2 * arch/arm64/include/asm/arch_timer.h
4 * Copyright (C) 2012 ARM Ltd.
5 * Author: Marc Zyngier <marc.zyngier@arm.com>
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.
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.
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/>.
19 #ifndef __ASM_ARCH_TIMER_H
20 #define __ASM_ARCH_TIMER_H
22 #include <asm/barrier.h>
23 #include <asm/sysreg.h>
25 #include <linux/bug.h>
26 #include <linux/init.h>
27 #include <linux/jump_label.h>
28 #include <linux/smp.h>
29 #include <linux/types.h>
31 #include <clocksource/arm_arch_timer.h>
33 #if IS_ENABLED(CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND)
34 extern struct static_key_false arch_timer_read_ool_enabled;
35 #define needs_unstable_timer_counter_workaround() \
36 static_branch_unlikely(&arch_timer_read_ool_enabled)
38 #define needs_unstable_timer_counter_workaround() false
41 enum arch_timer_erratum_match_type {
43 ate_match_local_cap_id,
44 ate_match_acpi_oem_info,
47 struct clock_event_device;
49 struct arch_timer_erratum_workaround {
50 enum arch_timer_erratum_match_type match_type;
53 u32 (*read_cntp_tval_el0)(void);
54 u32 (*read_cntv_tval_el0)(void);
55 u64 (*read_cntvct_el0)(void);
56 int (*set_next_event_phys)(unsigned long, struct clock_event_device *);
57 int (*set_next_event_virt)(unsigned long, struct clock_event_device *);
60 DECLARE_PER_CPU(const struct arch_timer_erratum_workaround *,
61 timer_unstable_counter_workaround);
63 #define arch_timer_reg_read_stable(reg) \
66 if (needs_unstable_timer_counter_workaround()) { \
67 const struct arch_timer_erratum_workaround *wa; \
68 preempt_disable_notrace(); \
69 wa = __this_cpu_read(timer_unstable_counter_workaround); \
70 if (wa && wa->read_##reg) \
71 _val = wa->read_##reg(); \
73 _val = read_sysreg(reg); \
74 preempt_enable_notrace(); \
76 _val = read_sysreg(reg); \
82 * These register accessors are marked inline so the compiler can
83 * nicely work out which register we want, and chuck away the rest of
86 static __always_inline
87 void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u32 val)
89 if (access == ARCH_TIMER_PHYS_ACCESS) {
91 case ARCH_TIMER_REG_CTRL:
92 write_sysreg(val, cntp_ctl_el0);
94 case ARCH_TIMER_REG_TVAL:
95 write_sysreg(val, cntp_tval_el0);
98 } else if (access == ARCH_TIMER_VIRT_ACCESS) {
100 case ARCH_TIMER_REG_CTRL:
101 write_sysreg(val, cntv_ctl_el0);
103 case ARCH_TIMER_REG_TVAL:
104 write_sysreg(val, cntv_tval_el0);
112 static __always_inline
113 u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
115 if (access == ARCH_TIMER_PHYS_ACCESS) {
117 case ARCH_TIMER_REG_CTRL:
118 return read_sysreg(cntp_ctl_el0);
119 case ARCH_TIMER_REG_TVAL:
120 return arch_timer_reg_read_stable(cntp_tval_el0);
122 } else if (access == ARCH_TIMER_VIRT_ACCESS) {
124 case ARCH_TIMER_REG_CTRL:
125 return read_sysreg(cntv_ctl_el0);
126 case ARCH_TIMER_REG_TVAL:
127 return arch_timer_reg_read_stable(cntv_tval_el0);
134 static inline u32 arch_timer_get_cntfrq(void)
136 return read_sysreg(cntfrq_el0);
139 static inline u32 arch_timer_get_cntkctl(void)
141 return read_sysreg(cntkctl_el1);
144 static inline void arch_timer_set_cntkctl(u32 cntkctl)
146 write_sysreg(cntkctl, cntkctl_el1);
149 static inline u64 arch_counter_get_cntpct(void)
152 * AArch64 kernel and user space mandate the use of CNTVCT.
158 static inline u64 arch_counter_get_cntvct(void)
161 return arch_timer_reg_read_stable(cntvct_el0);
164 static inline int arch_timer_arch_init(void)