arch/arm64/include/asm/arch_timer.h

   1 /*
   2  * arch/arm64/include/asm/arch_timer.h
   3  *
   4  * Copyright (C) 2012 ARM Ltd.
   5  * Author: Marc Zyngier <marc.zyngier@arm.com>
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19 #ifndef __ASM_ARCH_TIMER_H
  20 #define __ASM_ARCH_TIMER_H
  21
  22 #include <asm/barrier.h>
  23
  24 #include <linux/init.h>
  25 #include <linux/types.h>
  26
  27 #include <clocksource/arm_arch_timer.h>
  28
  29 /*
  30  * These register accessors are marked inline so the compiler can
  31  * nicely work out which register we want, and chuck away the rest of
  32  * the code.
  33  */
  34 static __always_inline
  35 void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u32 val)
  36 {
  37         if (access == ARCH_TIMER_PHYS_ACCESS) {
  38                 switch (reg) {
  39                 case ARCH_TIMER_REG_CTRL:
  40                         asm volatile("msr cntp_ctl_el0,  %0" : : "r" (val));
  41                         break;
  42                 case ARCH_TIMER_REG_TVAL:
  43                         asm volatile("msr cntp_tval_el0, %0" : : "r" (val));
  44                         break;
  45                 }
  46         } else if (access == ARCH_TIMER_VIRT_ACCESS) {
  47                 switch (reg) {
  48                 case ARCH_TIMER_REG_CTRL:
  49                         asm volatile("msr cntv_ctl_el0,  %0" : : "r" (val));
  50                         break;
  51                 case ARCH_TIMER_REG_TVAL:
  52                         asm volatile("msr cntv_tval_el0, %0" : : "r" (val));
  53                         break;
  54                 }
  55         }
  56
  57         isb();
  58 }
  59
  60 static __always_inline
  61 u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
  62 {
  63         u32 val;
  64
  65         if (access == ARCH_TIMER_PHYS_ACCESS) {
  66                 switch (reg) {
  67                 case ARCH_TIMER_REG_CTRL:
  68                         asm volatile("mrs %0,  cntp_ctl_el0" : "=r" (val));
  69                         break;
  70                 case ARCH_TIMER_REG_TVAL:
  71                         asm volatile("mrs %0, cntp_tval_el0" : "=r" (val));
  72                         break;
  73                 }
  74         } else if (access == ARCH_TIMER_VIRT_ACCESS) {
  75                 switch (reg) {
  76                 case ARCH_TIMER_REG_CTRL:
  77                         asm volatile("mrs %0,  cntv_ctl_el0" : "=r" (val));
  78                         break;
  79                 case ARCH_TIMER_REG_TVAL:
  80                         asm volatile("mrs %0, cntv_tval_el0" : "=r" (val));
  81                         break;
  82                 }
  83         }
  84
  85         return val;
  86 }
  87
  88 static inline u32 arch_timer_get_cntfrq(void)
  89 {
  90         u32 val;
  91         asm volatile("mrs %0,   cntfrq_el0" : "=r" (val));
  92         return val;
  93 }
  94
  95 static inline void arch_counter_set_user_access(void)
  96 {
  97         u32 cntkctl;
  98
  99         /* Disable user access to the timers and the physical counter. */
 100         asm volatile("mrs       %0, cntkctl_el1" : "=r" (cntkctl));
 101         cntkctl &= ~((3 << 8) | (1 << 0));
 102
 103         /* Enable user access to the virtual counter and frequency. */
 104         cntkctl |= (1 << 1);
 105         asm volatile("msr       cntkctl_el1, %0" : : "r" (cntkctl));
 106 }
 107
 108 static inline u64 arch_counter_get_cntvct(void)
 109 {
 110         u64 cval;
 111
 112         isb();
 113         asm volatile("mrs %0, cntvct_el0" : "=r" (cval));
 114
 115         return cval;
 116 }
 117
 118 static inline int arch_timer_arch_init(void)
 119 {
 120         return 0;
 121 }
 122
 123 #endif