Add sysfs attributes for binding and unbinding VT console drivers. The
attributes are located in /sys/class/tty/console and are namely:
A. backend - list registered drivers in the following format:
"I C: Description"
Where: I = ID number of the driver
C = status of the driver which can be:
S = system driver
B = bound modular driver
U = unbound modular driver
Description - text description of the driver
B. bind - binds a driver to the console layer
echo <ID> > /sys/class/tty/console/bind
C. unbind - unbinds a driver from the console layer
echo <ID> > /sys/class/tty/console/unbind
The tty layer does nothing to these attributes except create them and punt all
requests to the VT layer.
Signed-off-by: Antonino Daplas <pol.net>
---
drivers/char/tty_io.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++-
include/linux/tty.h | 19 ++++++++++++++++++
2 files changed, 71 insertions(+), 1 deletions(-)
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index a5730a6..e23d360 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -3231,6 +3231,47 @@ #ifdef CONFIG_VT
static struct cdev vc0_cdev;
#endif
+static ssize_t store_bind(struct class_device *class_device,
+ const char *buf, size_t count)
+{
+ int index = simple_strtoul(buf, NULL, 0);
+
+ vt_bind(index);
+ return count;
+}
+
+static ssize_t store_unbind(struct class_device *class_device,
+ const char *buf, size_t count)
+{
+ int index = simple_strtoul(buf, NULL, 0);
+
+ vt_unbind(index);
+ return count;
+}
+
+static ssize_t show_con_drivers(struct class_device *class_device, char *buf)
+{
+ return vt_show_drivers(buf);
+}
+
+static struct class_device_attribute class_device_attrs[] = {
+ __ATTR(bind, S_IWUSR, NULL, store_bind),
+ __ATTR(unbind, S_IWUSR, NULL, store_unbind),
+ __ATTR(backend, S_IRUGO, show_con_drivers, NULL),
+};
+
+static struct class_device *console_class_device;
+
+static int console_init_class_device(void)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(class_device_attrs); i++)
+ class_device_create_file(console_class_device,
+ &class_device_attrs[i]);
+ return 0;
+}
+
/*
* Ok, now we can initialize the rest of the tty devices and can count
* on memory allocations, interrupts etc..
@@ -3249,7 +3290,17 @@ static int __init tty_init(void)
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
panic("Couldn't register /dev/console driver\n");
devfs_mk_cdev(MKDEV(TTYAUX_MAJOR, 1), S_IFCHR|S_IRUSR|S_IWUSR, "console");
- class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL, "console");
+ console_class_device = class_device_create(tty_class, NULL,
+ MKDEV(TTYAUX_MAJOR, 1),
+ NULL, "console");
+ if (IS_ERR(console_class_device)) {
+ printk(KERN_WARNING "Unable to create class device "
+ "for console; errno = %ldn",
+ PTR_ERR(console_class_device));
+ console_class_device = NULL;
+ } else
+ console_init_class_device();
+
#ifdef CONFIG_UNIX98_PTYS
cdev_init(&ptmx_cdev, &ptmx_fops);
diff --git a/include/linux/tty.h b/include/linux/tty.h
index cb35ca5..3edaa5d 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -347,6 +347,25 @@ extern void console_print(const char *);
extern int vt_ioctl(struct tty_struct *tty, struct file * file,
unsigned int cmd, unsigned long arg);
+#ifdef CONFIG_VT
+extern int vt_bind(int index);
+extern int vt_unbind(int index);
+extern int vt_show_drivers(char *buf);
+#else
+static inline int vt_bind(int index)
+{
+ return 0;
+}
+static inline int vt_unbind(int index)
+{
+ return 0;
+}
+static inline int vt_show_drivers(char *buf)
+{
+ return 0;
+}
+#endif
+
static inline dev_t tty_devnum(struct tty_struct *tty)
{
return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
-
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