x86, setup: Only set early_serial_base after port is initialized

putchar is using early_serial_base to check if port is initialized.

So we only assign it after early_serial_init() is called,
in case we need use VGA to debug early serial console.

Also add display for port addr and baud.

-v2: update to current tip

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4C3E0171.6050008@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 33 insertions, 30 deletions

diff --git a/arch/x86/boot/tty.c b/arch/x86/boot/tty.c
index f6d52e65f97a..ff4b27a0fc5e 100644
--- a/arch/x86/boot/tty.c
+++ b/arch/x86/boot/tty.c
@@ -152,35 +152,40 @@ int getchar_timeout(void)
         return 0;               /* Timeout! */
 }
 
-static void early_serial_init(int baud)
+static void early_serial_init(int port, int baud)
 {
         unsigned char c;
         unsigned divisor;
 
-        outb(0x3, early_serial_base + LCR);     /* 8n1 */
-        outb(0, early_serial_base + IER);       /* no interrupt */
-        outb(0, early_serial_base + FCR);       /* no fifo */
-        outb(0x3, early_serial_base + MCR);     /* DTR + RTS */
+        outb(0x3, port + LCR);  /* 8n1 */
+        outb(0, port + IER);    /* no interrupt */
+        outb(0, port + FCR);    /* no fifo */
+        outb(0x3, port + MCR);  /* DTR + RTS */
 
         divisor = 115200 / baud;
-        c = inb(early_serial_base + LCR);
-        outb(c | DLAB, early_serial_base + LCR);
-        outb(divisor & 0xff, early_serial_base + DLL);
-        outb((divisor >> 8) & 0xff, early_serial_base + DLH);
-        outb(c & ~DLAB, early_serial_base + LCR);
+        c = inb(port + LCR);
+        outb(c | DLAB, port + LCR);
+        outb(divisor & 0xff, port + DLL);
+        outb((divisor >> 8) & 0xff, port + DLH);
+        outb(c & ~DLAB, port + LCR);
+
+        early_serial_base = port;
+
+        printf("Early serial console at I/O port 0x%x baud: %d\n", port, baud);
 }
 
-static int parse_earlyprintk(void)
+static void parse_earlyprintk(void)
 {
         int baud = DEFAULT_BAUD;
         char arg[32];
         int pos = 0;
+        int port = 0;
 
         if (cmdline_find_option("earlyprintk", arg, sizeof arg) > 0) {
                 char *e;
 
                 if (!strncmp(arg, "serial", 6)) {
-                        early_serial_base = DEFAULT_SERIAL_PORT;
+                        port = DEFAULT_SERIAL_PORT;
                         pos += 6;
                 }
 
@@ -189,15 +194,15 @@ static int parse_earlyprintk(void)
 
                 if (!strncmp(arg, "ttyS", 4)) {
                         static const int bases[] = { 0x3f8, 0x2f8 };
-                        int port = 0;
+                        int idx = 0;
 
                         if (!strncmp(arg + pos, "ttyS", 4))
                                 pos += 4;
 
                         if (arg[pos++] == '1')
-                                port = 1;
+                                idx = 1;
 
-                        early_serial_base = bases[port];
+                        port = bases[idx];
                 }
 
                 if (arg[pos] == ',')
@@ -208,7 +213,8 @@ static int parse_earlyprintk(void)
                         baud = DEFAULT_BAUD;
         }
 
-        return baud;
+        if (port)
+                early_serial_init(port, baud);
 }
 
 #define BASE_BAUD (1843200/16)
@@ -227,44 +233,41 @@ static unsigned int probe_baud(int port)
         return BASE_BAUD / quot;
 }
 
-static int parse_console_uart8250(void)
+static void parse_console_uart8250(void)
 {
         char optstr[64], *options;
         int baud = DEFAULT_BAUD;
+        int port = 0;
 
         /*
          * 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;
+                return;
 
         options = optstr;
 
         if (!strncmp(options, "uart8250,io,", 12))
-                early_serial_base = simple_strtoull(options + 12, &options, 0);
+                port = simple_strtoull(options + 12, &options, 0);
         else if (!strncmp(options, "uart,io,", 8))
-                early_serial_base = simple_strtoull(options + 8, &options, 0);
+                port = simple_strtoull(options + 8, &options, 0);
         else
-                return baud;
+                return;
 
         if (options && (options[0] == ','))
                 baud = simple_strtoull(options + 1, &options, 0);
         else
-                baud = probe_baud(early_serial_base);
+                baud = probe_baud(port);
 
-        return baud;
+        if (port)
+                early_serial_init(port, baud);
 }
 
 void console_init(void)
 {
-        int baud;
-
-        baud = parse_earlyprintk();
+        parse_earlyprintk();
 
         if (!early_serial_base)
-                baud = parse_console_uart8250();
-
-        if (early_serial_base != 0)
-                early_serial_init(baud);
+                parse_console_uart8250();
 }