powerpc/powermac: Fixup default serial port device for pmac_zilog

This removes the non-working code in legacy_serial that tried to handle
the powermac SCC ports, and instead add a (now working) function to the
powermac platform code to find the default serial console if any.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

2 files changed, 89 insertions, 27 deletions

diff --git a/arch/powerpc/kernel/legacy_serial.c b/arch/powerpc/kernel/legacy_serial.c
index 4d96e1db55ee..9ddfaef1a184 100644
--- a/arch/powerpc/kernel/legacy_serial.c
+++ b/arch/powerpc/kernel/legacy_serial.c
@@ -493,18 +493,18 @@ static int __init serial_dev_init(void)
 device_initcall(serial_dev_init);
 
 
+#ifdef CONFIG_SERIAL_8250_CONSOLE
 /*
  * This is called very early, as part of console_init() (typically just after
  * time_init()). This function is respondible for trying to find a good
  * default console on serial ports. It tries to match the open firmware
- * default output with one of the available serial console drivers, either
- * one of the platform serial ports that have been probed earlier by
- * find_legacy_serial_ports() or some more platform specific ones.
+ * default output with one of the available serial console drivers that have
+ * been probed earlier by find_legacy_serial_ports()
  */
 static int __init check_legacy_serial_console(void)
 {
         struct device_node *prom_stdout = NULL;
-        int speed = 0, offset = 0;
+        int i, speed = 0, offset = 0;
         const char *name;
         const u32 *spd;
 
@@ -548,31 +548,20 @@ static int __init check_legacy_serial_console(void)
         if (spd)
                 speed = *spd;
 
-        if (0)
-                ;
-#ifdef CONFIG_SERIAL_8250_CONSOLE
-        else if (strcmp(name, "serial") == 0) {
-                int i;
-                /* Look for it in probed array */
-                for (i = 0; i < legacy_serial_count; i++) {
-                        if (prom_stdout != legacy_serial_infos[i].np)
-                                continue;
-                        offset = i;
-                        speed = legacy_serial_infos[i].speed;
-                        break;
-                }
-                if (i >= legacy_serial_count)
-                        goto not_found;
+        if (strcmp(name, "serial") != 0)
+                goto not_found;
+
+        /* Look for it in probed array */
+        for (i = 0; i < legacy_serial_count; i++) {
+                if (prom_stdout != legacy_serial_infos[i].np)
+                        continue;
+                offset = i;
+                speed = legacy_serial_infos[i].speed;
+                break;
         }
-#endif /* CONFIG_SERIAL_8250_CONSOLE */
-#ifdef CONFIG_SERIAL_PMACZILOG_CONSOLE
-        else if (strcmp(name, "ch-a") == 0)
-                offset = 0;
-        else if (strcmp(name, "ch-b") == 0)
-                offset = 1;
-#endif /* CONFIG_SERIAL_PMACZILOG_CONSOLE */
-        else
+        if (i >= legacy_serial_count)
                 goto not_found;
+
         of_node_put(prom_stdout);
 
         DBG("Found serial console at ttyS%d\n", offset);
@@ -591,3 +580,4 @@ static int __init check_legacy_serial_console(void)
 }
 console_initcall(check_legacy_serial_console);
 
+#endif /* CONFIG_SERIAL_8250_CONSOLE */
diff --git a/arch/powerpc/platforms/powermac/setup.c b/arch/powerpc/platforms/powermac/setup.c
index 31635446901a..88ccf3a08a9c 100644
--- a/arch/powerpc/platforms/powermac/setup.c
+++ b/arch/powerpc/platforms/powermac/setup.c
@@ -541,6 +541,78 @@ static int __init pmac_declare_of_platform_devices(void)
 }
 machine_device_initcall(powermac, pmac_declare_of_platform_devices);
 
+#ifdef CONFIG_SERIAL_PMACZILOG_CONSOLE
+/*
+ * This is called very early, as part of console_init() (typically just after
+ * time_init()). This function is respondible for trying to find a good
+ * default console on serial ports. It tries to match the open firmware
+ * default output with one of the available serial console drivers.
+ */
+static int __init check_pmac_serial_console(void)
+{
+        struct device_node *prom_stdout = NULL;
+        int offset = 0;
+        const char *name;
+#ifdef CONFIG_SERIAL_PMACZILOG_TTYS
+        char *devname = "ttyS";
+#else
+        char *devname = "ttyPZ";
+#endif
+
+        pr_debug(" -> check_pmac_serial_console()\n");
+
+        /* The user has requested a console so this is already set up. */
+        if (strstr(boot_command_line, "console=")) {
+                pr_debug(" console was specified !\n");
+                return -EBUSY;
+        }
+
+        if (!of_chosen) {
+                pr_debug(" of_chosen is NULL !\n");
+                return -ENODEV;
+        }
+
+        /* We are getting a weird phandle from OF ... */
+        /* ... So use the full path instead */
+        name = of_get_property(of_chosen, "linux,stdout-path", NULL);
+        if (name == NULL) {
+                pr_debug(" no linux,stdout-path !\n");
+                return -ENODEV;
+        }
+        prom_stdout = of_find_node_by_path(name);
+        if (!prom_stdout) {
+                pr_debug(" can't find stdout package %s !\n", name);
+                return -ENODEV;
+        }
+        pr_debug("stdout is %s\n", prom_stdout->full_name);
+
+        name = of_get_property(prom_stdout, "name", NULL);
+        if (!name) {
+                pr_debug(" stdout package has no name !\n");
+                goto not_found;
+        }
+
+        if (strcmp(name, "ch-a") == 0)
+                offset = 0;
+        else if (strcmp(name, "ch-b") == 0)
+                offset = 1;
+        else
+                goto not_found;
+        of_node_put(prom_stdout);
+
+        pr_debug("Found serial console at %s%d\n", devname, offset);
+
+        return add_preferred_console(devname, offset, NULL);
+
+ not_found:
+        pr_debug("No preferred console found !\n");
+        of_node_put(prom_stdout);
+        return -ENODEV;
+}
+console_initcall(check_pmac_serial_console);
+
+#endif /* CONFIG_SERIAL_PMACZILOG_CONSOLE */
+
 /*
  * Called very early, MMU is off, device-tree isn't unflattened
  */