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authorTobias Klauser <tklauser@distanz.ch>2017-03-22 15:50:13 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-03-31 17:56:10 +0300
commit4d9d7d896d77e70e6868cfe681e7fcd58dc9526d (patch)
treee51c87225e31ee349087ecc0e65d3103463bb54f /drivers/tty
parenta4199f5eb8096d63828f7333fa45650a7b0a99ed (diff)
downloadlinux-4d9d7d896d77e70e6868cfe681e7fcd58dc9526d.tar.xz
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 <lftan@altera.com> Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/Kconfig1
-rw-r--r--drivers/tty/serial/altera_uart.c32
2 files changed, 33 insertions, 0 deletions
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