| /* |
| * 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; |
| loops_per_jiffy = lpj_fine; |
| 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 |