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authorLinus Torvalds <torvalds@linux-foundation.org>2012-07-27 18:14:26 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-27 18:14:26 -0400
commitcea8f46c36c3f82860b038aa23a46e16757666ba (patch)
treee09dc37d2b6880d86dac09afbc0c686139d86df0 /arch/arm/lib/delay.c
parentc1e7179a38919f02dd950801529176b72f5e5a8a (diff)
parent91b006def384d8f07f9f324ab211fefe2b085c90 (diff)
Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-arm
Pull ARM updates from Russell King: "First ARM push of this merge window, post me coming back from holiday. This is what has been in linux-next for the last few weeks. Not much to say which isn't described by the commit summaries." * 'for-linus' of git://git.linaro.org/people/rmk/linux-arm: (32 commits) ARM: 7463/1: topology: Update cpu_power according to DT information ARM: 7462/1: topology: factorize the update of sibling masks ARM: 7461/1: topology: Add arch_scale_freq_power function ARM: 7456/1: ptrace: provide separate functions for tracing syscall {entry,exit} ARM: 7455/1: audit: move syscall auditing until after ptrace SIGTRAP handling ARM: 7454/1: entry: don't bother with syscall tracing on ret_from_fork path ARM: 7453/1: audit: only allow syscall auditing for pure EABI userspace ARM: 7452/1: delay: allow timer-based delay implementation to be selected ARM: 7451/1: arch timer: implement read_current_timer and get_cycles ARM: 7450/1: dcache: select DCACHE_WORD_ACCESS for little-endian ARMv6+ CPUs ARM: 7449/1: use generic strnlen_user and strncpy_from_user functions ARM: 7448/1: perf: remove arm_perf_pmu_ids global enumeration ARM: 7447/1: rwlocks: remove unused branch labels from trylock routines ARM: 7446/1: spinlock: use ticket algorithm for ARMv6+ locking implementation ARM: 7445/1: mm: update CONTEXTIDR register to contain PID of current process ARM: 7444/1: kernel: add arch-timer C3STOP feature ARM: 7460/1: remove asm/locks.h ARM: 7439/1: head.S: simplify initial page table mapping ARM: 7437/1: zImage: Allow DTB command line concatenation with ATAG_CMDLINE ARM: 7436/1: Do not map the vectors page as write-through on UP systems ...
Diffstat (limited to 'arch/arm/lib/delay.c')
-rw-r--r--arch/arm/lib/delay.c71
1 files changed, 71 insertions, 0 deletions
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 @@
1/*
2 * Delay loops based on the OpenRISC implementation.
3 *
4 * Copyright (C) 2012 ARM Limited
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 * Author: Will Deacon <will.deacon@arm.com>
20 */
21
22#include <linux/delay.h>
23#include <linux/init.h>
24#include <linux/kernel.h>
25#include <linux/module.h>
26#include <linux/timex.h>
27
28/*
29 * Default to the loop-based delay implementation.
30 */
31struct arm_delay_ops arm_delay_ops = {
32 .delay = __loop_delay,
33 .const_udelay = __loop_const_udelay,
34 .udelay = __loop_udelay,
35};
36
37#ifdef ARCH_HAS_READ_CURRENT_TIMER
38static void __timer_delay(unsigned long cycles)
39{
40 cycles_t start = get_cycles();
41
42 while ((get_cycles() - start) < cycles)
43 cpu_relax();
44}
45
46static void __timer_const_udelay(unsigned long xloops)
47{
48 unsigned long long loops = xloops;
49 loops *= loops_per_jiffy;
50 __timer_delay(loops >> UDELAY_SHIFT);
51}
52
53static void __timer_udelay(unsigned long usecs)
54{
55 __timer_const_udelay(usecs * UDELAY_MULT);
56}
57
58void __init init_current_timer_delay(unsigned long freq)
59{
60 pr_info("Switching to timer-based delay loop\n");
61 lpj_fine = freq / HZ;
62 arm_delay_ops.delay = __timer_delay;
63 arm_delay_ops.const_udelay = __timer_const_udelay;
64 arm_delay_ops.udelay = __timer_udelay;
65}
66
67unsigned long __cpuinit calibrate_delay_is_known(void)
68{
69 return lpj_fine;
70}
71#endif