This adds support early console for MPS2 UART which can be enabled via
earlycon=mps2,0x40004000
Signed-off-by: Vladimir Murzin <vladimir.murzin@xxxxxxx>
---
drivers/tty/serial/Kconfig | 1 +
drivers/tty/serial/mps2-uart.c | 30 ++++++++++++++++++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index e98bfea..33d1365 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1477,6 +1477,7 @@ 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 09bac16..5f3252e 100644
--- a/drivers/tty/serial/mps2-uart.c
+++ b/drivers/tty/serial/mps2-uart.c
@@ -445,6 +445,36 @@ 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 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;
+}
+EARLYCON_DECLARE(mps2, mps2_early_console_setup);
+OF_EARLYCON_DECLARE(mps2, "arm,mps2-uart", mps2_early_console_setup);
+
#else
#define MPS2_SERIAL_CONSOLE NULL
#endif
--
1.7.9.5
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