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>

1 files changed, 91 insertions, 0 deletions

diff --git a/include/linux/uio_driver.h b/include/linux/uio_driver.h
new file mode 100644
index 000000000000..44c28e94df50
--- /dev/null
+++ b/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_ */