[POWERPC] Autodetect serial console on efika

Efika boards have to be booted with console=ttyPSC0 unless there is a
graphics card plugged in. Detect if the firmware stdout is the serial
connector.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/52xx/efika.c b/arch/powerpc/platforms/52xx/efika.c
index 8de034116681..31a2a8ca1de7 100644
--- a/arch/powerpc/platforms/52xx/efika.c
+++ b/arch/powerpc/platforms/52xx/efika.c
@@ -21,6 +21,7 @@
 #include <linux/initrd.h>
 #include <linux/timer.h>
 #include <linux/pci.h>
+#include <linux/console.h>
 
 #include <asm/io.h>
 #include <asm/irq.h>
@@ -221,12 +222,37 @@ static int __init efika_probe(void)
         return 1;
 }
 
+static void __init efika_init_early(void)
+{
+#ifdef CONFIG_SERIAL_MPC52xx
+        struct device_node *stdout_node;
+        const char *device_type;
+
+        if (strstr(cmd_line, "console="))
+                return;
+        /* find the boot console from /chosen/stdout */
+        if (!of_chosen)
+                return;
+        device_type = get_property(of_chosen, "linux,stdout-path", NULL);
+        if (!device_type)
+                return;
+        stdout_node = of_find_node_by_path(device_type);
+        if (stdout_node) {
+                device_type = get_property(stdout_node, "device_type", NULL);
+                if (device_type && strcmp(device_type, "serial") == 0)
+                        add_preferred_console("ttyPSC", 0, NULL);
+                of_node_put(stdout_node);
+        }
+#endif
+}
+
 define_machine(efika)
 {
         .name                   = EFIKA_PLATFORM_NAME,
         .probe                  = efika_probe,
         .setup_arch             = efika_setup_arch,
         .init                   = mpc52xx_declare_of_platform_devices,
+        .init_early             = efika_init_early,
         .show_cpuinfo           = efika_show_cpuinfo,
         .init_IRQ               = mpc52xx_init_irq,
         .get_irq                = mpc52xx_get_irq,