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serial: uartps: Add a timeout to the tx empty wait 

In case the cable is not connected then the target gets into
an infinite wait for tx empty.
Add a timeout to the tx empty wait.

Reported-by: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Shubhrajyoti Datta 2019-05-24 14:41:29 +05:30 committed by Greg Kroah-Hartman
parent 107475685a
commit 277375b864
1 changed files with 10 additions and 4 deletions
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14
drivers/tty/serial/xilinx_uartps.c
View File

@ -26,12 +26,14 @@
#include <linux/of.h> #include <linux/of.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/pm_runtime.h> #include <linux/pm_runtime.h>
#include <linux/iopoll.h>
#define CDNS_UART_TTY_NAME "ttyPS" #define CDNS_UART_TTY_NAME "ttyPS"
#define CDNS_UART_NAME "xuartps" #define CDNS_UART_NAME "xuartps"
#define CDNS_UART_MAJOR 0 /* use dynamic node allocation */ #define CDNS_UART_MAJOR 0 /* use dynamic node allocation */
#define CDNS_UART_FIFO_SIZE 64 /* FIFO size */ #define CDNS_UART_FIFO_SIZE 64 /* FIFO size */
#define CDNS_UART_REGISTER_SPACE 0x1000 #define CDNS_UART_REGISTER_SPACE 0x1000
#define TX_TIMEOUT 500000
/* Rx Trigger level */ /* Rx Trigger level */
static int rx_trigger_level = 56; static int rx_trigger_level = 56;
@ -684,14 +686,18 @@ static void cdns_uart_set_termios(struct uart_port *port,
unsigned int cval = 0; unsigned int cval = 0;
unsigned int baud, minbaud, maxbaud; unsigned int baud, minbaud, maxbaud;
unsigned long flags; unsigned long flags;
unsigned int ctrl_reg, mode_reg; unsigned int ctrl_reg, mode_reg, val;
int err;
/* Wait for the transmit FIFO to empty before making changes */ /* Wait for the transmit FIFO to empty before making changes */
if (!(readl(port->membase + CDNS_UART_CR) & if (!(readl(port->membase + CDNS_UART_CR) &
CDNS_UART_CR_TX_DIS)) { CDNS_UART_CR_TX_DIS)) {
while (!(readl(port->membase + CDNS_UART_SR) & err = readl_poll_timeout(port->membase + CDNS_UART_SR,
CDNS_UART_SR_TXEMPTY)) { val, (val & CDNS_UART_SR_TXEMPTY),
cpu_relax(); 1000, TX_TIMEOUT);
if (err) {
dev_err(port->dev, "timed out waiting for tx empty");
return;
} }
} }
spin_lock_irqsave(&port->lock, flags); spin_lock_irqsave(&port->lock, flags);