From: Ryan Case <ryandcase@chromium.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.com>
Cc: Evan Green <evgreen@chromium.org>,
Doug Anderson <dianders@chromium.org>,
linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
Ryan Case <ryandcase@chromium.org>
Subject: [PATCH] tty: serial: qcom_geni_serial: Fix UART hang
Date: Wed, 19 Dec 2018 12:33:53 -0800 [thread overview]
Message-ID: <20181219203353.172335-1-ryandcase@chromium.org> (raw)
If a serial console write occured while a UART transmit command was
waiting for a done signal then no further data would be sent until
something new kicked the system into gear. If there is already data
waiting in the circular buffer we must re-enable the tx watermark so we
receive the expected interrupts.
Signed-off-by: Ryan Case <ryandcase@chromium.org>
---
drivers/tty/serial/qcom_geni_serial.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 0c93beb69e73..a694a47747c7 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -442,6 +442,7 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s,
bool locked = true;
unsigned long flags;
u32 geni_status;
+ u32 irq_en;
WARN_ON(co->index < 0 || co->index >= GENI_UART_CONS_PORTS);
@@ -476,6 +477,13 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s,
* has been sent, in which case we need to look for done first.
*/
qcom_geni_serial_poll_tx_done(uport);
+
+ if (uart_circ_chars_pending(&uport->state->xmit)) {
+ irq_en = readl_relaxed(uport->membase +
+ SE_GENI_M_IRQ_EN);
+ writel_relaxed(irq_en | M_TX_FIFO_WATERMARK_EN,
+ uport->membase + SE_GENI_M_IRQ_EN);
+ }
}
__qcom_geni_serial_console_write(uport, s, count);
--
2.20.1.415.g653613c723-goog
next reply other threads:[~2018-12-19 20:34 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-19 20:33 Ryan Case [this message]
2018-12-19 22:12 ` [PATCH] tty: serial: qcom_geni_serial: Fix UART hang Evan Green
2018-12-19 23:01 ` Doug Anderson
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