hvc_xen: introduce HVC_XEN_FRONTEND

Introduce a new config option HVC_XEN_FRONTEND to enable/disable the
xenbus based pv console frontend.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

2 files changed, 70 insertions, 54 deletions

diff --git a/drivers/tty/hvc/Kconfig b/drivers/tty/hvc/Kconfig
index 4222035acfb7..192e21e2239c 100644
--- a/drivers/tty/hvc/Kconfig
+++ b/drivers/tty/hvc/Kconfig
@@ -76,6 +76,14 @@ config HVC_XEN
         help
           Xen virtual console device driver
 
+config HVC_XEN_FRONTEND
+        bool "Xen Hypervisor Multiple Consoles support"
+        depends on HVC_XEN
+        select XEN_XENBUS_FRONTEND
+        default y
+        help
+          Xen driver for secondary virtual consoles
+
 config HVC_UDBG
        bool "udbg based fake hypervisor console"
        depends on PPC && EXPERIMENTAL
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index 26090c736bcf..83d5c88e7165 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -55,7 +55,6 @@ struct xencons_info {
 
 static LIST_HEAD(xenconsoles);
 static DEFINE_SPINLOCK(xencons_lock);
-static struct xenbus_driver xencons_driver;
 
 /* ------------------------------------------------------------------ */
 
@@ -298,53 +297,6 @@ static int xen_initial_domain_console_init(void)
         return 0;
 }
 
-static int __init xen_hvc_init(void)
-{
-        int r;
-        struct xencons_info *info;
-        const struct hv_ops *ops;
-
-        if (!xen_domain())
-                return -ENODEV;
-
-        if (xen_initial_domain()) {
-                ops = &dom0_hvc_ops;
-                r = xen_initial_domain_console_init();
-                if (r < 0)
-                        return r;
-                info = vtermno_to_xencons(HVC_COOKIE);
-        } else {
-                ops = &domU_hvc_ops;
-                if (xen_hvm_domain())
-                        r = xen_hvm_console_init();
-                else
-                        r = xen_pv_console_init();
-                if (r < 0)
-                        return r;
-
-                info = vtermno_to_xencons(HVC_COOKIE);
-                info->irq = bind_evtchn_to_irq(info->evtchn);
-        }
-        if (info->irq < 0)
-                info->irq = 0; /* NO_IRQ */
-        else
-                irq_set_noprobe(info->irq);
-
-        info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
-        if (IS_ERR(info->hvc)) {
-                r = PTR_ERR(info->hvc);
-                spin_lock(&xencons_lock);
-                list_del(&info->list);
-                spin_unlock(&xencons_lock);
-                if (info->irq)
-                        unbind_from_irqhandler(info->irq, NULL);
-                kfree(info);
-                return r;
-        }
-
-        return xenbus_register_frontend(&xencons_driver);
-}
-
 void xen_console_resume(void)
 {
         struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
@@ -392,6 +344,9 @@ static int xen_console_remove(struct xencons_info *info)
         return 0;
 }
 
+#ifdef CONFIG_HVC_XEN_FRONTEND
+static struct xenbus_driver xencons_driver;
+
 static int xencons_remove(struct xenbus_device *dev)
 {
         return xen_console_remove(dev_get_drvdata(&dev->dev));
@@ -543,6 +498,65 @@ static const struct xenbus_device_id xencons_ids[] = {
 };
 
 
+static DEFINE_XENBUS_DRIVER(xencons, "xenconsole",
+        .probe = xencons_probe,
+        .remove = xencons_remove,
+        .resume = xencons_resume,
+        .otherend_changed = xencons_backend_changed,
+);
+#endif /* CONFIG_HVC_XEN_FRONTEND */
+
+static int __init xen_hvc_init(void)
+{
+        int r;
+        struct xencons_info *info;
+        const struct hv_ops *ops;
+
+        if (!xen_domain())
+                return -ENODEV;
+
+        if (xen_initial_domain()) {
+                ops = &dom0_hvc_ops;
+                r = xen_initial_domain_console_init();
+                if (r < 0)
+                        return r;
+                info = vtermno_to_xencons(HVC_COOKIE);
+        } else {
+                ops = &domU_hvc_ops;
+                if (xen_hvm_domain())
+                        r = xen_hvm_console_init();
+                else
+                        r = xen_pv_console_init();
+                if (r < 0)
+                        return r;
+
+                info = vtermno_to_xencons(HVC_COOKIE);
+                info->irq = bind_evtchn_to_irq(info->evtchn);
+        }
+        if (info->irq < 0)
+                info->irq = 0; /* NO_IRQ */
+        else
+                irq_set_noprobe(info->irq);
+
+        info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
+        if (IS_ERR(info->hvc)) {
+                r = PTR_ERR(info->hvc);
+                spin_lock(&xencons_lock);
+                list_del(&info->list);
+                spin_unlock(&xencons_lock);
+                if (info->irq)
+                        unbind_from_irqhandler(info->irq, NULL);
+                kfree(info);
+                return r;
+        }
+
+        r = 0;
+#ifdef CONFIG_HVC_XEN_FRONTEND
+        r = xenbus_register_frontend(&xencons_driver);
+#endif
+        return r;
+}
+
 static void __exit xen_hvc_fini(void)
 {
         struct xencons_info *entry, *next;
@@ -580,12 +594,6 @@ static int xen_cons_init(void)
         return 0;
 }
 
-static DEFINE_XENBUS_DRIVER(xencons, "xenconsole",
-        .probe = xencons_probe,
-        .remove = xencons_remove,
-        .resume = xencons_resume,
-        .otherend_changed = xencons_backend_changed,
-);
 
 module_init(xen_hvc_init);
 module_exit(xen_hvc_fini);