These changes are the raw update to linux-4.4.6-rt14. Kernel sources

are taken from kernel.org, and rt patch from the rt wiki download page.

During the rebasing, the following patch collided:

Force tick interrupt and get rid of softirq magic(I70131fb85).

Collisions have been removed because its logic was found on the
source already.

Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>

11 files changed, 451 insertions, 46 deletions

diff --git a/kernel/drivers/input/serio/Kconfig b/kernel/drivers/input/serio/Kconfig
index 77833d7a0..c3d05b4d3 100644
--- a/kernel/drivers/input/serio/Kconfig
+++ b/kernel/drivers/input/serio/Kconfig
@@ -244,6 +244,7 @@ config SERIO_PS2MULT
 
 config SERIO_ARC_PS2
 	tristate "ARC PS/2 support"
+	depends on HAS_IOMEM
 	help
 	  Say Y here if you have an ARC FPGA platform with a PS/2
 	  controller in it.
@@ -291,4 +292,18 @@ config SERIO_SUN4I_PS2
 	  To compile this driver as a module, choose M here: the
 	  module will be called sun4i-ps2.
 
+config USERIO
+	tristate "User space serio port driver support"
+	help
+	  Say Y here if you want to support user level drivers for serio
+	  subsystem accessible under char device 10:240 - /dev/userio. Using
+	  this facility userspace programs can implement serio ports that
+	  will be used by the standard in-kernel serio consumer drivers,
+	  such as psmouse and atkbd.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called userio.
+
+	  If you are unsure, say N.
+
 endif
diff --git a/kernel/drivers/input/serio/Makefile b/kernel/drivers/input/serio/Makefile
index c600089b7..2374ef9b3 100644
--- a/kernel/drivers/input/serio/Makefile
+++ b/kernel/drivers/input/serio/Makefile
@@ -30,3 +30,4 @@ obj-$(CONFIG_SERIO_APBPS2)	+= apbps2.o
 obj-$(CONFIG_SERIO_OLPC_APSP)	+= olpc_apsp.o
 obj-$(CONFIG_HYPERV_KEYBOARD)	+= hyperv-keyboard.o
 obj-$(CONFIG_SERIO_SUN4I_PS2)	+= sun4i-ps2.o
+obj-$(CONFIG_USERIO)		+= userio.o
diff --git a/kernel/drivers/input/serio/ambakmi.c b/kernel/drivers/input/serio/ambakmi.c
index 8b748d99b..c6606cacb 100644
--- a/kernel/drivers/input/serio/ambakmi.c
+++ b/kernel/drivers/input/serio/ambakmi.c
@@ -175,9 +175,9 @@ static int amba_kmi_remove(struct amba_device *dev)
 	return 0;
 }
 
-static int amba_kmi_resume(struct amba_device *dev)
+static int __maybe_unused amba_kmi_resume(struct device *dev)
 {
-	struct amba_kmi_port *kmi = amba_get_drvdata(dev);
+	struct amba_kmi_port *kmi = dev_get_drvdata(dev);
 
 	/* kick the serio layer to rescan this port */
 	serio_reconnect(kmi->io);
@@ -185,6 +185,8 @@ static int amba_kmi_resume(struct amba_device *dev)
 	return 0;
 }
 
+static SIMPLE_DEV_PM_OPS(amba_kmi_dev_pm_ops, NULL, amba_kmi_resume);
+
 static struct amba_id amba_kmi_idtable[] = {
 	{
 		.id	= 0x00041050,
@@ -199,11 +201,11 @@ static struct amba_driver ambakmi_driver = {
 	.drv		= {
 		.name	= "kmi-pl050",
 		.owner	= THIS_MODULE,
+		.pm	= &amba_kmi_dev_pm_ops,
 	},
 	.id_table	= amba_kmi_idtable,
 	.probe		= amba_kmi_probe,
 	.remove		= amba_kmi_remove,
-	.resume		= amba_kmi_resume,
 };
 
 module_amba_driver(ambakmi_driver);
diff --git a/kernel/drivers/input/serio/i8042-x86ia64io.h b/kernel/drivers/input/serio/i8042-x86ia64io.h
index c11556563..68f5f4a0f 100644
--- a/kernel/drivers/input/serio/i8042-x86ia64io.h
+++ b/kernel/drivers/input/serio/i8042-x86ia64io.h
@@ -258,6 +258,13 @@ static const struct dmi_system_id __initconst i8042_dmi_nomux_table[] = {
 		},
 	},
 	{
+		/* Fujitsu Lifebook U745 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK U745"),
+		},
+	},
+	{
 		/* Fujitsu T70H */
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
diff --git a/kernel/drivers/input/serio/i8042.c b/kernel/drivers/input/serio/i8042.c
index cb5ece77f..454195709 100644
--- a/kernel/drivers/input/serio/i8042.c
+++ b/kernel/drivers/input/serio/i8042.c
@@ -24,6 +24,7 @@
 #include <linux/platform_device.h>
 #include <linux/i8042.h>
 #include <linux/slab.h>
+#include <linux/suspend.h>
 
 #include <asm/io.h>
 
@@ -88,6 +89,10 @@ MODULE_PARM_DESC(nopnp, "Do not use PNP to detect controller settings");
 static bool i8042_debug;
 module_param_named(debug, i8042_debug, bool, 0600);
 MODULE_PARM_DESC(debug, "Turn i8042 debugging mode on and off");
+
+static bool i8042_unmask_kbd_data;
+module_param_named(unmask_kbd_data, i8042_unmask_kbd_data, bool, 0600);
+MODULE_PARM_DESC(unmask_kbd_data, "Unconditional enable (may reveal sensitive data) of normally sanitize-filtered kbd data traffic debug log [pre-condition: i8042.debug=1 enabled]");
 #endif
 
 static bool i8042_bypass_aux_irq_test;
@@ -116,6 +121,7 @@ struct i8042_port {
 	struct serio *serio;
 	int irq;
 	bool exists;
+	bool driver_bound;
 	signed char mux;
 };
 
@@ -133,6 +139,7 @@ static bool i8042_kbd_irq_registered;
 static bool i8042_aux_irq_registered;
 static unsigned char i8042_suppress_kbd_ack;
 static struct platform_device *i8042_platform_device;
+static struct notifier_block i8042_kbd_bind_notifier_block;
 
 static irqreturn_t i8042_interrupt(int irq, void *dev_id);
 static bool (*i8042_platform_filter)(unsigned char data, unsigned char str,
@@ -528,10 +535,10 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id)
 	port = &i8042_ports[port_no];
 	serio = port->exists ? port->serio : NULL;
 
-	dbg("%02x <- i8042 (interrupt, %d, %d%s%s)\n",
-	    data, port_no, irq,
-	    dfl & SERIO_PARITY ? ", bad parity" : "",
-	    dfl & SERIO_TIMEOUT ? ", timeout" : "");
+	filter_dbg(port->driver_bound, data, "<- i8042 (interrupt, %d, %d%s%s)\n",
+		   port_no, irq,
+		   dfl & SERIO_PARITY ? ", bad parity" : "",
+		   dfl & SERIO_TIMEOUT ? ", timeout" : "");
 
 	filtered = i8042_filter(data, str, serio);
 
@@ -871,7 +878,7 @@ static int __init i8042_check_aux(void)
 static int i8042_controller_check(void)
 {
 	if (i8042_flush()) {
-		pr_err("No controller found\n");
+		pr_info("No controller found\n");
 		return -ENODEV;
 	}
 
@@ -1164,7 +1171,8 @@ static int i8042_pm_suspend(struct device *dev)
 {
 	int i;
 
-	i8042_controller_reset(true);
+	if (pm_suspend_via_firmware())
+		i8042_controller_reset(true);
 
 	/* Set up serio interrupts for system wakeup. */
 	for (i = 0; i < I8042_NUM_PORTS; i++) {
@@ -1177,8 +1185,17 @@ static int i8042_pm_suspend(struct device *dev)
 	return 0;
 }
 
+static int i8042_pm_resume_noirq(struct device *dev)
+{
+	if (!pm_resume_via_firmware())
+		i8042_interrupt(0, NULL);
+
+	return 0;
+}
+
 static int i8042_pm_resume(struct device *dev)
 {
+	bool force_reset;
 	int i;
 
 	for (i = 0; i < I8042_NUM_PORTS; i++) {
@@ -1189,11 +1206,21 @@ static int i8042_pm_resume(struct device *dev)
 	}
 
 	/*
-	 * On resume from S2R we always try to reset the controller
-	 * to bring it in a sane state. (In case of S2D we expect
-	 * BIOS to reset the controller for us.)
+	 * If platform firmware was not going to be involved in suspend, we did
+	 * not restore the controller state to whatever it had been at boot
+	 * time, so we do not need to do anything.
 	 */
-	return i8042_controller_resume(true);
+	if (!pm_suspend_via_firmware())
+		return 0;
+
+	/*
+	 * We only need to reset the controller if we are resuming after handing
+	 * off control to the platform firmware, otherwise we can simply restore
+	 * the mode.
+	 */
+	force_reset = pm_resume_via_firmware();
+
+	return i8042_controller_resume(force_reset);
 }
 
 static int i8042_pm_thaw(struct device *dev)
@@ -1217,6 +1244,7 @@ static int i8042_pm_restore(struct device *dev)
 
 static const struct dev_pm_ops i8042_pm_ops = {
 	.suspend	= i8042_pm_suspend,
+	.resume_noirq	= i8042_pm_resume_noirq,
 	.resume		= i8042_pm_resume,
 	.thaw		= i8042_pm_thaw,
 	.poweroff	= i8042_pm_reset,
@@ -1438,6 +1466,29 @@ static int __init i8042_setup_kbd(void)
 	return error;
 }
 
+static int i8042_kbd_bind_notifier(struct notifier_block *nb,
+				   unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct serio *serio = to_serio_port(dev);
+	struct i8042_port *port = serio->port_data;
+
+	if (serio != i8042_ports[I8042_KBD_PORT_NO].serio)
+		return 0;
+
+	switch (action) {
+	case BUS_NOTIFY_BOUND_DRIVER:
+		port->driver_bound = true;
+		break;
+
+	case BUS_NOTIFY_UNBIND_DRIVER:
+		port->driver_bound = false;
+		break;
+	}
+
+	return 0;
+}
+
 static int __init i8042_probe(struct platform_device *dev)
 {
 	int error;
@@ -1507,6 +1558,10 @@ static struct platform_driver i8042_driver = {
 	.shutdown	= i8042_shutdown,
 };
 
+static struct notifier_block i8042_kbd_bind_notifier_block = {
+	.notifier_call = i8042_kbd_bind_notifier,
+};
+
 static int __init i8042_init(void)
 {
 	struct platform_device *pdev;
@@ -1528,6 +1583,7 @@ static int __init i8042_init(void)
 		goto err_platform_exit;
 	}
 
+	bus_register_notifier(&serio_bus, &i8042_kbd_bind_notifier_block);
 	panic_blink = i8042_panic_blink;
 
 	return 0;
@@ -1543,6 +1599,7 @@ static void __exit i8042_exit(void)
 	platform_driver_unregister(&i8042_driver);
 	i8042_platform_exit();
 
+	bus_unregister_notifier(&serio_bus, &i8042_kbd_bind_notifier_block);
 	panic_blink = NULL;
 }
 
diff --git a/kernel/drivers/input/serio/i8042.h b/kernel/drivers/input/serio/i8042.h
index fc080beff..1db0a40c9 100644
--- a/kernel/drivers/input/serio/i8042.h
+++ b/kernel/drivers/input/serio/i8042.h
@@ -73,6 +73,17 @@ static unsigned long i8042_start_time;
 			printk(KERN_DEBUG KBUILD_MODNAME ": [%d] " format,	\
 			       (int) (jiffies - i8042_start_time), ##arg);	\
 	} while (0)
+
+#define filter_dbg(filter, data, format, args...)		\
+	do {							\
+		if (!i8042_debug)				\
+			break;					\
+								\
+		if (!filter || i8042_unmask_kbd_data)		\
+			dbg("%02x " format, data, ##args);	\
+		else						\
+			dbg("** " format, ##args);		\
+	} while (0)
 #else
 #define dbg_init() do { } while (0)
 #define dbg(format, arg...)							\
@@ -80,6 +91,8 @@ static unsigned long i8042_start_time;
 		if (0)								\
 			printk(KERN_DEBUG pr_fmt(format), ##arg);		\
 	} while (0)
+
+#define filter_dbg(filter, data, format, args...) do { } while (0)
 #endif
 
 #endif /* _I8042_H */
diff --git a/kernel/drivers/input/serio/libps2.c b/kernel/drivers/input/serio/libps2.c
index 75516996d..316f2c897 100644
--- a/kernel/drivers/input/serio/libps2.c
+++ b/kernel/drivers/input/serio/libps2.c
@@ -212,12 +212,17 @@ int __ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 	 * time before the ACK arrives.
 	 */
 	if (ps2_sendbyte(ps2dev, command & 0xff,
-			 command == PS2_CMD_RESET_BAT ? 1000 : 200))
-		goto out;
+			 command == PS2_CMD_RESET_BAT ? 1000 : 200)) {
+		serio_pause_rx(ps2dev->serio);
+		goto out_reset_flags;
+	}
 
-	for (i = 0; i < send; i++)
-		if (ps2_sendbyte(ps2dev, param[i], 200))
-			goto out;
+	for (i = 0; i < send; i++) {
+		if (ps2_sendbyte(ps2dev, param[i], 200)) {
+			serio_pause_rx(ps2dev->serio);
+			goto out_reset_flags;
+		}
+	}
 
 	/*
 	 * The reset command takes a long time to execute.
@@ -234,17 +239,18 @@ int __ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 				   !(ps2dev->flags & PS2_FLAG_CMD), timeout);
 	}
 
+	serio_pause_rx(ps2dev->serio);
+
 	if (param)
 		for (i = 0; i < receive; i++)
 			param[i] = ps2dev->cmdbuf[(receive - 1) - i];
 
 	if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
-		goto out;
+		goto out_reset_flags;
 
 	rc = 0;
 
- out:
-	serio_pause_rx(ps2dev->serio);
+ out_reset_flags:
 	ps2dev->flags = 0;
 	serio_continue_rx(ps2dev->serio);
 
diff --git a/kernel/drivers/input/serio/parkbd.c b/kernel/drivers/input/serio/parkbd.c
index 26b45936f..1edfac78d 100644
--- a/kernel/drivers/input/serio/parkbd.c
+++ b/kernel/drivers/input/serio/parkbd.c
@@ -141,19 +141,16 @@ static void parkbd_interrupt(void *dev_id)
 	parkbd_last = jiffies;
 }
 
-static int parkbd_getport(void)
+static int parkbd_getport(struct parport *pp)
 {
-	struct parport *pp;
+	struct pardev_cb parkbd_parport_cb;
 
-	pp = parport_find_number(parkbd_pp_no);
+	memset(&parkbd_parport_cb, 0, sizeof(parkbd_parport_cb));
+	parkbd_parport_cb.irq_func = parkbd_interrupt;
+	parkbd_parport_cb.flags = PARPORT_FLAG_EXCL;
 
-	if (pp == NULL) {
-		printk(KERN_ERR "parkbd: no such parport\n");
-		return -ENODEV;
-	}
-
-	parkbd_dev = parport_register_device(pp, "parkbd", NULL, NULL, parkbd_interrupt, PARPORT_DEV_EXCL, NULL);
-	parport_put_port(pp);
+	parkbd_dev = parport_register_dev_model(pp, "parkbd",
+						&parkbd_parport_cb, 0);
 
 	if (!parkbd_dev)
 		return -ENODEV;
@@ -168,7 +165,7 @@ static int parkbd_getport(void)
 	return 0;
 }
 
-static struct serio * __init parkbd_allocate_serio(void)
+static struct serio *parkbd_allocate_serio(void)
 {
 	struct serio *serio;
 
@@ -183,18 +180,21 @@ static struct serio * __init parkbd_allocate_serio(void)
 	return serio;
 }
 
-static int __init parkbd_init(void)
+static void parkbd_attach(struct parport *pp)
 {
-	int err;
+	if (pp->number != parkbd_pp_no) {
+		pr_debug("Not using parport%d.\n", pp->number);
+		return;
+	}
 
-	err = parkbd_getport();
-	if (err)
-		return err;
+	if (parkbd_getport(pp))
+		return;
 
 	parkbd_port = parkbd_allocate_serio();
 	if (!parkbd_port) {
 		parport_release(parkbd_dev);
-		return -ENOMEM;
+		parport_unregister_device(parkbd_dev);
+		return;
 	}
 
 	parkbd_writelines(3);
@@ -204,14 +204,35 @@ static int __init parkbd_init(void)
 	printk(KERN_INFO "serio: PARKBD %s adapter on %s\n",
                         parkbd_mode ? "AT" : "XT", parkbd_dev->port->name);
 
-	return 0;
+	return;
 }
 
-static void __exit parkbd_exit(void)
+static void parkbd_detach(struct parport *port)
 {
+	if (!parkbd_port || port->number != parkbd_pp_no)
+		return;
+
 	parport_release(parkbd_dev);
 	serio_unregister_port(parkbd_port);
 	parport_unregister_device(parkbd_dev);
+	parkbd_port = NULL;
+}
+
+static struct parport_driver parkbd_parport_driver = {
+	.name = "parkbd",
+	.match_port = parkbd_attach,
+	.detach = parkbd_detach,
+	.devmodel = true,
+};
+
+static int __init parkbd_init(void)
+{
+	return parport_register_driver(&parkbd_parport_driver);
+}
+
+static void __exit parkbd_exit(void)
+{
+	parport_unregister_driver(&parkbd_parport_driver);
 }
 
 module_init(parkbd_init);
diff --git a/kernel/drivers/input/serio/serio.c b/kernel/drivers/input/serio/serio.c
index a05a5179d..8f828975a 100644
--- a/kernel/drivers/input/serio/serio.c
+++ b/kernel/drivers/input/serio/serio.c
@@ -49,8 +49,6 @@ static DEFINE_MUTEX(serio_mutex);
 
 static LIST_HEAD(serio_list);
 
-static struct bus_type serio_bus;
-
 static void serio_add_port(struct serio *serio);
 static int serio_reconnect_port(struct serio *serio);
 static void serio_disconnect_port(struct serio *serio);
@@ -1017,7 +1015,7 @@ irqreturn_t serio_interrupt(struct serio *serio,
 }
 EXPORT_SYMBOL(serio_interrupt);
 
-static struct bus_type serio_bus = {
+struct bus_type serio_bus = {
 	.name		= "serio",
 	.drv_groups	= serio_driver_groups,
 	.match		= serio_bus_match,
@@ -1029,6 +1027,7 @@ static struct bus_type serio_bus = {
 	.pm		= &serio_pm_ops,
 #endif
 };
+EXPORT_SYMBOL(serio_bus);
 
 static int __init serio_init(void)
 {
diff --git a/kernel/drivers/input/serio/serport.c b/kernel/drivers/input/serio/serport.c
index 69175b825..9c927d35c 100644
--- a/kernel/drivers/input/serio/serport.c
+++ b/kernel/drivers/input/serio/serport.c
@@ -167,7 +167,6 @@ static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file, u
 {
 	struct serport *serport = (struct serport*) tty->disc_data;
 	struct serio *serio;
-	char name[64];
 
 	if (test_and_set_bit(SERPORT_BUSY, &serport->flags))
 		return -EBUSY;
@@ -177,7 +176,7 @@ static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file, u
 		return -ENOMEM;
 
 	strlcpy(serio->name, "Serial port", sizeof(serio->name));
-	snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty, name));
+	snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty));
 	serio->id = serport->id;
 	serio->id.type = SERIO_RS232;
 	serio->write = serport_serio_write;
@@ -187,7 +186,7 @@ static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file, u
 	serio->dev.parent = tty->dev;
 
 	serio_register_port(serport->serio);
-	printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty, name));
+	printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty));
 
 	wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags));
 	serio_unregister_port(serport->serio);
diff --git a/kernel/drivers/input/serio/userio.c b/kernel/drivers/input/serio/userio.c
new file mode 100644
index 000000000..df1fd4186
--- /dev/null
+++ b/kernel/drivers/input/serio/userio.c
@@ -0,0 +1,285 @@
+/*
+ * userio kernel serio device emulation module
+ * Copyright (C) 2015 Red Hat
+ * Copyright (C) 2015 Stephen Chandler Paul <thatslyude@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+ * General Public License for more details.
+ */
+
+#include <linux/circ_buf.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/serio.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/sched.h>
+#include <linux/poll.h>
+#include <uapi/linux/userio.h>
+
+#define USERIO_NAME		"userio"
+#define USERIO_BUFSIZE		16
+
+static struct miscdevice userio_misc;
+
+struct userio_device {
+	struct serio *serio;
+	struct mutex mutex;
+
+	bool running;
+
+	u8 head;
+	u8 tail;
+
+	spinlock_t buf_lock;
+	unsigned char buf[USERIO_BUFSIZE];
+
+	wait_queue_head_t waitq;
+};
+
+/**
+ * userio_device_write - Write data from serio to a userio device in userspace
+ * @id: The serio port for the userio device
+ * @val: The data to write to the device
+ */
+static int userio_device_write(struct serio *id, unsigned char val)
+{
+	struct userio_device *userio = id->port_data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&userio->buf_lock, flags);
+
+	userio->buf[userio->head] = val;
+	userio->head = (userio->head + 1) % USERIO_BUFSIZE;
+
+	if (userio->head == userio->tail)
+		dev_warn(userio_misc.this_device,
+			 "Buffer overflowed, userio client isn't keeping up");
+
+	spin_unlock_irqrestore(&userio->buf_lock, flags);
+
+	wake_up_interruptible(&userio->waitq);
+
+	return 0;
+}
+
+static int userio_char_open(struct inode *inode, struct file *file)
+{
+	struct userio_device *userio;
+
+	userio = kzalloc(sizeof(struct userio_device), GFP_KERNEL);
+	if (!userio)
+		return -ENOMEM;
+
+	mutex_init(&userio->mutex);
+	spin_lock_init(&userio->buf_lock);
+	init_waitqueue_head(&userio->waitq);
+
+	userio->serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
+	if (!userio->serio) {
+		kfree(userio);
+		return -ENOMEM;
+	}
+
+	userio->serio->write = userio_device_write;
+	userio->serio->port_data = userio;
+
+	file->private_data = userio;
+
+	return 0;
+}
+
+static int userio_char_release(struct inode *inode, struct file *file)
+{
+	struct userio_device *userio = file->private_data;
+
+	if (userio->running) {
+		/*
+		 * Don't free the serio port here, serio_unregister_port()
+		 * does it for us.
+		 */
+		serio_unregister_port(userio->serio);
+	} else {
+		kfree(userio->serio);
+	}
+
+	kfree(userio);
+
+	return 0;
+}
+
+static ssize_t userio_char_read(struct file *file, char __user *user_buffer,
+				size_t count, loff_t *ppos)
+{
+	struct userio_device *userio = file->private_data;
+	int error;
+	size_t nonwrap_len, copylen;
+	unsigned char buf[USERIO_BUFSIZE];
+	unsigned long flags;
+
+	/*
+	 * By the time we get here, the data that was waiting might have
+	 * been taken by another thread. Grab the buffer lock and check if
+	 * there's still any data waiting, otherwise repeat this process
+	 * until we have data (unless the file descriptor is non-blocking
+	 * of course).
+	 */
+	for (;;) {
+		spin_lock_irqsave(&userio->buf_lock, flags);
+
+		nonwrap_len = CIRC_CNT_TO_END(userio->head,
+					      userio->tail,
+					      USERIO_BUFSIZE);
+		copylen = min(nonwrap_len, count);
+		if (copylen) {
+			memcpy(buf, &userio->buf[userio->tail], copylen);
+			userio->tail = (userio->tail + copylen) %
+							USERIO_BUFSIZE;
+		}
+
+		spin_unlock_irqrestore(&userio->buf_lock, flags);
+
+		if (nonwrap_len)
+			break;
+
+		/* buffer was/is empty */
+		if (file->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+
+		/*
+		 * count == 0 is special - no IO is done but we check
+		 * for error conditions (see above).
+		 */
+		if (count == 0)
+			return 0;
+
+		error = wait_event_interruptible(userio->waitq,
+						 userio->head != userio->tail);
+		if (error)
+			return error;
+	}
+
+	if (copylen)
+		if (copy_to_user(user_buffer, buf, copylen))
+			return -EFAULT;
+
+	return copylen;
+}
+
+static ssize_t userio_char_write(struct file *file, const char __user *buffer,
+				 size_t count, loff_t *ppos)
+{
+	struct userio_device *userio = file->private_data;
+	struct userio_cmd cmd;
+	int error;
+
+	if (count != sizeof(cmd)) {
+		dev_warn(userio_misc.this_device, "Invalid payload size\n");
+		return -EINVAL;
+	}
+
+	if (copy_from_user(&cmd, buffer, sizeof(cmd)))
+		return -EFAULT;
+
+	error = mutex_lock_interruptible(&userio->mutex);
+	if (error)
+		return error;
+
+	switch (cmd.type) {
+	case USERIO_CMD_REGISTER:
+		if (!userio->serio->id.type) {
+			dev_warn(userio_misc.this_device,
+				 "No port type given on /dev/userio\n");
+
+			error = -EINVAL;
+			goto out;
+		}
+
+		if (userio->running) {
+			dev_warn(userio_misc.this_device,
+				 "Begin command sent, but we're already running\n");
+			error = -EBUSY;
+			goto out;
+		}
+
+		userio->running = true;
+		serio_register_port(userio->serio);
+		break;
+
+	case USERIO_CMD_SET_PORT_TYPE:
+		if (userio->running) {
+			dev_warn(userio_misc.this_device,
+				 "Can't change port type on an already running userio instance\n");
+			error = -EBUSY;
+			goto out;
+		}
+
+		userio->serio->id.type = cmd.data;
+		break;
+
+	case USERIO_CMD_SEND_INTERRUPT:
+		if (!userio->running) {
+			dev_warn(userio_misc.this_device,
+				 "The device must be registered before sending interrupts\n");
+			error = -ENODEV;
+			goto out;
+		}
+
+		serio_interrupt(userio->serio, cmd.data, 0);
+		break;
+
+	default:
+		error = -EOPNOTSUPP;
+		goto out;
+	}
+
+out:
+	mutex_unlock(&userio->mutex);
+	return error ?: count;
+}
+
+static unsigned int userio_char_poll(struct file *file, poll_table *wait)
+{
+	struct userio_device *userio = file->private_data;
+
+	poll_wait(file, &userio->waitq, wait);
+
+	if (userio->head != userio->tail)
+		return POLLIN | POLLRDNORM;
+
+	return 0;
+}
+
+static const struct file_operations userio_fops = {
+	.owner		= THIS_MODULE,
+	.open		= userio_char_open,
+	.release	= userio_char_release,
+	.read		= userio_char_read,
+	.write		= userio_char_write,
+	.poll		= userio_char_poll,
+	.llseek		= no_llseek,
+};
+
+static struct miscdevice userio_misc = {
+	.fops	= &userio_fops,
+	.minor	= USERIO_MINOR,
+	.name	= USERIO_NAME,
+};
+module_driver(userio_misc, misc_register, misc_deregister);
+
+MODULE_ALIAS_MISCDEV(USERIO_MINOR);
+MODULE_ALIAS("devname:" USERIO_NAME);
+
+MODULE_AUTHOR("Stephen Chandler Paul <thatslyude@gmail.com>");
+MODULE_DESCRIPTION("Virtual Serio Device Support");
+MODULE_LICENSE("GPL");