From afd9c690d864d13ca9092672fa1ba3e4233c548c Mon Sep 17 00:00:00 2001 From: Shubhrajyoti Datta Date: Fri, 29 Jul 2022 17:17:46 +0530 Subject: [PATCH] tty: xilinx_uartps: Prevent writes when the controller is disabled Prevent writing to the fifo if the controller is disabled. Signed-off-by: Shubhrajyoti Datta Link: https://lore.kernel.org/r/20220729114748.18332-6-shubhrajyoti.datta@xilinx.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/xilinx_uartps.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index ae99e1164f0c4..d1aa44febaea7 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); -- 2.39.5