x86, setup: Make the setup code also accept console=uart8250

[net-next-2.6.git] / arch / x86 / boot / tty.c

diff --git a/arch/x86/boot/tty.c b/arch/x86/boot/tty.c
index f3ceee20ff122f8793d39c91b85f8c5b45269a7d..f6d52e65f97aad3cb212f3cb4a4b7c88a59f8a39 100644 (file)
--- a/arch/x86/boot/tty.c
+++ b/arch/x86/boot/tty.c
@@ -170,7 +170,7 @@ static void early_serial_init(int baud)
        outb(c & ~DLAB, early_serial_base + LCR);
 }
 
-void console_init(void)
+static int parse_earlyprintk(void)
 {
        int baud = DEFAULT_BAUD;
        char arg[32];
@@ -208,6 +208,63 @@ void console_init(void)
                        baud = DEFAULT_BAUD;
        }
 
+       return baud;
+}
+
+#define BASE_BAUD (1843200/16)
+static unsigned int probe_baud(int port)
+{
+       unsigned char lcr, dll, dlh;
+       unsigned int quot;
+
+       lcr = inb(port + LCR);
+       outb(lcr | DLAB, port + LCR);
+       dll = inb(port + DLL);
+       dlh = inb(port + DLH);
+       outb(lcr, port + LCR);
+       quot = (dlh << 8) | dll;
+
+       return BASE_BAUD / quot;
+}
+
+static int parse_console_uart8250(void)
+{
+       char optstr[64], *options;
+       int baud = DEFAULT_BAUD;
+
+       /*
+        * console=uart8250,io,0x3f8,115200n8
+        * need to make sure it is last one console !
+        */
+       if (cmdline_find_option("console", optstr, sizeof optstr) <= 0)
+               return baud;
+
+       options = optstr;
+
+       if (!strncmp(options, "uart8250,io,", 12))
+               early_serial_base = simple_strtoull(options + 12, &options, 0);
+       else if (!strncmp(options, "uart,io,", 8))
+               early_serial_base = simple_strtoull(options + 8, &options, 0);
+       else
+               return baud;
+
+       if (options && (options[0] == ','))
+               baud = simple_strtoull(options + 1, &options, 0);
+       else
+               baud = probe_baud(early_serial_base);
+
+       return baud;
+}
+
+void console_init(void)
+{
+       int baud;
+
+       baud = parse_earlyprintk();
+
+       if (!early_serial_base)
+               baud = parse_console_uart8250();
+
        if (early_serial_base != 0)
                early_serial_init(baud);
 }