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| author | Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org> | 2019-06-10 20:23:08 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-08-04 10:34:56 +0300 |
| commit | e14829d6f80f635dacb84615b67666dfd6457e26 (patch) | |
| tree | db74a74233831e8b423db67af2129cad90e2997c /drivers/tty | |
| parent | d6ad3a06c646b5fa6b0d92df4a31ae87204c6d20 (diff) | |
| download | linux-e14829d6f80f635dacb84615b67666dfd6457e26.tar.xz | |
tty: serial: msm_serial: avoid system lockup condition
[ Upstream commit ba3684f99f1b25d2a30b6956d02d339d7acb9799 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/msm_serial.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c index 5f0ded6fc4e9..eaeb098b5d6a 100644 --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -222,10 +222,14 @@ 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); } |