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| author | Alex Maestas <git@se30.xyz> | 2023-12-17 17:39:59 +0000 |
|---|---|---|
| committer | Alex Maestas <git@se30.xyz> | 2023-12-17 17:39:59 +0000 |
| commit | 89e86fe6294948df0ca8aade93e9893f317dd5fc (patch) | |
| tree | 0e9b3456e9421faaf7bccf7243f2ec06603943eb | |
| parent | 63d6bc6aa0ddf4cc1ce1918ef7650852a25e581b (diff) | |
| download | Sensor-Watch-89e86fe6294948df0ca8aade93e9893f317dd5fc.tar.gz Sensor-Watch-89e86fe6294948df0ca8aade93e9893f317dd5fc.tar.bz2 Sensor-Watch-89e86fe6294948df0ca8aade93e9893f317dd5fc.zip | |
work around silicon erratum in TRNG
| -rw-r--r-- | movement/watch_faces/complication/randonaut_face.c | 2 | ||||
| -rw-r--r-- | movement/watch_faces/complication/toss_up_face.c | 3 | ||||
| -rw-r--r-- | watch-library/hardware/watch/watch_private.c | 11 | ||||
| -rw-r--r-- | watch-library/shared/watch/watch.h | 6 |
4 files changed, 18 insertions, 4 deletions
diff --git a/movement/watch_faces/complication/randonaut_face.c b/movement/watch_faces/complication/randonaut_face.c index bca334fb..886aabb7 100644 --- a/movement/watch_faces/complication/randonaut_face.c +++ b/movement/watch_faces/complication/randonaut_face.c @@ -357,7 +357,7 @@ static uint32_t _get_true_entropy(void) { while (!hri_trng_get_INTFLAG_reg(TRNG, TRNG_INTFLAG_DATARDY)); // Wait for TRNG data to be ready - hri_trng_clear_CTRLA_ENABLE_bit(TRNG); + watch_disable_TRNG(TRNG); hri_mclk_clear_APBCMASK_TRNG_bit(MCLK); return hri_trng_read_DATA_reg(TRNG); // Read a single 32-bit word from TRNG and return it #endif diff --git a/movement/watch_faces/complication/toss_up_face.c b/movement/watch_faces/complication/toss_up_face.c index 08dd0052..dedc9042 100644 --- a/movement/watch_faces/complication/toss_up_face.c +++ b/movement/watch_faces/complication/toss_up_face.c @@ -255,7 +255,8 @@ uint32_t get_true_entropy(void) { while (!hri_trng_get_INTFLAG_reg(TRNG, TRNG_INTFLAG_DATARDY)); // Wait for TRNG data to be ready - hri_trng_clear_CTRLA_ENABLE_bit(TRNG); + watch_disable_TRNG(TRNG); + hri_mclk_clear_APBCMASK_TRNG_bit(MCLK); return hri_trng_read_DATA_reg(TRNG); // Read a single 32-bit word from TRNG and return it #endif diff --git a/watch-library/hardware/watch/watch_private.c b/watch-library/hardware/watch/watch_private.c index cd607b8e..4cae3ccb 100644 --- a/watch-library/hardware/watch/watch_private.c +++ b/watch-library/hardware/watch/watch_private.c @@ -106,12 +106,21 @@ int getentropy(void *buf, size_t buflen) { } } - hri_trng_clear_CTRLA_ENABLE_bit(TRNG); + watch_disable_TRNG(TRNG); hri_mclk_clear_APBCMASK_TRNG_bit(MCLK); return 0; } +void watch_disable_TRNG(Trng *hw) { + hri_trng_clear_CTRLA_ENABLE_bit(hw); + // silicon erratum: the TRNG may leave internal components powered after disable. + // the workaround is to clear the register twice. + hri_trng_write_CTRLA_reg(hw, 0); + hri_trng_write_CTRLA_reg(hw, 0); +} + + void _watch_enable_tcc(void) { // clock TCC0 with the main clock (8 MHz) and enable the peripheral clock. hri_gclk_write_PCHCTRL_reg(GCLK, TCC0_GCLK_ID, GCLK_PCHCTRL_GEN_GCLK0_Val | GCLK_PCHCTRL_CHEN); diff --git a/watch-library/shared/watch/watch.h b/watch-library/shared/watch/watch.h index 790f9a16..4043fdf7 100644 --- a/watch-library/shared/watch/watch.h +++ b/watch-library/shared/watch/watch.h @@ -96,4 +96,8 @@ void watch_reset_to_bootloader(void); */ int read(int file, char *ptr, int len); -#endif /* WATCH_H_ */
\ No newline at end of file +/** @brief Disables the TRNG, working around a silicon erratum. + */ +void watch_disable_TRNG(Trng* hw); + +#endif /* WATCH_H_ */ |