<p>laforge has uploaded this change for <strong>review</strong>.</p><p><a href="https://gerrit.osmocom.org/c/osmo-ccid-firmware/+/15692">View Change</a></p><pre style="font-family: monospace,monospace; white-space: pre-wrap;">cuart_driver_tty: Work around linux kernel bug ignoring CREAD<br><br>Almost all linux USB serial drivers are ignoring CREAD and hence<br>cannot disable the receiver hardware, see https://bugzilla.kernel.org/show_bug.cgi?id=205033<br><br>We therefore have to receive every byte we transmit before notifying the<br>user of transmit completion.<br><br>Change-Id: Id3cca29f78ee5469a1142aaa1ff754cc0427ec93<br>---<br>M ccid/cuart.c<br>M ccid/cuart.h<br>M ccid/cuart_driver_tty.c<br>M ccid/cuart_test.c<br>4 files changed, 24 insertions(+), 4 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">git pull ssh://gerrit.osmocom.org:29418/osmo-ccid-firmware refs/changes/92/15692/1</pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/ccid/cuart.c b/ccid/cuart.c</span><br><span>index 2c0428e..393bf55 100644</span><br><span>--- a/ccid/cuart.c</span><br><span>+++ b/ccid/cuart.c</span><br><span>@@ -113,7 +113,6 @@</span><br><span> case CUART_E_TX_COMPLETE:</span><br><span> cuart->tx_busy = false;</span><br><span> /* re-enable receiver if we're done with transmit */</span><br><span style="color: hsl(0, 100%, 40%);">- sleep(1);</span><br><span> card_uart_ctrl(cuart, CUART_CTL_RX, true);</span><br><span> break;</span><br><span> default:</span><br><span>diff --git a/ccid/cuart.h b/ccid/cuart.h</span><br><span>index 7e217db..c28209f 100644</span><br><span>--- a/ccid/cuart.h</span><br><span>+++ b/ccid/cuart.h</span><br><span>@@ -77,6 +77,8 @@</span><br><span> size_t tx_buf_len;</span><br><span> /* index: offset of next to be transmitted byte in tx_buf */</span><br><span> size_t tx_index;</span><br><span style="color: hsl(120, 100%, 40%);">+ /* number of bytes we have received echoed back during transmit */</span><br><span style="color: hsl(120, 100%, 40%);">+ uint32_t rx_count_during_tx;</span><br><span> </span><br><span> struct osmo_fd ofd;</span><br><span> unsigned int baudrate;</span><br><span>@@ -104,4 +106,3 @@</span><br><span> void card_uart_notification(struct card_uart *cuart, enum card_uart_event evt, void *data);</span><br><span> </span><br><span> int card_uart_driver_register(struct card_uart_driver *drv);</span><br><span style="color: hsl(0, 100%, 40%);">-</span><br><span>diff --git a/ccid/cuart_driver_tty.c b/ccid/cuart_driver_tty.c</span><br><span>index 6bd2b52..7fc8d3a 100644</span><br><span>--- a/ccid/cuart_driver_tty.c</span><br><span>+++ b/ccid/cuart_driver_tty.c</span><br><span>@@ -125,7 +125,21 @@</span><br><span> rc = read(ofd->fd, buf, sizeof(buf));</span><br><span> OSMO_ASSERT(rc > 0);</span><br><span> for (i = 0; i < rc; i++) {</span><br><span style="color: hsl(120, 100%, 40%);">+#ifndef CREAD_ACTUALLY_WORKS</span><br><span> /* work-around for https://bugzilla.kernel.org/show_bug.cgi?id=205033 */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (cuart->tx_busy) {</span><br><span style="color: hsl(120, 100%, 40%);">+ if (cuart->u.tty.rx_count_during_tx < cuart->u.tty.tx_buf_len) {</span><br><span style="color: hsl(120, 100%, 40%);">+ /* FIXME: compare! */</span><br><span style="color: hsl(120, 100%, 40%);">+ cuart->u.tty.rx_count_during_tx += 1;</span><br><span style="color: hsl(120, 100%, 40%);">+ if (cuart->u.tty.rx_count_during_tx == cuart->u.tty.tx_buf_len) {</span><br><span style="color: hsl(120, 100%, 40%);">+ cuart->tx_busy = false;</span><br><span style="color: hsl(120, 100%, 40%);">+ card_uart_notification(cuart, CUART_E_TX_COMPLETE,</span><br><span style="color: hsl(120, 100%, 40%);">+ (void *)cuart->u.tty.tx_buf);</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span style="color: hsl(120, 100%, 40%);">+ continue;</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span style="color: hsl(120, 100%, 40%);">+#endif</span><br><span> if (!cuart->rx_enabled)</span><br><span> continue;</span><br><span> </span><br><span>@@ -152,12 +166,15 @@</span><br><span> /* if no more bytes to transmit, disable OSMO_FD_WRITE */</span><br><span> if (cuart->u.tty.tx_index >= cuart->u.tty.tx_buf_len) {</span><br><span> ofd->when &= ~BSC_FD_WRITE;</span><br><span style="color: hsl(120, 100%, 40%);">+#ifndef CREAD_ACTUALLY_WORKS</span><br><span style="color: hsl(120, 100%, 40%);">+ /* don't immediately notify user; first wait for characters to be received */</span><br><span style="color: hsl(120, 100%, 40%);">+#else</span><br><span> /* ensure everything is written (tx queue/fifo drained) */</span><br><span> tcdrain(cuart->u.tty.ofd.fd);</span><br><span style="color: hsl(0, 100%, 40%);">- osmo_select_main(true);</span><br><span> cuart->tx_busy = false;</span><br><span> /* notify */</span><br><span> card_uart_notification(cuart, CUART_E_TX_COMPLETE, (void *)cuart->u.tty.tx_buf);</span><br><span style="color: hsl(120, 100%, 40%);">+#endif</span><br><span> }</span><br><span> }</span><br><span> return 0;</span><br><span>@@ -209,7 +226,8 @@</span><br><span> </span><br><span> cuart->u.tty.tx_buf = data;</span><br><span> cuart->u.tty.tx_buf_len = len;</span><br><span style="color: hsl(0, 100%, 40%);">- cuart->u.tty.tx_buf_len = len;</span><br><span style="color: hsl(120, 100%, 40%);">+ cuart->u.tty.tx_index = 0;</span><br><span style="color: hsl(120, 100%, 40%);">+ cuart->u.tty.rx_count_during_tx = 0;</span><br><span> cuart->tx_busy = true;</span><br><span> cuart->u.tty.ofd.when |= OSMO_FD_WRITE;</span><br><span> </span><br><span>diff --git a/ccid/cuart_test.c b/ccid/cuart_test.c</span><br><span>index aff9de7..0ed6614 100644</span><br><span>--- a/ccid/cuart_test.c</span><br><span>+++ b/ccid/cuart_test.c</span><br><span>@@ -47,6 +47,8 @@</span><br><span> card_uart_tx(&g_cuart, select_mf, 5, true);</span><br><span> </span><br><span> osmo_select_main(true);</span><br><span style="color: hsl(120, 100%, 40%);">+ sleep(1);</span><br><span style="color: hsl(120, 100%, 40%);">+ osmo_select_main(true);</span><br><span> /* we should get an RX_SINGLE event here */</span><br><span> }</span><br><span> </span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/c/osmo-ccid-firmware/+/15692">change 15692</a>. 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<div style="display:none"> Gerrit-Project: osmo-ccid-firmware </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-Change-Id: Id3cca29f78ee5469a1142aaa1ff754cc0427ec93 </div>
<div style="display:none"> Gerrit-Change-Number: 15692 </div>
<div style="display:none"> Gerrit-PatchSet: 1 </div>
<div style="display:none"> Gerrit-Owner: laforge <laforge@osmocom.org> </div>
<div style="display:none"> Gerrit-MessageType: newchange </div>