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Commit 85f8d252 authored by Maria Yu's avatar Maria Yu Committed by Teng Fei Fan
Browse files

tty: serial: msm: Add timeout for waiting TX ready 



At worst case, msm serial driver is stuck in waiting
TX ready, so have a 500ms timeout to avoid stuck
and only lost some log to uart.

Change-Id: I2984ed8ad094a040c8ae49ee6ffba5f0238ca336
Signed-off-by: default avatarMaria Yu <aiquny@codeaurora.org>
Signed-off-by: default avatarTeng Fei Fan <tengfei@codeaurora.org>
parent c1940edc

drivers/tty/serial/msm_serial.c

+12 −0
Original line number Diff line number Diff line
@@ -395,10 +395,22 @@ 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)

{

	u32 count = 500000;



	while (!(msm_read(port, UART_SR) & UART_SR_TX_EMPTY)) {

		if (msm_read(port, UART_ISR) & UART_ISR_TX_READY)

			break;

		udelay(1);



		/* At worst case, it is stuck in this loop for waiting

		 * TX ready, have a 500ms timeout to avoid stuck here

		 * and only miss some log to uart.

		 */

		if (count-- == 0) {

			msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);

			printk_deferred("uart may lost data, resetting TX!\n");

			break;

		}

	}

	msm_write(port, UART_CR_CMD_RESET_TX_READY, UART_CR);

}