svn commit: r359900 - head/sys/dev/uart
John Baldwin
jhb at FreeBSD.org
Mon Apr 13 20:59:10 UTC 2020
Author: jhb
Date: Mon Apr 13 20:59:09 2020
New Revision: 359900
URL: https://svnweb.freebsd.org/changeset/base/359900
Log:
Export a sysctl count of RX FIFO overrun events.
uart(4) backends currently detect RX FIFO overrun errors and report
them to the uart(4) core layer. They are then reported to the generic
TTY layer which promptly ignores them. As a result, there is
currently no good way to determine if a uart is experiencing RX FIFO
overruns. One could add a generic per-tty counter, but there did not
appear to be a good way to export those. Instead, add a sysctl under
the uart(4) sysctl tree to export the count of overruns.
Reviewed by: brooks
MFC after: 2 weeks
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D24368
Modified:
head/sys/dev/uart/uart_bus.h
head/sys/dev/uart/uart_core.c
Modified: head/sys/dev/uart/uart_bus.h
==============================================================================
--- head/sys/dev/uart/uart_bus.h Mon Apr 13 20:43:57 2020 (r359899)
+++ head/sys/dev/uart/uart_bus.h Mon Apr 13 20:59:09 2020 (r359900)
@@ -111,6 +111,7 @@ struct uart_softc {
int sc_rxput;
int sc_rxget;
int sc_rxfifosz; /* Size of RX FIFO. */
+ int sc_rxoverruns;
/* Transmitter data. */
uint8_t *sc_txbuf;
Modified: head/sys/dev/uart/uart_core.c
==============================================================================
--- head/sys/dev/uart/uart_core.c Mon Apr 13 20:43:57 2020 (r359899)
+++ head/sys/dev/uart/uart_core.c Mon Apr 13 20:59:09 2020 (r359900)
@@ -333,6 +333,7 @@ uart_intr_overrun(void *arg)
sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;
uart_sched_softih(sc, SER_INT_RXREADY);
}
+ sc->sc_rxoverruns++;
UART_FLUSH(sc, UART_FLUSH_RECEIVER);
return (0);
}
@@ -740,6 +741,12 @@ uart_bus_attach(device_t dev)
if (sc->sc_sysdev != NULL)
sc->sc_sysdev->hwmtx = sc->sc_hwmtx;
+
+ if (sc->sc_rxfifosz > 1)
+ SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
+ SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO,
+ "rx_overruns", CTLFLAG_RD, &sc->sc_rxoverruns, 0,
+ "Receive overruns");
return (0);
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