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-rw-r--r--arch/x86/boot/string.c22
-rw-r--r--arch/x86/boot/tty.c59
2 files changed, 80 insertions, 1 deletions
diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c
index aba29df4a7bb..3cbc4058dd26 100644
--- a/arch/x86/boot/string.c
+++ b/arch/x86/boot/string.c
@@ -68,10 +68,32 @@ unsigned int atou(const char *s)
/* Works only for digits and letters, but small and fast */
#define TOLOWER(x) ((x) | 0x20)
+static unsigned int simple_guess_base(const char *cp)
+{
+ if (cp[0] == '0') {
+ if (TOLOWER(cp[1]) == 'x' && isxdigit(cp[2]))
+ return 16;
+ else
+ return 8;
+ } else {
+ return 10;
+ }
+}
+
+/**
+ * simple_strtoull - convert a string to an unsigned long long
+ * @cp: The start of the string
+ * @endp: A pointer to the end of the parsed string will be placed here
+ * @base: The number base to use
+ */
+
unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
{
unsigned long long result = 0;
+ if (!base)
+ base = simple_guess_base(cp);
+
if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x')
cp += 2;
diff --git a/arch/x86/boot/tty.c b/arch/x86/boot/tty.c
index f3ceee20ff12..f6d52e65f97a 100644
--- 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);
}