| Message ID | 20190610172308.21129-1-jorge.ramirez-ortiz@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] tty: serial: msm_serial: avoid system lockup condition | expand |
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 @@ static void msm_request_rx_dma(struct msm_port *msm_port, resource_size_t base) 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); }
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> --- v2: fix exit condition (timeout --> !timeout) v3: add these clarification messages drivers/tty/serial/msm_serial.c | 4 ++++ 1 file changed, 4 insertions(+) -- 2.21.0