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tty: serial: qcom_geni_serial: Fix UART hang 

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>
Reviewed-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ryan Case 2018-12-19 12:33:53 -08:00 committed by Greg Kroah-Hartman
parent 3c66eb4ba1
commit 663abb1a7a
1 changed files with 8 additions and 0 deletions
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8
drivers/tty/serial/qcom_geni_serial.c
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@ -440,6 +440,7 @@ 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);
@ -474,6 +475,13 @@ 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);