In commit d3755f5e6cd2 ("tty: xuartps: Force enable the UART in
xuartps_console_write") added some logic to enable TX before writing
and resetting it back to the original state. Uwe Kleine-König
discovered that commit e3538c37ee38 ("tty: xuartps: Beautify
read-modify writes") breaks that logic and always leaves TX enabled.
This commit reverts the unintended functional change.
Fixes: e3538c37ee38 ("tty: xuartps: Beautify read-modify writes")
Signed-off-by: Helmut Grohne <h.grohne@xxxxxxxxxx>
---
drivers/tty/serial/xilinx_uartps.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
Note that e3538c37ee38 partially hides a hardware race condition that
becomes visible again after applying this patch.
The recipient list is a combination of get_maintainer.pl output and the
reviewers of e3538c37ee38.
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index cd46e64..acaf83c 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1092,7 +1092,7 @@ static void cdns_uart_console_write(struct console *co, const char *s,
{
struct uart_port *port = &cdns_uart_port[co->index];
unsigned long flags;
- unsigned int imr, ctrl;
+ unsigned int imr, orig_ctrl, ctrl;
int locked = 1;
if (port->sysrq)
@@ -1110,7 +1110,7 @@ static void cdns_uart_console_write(struct console *co, const char *s,
* Make sure that the tx part is enabled. Set the TX enable bit and
* clear the TX disable bit to enable the transmitter.
*/
- ctrl = readl(port->membase + CDNS_UART_CR);
+ orig_ctrl = ctrl = readl(port->membase + CDNS_UART_CR);
ctrl &= ~CDNS_UART_CR_TX_DIS;
ctrl |= CDNS_UART_CR_TX_EN;
writel(ctrl, port->membase + CDNS_UART_CR);
@@ -1118,7 +1118,7 @@ static void cdns_uart_console_write(struct console *co, const char *s,
uart_console_write(port, s, count, cdns_uart_console_putchar);
cdns_uart_console_wait_tx(port);
- writel(ctrl, port->membase + CDNS_UART_CR);
+ writel(orig_ctrl, port->membase + CDNS_UART_CR);
/* restore interrupt state */
writel(imr, port->membase + CDNS_UART_IER);
--
2.1.4
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