and the write fails. Were it to get past that, the following flash_area_erase of a full page would take storage_partition with it. Measured on a picopad running zephyr-cp: len(microcontroller.nvm) is 2048 and nvm[0:4] = b"ABCD" raises RuntimeError: Unable to write to nvm. The same code on the raspberrypi port, where nvm is a full 4096, writes and reads back fine. Both partitions grow to one erase block, which shifts circuitpy_partition 4 KB up. The filesystem moves with it, so a board updating to this comes up with an empty CIRCUITPY drive and whatever was on it is gone.
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nvm_partition and storage_partition are 0x800 on all five RP2040/RP2350 boards, but the erase block on those chips is 4096.
common_hal_nvm_bytearray_set_bytes reads a whole erase page before modifying it, and takes that page size from the flash device rather than the partition, so it asks flash_area_read for 4096 bytes out of a 2048-byte area. flash_area_read bounds-checks and returns -EINVAL.
Measured on a picopad running zephyr-cp:
The same test on the raspberrypi port, where nvm is a full 4096, writes and reads back fine.
Both partitions grow to one erase block, which shifts circuitpy_partition 4 KB up. The filesystem moves with it, so a board updating to this comes up with an empty CIRCUITPY drive...