serial: fsl_lpuart: Reset prior to registration

commit 60f361722ad2ae5ee667d0b0545d40c42f754daf upstream.

Since commit bd5305dcabbc ("tty: serial: fsl_lpuart: do software reset
for imx7ulp and imx8qxp"), certain i.MX UARTs are reset after they've
already been registered.  Register state may thus be clobbered after
user space has begun to open and access the UART.

Avoid by performing the reset prior to registration.

Fixes: bd5305dcabbc ("tty: serial: fsl_lpuart: do software reset for imx7ulp and imx8qxp")
Cc: stable@vger.kernel.org # v5.15+
Cc: Fugang Duan <fugang.duan@nxp.com>
Cc: Sherry Sun <sherry.sun@nxp.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/72fb646c1b0b11c989850c55f52f9ff343d1b2fa.1662884345.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 2945c1b89088031dfa1fc313d23dfe94cac98218..cb83c66bd8a8230010732a6ac8240a2613d34e2c 100644 (file)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -2706,14 +2706,15 @@ static int lpuart_probe(struct platform_device *pdev)
                lpuart_reg.cons = LPUART_CONSOLE;
                handler = lpuart_int;
        }
-       ret = uart_add_one_port(&lpuart_reg, &sport->port);
-       if (ret)
-               goto failed_attach_port;
 
        ret = lpuart_global_reset(sport);
        if (ret)
                goto failed_reset;
 
+       ret = uart_add_one_port(&lpuart_reg, &sport->port);
+       if (ret)
+               goto failed_attach_port;
+
        ret = uart_get_rs485_mode(&sport->port);
        if (ret)
                goto failed_get_rs485;
@@ -2736,9 +2737,9 @@ static int lpuart_probe(struct platform_device *pdev)
 
 failed_irq_request:
 failed_get_rs485:
-failed_reset:
        uart_remove_one_port(&lpuart_reg, &sport->port);
 failed_attach_port:
+failed_reset:
        lpuart_disable_clks(sport);
        return ret;
 }