arm_generic.h

Go to the documentation of this file.

/*
 * arch/arm64/include/asm/arm_generic.h
 *
 * Copyright (C) 2012 ARM Ltd.
 * Author: Marc Zyngier <[email protected]>
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */
#ifndef __ASM_ARM_GENERIC_H
#define __ASM_ARM_GENERIC_H

#include <linux/clocksource.h>

#define ARCH_TIMER_CTRL_ENABLE      (1 << 0)
#define ARCH_TIMER_CTRL_IMASK       (1 << 1)
#define ARCH_TIMER_CTRL_ISTATUS     (1 << 2)

#define ARCH_TIMER_REG_CTRL     0
#define ARCH_TIMER_REG_FREQ     1
#define ARCH_TIMER_REG_TVAL     2

static inline void arch_timer_reg_write(int reg, u32 val)
{
    switch (reg) {
    case ARCH_TIMER_REG_CTRL:
        asm volatile("msr cntp_ctl_el0,  %0" : : "r" (val));
        break;
    case ARCH_TIMER_REG_TVAL:
        asm volatile("msr cntp_tval_el0, %0" : : "r" (val));
        break;
    default:
        BUILD_BUG();
    }

    isb();
}

static inline u32 arch_timer_reg_read(int reg)
{
    u32 val;

    switch (reg) {
    case ARCH_TIMER_REG_CTRL:
        asm volatile("mrs %0,  cntp_ctl_el0" : "=r" (val));
        break;
    case ARCH_TIMER_REG_FREQ:
        asm volatile("mrs %0,   cntfrq_el0" : "=r" (val));
        break;
    case ARCH_TIMER_REG_TVAL:
        asm volatile("mrs %0, cntp_tval_el0" : "=r" (val));
        break;
    default:
        BUILD_BUG();
    }

    return val;
}

static inline void __cpuinit arch_counter_enable_user_access(void)
{
    u32 cntkctl;

    /* Disable user access to the timers and the virtual counter. */
    asm volatile("mrs   %0, cntkctl_el1" : "=r" (cntkctl));
    cntkctl &= ~((3 << 8) | (1 << 1));

    /* Enable user access to the physical counter and frequency. */
    cntkctl |= 1;
    asm volatile("msr   cntkctl_el1, %0" : : "r" (cntkctl));
}

static inline cycle_t arch_counter_get_cntpct(void)
{
    cycle_t cval;

    asm volatile("mrs %0, cntpct_el0" : "=r" (cval));

    return cval;
}

static inline cycle_t arch_counter_get_cntvct(void)
{
    cycle_t cval;

    asm volatile("mrs %0, cntvct_el0" : "=r" (cval));

    return cval;
}

#endif