UIO: Add the User IO core code

This interface allows the ability to write the majority of a driver in
userspace with only a very small shell of a driver in the kernel itself.
It uses a char device and sysfs to interact with a userspace process to
process interrupts and control memory accesses.

See the docbook documentation for more details on how to use this
interface.

From: Hans J. Koch <hjk@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benedikt Spranger <b.spranger@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/Kconfig

@@ -84,4 +84,5 @@ source "drivers/auxdisplay/Kconfig"
 
 source "drivers/kvm/Kconfig"
 
+source "drivers/uio/Kconfig"
 endmenu

drivers/Makefile

@@ -40,6 +40,7 @@ obj-$(CONFIG_ATA)		+= ata/
 obj-$(CONFIG_FUSION)		+= message/
 obj-$(CONFIG_FIREWIRE)		+= firewire/
 obj-$(CONFIG_IEEE1394)		+= ieee1394/
+obj-$(CONFIG_UIO)		+= uio/
 obj-y				+= cdrom/
 obj-y				+= auxdisplay/
 obj-$(CONFIG_MTD)		+= mtd/

drivers/uio/Kconfig

@@ -0,0 +1,16 @@
+menu "Userspace I/O"
+	depends on !S390
+
+config UIO
+	tristate "Userspace I/O drivers"
+	default n
+	help
+	  Enable this to allow the userspace driver core code to be
+	  built.  This code allows userspace programs easy access to
+	  kernel interrupts and memory locations, allowing some drivers
+	  to be written in userspace.  Note that a small kernel driver
+	  is also required for interrupt handling to work properly.
+
+	  If you don't know what to do here, say N.
+
+endmenu

drivers/uio/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_UIO) += uio.o

include/linux/uio_driver.h

@@ -0,0 +1,91 @@
+/*
+ * include/linux/uio_driver.h
+ *
+ * Copyright(C) 2005, Benedikt Spranger <b.spranger@linutronix.de>
+ * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
+ * Copyright(C) 2006, Hans J. Koch <hjk@linutronix.de>
+ * Copyright(C) 2006, Greg Kroah-Hartman <greg@kroah.com>
+ *
+ * Userspace IO driver.
+ *
+ * Licensed under the GPLv2 only.
+ */
+
+#ifndef _UIO_DRIVER_H_
+#define _UIO_DRIVER_H_
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+
+/**
+ * struct uio_mem - description of a UIO memory region
+ * @kobj:		kobject for this mapping
+ * @addr:		address of the device's memory
+ * @size:		size of IO
+ * @memtype:		type of memory addr points to
+ * @internal_addr:	ioremap-ped version of addr, for driver internal use
+ */
+struct uio_mem {
+	struct kobject		kobj;
+	unsigned long		addr;
+	unsigned long		size;
+	int			memtype;
+	void __iomem		*internal_addr;
+};
+
+#define MAX_UIO_MAPS 	5
+
+struct uio_device;
+
+/**
+ * struct uio_info - UIO device capabilities
+ * @uio_dev:		the UIO device this info belongs to
+ * @name:		device name
+ * @version:		device driver version
+ * @mem:		list of mappable memory regions, size==0 for end of list
+ * @irq:		interrupt number or UIO_IRQ_CUSTOM
+ * @irq_flags:		flags for request_irq()
+ * @priv:		optional private data
+ * @handler:		the device's irq handler
+ * @mmap:		mmap operation for this uio device
+ * @open:		open operation for this uio device
+ * @release:		release operation for this uio device
+ */
+struct uio_info {
+	struct uio_device	*uio_dev;
+	char			*name;
+	char			*version;
+	struct uio_mem		mem[MAX_UIO_MAPS];
+	long			irq;
+	unsigned long		irq_flags;
+	void			*priv;
+	irqreturn_t (*handler)(int irq, struct uio_info *dev_info);
+	int (*mmap)(struct uio_info *info, struct vm_area_struct *vma);
+	int (*open)(struct uio_info *info, struct inode *inode);
+	int (*release)(struct uio_info *info, struct inode *inode);
+};
+
+extern int __must_check
+	__uio_register_device(struct module *owner,
+			      struct device *parent,
+			      struct uio_info *info);
+static inline int __must_check
+	uio_register_device(struct device *parent, struct uio_info *info)
+{
+	return __uio_register_device(THIS_MODULE, parent, info);
+}
+extern void uio_unregister_device(struct uio_info *info);
+extern void uio_event_notify(struct uio_info *info);
+
+/* defines for uio_device->irq */
+#define UIO_IRQ_CUSTOM	-1
+#define UIO_IRQ_NONE	-2
+
+/* defines for uio_device->memtype */
+#define UIO_MEM_NONE	0
+#define UIO_MEM_PHYS	1
+#define UIO_MEM_LOGICAL	2
+#define UIO_MEM_VIRTUAL 3
+
+#endif /* _LINUX_UIO_DRIVER_H_ */