kevin/linux
1
Fork 0
Code
f21760b15d
linux/include/asm-generic/delay.h

45 lines
1.1 KiB
C
Raw Normal View History

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>
2009-05-13 15:56:33 -07:00
#ifndef __ASM_GENERIC_DELAY_H
#define __ASM_GENERIC_DELAY_H
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>
2011-07-02 01:29:24 -07:00
/* Undefined functions to get compile-time errors */
extern void __bad_udelay(void);
extern void __bad_ndelay(void);
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>
2009-05-13 15:56:33 -07:00
extern void __udelay(unsigned long usecs);
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>
2011-07-02 01:29:24 -07:00
extern void __ndelay(unsigned long nsecs);
extern void __const_udelay(unsigned long xloops);
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>
2009-05-13 15:56:33 -07:00
extern void __delay(unsigned long loops);
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>
2011-07-18 06:28:20 -07:00
/*
* The weird n/20000 thing suppresses a "comparison is always false due to
* limited range of data type" warning with non-const 8-bit arguments.
*/
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>
2011-07-02 01:29:24 -07:00
/* 0x10c7 is 2**32 / 1000000 (rounded up) */
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>
2011-07-18 06:28:20 -07:00
#define udelay(n) \
({ \
if (__builtin_constant_p(n)) { \
if ((n) / 20000 >= 1) \
__bad_udelay(); \
else \
__const_udelay((n) * 0x10c7ul); \
} else { \
__udelay(n); \
} \
})
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>
2011-07-02 01:29:24 -07:00
/* 0x5 is 2**32 / 1000000000 (rounded up) */
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>
2011-07-18 06:28:20 -07:00
#define ndelay(n) \
({ \
if (__builtin_constant_p(n)) { \
if ((n) / 20000 >= 1) \
__bad_ndelay(); \
else \
__const_udelay((n) * 5ul); \
} else { \
__ndelay(n); \
} \
})
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>
2009-05-13 15:56:33 -07:00
#endif /* __ASM_GENERIC_DELAY_H */
Copy Permalink