arch/arm64/include/asm/arm_generic.h

   1 /*
   2  * arch/arm64/include/asm/arm_generic.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_ARM_GENERIC_H
  20 #define __ASM_ARM_GENERIC_H
  21
  22 #include <linux/clocksource.h>
  23
  24 #define ARCH_TIMER_CTRL_ENABLE          (1 << 0)
  25 #define ARCH_TIMER_CTRL_IMASK           (1 << 1)
  26 #define ARCH_TIMER_CTRL_ISTATUS         (1 << 2)
  27
  28 #define ARCH_TIMER_REG_CTRL             0
  29 #define ARCH_TIMER_REG_FREQ             1
  30 #define ARCH_TIMER_REG_TVAL             2
  31
  32 static inline void arch_timer_reg_write(int reg, u32 val)
  33 {
  34         switch (reg) {
  35         case ARCH_TIMER_REG_CTRL:
  36                 asm volatile("msr cntp_ctl_el0,  %0" : : "r" (val));
  37                 break;
  38         case ARCH_TIMER_REG_TVAL:
  39                 asm volatile("msr cntp_tval_el0, %0" : : "r" (val));
  40                 break;
  41         default:
  42                 BUILD_BUG();
  43         }
  44
  45         isb();
  46 }
  47
  48 static inline u32 arch_timer_reg_read(int reg)
  49 {
  50         u32 val;
  51
  52         switch (reg) {
  53         case ARCH_TIMER_REG_CTRL:
  54                 asm volatile("mrs %0,  cntp_ctl_el0" : "=r" (val));
  55                 break;
  56         case ARCH_TIMER_REG_FREQ:
  57                 asm volatile("mrs %0,   cntfrq_el0" : "=r" (val));
  58                 break;
  59         case ARCH_TIMER_REG_TVAL:
  60                 asm volatile("mrs %0, cntp_tval_el0" : "=r" (val));
  61                 break;
  62         default:
  63                 BUILD_BUG();
  64         }
  65
  66         return val;
  67 }
  68
  69 static inline void __cpuinit arch_counter_enable_user_access(void)
  70 {
  71         u32 cntkctl;
  72
  73         /* Disable user access to the timers and the physical counter. */
  74         asm volatile("mrs       %0, cntkctl_el1" : "=r" (cntkctl));
  75         cntkctl &= ~((3 << 8) | (1 << 0));
  76
  77         /* Enable user access to the virtual counter and frequency. */
  78         cntkctl |= (1 << 1);
  79         asm volatile("msr       cntkctl_el1, %0" : : "r" (cntkctl));
  80 }
  81
  82 static inline cycle_t arch_counter_get_cntpct(void)
  83 {
  84         cycle_t cval;
  85
  86         asm volatile("mrs %0, cntpct_el0" : "=r" (cval));
  87
  88         return cval;
  89 }
  90
  91 static inline cycle_t arch_counter_get_cntvct(void)
  92 {
  93         cycle_t cval;
  94
  95         asm volatile("mrs %0, cntvct_el0" : "=r" (cval));
  96
  97         return cval;
  98 }
  99
 100 #endif