parisc: Autodetect default output device and set console= kernel parameter

Usually palo (the PA-RISC boot loader) will check at boot time if the
machine/firmware was configured to use the serial line (ttyS0, SERIAL_x)
or the graphical display (tty0, graph) as default output device and add
the correct "console=ttyS0" or "console=tty0" Linux kernel parameter to
the kernel command line when starting the Linux kernel.

But the kernel could also have been started via the HP-UX boot loader
or directly in qemu, in which cases the console parameter is missing.

This patch fixes this problem by adding the correct console= parameter
if it's missing in the current kernel command line.

Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/arch/parisc/kernel/setup.c b/arch/parisc/kernel/setup.c
index 456087a..b91cb45 100644 (file)
--- a/arch/parisc/kernel/setup.c
+++ b/arch/parisc/kernel/setup.c
@@ -48,6 +48,7 @@ struct proc_dir_entry * proc_mckinley_root __read_mostly = NULL;
 void __init setup_cmdline(char **cmdline_p)
 {
        extern unsigned int boot_args[];
+       char *p;
 
        /* Collect stuff passed in from the boot loader */
 
@@ -59,6 +60,16 @@ void __init setup_cmdline(char **cmdline_p)
                strscpy(boot_command_line, (char *)__va(boot_args[1]),
                        COMMAND_LINE_SIZE);
 
+       /* autodetect console type (if not done by palo yet) */
+       p = boot_command_line;
+       if (!str_has_prefix(p, "console=") && !strstr(p, " console=")) {
+               strlcat(p, " console=", COMMAND_LINE_SIZE);
+               if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
+                       strlcat(p, "ttyS0", COMMAND_LINE_SIZE);
+               else
+                       strlcat(p, "tty0", COMMAND_LINE_SIZE);
+       }
+
 #ifdef CONFIG_BLK_DEV_INITRD
                if (boot_args[2] != 0) /* did palo pass us a ramdisk? */
                {