Implement a bare bones earlycon; this assumes that the bootloader sets
up the tty parameters. Matches all three compatible strings.
Signed-off-by: Kevin Cernekee <cernekee@xxxxxxxxx>
---
drivers/tty/serial/pxa.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/drivers/tty/serial/pxa.c b/drivers/tty/serial/pxa.c
index f6cc773..0764cf5 100644
--- a/drivers/tty/serial/pxa.c
+++ b/drivers/tty/serial/pxa.c
@@ -761,6 +761,51 @@ static struct console serial_pxa_console = {
.data = &serial_pxa_reg,
};
+static struct uart_pxa_port serial_pxa_early_port;
+
+static void __init early_wait_for_xmitr(struct uart_pxa_port *up)
+{
+ /* it's unsafe to call udelay() in the "early" variant */
+ while ((serial_in(up, UART_LSR) & BOTH_EMPTY) != BOTH_EMPTY)
+ ;
+}
+
+static void __init serial_pxa_early_putchar(struct uart_port *port, int ch)
+{
+ struct uart_pxa_port *up = (struct uart_pxa_port *)port;
+
+ early_wait_for_xmitr(up);
+ serial_out(up, UART_TX, ch);
+}
+
+static void __init serial_pxa_early_write(struct console *con, const char *s,
+ unsigned n)
+{
+ uart_console_write(&serial_pxa_early_port.port, s, n,
+ serial_pxa_early_putchar);
+ early_wait_for_xmitr(&serial_pxa_early_port);
+}
+
+static int __init serial_pxa_early_console_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ if (!device->port.membase)
+ return -ENODEV;
+
+ serial_pxa_early_port.port.membase = device->port.membase;
+ serial_pxa_early_port.port.big_endian = device->port.big_endian;
+
+ device->con->write = serial_pxa_early_write;
+ return 0;
+}
+
+OF_EARLYCON_DECLARE(pxa_uart, "mrvl,pxa-uart",
+ serial_pxa_early_console_setup);
+OF_EARLYCON_DECLARE(mmp_uart, "mrvl,mmp-uart",
+ serial_pxa_early_console_setup);
+OF_EARLYCON_DECLARE(bcm7401_upg_uart, "brcm,bcm7401-upg-uart",
+ serial_pxa_early_console_setup);
+
#define PXA_CONSOLE &serial_pxa_console
#else
#define PXA_CONSOLE NULL
--
2.1.1
