From 92877a1f9ab2370e39887cb74c7f7552b17aa214 Mon Sep 17 00:00:00 2001
From: Keir Fraser <keir@xensource.com>
Date: Mon, 24 Sep 2007 21:41:46 +0100
Subject: [PATCH] x86: Auto-probe the serial port baud rate if 'com1' or 'com2'
 is specified as a Xen console target. Avoids need for 'com1=' or 'com2='
 command-line option in some cases. Signed-off-by: Keir Fraser
 <keir@xensource.com>

---
 xen/drivers/char/console.c   | 15 +++++++++++++++
 xen/drivers/char/ns16550.c   | 18 +++++++++---------
 xen/include/asm-x86/config.h |  2 +-
 xen/include/xen/console.h    |  1 +
 4 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index 7d52a4c3ca..e4acd802b4 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -592,6 +592,21 @@ void __init console_endboot(void)
     switch_serial_input();
 }
 
+int console_has(const char *device)
+{
+    char *p;
+
+    for ( p = opt_console; p != NULL; p = strchr(p, ',') )
+    {
+        if ( *p == ',' )
+            p++;
+        if ( strncmp(p, device, strlen(device)) == 0 )
+            return 1;
+    }
+
+    return 0;
+}
+
 void console_start_log_everything(void)
 {
     atomic_inc(&print_everything);
diff --git a/xen/drivers/char/ns16550.c b/xen/drivers/char/ns16550.c
index 4b37656270..8a67f54489 100644
--- a/xen/drivers/char/ns16550.c
+++ b/xen/drivers/char/ns16550.c
@@ -9,6 +9,7 @@
  */
 
 #include <xen/config.h>
+#include <xen/console.h>
 #include <xen/init.h>
 #include <xen/irq.h>
 #include <xen/sched.h>
@@ -368,15 +369,14 @@ void __init ns16550_init(int index, struct ns16550_defaults *defaults)
     if ( (index < 0) || (index > 1) )
         return;
 
-    if ( defaults != NULL )
-    {
-        uart->baud      = defaults->baud;
-        uart->data_bits = defaults->data_bits;
-        uart->parity    = parse_parity_char(defaults->parity);
-        uart->stop_bits = defaults->stop_bits;
-        uart->irq       = defaults->irq;
-        uart->io_base   = defaults->io_base;
-    }
+    uart->baud      = (defaults->baud ? :
+                       console_has((index == 0) ? "com1" : "com2")
+                       ? BAUD_AUTO : 0);
+    uart->data_bits = defaults->data_bits;
+    uart->parity    = parse_parity_char(defaults->parity);
+    uart->stop_bits = defaults->stop_bits;
+    uart->irq       = defaults->irq;
+    uart->io_base   = defaults->io_base;
 
     ns16550_parse_port_config(uart, (index == 0) ? opt_com1 : opt_com2);
 }
diff --git a/xen/include/asm-x86/config.h b/xen/include/asm-x86/config.h
index a9bfc7076e..698868fc74 100644
--- a/xen/include/asm-x86/config.h
+++ b/xen/include/asm-x86/config.h
@@ -45,7 +45,7 @@
 
 #define HZ 100
 
-#define OPT_CONSOLE_STR "com1,vga"
+#define OPT_CONSOLE_STR "vga"
 
 #ifdef MAX_PHYS_CPUS
 #define NR_CPUS MAX_PHYS_CPUS
diff --git a/xen/include/xen/console.h b/xen/include/xen/console.h
index d6c0510281..7c786ab5df 100644
--- a/xen/include/xen/console.h
+++ b/xen/include/xen/console.h
@@ -17,6 +17,7 @@ long read_console_ring(XEN_GUEST_HANDLE(char), u32 *, int);
 
 void init_console(void);
 void console_endboot(void);
+int console_has(const char *device);
 
 int fill_console_start_info(struct dom0_vga_console_info *);
 
-- 
2.30.2