[PATCH 4/3] tty: serial: bcm63xx: Enable DT earlycon support

[Kevin Cernekee]

This enables early console output if there is a chosen/stdout-path
property referencing a UART node with the "brcm,bcm6345-uart" compatible
string. The bootloader sets up the pinmux and baud/parity/etc.
Tested on bcm3384 (MIPS, DT).

Signed-off-by: Kevin Cernekee <***@gmail.com>
---
drivers/tty/serial/Kconfig | 1 +
drivers/tty/serial/bcm63xx_uart.c | 20 ++++++++++++++++++++
2 files changed, 21 insertions(+)

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 815b652..fdd851e 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1297,6 +1297,7 @@ config SERIAL_BCM63XX_CONSOLE
bool "Console on BCM63xx serial port"
depends on SERIAL_BCM63XX=y
select SERIAL_CORE_CONSOLE
+ select SERIAL_EARLYCON
help
If you have enabled the serial port on the BCM63xx CPU
you can make it the console by answering Y to this option.
diff --git a/drivers/tty/serial/bcm63xx_uart.c b/drivers/tty/serial/bcm63xx_uart.c
index 2315190..48bd509 100644
--- a/drivers/tty/serial/bcm63xx_uart.c
+++ b/drivers/tty/serial/bcm63xx_uart.c
@@ -782,6 +782,26 @@ static int __init bcm63xx_console_init(void)

console_initcall(bcm63xx_console_init);

+static void bcm_early_write(struct console *con, const char *s, unsigned n)
+{
+ struct earlycon_device *dev = con->data;
+
+ uart_console_write(&dev->port, s, n, bcm_console_putchar);
+ wait_for_xmitr(&dev->port);
+}
+
+static int __init bcm_early_console_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ if (!device->port.membase)
+ return -ENODEV;
+
+ device->con->write = bcm_early_write;
+ return 0;
+}
+
+OF_EARLYCON_DECLARE(bcm63xx_uart, "brcm,bcm6345-uart", bcm_early_console_setup);
+
#define BCM63XX_CONSOLE (&bcm63xx_console)
#else
#define BCM63XX_CONSOLE NULL