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authorMax Filippov <jcmvbkbc@gmail.com>2013-10-17 02:42:16 +0400
committerChris Zankel <chris@zankel.net>2014-01-14 22:19:53 +0400
commit01e3b3cb2d70ca9d95769e863ca71a85f84c3917 (patch)
tree1e29afd18198204a445a7d81bbd513441b74633f /arch/xtensa
parent5515daa9ca5a0992cc1c55d4c6c7ddb116e829b4 (diff)
downloadlinux-01e3b3cb2d70ca9d95769e863ca71a85f84c3917.tar.xz
xtensa: fix __delay for small loop count
Avoid __delay counter underflow for loop counts < 2. Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Chris Zankel <chris@zankel.net>
Diffstat (limited to 'arch/xtensa')
-rw-r--r--arch/xtensa/include/asm/delay.h9
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/xtensa/include/asm/delay.h b/arch/xtensa/include/asm/delay.h
index 3899610c1dff..742b89f3ca2c 100644
--- a/arch/xtensa/include/asm/delay.h
+++ b/arch/xtensa/include/asm/delay.h
@@ -19,9 +19,12 @@ extern unsigned long loops_per_jiffy;
static inline void __delay(unsigned long loops)
{
- /* 2 cycles per loop. */
- __asm__ __volatile__ ("1: addi %0, %0, -2; bgeui %0, 2, 1b"
- : "=r" (loops) : "0" (loops));
+ if (__builtin_constant_p(loops) && loops < 2)
+ __asm__ __volatile__ ("nop");
+ else if (loops >= 2)
+ /* 2 cycles per loop. */
+ __asm__ __volatile__ ("1: addi %0, %0, -2; bgeui %0, 2, 1b"
+ : "+r" (loops));
}
/* For SMP/NUMA systems, change boot_cpu_data to something like