From 4d9d7d896d77e70e6868cfe681e7fcd58dc9526d Mon Sep 17 00:00:00 2001 From: Tobias Klauser Date: Wed, 22 Mar 2017 13:50:13 +0100 Subject: serial: altera_uart: add earlycon support 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 Signed-off-by: Tobias Klauser Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/Kconfig | 1 + drivers/tty/serial/altera_uart.c | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 33 insertions(+) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index 896f5eb78da0..5c8850f7a2a0 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -1392,6 +1392,7 @@ 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 -- cgit