serial: clps711x: Give a chance to perform useful tasks during wait loop

This patch adds cond_sched() calls during wait loop to perform
other tasks.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 15 insertions, 6 deletions

diff --git a/drivers/tty/serial/clps711x.c b/drivers/tty/serial/clps711x.c
index b0eacb83f831..5e6fdb1ea73b 100644
--- a/drivers/tty/serial/clps711x.c
+++ b/drivers/tty/serial/clps711x.c
@@ -368,11 +368,16 @@ static const struct uart_ops uart_clps711x_ops = {
 static void uart_clps711x_console_putchar(struct uart_port *port, int ch)
 {
         struct clps711x_port *s = dev_get_drvdata(port->dev);
-        u32 sysflg = 0;
 
-        do {
+        /* Wait for FIFO is not full */
+        while (1) {
+                u32 sysflg = 0;
+
                 regmap_read(s->syscon, SYSFLG_OFFSET, &sysflg);
-        } while (sysflg & SYSFLG_UTXFF);
+                if (!(sysflg & SYSFLG_UTXFF))
+                        break;
+                cond_resched();
+        }
 
         writew(ch, port->membase + UARTDR_OFFSET);
 }
@@ -382,14 +387,18 @@ static void uart_clps711x_console_write(struct console *co, const char *c,
 {
         struct uart_port *port = clps711x_uart.state[co->index].uart_port;
         struct clps711x_port *s = dev_get_drvdata(port->dev);
-        u32 sysflg = 0;
 
         uart_console_write(port, c, n, uart_clps711x_console_putchar);
 
         /* Wait for transmitter to become empty */
-        do {
+        while (1) {
+                u32 sysflg = 0;
+
                 regmap_read(s->syscon, SYSFLG_OFFSET, &sysflg);
-        } while (sysflg & SYSFLG_UBUSY);
+                if (!(sysflg & SYSFLG_UBUSY))
+                        break;
+                cond_resched();
+        }
 }
 
 static int uart_clps711x_console_setup(struct console *co, char *options)