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d0a533b1 WD |
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 | */ | |
31 | struct 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 | |
38 | static 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 | ||
46 | static 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 | ||
53 | static void __timer_udelay(unsigned long usecs) | |
54 | { | |
55 | __timer_const_udelay(usecs * UDELAY_MULT); | |
56 | } | |
57 | ||
58 | void __init init_current_timer_delay(unsigned long freq) | |
59 | { | |
60 | pr_info("Switching to timer-based delay loop\n"); | |
61 | lpj_fine = freq / HZ; | |
beafa0de | 62 | loops_per_jiffy = lpj_fine; |
d0a533b1 WD |
63 | arm_delay_ops.delay = __timer_delay; |
64 | arm_delay_ops.const_udelay = __timer_const_udelay; | |
65 | arm_delay_ops.udelay = __timer_udelay; | |
66 | } | |
67 | ||
68 | unsigned long __cpuinit calibrate_delay_is_known(void) | |
69 | { | |
70 | return lpj_fine; | |
71 | } | |
72 | #endif |