diff mbox series

[v2,5/7] tty: xilinx_uartps: Prevent writes when the controller is disabled

Message ID 20220729114748.18332-6-shubhrajyoti.datta@xilinx.com
State New
Headers show
Series tty: xilinx_uartps: fixes and improvements | expand

Commit Message

Shubhrajyoti Datta July 29, 2022, 11:47 a.m. UTC 
Prevent writing to the fifo if the controller is disabled.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
---
v2:
Add atimeout

 drivers/tty/serial/xilinx_uartps.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
diff mbox series

Patch

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index ae99e1164f0c..e119da69e190 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1132,6 +1132,21 @@  static struct uart_driver cdns_uart_uart_driver;
  */
 static void cdns_uart_console_putchar(struct uart_port *port, unsigned char ch)
 {
+	unsigned int ctrl_reg;
+	unsigned long timeout;
+
+	timeout = jiffies + msecs_to_jiffies(1000);
+	while (1) {
+		ctrl_reg = readl(port->membase + CDNS_UART_CR);
+		if (!(ctrl_reg & CDNS_UART_CR_TX_DIS))
+			break;
+		if (time_after(jiffies, timeout)) {
+			dev_warn(port->dev,
+				 "timeout waiting for Enable\n");
+			return;
+		}
+		cpu_relax();
+	}
 	while (readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)
 		cpu_relax();
 	writel(ch, port->membase + CDNS_UART_FIFO);