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authorVladimir Murzin <vladimir.murzin@arm.com>2016-04-25 09:47:48 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-04-30 09:26:55 -0700
commitbd8d257fa3371a284568b8ee04c2bcf4757238ed (patch)
tree2ca1be7d29853b680bf23ea1bc343f619c99ae99 /drivers/tty
parent041f031def330582108bc37f97525d9e7c0e2b2f (diff)
serial: mps2-uart: add support for early console
This adds support early console for MPS2 UART which can be enabled via earlycon=mps2,0x40004000 Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> 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/mps2-uart.c28
2 files changed, 29 insertions, 0 deletions
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 3b0a9b3ec4e1..331638db6466 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1452,6 +1452,7 @@ config SERIAL_MPS2_UART_CONSOLE
bool "MPS2 UART console support"
depends on SERIAL_MPS2_UART
select SERIAL_CORE_CONSOLE
+ select SERIAL_EARLYCON
config SERIAL_MPS2_UART
bool "MPS2 UART port"
diff --git a/drivers/tty/serial/mps2-uart.c b/drivers/tty/serial/mps2-uart.c
index e571e4cdfab3..da9e27d3c263 100644
--- a/drivers/tty/serial/mps2-uart.c
+++ b/drivers/tty/serial/mps2-uart.c
@@ -450,6 +450,34 @@ static struct console mps2_uart_console = {
#define MPS2_SERIAL_CONSOLE (&mps2_uart_console)
+static void mps2_early_putchar(struct uart_port *port, int ch)
+{
+ while (readb(port->membase + UARTn_STATE) & UARTn_STATE_TX_FULL)
+ cpu_relax();
+
+ writeb((unsigned char)ch, port->membase + UARTn_DATA);
+}
+
+static void mps2_early_write(struct console *con, const char *s, unsigned int n)
+{
+ struct earlycon_device *dev = con->data;
+
+ uart_console_write(&dev->port, s, n, mps2_early_putchar);
+}
+
+static int __init mps2_early_console_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ if (!device->port.membase)
+ return -ENODEV;
+
+ device->con->write = mps2_early_write;
+
+ return 0;
+}
+
+OF_EARLYCON_DECLARE(mps2, "arm,mps2-uart", mps2_early_console_setup);
+
#else
#define MPS2_SERIAL_CONSOLE NULL
#endif