fixeria has uploaded this change for review.
soft_uart: demonstrate a problem with manual flush()ing
This problem can only happen if the user is flush()ing the Rx buffer
manually by calling osmo_soft_uart_flush_rx(). Let's demonstrate it
in the unit test, so that we don't forget about it (add FIXME).
Change-Id: Iad932a505d6fd98360f90510651501f8708ff5d2
---
M tests/soft_uart/soft_uart_test.c
M tests/soft_uart/soft_uart_test.ok
2 files changed, 37 insertions(+), 0 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/26/35326/1
diff --git a/tests/soft_uart/soft_uart_test.c b/tests/soft_uart/soft_uart_test.c
index e9adb29..0ea7fa8 100644
--- a/tests/soft_uart/soft_uart_test.c
+++ b/tests/soft_uart/soft_uart_test.c
@@ -226,6 +226,7 @@
static void test_rx_flush(void)
{
+ struct osmo_soft_uart_cfg cfg;
struct osmo_soft_uart *suart;
SUART_TEST_BEGIN;
@@ -242,6 +243,25 @@
printf("calling osmo_soft_uart_flush_rx() while Rx enabled, but no data\n");
osmo_soft_uart_flush_rx(suart);
+ /* FIXME: this scenario demonstrates a problem that may occur when the user
+ * flushes the Rx buffer manually while the soft-UART state reflects flags
+ * of an incomplete symbol, for which we're waiting the stop bit. */
+ printf("testing corner case: manual flushing during a parity error (8-E-1)\n");
+ cfg = suart_test_default_cfg;
+ cfg.parity_mode = OSMO_SUART_PARITY_EVEN;
+ osmo_soft_uart_configure(suart, &cfg);
+ test_rx_exec(suart, "1111111" /* no data */
+ "0 01010101 0 1" /* even parity, correct */
+ "0 10101010 0 1" /* even parity, correct */
+ "0 11111111 1" /* odd parity, incorrect, but stop bit is pending */
+ "F" /* manual flush happens before receiving the stop bit */
+ "1" /* finally, the stop bit is received */
+ );
+ /* test_rx_exec() @ 47: flush the Rx buffer
+ * suart_rx_cb(flags=02): aa 55 <--- this is wrong, should be flags=00
+ * suart_rx_cb(flags=02): ff <--- this is expected due to odd parity */
+
+
osmo_soft_uart_free(suart);
}
diff --git a/tests/soft_uart/soft_uart_test.ok b/tests/soft_uart/soft_uart_test.ok
index c42d0f5..baf3483 100644
--- a/tests/soft_uart/soft_uart_test.ok
+++ b/tests/soft_uart/soft_uart_test.ok
@@ -71,6 +71,10 @@
calling osmo_soft_uart_flush_rx() while Rx disabled
enabling the receiver
calling osmo_soft_uart_flush_rx() while Rx enabled, but no data
+testing corner case: manual flushing during a parity error (8-E-1)
+test_rx_exec() @ 47: flush the Rx buffer
+suart_rx_cb(flags=02): aa 55
+suart_rx_cb(flags=02): ff
Executing test_tx_rx
======== testing 8-N-1
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