serial/arc: Use generic earlycon infrastructure

With this change both earlyprintk and earlycon coexist
We switch over to latter in next patch

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 31 insertions, 0 deletions

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 7039238b134f..7f12a005c6cb 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1472,6 +1472,7 @@ config SERIAL_ARC_CONSOLE
         bool "Console on ARC UART"
         depends on SERIAL_ARC=y
         select SERIAL_CORE_CONSOLE
+        select SERIAL_EARLYCON
         help
           Enable system Console on ARC UART
 
diff --git a/drivers/tty/serial/arc_uart.c b/drivers/tty/serial/arc_uart.c
index ea954c3be18b..41d2e351c06d 100644
--- a/drivers/tty/serial/arc_uart.c
+++ b/drivers/tty/serial/arc_uart.c
@@ -638,6 +638,36 @@ static int __init arc_serial_probe_earlyprintk(struct platform_device *pdev)
         register_console(&arc_early_serial_console);
         return 0;
 }
+
+static __init void arc_early_serial_write(struct console *con, const char *s,
+                                          unsigned int n)
+{
+        struct earlycon_device *dev = con->data;
+
+        uart_console_write(&dev->port, s, n, arc_serial_poll_putchar);
+}
+
+static int __init arc_early_console_setup(struct earlycon_device *dev,
+                                          const char *opt)
+{
+        struct uart_port *port = &dev->port;
+        unsigned int l, h, hw_val;
+
+        if (!dev->port.membase)
+                return -ENODEV;
+
+        hw_val = port->uartclk / (dev->baud * 4) - 1;
+        l = hw_val & 0xFF;
+        h = (hw_val >> 8) & 0xFF;
+
+        UART_SET_BAUDL(port, l);
+        UART_SET_BAUDH(port, h);
+
+        dev->con->write = arc_early_serial_write;
+        return 0;
+}
+EARLYCON_DECLARE(arc_uart, arc_early_console_setup);
+
 #endif  /* CONFIG_SERIAL_ARC_CONSOLE */
 
 static int arc_serial_probe(struct platform_device *pdev)