earlycon: 8250: Fix command line regression

Restore undocumented behavior of kernel command line parameters of
the forms:
    console=uart[8250],io|mmio|mmio32,<addr>[,options]
    console=uart[8250],<addr>[,options]
where 'options' have not been specified; in this case, the hardware
is assumed to be initialized.

Fixes: c7cef0a84912cab3c9df8 ("console: Add extensible console matching")
Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 24 insertions, 26 deletions

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index e0fb5f053d09..18142ee3c013 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -3412,9 +3412,23 @@ static void univ8250_console_write(struct console *co, const char *s,
         serial8250_console_write(up, s, count);
 }
 
-static int serial8250_console_setup(struct uart_8250_port *up, char *options)
+static unsigned int probe_baud(struct uart_port *port)
+{
+        unsigned char lcr, dll, dlm;
+        unsigned int quot;
+
+        lcr = serial_port_in(port, UART_LCR);
+        serial_port_out(port, UART_LCR, lcr | UART_LCR_DLAB);
+        dll = serial_port_in(port, UART_DLL);
+        dlm = serial_port_in(port, UART_DLM);
+        serial_port_out(port, UART_LCR, lcr);
+
+        quot = (dlm << 8) | dll;
+        return (port->uartclk / 16) / quot;
+}
+
+static int serial8250_console_setup(struct uart_port *port, char *options, bool probe)
 {
-        struct uart_port *port = &up->port;
         int baud = 9600;
         int bits = 8;
         int parity = 'n';
@@ -3425,13 +3439,15 @@ static int serial8250_console_setup(struct uart_8250_port *up, char *options)
 
         if (options)
                 uart_parse_options(options, &baud, &parity, &bits, &flow);
+        else if (probe)
+                baud = probe_baud(port);
 
         return uart_set_options(port, port->cons, baud, parity, bits, flow);
 }
 
 static int univ8250_console_setup(struct console *co, char *options)
 {
-        struct uart_8250_port *up;
+        struct uart_port *port;
 
         /*
          * Check whether an invalid uart number has been specified, and
@@ -3440,11 +3456,11 @@ static int univ8250_console_setup(struct console *co, char *options)
          */
         if (co->index >= nr_uarts)
                 co->index = 0;
-        up = &serial8250_ports[co->index];
+        port = &serial8250_ports[co->index].port;
         /* link port to console */
-        up->port.cons = co;
+        port->cons = co;
 
-        return serial8250_console_setup(up, options);
+        return serial8250_console_setup(port, options, false);
 }
 
 /**
@@ -3491,7 +3507,8 @@ static int univ8250_console_match(struct console *co, char *name, int idx,
                         continue;
 
                 co->index = i;
-                return univ8250_console_setup(co, options);
+                port->cons = co;
+                return serial8250_console_setup(port, options, true);
         }
 
         return -ENODEV;
diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
index e95ebfe8427f..8e119682266a 100644
--- a/drivers/tty/serial/8250/8250_early.c
+++ b/drivers/tty/serial/8250/8250_early.c
@@ -105,21 +105,6 @@ static void __init early_serial8250_write(struct console *console,
                 serial8250_early_out(port, UART_IER, ier);
 }
 
-static unsigned int __init probe_baud(struct uart_port *port)
-{
-        unsigned char lcr, dll, dlm;
-        unsigned int quot;
-
-        lcr = serial8250_early_in(port, UART_LCR);
-        serial8250_early_out(port, UART_LCR, lcr | UART_LCR_DLAB);
-        dll = serial8250_early_in(port, UART_DLL);
-        dlm = serial8250_early_in(port, UART_DLM);
-        serial8250_early_out(port, UART_LCR, lcr);
-
-        quot = (dlm << 8) | dll;
-        return (port->uartclk / 16) / quot;
-}
-
 static void __init init_port(struct earlycon_device *device)
 {
         struct uart_port *port = &device->port;
@@ -151,10 +136,6 @@ static int __init early_serial8250_setup(struct earlycon_device *device,
                 struct uart_port *port = &device->port;
                 unsigned int ier;
 
-                device->baud = probe_baud(&device->port);
-                snprintf(device->options, sizeof(device->options), "%u",
-                         device->baud);
-
                 /* 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);