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tty: xilinx_uartps: Prevent writes when the controller is disabled

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Prevent writing to the fifo if the controller is disabled.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Link: https://lore.kernel.org/r/20220729114748.18332-6-shubhrajyoti.datta@xilinx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Shubhrajyoti Datta 2022-07-29 17:17:46 +05:30 committed by Greg Kroah-Hartman
parent b8a6c3b3d4
commit b36962896f
1 changed files with 15 additions and 0 deletions
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15
drivers/tty/serial/xilinx_uartps.c
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@ -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) 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) while (readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)
cpu_relax(); cpu_relax();
writel(ch, port->membase + CDNS_UART_FIFO); writel(ch, port->membase + CDNS_UART_FIFO);