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authorJorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>2019-06-10 19:23:08 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-06-10 19:42:35 +0200
commitba3684f99f1b25d2a30b6956d02d339d7acb9799 (patch)
tree0130292396d51a5e16ce0203c019aaec5e7e4a01 /drivers/tty
parentdb1b5bc047b3cadaedab3826bba82c3d9e023c4b (diff)
downloadlinux-ba3684f99f1b25d2a30b6956d02d339d7acb9799.tar.bz2
tty: serial: msm_serial: avoid system lockup condition
The function msm_wait_for_xmitr can be taken with interrupts disabled. In order to avoid a potential system lockup - demonstrated under stress testing conditions on SoC QCS404/5 - make sure we wait for a bounded amount of time. Tested on SoC QCS404. Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/msm_serial.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
index 23833ad952ba..3657a24913fc 100644
--- a/drivers/tty/serial/msm_serial.c
+++ b/drivers/tty/serial/msm_serial.c
@@ -383,10 +383,14 @@ no_rx:
static inline void msm_wait_for_xmitr(struct uart_port *port)
{
+ unsigned int timeout = 500000;
+
while (!(msm_read(port, UART_SR) & UART_SR_TX_EMPTY)) {
if (msm_read(port, UART_ISR) & UART_ISR_TX_READY)
break;
udelay(1);
+ if (!timeout--)
+ break;
}
msm_write(port, UART_CR_CMD_RESET_TX_READY, UART_CR);
}