earlycon: Initialize port->uartclk based on clock-frequency property

On DT based platforms when current-speed property is present baudrate
is setup. Also port->uartclk is initialized to bogus BASE_BAUD * 16
value. Drivers like uartps/ns16550 contain logic when baudrate and
uartclk is used for baudrate calculation.

The patch is reading optional clock-frequency property to replace bogus
BASE_BAUD * 16 calculation to have proper baudrate calculation.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
index a24278380fec2a6a67b2513514f08ecd6688dfe2..eb1f84258c44b7612f96d9b9b116c1e667683161 100644 (file)
--- a/drivers/tty/serial/earlycon.c
+++ b/drivers/tty/serial/earlycon.c
@@ -279,6 +279,10 @@ int __init of_setup_earlycon(const struct earlycon_id *match,
        if (val)
                early_console_dev.baud = be32_to_cpu(*val);
 
+       val = of_get_flat_dt_prop(node, "clock-frequency", NULL);
+       if (val)
+               port->uartclk = be32_to_cpu(*val);
+
        if (options) {
                early_console_dev.baud = simple_strtoul(options, NULL, 0);
                strlcpy(early_console_dev.options, options,