The firmware in TKey from the Castor release and onwards supports system calls. You will typically use them through the system call wrappers in tkey-libs
sys_reset
#
int sys_reset(struct reset *rst, size_t len)
Reset the TKey. Leave the reset type (enum reset_start) in rst as
well as an optional app_digest, forcing firmware to only allow that
specific app digest, as well as some data to leave to the next app in
chain in next_app_data. Send the length of the next_app_data in
len.
Typically doesn’t return. The TKey is reset and firmware starts again.
If it returns, it returns an error, probably because the reset length
being too large or that rst was pointing to memory outside of RAM.
sys_alloc
#
int sys_alloc(void)
Allocate a flash area for the current app. Must be done before
sys_write() or sys_read(). If the current app already has an area
allocated no new area will be allocated.
Returns 0 on success.
sys_dealloc
#
int sys_dealloc(void)
Free an already allocated flash area for the current app.
Returns 0 on success.
sys_write
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int sys_write(uint32_t offset, void *buf, size_t len)
Write data in buf to the app’s flash area at byte offset within
the area.
Up to storage area size bytes can be written at once and offset must
be a multiple of 256 bytes.
Returns 0 on success.
sys_read
#
int sys_read(uint32_t offset, void *buf, size_t len)
Read len bytes into buf at byte offset from the app’s flash
area.
Returns 0 on success.
sys_erase
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int sys_erase(uint32_t offset, size_t len)
Erase len bytes from offset within the area.
Both len and offset must be a multiple of 4096 bytes.
Returns 0 on success.
sys_get_vidpid
#
int sys_get_vidpid(void)
Returns the TKey Vendor and Product ID.
sys_preload_delete
#
int sys_preload_delete(void)
Delete the app in flash slot 1. Only available for the verified management app.
Returns 0 on success.
sys_preload_store
#
int sys_preload_store(uint32_t offset, void *app, size_t len)
Store an app, or possibly just a block of an app, from the app
buffer in flash slot 1 at byte offset.
If you can’t fit your entire app in the buffer, call
sys_preload_store many times as you receive the binary from the
client.
Up to preloaded app area size bytes can be written at once and
offset must be a multiple of 256 bytes.
Only available for the verified management app.
Returns 0 on success.
sys_preload_store_fin
#
int sys_preload_store_fin(size_t len, uint8_t digest[32], uint8_t signature[64])
Finalize storing of an app where the complete binary size is len
in flash slot 1. Returns 0 on success. Only available for the
verified management app.
Compute a BLAKE2s hash digest over the entire binary. Pass the
result in app_digest.
Sign app_digest with your Ed25519 private key and pass the
resulting signature in app_signature.
Returns 0 on success.
sys_get_digsig
#
int sys_get_digsig(uint8_t digest[32], uint8_t signature[64])
Copies the digest and signature of app in flash slot 1 to
app_digest and app_signature. Returns 0 on success. Only
available for the verified management app.
Returns 0 on success.
sys_status
#
int sys_status(void)
Returns filesystem status. Non-zero when problems have been detected, so far only that the first copy of the partition table didn’t pass checks.
sys_reset_data
#
void sys_reset_data(uint8_t next_app_data[RESET_DATA_SIZE])
Fills in data left from previous app in the chain into
next_app_data. Buffer needs to be large enough to receive
RESET_DATA_SIZE bytes.