diff options
| -rw-r--r-- | chip/stm32/i2c.c | 38 |
1 files changed, 31 insertions, 7 deletions
diff --git a/chip/stm32/i2c.c b/chip/stm32/i2c.c index 2d98d37e1e..42b6da1be4 100644 --- a/chip/stm32/i2c.c +++ b/chip/stm32/i2c.c @@ -57,8 +57,16 @@ #define I2C2 STM32_I2C2_PORT enum { - /* A stop condition should take 2 clocks, so allow 8 */ - TIMEOUT_STOP_SENT_US = I2C_PERIOD_US * 8, + /* + * A stop condition should take 2 clocks, but the process may need more + * time to notice if it is preempted, so we poll repeatedly for 8 + * clocks, before backing off and only check once every + * STOP_SENT_RETRY_US for up to TIMEOUT_STOP_SENT clocks before + * giving up. + */ + SLOW_STOP_SENT_US = I2C_PERIOD_US * 8, + TIMEOUT_STOP_SENT_US = I2C_PERIOD_US * 200, + STOP_SENT_RETRY_US = 150, }; static uint16_t i2c_sr1[NUM_PORTS]; @@ -333,9 +341,9 @@ static void i2c_error_handler(int port) /* ACK failed (NACK); expected when AP reads final byte. * Software must clear AF bit. */ } else { - CPRINTF("%s: I2C_SR1(%s): 0x%04x\n", + CPRINTF("%s: I2C_SR1(%d): 0x%04x\n", __func__, port, i2c_sr1[port]); - CPRINTF("%s: I2C_SR2(%s): 0x%04x\n", + CPRINTF("%s: I2C_SR2(%d): 0x%04x\n", __func__, port, STM32_I2C_SR2(port)); } @@ -573,16 +581,32 @@ static void master_stop(int port) static int wait_until_stop_sent(int port) { timestamp_t deadline; + timestamp_t slow_cutoff; + uint8_t is_slow; - deadline = get_time(); + deadline = slow_cutoff = get_time(); deadline.val += TIMEOUT_STOP_SENT_US; + slow_cutoff.val += SLOW_STOP_SENT_US; while (STM32_I2C_CR1(port) & (1 << 9)) { if (timestamp_expired(deadline, NULL)) { - ccprintf("Stop event deadline passed: CR1=%016b\n", - STM32_I2C_CR1(port)); + ccprintf("Stop event deadline passed:\ttask=%d" + "\tCR1=%016b\n", + (int)task_get_current(), STM32_I2C_CR1(port)); return EC_ERROR_TIMEOUT; } + + if (is_slow) { + /* If we haven't gotten a fast response, sleep */ + usleep(STOP_SENT_RETRY_US); + } else { + /* Check to see if this request is taking a while */ + if (timestamp_expired(slow_cutoff, NULL)) { + ccprintf("Stop event taking a while: task=%d", + (int)task_get_current()); + is_slow = 1; + } + } } return EC_SUCCESS; |