xref: /linux/arch/arm64/include/asm/arch_timer.h (revision bb9707077b4ee5f77bc9939b057ff8a0d410296f) 
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/bug.h>
25 #include <linux/init.h>
26 #include <linux/types.h>
27 
28 #include <clocksource/arm_arch_timer.h>
29 
30 /*
31  * These register accessors are marked inline so the compiler can
32  * nicely work out which register we want, and chuck away the rest of
33  * the code.
34  */
35 static __always_inline
36 void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u32 val)
37 {
38 	if (access == ARCH_TIMER_PHYS_ACCESS) {
39 		switch (reg) {
40 		case ARCH_TIMER_REG_CTRL:
41 			asm volatile("msr cntp_ctl_el0,  %0" : : "r" (val));
42 			break;
43 		case ARCH_TIMER_REG_TVAL:
44 			asm volatile("msr cntp_tval_el0, %0" : : "r" (val));
45 			break;
46 		}
47 	} else if (access == ARCH_TIMER_VIRT_ACCESS) {
48 		switch (reg) {
49 		case ARCH_TIMER_REG_CTRL:
50 			asm volatile("msr cntv_ctl_el0,  %0" : : "r" (val));
51 			break;
52 		case ARCH_TIMER_REG_TVAL:
53 			asm volatile("msr cntv_tval_el0, %0" : : "r" (val));
54 			break;
55 		}
56 	}
57 
58 	isb();
59 }
60 
61 static __always_inline
62 u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
63 {
64 	u32 val;
65 
66 	if (access == ARCH_TIMER_PHYS_ACCESS) {
67 		switch (reg) {
68 		case ARCH_TIMER_REG_CTRL:
69 			asm volatile("mrs %0,  cntp_ctl_el0" : "=r" (val));
70 			break;
71 		case ARCH_TIMER_REG_TVAL:
72 			asm volatile("mrs %0, cntp_tval_el0" : "=r" (val));
73 			break;
74 		}
75 	} else if (access == ARCH_TIMER_VIRT_ACCESS) {
76 		switch (reg) {
77 		case ARCH_TIMER_REG_CTRL:
78 			asm volatile("mrs %0,  cntv_ctl_el0" : "=r" (val));
79 			break;
80 		case ARCH_TIMER_REG_TVAL:
81 			asm volatile("mrs %0, cntv_tval_el0" : "=r" (val));
82 			break;
83 		}
84 	}
85 
86 	return val;
87 }
88 
89 static inline u32 arch_timer_get_cntfrq(void)
90 {
91 	u32 val;
92 	asm volatile("mrs %0,   cntfrq_el0" : "=r" (val));
93 	return val;
94 }
95 
96 static inline u32 arch_timer_get_cntkctl(void)
97 {
98 	u32 cntkctl;
99 	asm volatile("mrs	%0, cntkctl_el1" : "=r" (cntkctl));
100 	return cntkctl;
101 }
102 
103 static inline void arch_timer_set_cntkctl(u32 cntkctl)
104 {
105 	asm volatile("msr	cntkctl_el1, %0" : : "r" (cntkctl));
106 }
107 
108 static inline u64 arch_counter_get_cntpct(void)
109 {
110 	/*
111 	 * AArch64 kernel and user space mandate the use of CNTVCT.
112 	 */
113 	BUG();
114 	return 0;
115 }
116 
117 static inline u64 arch_counter_get_cntvct(void)
118 {
119 	u64 cval;
120 
121 	isb();
122 	asm volatile("mrs %0, cntvct_el0" : "=r" (cval));
123 
124 	return cval;
125 }
126 
127 static inline int arch_timer_arch_init(void)
128 {
129 	return 0;
130 }
131 
132 #endif
133