fixeria has uploaded this change for review. ( https://gerrit.osmocom.org/c/libosmocore/+/35171?usp=email )

Change subject: soft_uart: check Rx/Tx state once in osmo_soft_uart_{rx,tx}_ubits() ......................................................................

soft_uart: check Rx/Tx state once in osmo_soft_uart_{rx,tx}_ubits()

Check it once rather than doing this in a loop. Return -EAGAIN if Rx or Tx is not enabled when calling osmo_soft_uart_{rx,tx}_ubits().

This [theoretically] improves performance by reducing the number of conditional statements in loops. In the Tx path, this also prevents calling the .tx_cb() when the transmitter is disabled, so that we don't loose the application data.

Change-Id: I70f93b3655eb21c2323e451052c40cd305c016c8 Related: OS#4396 --- M src/core/soft_uart.c M tests/soft_uart/soft_uart_test.c 2 files changed, 31 insertions(+), 6 deletions(-)

git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/71/35171/1

diff --git a/src/core/soft_uart.c b/src/core/soft_uart.c index 8d9142b..1d9984b 100644 --- a/src/core/soft_uart.c +++ b/src/core/soft_uart.c @@ -111,9 +111,6 @@ /* receive a single bit */ static inline void osmo_uart_rx_bit(struct osmo_soft_uart *suart, const ubit_t bit) { - if (!suart->rx.running) - return; - switch (suart->rx.flow_state) { case SUART_FLOW_ST_IDLE: if (bit == 0) { /* start bit condition */ @@ -199,6 +196,8 @@ * \returns 0 on success; negative on error. */ int osmo_soft_uart_rx_ubits(struct osmo_soft_uart *suart, const ubit_t *ubits, size_t n_ubits) { + if (!suart->rx.running) + return -EAGAIN; for (size_t i = 0; i < n_ubits; i++) osmo_uart_rx_bit(suart, ubits[i]); return 0; @@ -213,9 +212,6 @@ { ubit_t tx_bit = 1;

- if (!suart->tx.running) - return tx_bit; - switch (suart->tx.flow_state) { case SUART_FLOW_ST_IDLE: if (msg && msgb_length(msg) > 0) { /* if we have pending data */ @@ -290,6 +286,9 @@ if (OSMO_UNLIKELY(n_ubits == 0)) return -EINVAL;

+ if (!suart->tx.running) + return -EAGAIN; + /* calculate UART frame size for the effective config */ n_frame_bits = 1 + cfg->num_data_bits + cfg->num_stop_bits; if (cfg->parity_mode != OSMO_SUART_PARITY_NONE) diff --git a/tests/soft_uart/soft_uart_test.c b/tests/soft_uart/soft_uart_test.c index 522739a..f1b0b25 100644 --- a/tests/soft_uart/soft_uart_test.c +++ b/tests/soft_uart/soft_uart_test.c @@ -256,10 +256,18 @@ { struct osmo_soft_uart_cfg cfg; struct osmo_soft_uart *suart; + int rc;

suart = osmo_soft_uart_alloc(NULL, __func__, &suart_test_default_cfg); OSMO_ASSERT(suart != NULL);

+ /* expect -EAGAIN when the transmitter is not enabled */ + rc = osmo_soft_uart_tx_ubits(suart, NULL, 42); + OSMO_ASSERT(rc == -EAGAIN); + /* expect -EAGAIN when the receicer is not enabled */ + rc = osmo_soft_uart_rx_ubits(suart, NULL, 42); + OSMO_ASSERT(rc == -EAGAIN); + osmo_soft_uart_set_tx(suart, true); osmo_soft_uart_set_rx(suart, true);