[POWERPC] Autodetect serial console on pegasos2

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/chrp/setup.c b/arch/powerpc/platforms/chrp/setup.c
index 42a21bab76c8..116babbaaf81 100644
--- a/arch/powerpc/platforms/chrp/setup.c
+++ b/arch/powerpc/platforms/chrp/setup.c
@@ -256,6 +256,57 @@ static void briq_restart(char *cmd)
         for(;;);
 }
 
+/*
+ * Per default, input/output-device points to the keyboard/screen
+ * If no card is installed, the built-in serial port is used as a fallback.
+ * But unfortunately, the firmware does not connect /chosen/{stdin,stdout}
+ * the the built-in serial node. Instead, a /failsafe node is created.
+ */
+static void chrp_init_early(void)
+{
+        struct device_node *node;
+        const char *property;
+
+        if (strstr(cmd_line, "console="))
+                return;
+        /* find the boot console from /chosen/stdout */
+        if (!of_chosen)
+                return;
+        node = of_find_node_by_path("/");
+        if (!node)
+                return;
+        property = of_get_property(node, "model", NULL);
+        if (!property)
+                goto out_put;
+        if (strcmp(property, "Pegasos2"))
+                goto out_put;
+        /* this is a Pegasos2 */
+        property = of_get_property(of_chosen, "linux,stdout-path", NULL);
+        if (!property)
+                goto out_put;
+        of_node_put(node);
+        node = of_find_node_by_path(property);
+        if (!node)
+                return;
+        property = of_get_property(node, "device_type", NULL);
+        if (!property)
+                goto out_put;
+        if (strcmp(property, "serial"))
+                goto out_put;
+        /*
+         * The 9pin connector is either /failsafe
+         * or /pci@80000000/isa@C/serial@i2F8
+         * The optional graphics card has also type 'serial' in VGA mode.
+         */
+        property = of_get_property(node, "name", NULL);
+        if (!property)
+                goto out_put;
+        if (!strcmp(property, "failsafe") || !strcmp(property, "serial"))
+                add_preferred_console("ttyS", 0, NULL);
+out_put:
+        of_node_put(node);
+}
+
 void __init chrp_setup_arch(void)
 {
         struct device_node *root = of_find_node_by_path("/");
@@ -599,6 +650,7 @@ define_machine(chrp) {
         .probe                  = chrp_probe,
         .setup_arch             = chrp_setup_arch,
         .init                   = chrp_init2,
+        .init_early             = chrp_init_early,
         .show_cpuinfo           = chrp_show_cpuinfo,
         .init_IRQ               = chrp_init_IRQ,
         .restart                = rtas_restart,