add hvc compatibility mode to xencons.

Makes switching back and forth with a pvops kernel easier. Taken from
http://lists.alioth.debian.org/pipermail/pkg-xen-devel/2008-October/002098.html
http://svn.debian.org/viewsvn/kernel?rev=12337&view=rev with thanks to
Bastian Blank.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>

diff --git a/drivers/xen/console/console.c b/drivers/xen/console/console.c
index 873266dda81d8f3698cbd756a5e47ddbbd3d9e7f..ced025d9aef5be1cae35e58796a73d3f64699adf 100644 (file)
--- a/drivers/xen/console/console.c
+++ b/drivers/xen/console/console.c
@@ -66,13 +66,14 @@
  *  'xencons=tty'  [XC_TTY]:     Console attached to '/dev/tty[0-9]+'.
  *  'xencons=ttyS' [XC_SERIAL]:  Console attached to '/dev/ttyS[0-9]+'.
  *  'xencons=xvc'  [XC_XVC]:     Console attached to '/dev/xvc0'.
+ *  'xencons=hvc'  [XC_HVC]:     Console attached to '/dev/hvc0'.
  *  default:                     XC_XVC
  * 
  * NB. In mode XC_TTY, we create dummy consoles for tty2-63. This suppresses
  * warnings from standard distro startup scripts.
  */
 static enum {
-       XC_OFF, XC_TTY, XC_SERIAL, XC_XVC
+       XC_OFF, XC_TTY, XC_SERIAL, XC_XVC, XC_HVC
 } xc_mode = XC_XVC;
 static int xc_num = -1;
 
@@ -80,6 +81,10 @@ static int xc_num = -1;
 #define XEN_XVC_MAJOR 204
 #define XEN_XVC_MINOR 191
 
+/* /dev/hvc0 device number */
+#define XEN_HVC_MAJOR 229
+#define XEN_HVC_MINOR 0
+
 #ifdef CONFIG_MAGIC_SYSRQ
 static unsigned long sysrq_requested;
 extern int sysrq_enabled;
@@ -102,6 +107,9 @@ static int __init xencons_setup(char *str)
        } else if (!strncmp(str, "xvc", 3)) {
                xc_mode = XC_XVC;
                str += 3;
+       } else if (!strncmp(str, "hvc", 3)) {
+               xc_mode = XC_HVC;
+               str += 3;
        } else if (!strncmp(str, "off", 3)) {
                xc_mode = XC_OFF;
                str += 3;
@@ -210,6 +218,14 @@ static int __init xen_console_init(void)
                        xc_num = 0;
                break;
 
+       case XC_HVC:
+               strcpy(kcons_info.name, "hvc");
+               if (xc_num == -1)
+                       xc_num = 0;
+               if (!is_initial_xendomain())
+                       add_preferred_console(kcons_info.name, xc_num, NULL);
+               break;
+
        case XC_SERIAL:
                strcpy(kcons_info.name, "ttyS");
                if (xc_num == -1)
@@ -685,6 +701,12 @@ static int __init xencons_init(void)
                DRV(xencons_driver)->minor_start = XEN_XVC_MINOR;
                DRV(xencons_driver)->name_base   = xc_num;
                break;
+       case XC_HVC:
+               DRV(xencons_driver)->name        = "hvc";
+               DRV(xencons_driver)->major       = XEN_HVC_MAJOR;
+               DRV(xencons_driver)->minor_start = XEN_HVC_MINOR;
+               DRV(xencons_driver)->name_base   = xc_num;
+               break;
        case XC_SERIAL:
                DRV(xencons_driver)->name        = "ttyS";
                DRV(xencons_driver)->minor_start = 64 + xc_num;