laforge has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-ccid-firmware/+/15692
Change subject: cuart_driver_tty: Work around linux kernel bug ignoring CREAD ...................................................................... cuart_driver_tty: Work around linux kernel bug ignoring CREAD Almost all linux USB serial drivers are ignoring CREAD and hence cannot disable the receiver hardware, see https://bugzilla.kernel.org/show_bug.cgi?id=205033 We therefore have to receive every byte we transmit before notifying the user of transmit completion. Change-Id: Id3cca29f78ee5469a1142aaa1ff754cc0427ec93 --- M ccid/cuart.c M ccid/cuart.h M ccid/cuart_driver_tty.c M ccid/cuart_test.c 4 files changed, 24 insertions(+), 4 deletions(-) git pull ssh://gerrit.osmocom.org:29418/osmo-ccid-firmware refs/changes/92/15692/1 diff --git a/ccid/cuart.c b/ccid/cuart.c index 2c0428e..393bf55 100644 --- a/ccid/cuart.c +++ b/ccid/cuart.c @@ -113,7 +113,6 @@ case CUART_E_TX_COMPLETE: cuart->tx_busy = false; /* re-enable receiver if we're done with transmit */ - sleep(1); card_uart_ctrl(cuart, CUART_CTL_RX, true); break; default: diff --git a/ccid/cuart.h b/ccid/cuart.h index 7e217db..c28209f 100644 --- a/ccid/cuart.h +++ b/ccid/cuart.h @@ -77,6 +77,8 @@ size_t tx_buf_len; /* index: offset of next to be transmitted byte in tx_buf */ size_t tx_index; + /* number of bytes we have received echoed back during transmit */ + uint32_t rx_count_during_tx; struct osmo_fd ofd; unsigned int baudrate; @@ -104,4 +106,3 @@ void card_uart_notification(struct card_uart *cuart, enum card_uart_event evt, void *data); int card_uart_driver_register(struct card_uart_driver *drv); - diff --git a/ccid/cuart_driver_tty.c b/ccid/cuart_driver_tty.c index 6bd2b52..7fc8d3a 100644 --- a/ccid/cuart_driver_tty.c +++ b/ccid/cuart_driver_tty.c @@ -125,7 +125,21 @@ rc = read(ofd->fd, buf, sizeof(buf)); OSMO_ASSERT(rc > 0); for (i = 0; i < rc; i++) { +#ifndef CREAD_ACTUALLY_WORKS /* work-around for https://bugzilla.kernel.org/show_bug.cgi?id=205033 */ + if (cuart->tx_busy) { + if (cuart->u.tty.rx_count_during_tx < cuart->u.tty.tx_buf_len) { + /* FIXME: compare! */ + cuart->u.tty.rx_count_during_tx += 1; + if (cuart->u.tty.rx_count_during_tx == cuart->u.tty.tx_buf_len) { + cuart->tx_busy = false; + card_uart_notification(cuart, CUART_E_TX_COMPLETE, + (void *)cuart->u.tty.tx_buf); + } + continue; + } + } +#endif if (!cuart->rx_enabled) continue; @@ -152,12 +166,15 @@ /* if no more bytes to transmit, disable OSMO_FD_WRITE */ if (cuart->u.tty.tx_index >= cuart->u.tty.tx_buf_len) { ofd->when &= ~BSC_FD_WRITE; +#ifndef CREAD_ACTUALLY_WORKS + /* don't immediately notify user; first wait for characters to be received */ +#else /* ensure everything is written (tx queue/fifo drained) */ tcdrain(cuart->u.tty.ofd.fd); - osmo_select_main(true); cuart->tx_busy = false; /* notify */ card_uart_notification(cuart, CUART_E_TX_COMPLETE, (void *)cuart->u.tty.tx_buf); +#endif } } return 0; @@ -209,7 +226,8 @@ cuart->u.tty.tx_buf = data; cuart->u.tty.tx_buf_len = len; - cuart->u.tty.tx_buf_len = len; + cuart->u.tty.tx_index = 0; + cuart->u.tty.rx_count_during_tx = 0; cuart->tx_busy = true; cuart->u.tty.ofd.when |= OSMO_FD_WRITE; diff --git a/ccid/cuart_test.c b/ccid/cuart_test.c index aff9de7..0ed6614 100644 --- a/ccid/cuart_test.c +++ b/ccid/cuart_test.c @@ -47,6 +47,8 @@ card_uart_tx(&g_cuart, select_mf, 5, true); osmo_select_main(true); + sleep(1); + osmo_select_main(true); /* we should get an RX_SINGLE event here */ } -- To view, visit https://gerrit.osmocom.org/c/osmo-ccid-firmware/+/15692 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-ccid-firmware Gerrit-Branch: master Gerrit-Change-Id: Id3cca29f78ee5469a1142aaa1ff754cc0427ec93 Gerrit-Change-Number: 15692 Gerrit-PatchSet: 1 Gerrit-Owner: laforge <lafo...@osmocom.org> Gerrit-MessageType: newchange
