The <baud><parity><bit> option string is not supplied if the earlycon
is started via devicetree and OF_EARLYCON_DECLARE(). The option string
is also not required if started via kernel command line parameters of
the form:
earlycon=uart,mmio,<addr>
console=uart,mmio,<addr>
If earlycon_device->baud is 0, then an option string was not supplied.
In this case, assume the uart has already been initialized by the
bootloader or firmware.
Signed-off-by: Peter Hurley <pe...@hurleysoftware.com>
---
drivers/tty/serial/8250/8250_early.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_early.c
b/drivers/tty/serial/8250/8250_early.c
index d7b831b..1701d00 100644
--- a/drivers/tty/serial/8250/8250_early.c
+++ b/drivers/tty/serial/8250/8250_early.c
@@ -149,12 +149,18 @@ static int __init early_serial8250_setup(struct
earlycon_device *device,
return 0;
if (!device->baud) {
+ struct uart_port *port = &device->port;
+ unsigned int ier;
+
device->baud = probe_baud(&device->port);
snprintf(device->options, sizeof(device->options), "%u",
device->baud);
- }
- init_port(device);
+ /* assume the device was initialized, only mask interrupts */
+ ier = serial8250_early_in(port, UART_IER);
+ serial8250_early_out(port, UART_IER, ier & UART_IER_UUE);
+ } else
+ init_port(device);
device->con->write = early_serial8250_write;
return 0;
--
2.3.0
--
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