Commit graph

3 commits

Author SHA1 Message Date
Andrew Morton
a87e553fab asm-generic: delay.h fix udelay and ndelay for 8 bit args
With a non-constant 8-bit argument, a call to udelay() generates a warning:

drivers/gpu/drm/radeon/atom.c: In function 'atom_op_delay':
drivers/gpu/drm/radeon/atom.c:654: warning: comparison is always false due to limited range of data type

The code looks like it works OK with an 8-bit arg, and the calling code is
doing nothing wrong, so udelay() needs fixing.

Fixing it was rather tricky.  Simply typecasting `n' in the comparison with
20000 didn't change anything.  Hence the divide-by-20000 trick.

Using a do{}while loop didn't work because udelay() is used in ?: statements,
hence the ({...}) construct.

While I was there I replaced the brain-bending ?:?:?: mess with nice if/else
code.

Probably other architectures are generating the same warning and can use a
similar change.

[Taken from the x86 tree and moved to asm-generic by Jonas Bonn]

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jonas Bonn <jonas@southpole.se>
2011-07-22 18:45:33 +02:00
Jonas Bonn
30ab2b034f asm-generic: adapt delay.h to common implementation
Several architectures are using a common delay.h implementation that
appears to have originated with the x86 architecture.  This common
implementation is a bit fuller than the current asm-generic version
and has some compile-time checks that should be interesting for all
architectures.

This patch takes the common delay.h version and replaces the rather
trivial asm-generic version with it.  As no architecture was actually
using asm-generic/delay.h, this change is rather innocuous; it will,
however, allow us to switch at least four architectures over to using
the asm-generic version.

Signed-off-by: Jonas Bonn <jonas@southpole.se>
Acked-by: Arnd Bergmann <arnd@arndb.de>
2011-07-07 20:11:39 +02:00
Arnd Bergmann
aafe4dbed0 asm-generic: add generic versions of common headers
These are all kernel internal interfaces that get copied
around a lot. In most cases, architectures can provide
their own optimized versions, but these generic versions
can work as well.

I have tried to use the most common contents of each
header to allow existing architectures to migrate easily.

Thanks to Remis for suggesting a number of cleanups.

Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2009-06-11 21:02:37 +02:00