diff options
author | Ingo Molnar <mingo@elte.hu> | 2009-06-07 12:22:15 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-06-07 12:22:15 +0200 |
commit | 5f4457a4f62cc9d78e04c0eb12ff0540899aad89 (patch) | |
tree | 0b973d527ea6b2ae31e08da0746b4965a3c5a6d8 /arch/microblaze/include/asm/delay.h | |
parent | 9b94b3a19b13e094c10f65f24bc358f6ffe4eacd (diff) | |
parent | b87297fb405ef13cac375f202d114323b076a56d (diff) |
Merge branch 'linus' into x86/cpu
Diffstat (limited to 'arch/microblaze/include/asm/delay.h')
-rw-r--r-- | arch/microblaze/include/asm/delay.h | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/arch/microblaze/include/asm/delay.h b/arch/microblaze/include/asm/delay.h new file mode 100644 index 00000000000..05b7d39e439 --- /dev/null +++ b/arch/microblaze/include/asm/delay.h @@ -0,0 +1,72 @@ +/* + * include/asm-microblaze/delay.h + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2008 Michal Simek + * Copyright (C) 2007 John Williams + * Copyright (C) 2006 Atmark Techno, Inc. + */ + +#ifndef _ASM_MICROBLAZE_DELAY_H +#define _ASM_MICROBLAZE_DELAY_H + +extern inline void __delay(unsigned long loops) +{ + asm volatile ("# __delay \n\t" \ + "1: addi %0, %0, -1\t\n" \ + "bneid %0, 1b \t\n" \ + "nop \t\n" + : "=r" (loops) + : "0" (loops)); +} + +/* + * Note that 19 * 226 == 4294 ==~ 2^32 / 10^6, so + * loops = (4294 * usecs * loops_per_jiffy * HZ) / 2^32. + * + * The mul instruction gives us loops = (a * b) / 2^32. + * We choose a = usecs * 19 * HZ and b = loops_per_jiffy * 226 + * because this lets us support a wide range of HZ and + * loops_per_jiffy values without either a or b overflowing 2^32. + * Thus we need usecs * HZ <= (2^32 - 1) / 19 = 226050910 and + * loops_per_jiffy <= (2^32 - 1) / 226 = 19004280 + * (which corresponds to ~3800 bogomips at HZ = 100). + * -- paulus + */ +#define __MAX_UDELAY (226050910UL/HZ) /* maximum udelay argument */ +#define __MAX_NDELAY (4294967295UL/HZ) /* maximum ndelay argument */ + +extern unsigned long loops_per_jiffy; + +extern inline void __udelay(unsigned int x) +{ + + unsigned long long tmp = + (unsigned long long)x * (unsigned long long)loops_per_jiffy \ + * 226LL; + unsigned loops = tmp >> 32; + +/* + __asm__("mulxuu %0,%1,%2" : "=r" (loops) : + "r" (x), "r" (loops_per_jiffy * 226)); +*/ + __delay(loops); +} + +extern void __bad_udelay(void); /* deliberately undefined */ +extern void __bad_ndelay(void); /* deliberately undefined */ + +#define udelay(n) (__builtin_constant_p(n) ? \ + ((n) > __MAX_UDELAY ? __bad_udelay() : __udelay((n) * (19 * HZ))) : \ + __udelay((n) * (19 * HZ))) + +#define ndelay(n) (__builtin_constant_p(n) ? \ + ((n) > __MAX_NDELAY ? __bad_ndelay() : __udelay((n) * HZ)) : \ + __udelay((n) * HZ)) + +#define muldiv(a, b, c) (((a)*(b))/(c)) + +#endif /* _ASM_MICROBLAZE_DELAY_H */ |