diff options
Diffstat (limited to 'arch/arm/lib')
| -rw-r--r-- | arch/arm/lib/Makefile | 2 | ||||
| -rw-r--r-- | arch/arm/lib/delay-loop.S (renamed from arch/arm/lib/delay.S) | 20 | ||||
| -rw-r--r-- | arch/arm/lib/delay.c | 71 |
3 files changed, 81 insertions, 12 deletions
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile index 992769ae2599..b621114644fd 100644 --- a/arch/arm/lib/Makefile +++ b/arch/arm/lib/Makefile @@ -6,7 +6,7 @@ lib-y := backtrace.o changebit.o csumipv6.o csumpartial.o \ csumpartialcopy.o csumpartialcopyuser.o clearbit.o \ - delay.o findbit.o memchr.o memcpy.o \ + delay.o delay-loop.o findbit.o memchr.o memcpy.o \ memmove.o memset.o memzero.o setbit.o \ strncpy_from_user.o strnlen_user.o \ strchr.o strrchr.o \ diff --git a/arch/arm/lib/delay.S b/arch/arm/lib/delay-loop.S index 3c9a05c8d20b..36b668d8e121 100644 --- a/arch/arm/lib/delay.S +++ b/arch/arm/lib/delay-loop.S @@ -9,11 +9,11 @@ */ #include <linux/linkage.h> #include <asm/assembler.h> -#include <asm/param.h> +#include <asm/delay.h> .text .LC0: .word loops_per_jiffy -.LC1: .word (2199023*HZ)>>11 +.LC1: .word UDELAY_MULT /* * r0 <= 2000 @@ -21,10 +21,10 @@ * HZ <= 1000 */ -ENTRY(__udelay) +ENTRY(__loop_udelay) ldr r2, .LC1 mul r0, r2, r0 -ENTRY(__const_udelay) @ 0 <= r0 <= 0x7fffff06 +ENTRY(__loop_const_udelay) @ 0 <= r0 <= 0x7fffff06 mov r1, #-1 ldr r2, .LC0 ldr r2, [r2] @ max = 0x01ffffff @@ -39,12 +39,10 @@ ENTRY(__const_udelay) @ 0 <= r0 <= 0x7fffff06 /* * loops = r0 * HZ * loops_per_jiffy / 1000000 - * - * Oh, if only we had a cycle counter... */ @ Delay routine -ENTRY(__delay) +ENTRY(__loop_delay) subs r0, r0, #1 #if 0 movls pc, lr @@ -62,8 +60,8 @@ ENTRY(__delay) movls pc, lr subs r0, r0, #1 #endif - bhi __delay + bhi __loop_delay mov pc, lr -ENDPROC(__udelay) -ENDPROC(__const_udelay) -ENDPROC(__delay) +ENDPROC(__loop_udelay) +ENDPROC(__loop_const_udelay) +ENDPROC(__loop_delay) diff --git a/arch/arm/lib/delay.c b/arch/arm/lib/delay.c new file mode 100644 index 000000000000..d6dacc69254e --- /dev/null +++ b/arch/arm/lib/delay.c @@ -0,0 +1,71 @@ +/* + * Delay loops based on the OpenRISC implementation. + * + * Copyright (C) 2012 ARM Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * Author: Will Deacon <will.deacon@arm.com> + */ + +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/timex.h> + +/* + * Default to the loop-based delay implementation. + */ +struct arm_delay_ops arm_delay_ops = { + .delay = __loop_delay, + .const_udelay = __loop_const_udelay, + .udelay = __loop_udelay, +}; + +#ifdef ARCH_HAS_READ_CURRENT_TIMER +static void __timer_delay(unsigned long cycles) +{ + cycles_t start = get_cycles(); + + while ((get_cycles() - start) < cycles) + cpu_relax(); +} + +static void __timer_const_udelay(unsigned long xloops) +{ + unsigned long long loops = xloops; + loops *= loops_per_jiffy; + __timer_delay(loops >> UDELAY_SHIFT); +} + +static void __timer_udelay(unsigned long usecs) +{ + __timer_const_udelay(usecs * UDELAY_MULT); +} + +void __init init_current_timer_delay(unsigned long freq) +{ + pr_info("Switching to timer-based delay loop\n"); + lpj_fine = freq / HZ; + arm_delay_ops.delay = __timer_delay; + arm_delay_ops.const_udelay = __timer_const_udelay; + arm_delay_ops.udelay = __timer_udelay; +} + +unsigned long __cpuinit calibrate_delay_is_known(void) +{ + return lpj_fine; +} +#endif |
