X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fchar%2Fhvc_console.c;h=8252f86685385f341aa6f34797d52581264ed543;hb=ce8c628abadaf16a44953301c68b9f54cf6898cc;hp=322bc5f7d86b791dd8350642c1b390fe6b54784c;hpb=6ec129c3a2f8b38bc37e42348470ccfcb7460146;p=linux-2.6-omap-h63xx.git

diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
index 322bc5f7d86..8252f866853 100644
--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -69,6 +69,8 @@ static struct task_struct *hvc_task;
 /* Picks up late kicks after list walk but before schedule() */
 static int hvc_kicked;
 
+static int hvc_init(void);
+
 #ifdef CONFIG_MAGIC_SYSRQ
 static int sysrq_pressed;
 #endif
@@ -674,11 +676,12 @@ static const cpumask_t cpus_in_xmon = CPU_MASK_NONE;
  * calling hvc_poll() who determines whether a console adapter support
  * interrupts.
  */
-int khvcd(void *unused)
+static int khvcd(void *unused)
 {
 	int poll_mask;
 	struct hvc_struct *hp;
 
+	set_freezable();
 	__set_current_state(TASK_RUNNING);
 	do {
 		poll_mask = 0;
@@ -753,6 +756,13 @@ struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq,
 	struct hvc_struct *hp;
 	int i;
 
+	/* We wait until a driver actually comes along */
+	if (!hvc_driver) {
+		int err = hvc_init();
+		if (err)
+			return ERR_PTR(err);
+	}
+
 	hp = kmalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
 			GFP_KERNEL);
 	if (!hp)
@@ -828,16 +838,18 @@ int __devexit hvc_remove(struct hvc_struct *hp)
 	return 0;
 }
 
-/* Driver initialization.  Follow console initialization.  This is where the TTY
- * interfaces start to become available. */
-static int __init hvc_init(void)
+/* Driver initialization: called as soon as someone uses hvc_alloc(). */
+static int hvc_init(void)
 {
 	struct tty_driver *drv;
+	int err;
 
 	/* We need more than hvc_count adapters due to hotplug additions. */
 	drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
-	if (!drv)
-		return -ENOMEM;
+	if (!drv) {
+		err = -ENOMEM;
+		goto out;
+	}
 
 	drv->owner = THIS_MODULE;
 	drv->driver_name = "hvc";
@@ -853,30 +865,43 @@ static int __init hvc_init(void)
 	 * added later. */
 	hvc_task = kthread_run(khvcd, NULL, "khvcd");
 	if (IS_ERR(hvc_task)) {
-		panic("Couldn't create kthread for console.\n");
-		put_tty_driver(drv);
-		return -EIO;
+		printk(KERN_ERR "Couldn't create kthread for console.\n");
+		err = PTR_ERR(hvc_task);
+		goto put_tty;
 	}
 
-	if (tty_register_driver(drv))
-		panic("Couldn't register hvc console driver\n");
+	err = tty_register_driver(drv);
+	if (err) {
+		printk(KERN_ERR "Couldn't register hvc console driver\n");
+		goto stop_thread;
+	}
 
+	/* FIXME: This mb() seems completely random.  Remove it. */
 	mb();
 	hvc_driver = drv;
 	return 0;
+
+put_tty:
+	put_tty_driver(hvc_driver);
+stop_thread:
+	kthread_stop(hvc_task);
+	hvc_task = NULL;
+out:
+	return err;
 }
-module_init(hvc_init);
 
 /* This isn't particularly necessary due to this being a console driver
  * but it is nice to be thorough.
  */
 static void __exit hvc_exit(void)
 {
-	kthread_stop(hvc_task);
+	if (hvc_driver) {
+		kthread_stop(hvc_task);
 
-	tty_unregister_driver(hvc_driver);
-	/* return tty_struct instances allocated in hvc_init(). */
-	put_tty_driver(hvc_driver);
-	unregister_console(&hvc_con_driver);
+		tty_unregister_driver(hvc_driver);
+		/* return tty_struct instances allocated in hvc_init(). */
+		put_tty_driver(hvc_driver);
+		unregister_console(&hvc_con_driver);
+	}
 }
 module_exit(hvc_exit);