Nios2 currently uses its own early printk implementation, rather than
using unified earlycon support to show boot messages on altera_uart.
Add earlycon support to altera_uart so that other archs may use it.
Also, this (together with the corresponding patch for altera_jtaguart)
will allow the early printk implementation in arch/nios2 to be removed
in a future patch.
Cc: Ley Foon Tan <lftan@xxxxxxxxxx>
Signed-off-by: Tobias Klauser <tklauser@xxxxxxxxxx>
---
drivers/tty/serial/Kconfig | 1 +
drivers/tty/serial/altera_uart.c | 32 ++++++++++++++++++++++++++++++++
2 files changed, 33 insertions(+)
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 6117ac8da48f..a6ad31e10187 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1382,6 +1382,7 @@ config SERIAL_ALTERA_UART_CONSOLE
bool "Altera UART console support"
depends on SERIAL_ALTERA_UART=y
select SERIAL_CORE_CONSOLE
+ select SERIAL_EARLYCON
help
Enable a Altera UART port to be the system console.
diff --git a/drivers/tty/serial/altera_uart.c b/drivers/tty/serial/altera_uart.c
index 820a74208696..46d3438a0d27 100644
--- a/drivers/tty/serial/altera_uart.c
+++ b/drivers/tty/serial/altera_uart.c
@@ -489,6 +489,38 @@ console_initcall(altera_uart_console_init);
#define ALTERA_UART_CONSOLE (&altera_uart_console)
+static void altera_uart_earlycon_write(struct console *co, const char *s,
+ unsigned int count)
+{
+ struct earlycon_device *dev = co->data;
+
+ uart_console_write(&dev->port, s, count, altera_uart_console_putc);
+}
+
+static int __init altera_uart_earlycon_setup(struct earlycon_device *dev,
+ const char *options)
+{
+ struct uart_port *port = &dev->port;
+
+ if (!port->membase)
+ return -ENODEV;
+
+ /* Enable RX interrupts now */
+ writel(ALTERA_UART_CONTROL_RRDY_MSK,
+ port->membase + ALTERA_UART_CONTROL_REG);
+
+ if (dev->baud) {
+ unsigned int baudclk = port->uartclk / dev->baud;
+
+ writel(baudclk, port->membase + ALTERA_UART_DIVISOR_REG);
+ }
+
+ dev->con->write = altera_uart_earlycon_write;
+ return 0;
+}
+
+OF_EARLYCON_DECLARE(uart, "altr,uart-1.0", altera_uart_earlycon_setup);
+
#else
#define ALTERA_UART_CONSOLE NULL
--
2.11.0
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