[PATCH] Generic ioctl.h

Most arches copied the i386 ioctl.h.  Combine them into a generic header.

Signed-off-by: Brian Gerst <bgerst@didntduck.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 80 insertions, 0 deletions

diff --git a/include/asm-generic/ioctl.h b/include/asm-generic/ioctl.h
new file mode 100644
index 000000000000..cd027298beb1
--- /dev/null
+++ b/include/asm-generic/ioctl.h
@@ -0,0 +1,80 @@
+#ifndef _ASM_GENERIC_IOCTL_H
+#define _ASM_GENERIC_IOCTL_H
+
+/* ioctl command encoding: 32 bits total, command in lower 16 bits,
+ * size of the parameter structure in the lower 14 bits of the
+ * upper 16 bits.
+ * Encoding the size of the parameter structure in the ioctl request
+ * is useful for catching programs compiled with old versions
+ * and to avoid overwriting user space outside the user buffer area.
+ * The highest 2 bits are reserved for indicating the ``access mode''.
+ * NOTE: This limits the max parameter size to 16kB -1 !
+ */
+
+/*
+ * The following is for compatibility across the various Linux
+ * platforms.  The generic ioctl numbering scheme doesn't really enforce
+ * a type field.  De facto, however, the top 8 bits of the lower 16
+ * bits are indeed used as a type field, so we might just as well make
+ * this explicit here.  Please be sure to use the decoding macros
+ * below from now on.
+ */
+#define _IOC_NRBITS     8
+#define _IOC_TYPEBITS   8
+#define _IOC_SIZEBITS   14
+#define _IOC_DIRBITS    2
+
+#define _IOC_NRMASK     ((1 << _IOC_NRBITS)-1)
+#define _IOC_TYPEMASK   ((1 << _IOC_TYPEBITS)-1)
+#define _IOC_SIZEMASK   ((1 << _IOC_SIZEBITS)-1)
+#define _IOC_DIRMASK    ((1 << _IOC_DIRBITS)-1)
+
+#define _IOC_NRSHIFT    0
+#define _IOC_TYPESHIFT  (_IOC_NRSHIFT+_IOC_NRBITS)
+#define _IOC_SIZESHIFT  (_IOC_TYPESHIFT+_IOC_TYPEBITS)
+#define _IOC_DIRSHIFT   (_IOC_SIZESHIFT+_IOC_SIZEBITS)
+
+/*
+ * Direction bits.
+ */
+#define _IOC_NONE       0U
+#define _IOC_WRITE      1U
+#define _IOC_READ       2U
+
+#define _IOC(dir,type,nr,size) \
+        (((dir)  << _IOC_DIRSHIFT) | \
+         ((type) << _IOC_TYPESHIFT) | \
+         ((nr)   << _IOC_NRSHIFT) | \
+         ((size) << _IOC_SIZESHIFT))
+
+/* provoke compile error for invalid uses of size argument */
+extern unsigned int __invalid_size_argument_for_IOC;
+#define _IOC_TYPECHECK(t) \
+        ((sizeof(t) == sizeof(t[1]) && \
+          sizeof(t) < (1 << _IOC_SIZEBITS)) ? \
+          sizeof(t) : __invalid_size_argument_for_IOC)
+
+/* used to create numbers */
+#define _IO(type,nr)            _IOC(_IOC_NONE,(type),(nr),0)
+#define _IOR(type,nr,size)      _IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size)))
+#define _IOW(type,nr,size)      _IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
+#define _IOWR(type,nr,size)     _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
+#define _IOR_BAD(type,nr,size)  _IOC(_IOC_READ,(type),(nr),sizeof(size))
+#define _IOW_BAD(type,nr,size)  _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
+#define _IOWR_BAD(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
+
+/* used to decode ioctl numbers.. */
+#define _IOC_DIR(nr)            (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
+#define _IOC_TYPE(nr)           (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
+#define _IOC_NR(nr)             (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
+#define _IOC_SIZE(nr)           (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
+
+/* ...and for the drivers/sound files... */
+
+#define IOC_IN          (_IOC_WRITE << _IOC_DIRSHIFT)
+#define IOC_OUT         (_IOC_READ << _IOC_DIRSHIFT)
+#define IOC_INOUT       ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
+#define IOCSIZE_MASK    (_IOC_SIZEMASK << _IOC_SIZESHIFT)
+#define IOCSIZE_SHIFT   (_IOC_SIZESHIFT)
+
+#endif /* _ASM_GENERIC_IOCTL_H */