1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * arch/arm64/include/asm/arch_timer.h
4 *
5 * Copyright (C) 2012 ARM Ltd.
6 * Author: Marc Zyngier <marc.zyngier@arm.com>
7 */
8 #ifndef __ASM_ARCH_TIMER_H
9 #define __ASM_ARCH_TIMER_H
10
11 #include <asm/barrier.h>
12 #include <asm/hwcap.h>
13 #include <asm/sysreg.h>
14
15 #include <linux/bug.h>
16 #include <linux/init.h>
17 #include <linux/jump_label.h>
18 #include <linux/percpu.h>
19 #include <linux/types.h>
20
21 #include <clocksource/arm_arch_timer.h>
22
23 #if IS_ENABLED(CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND)
24 #define has_erratum_handler(h) \
25 ({ \
26 const struct arch_timer_erratum_workaround *__wa; \
27 __wa = __this_cpu_read(timer_unstable_counter_workaround); \
28 (__wa && __wa->h); \
29 })
30
31 #define erratum_handler(h) \
32 ({ \
33 const struct arch_timer_erratum_workaround *__wa; \
34 __wa = __this_cpu_read(timer_unstable_counter_workaround); \
35 (__wa && __wa->h) ? ({ isb(); __wa->h;}) : arch_timer_##h; \
36 })
37
38 #else
39 #define has_erratum_handler(h) false
40 #define erratum_handler(h) (arch_timer_##h)
41 #endif
42
43 enum arch_timer_erratum_match_type {
44 ate_match_dt,
45 ate_match_local_cap_id,
46 ate_match_acpi_oem_info,
47 };
48
49 struct clock_event_device;
50
51 struct arch_timer_erratum_workaround {
52 enum arch_timer_erratum_match_type match_type;
53 const void *id;
54 const char *desc;
55 u64 (*read_cntpct_el0)(void);
56 u64 (*read_cntvct_el0)(void);
57 int (*set_next_event_phys)(unsigned long, struct clock_event_device *);
58 int (*set_next_event_virt)(unsigned long, struct clock_event_device *);
59 bool disable_compat_vdso;
60 };
61
62 DECLARE_PER_CPU(const struct arch_timer_erratum_workaround *,
63 timer_unstable_counter_workaround);
64
65 static inline notrace u64 arch_timer_read_cntpct_el0(void)
66 {
67 u64 cnt;
68
69 asm volatile(ALTERNATIVE("isb\n mrs %0, cntpct_el0",
70 "nop\n" __mrs_s("%0", SYS_CNTPCTSS_EL0),
71 ARM64_HAS_ECV)
72 : "=r" (cnt));
73
74 return cnt;
75 }
76
77 static inline notrace u64 arch_timer_read_cntvct_el0(void)
78 {
79 u64 cnt;
80
81 asm volatile(ALTERNATIVE("isb\n mrs %0, cntvct_el0",
82 "nop\n" __mrs_s("%0", SYS_CNTVCTSS_EL0),
83 ARM64_HAS_ECV)
84 : "=r" (cnt));
85
86 return cnt;
87 }
88
89 #define arch_timer_reg_read_stable(reg) \
90 ({ \
91 erratum_handler(read_ ## reg)(); \
92 })
93
94 /*
95 * These register accessors are marked inline so the compiler can
96 * nicely work out which register we want, and chuck away the rest of
97 * the code.
98 */
99 static __always_inline
100 void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u64 val)
101 {
102 if (access == ARCH_TIMER_PHYS_ACCESS) {
103 switch (reg) {
104 case ARCH_TIMER_REG_CTRL:
105 write_sysreg(val, cntp_ctl_el0);
106 isb();
107 break;
108 case ARCH_TIMER_REG_CVAL:
109 write_sysreg(val, cntp_cval_el0);
110 break;
111 default:
112 BUILD_BUG();
113 }
114 } else if (access == ARCH_TIMER_VIRT_ACCESS) {
115 switch (reg) {
116 case ARCH_TIMER_REG_CTRL:
117 write_sysreg(val, cntv_ctl_el0);
118 isb();
119 break;
120 case ARCH_TIMER_REG_CVAL:
121 write_sysreg(val, cntv_cval_el0);
122 break;
123 default:
124 BUILD_BUG();
125 }
126 } else {
127 BUILD_BUG();
128 }
129 }
130
131 static __always_inline
132 u64 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
133 {
134 if (access == ARCH_TIMER_PHYS_ACCESS) {
135 switch (reg) {
136 case ARCH_TIMER_REG_CTRL:
137 return read_sysreg(cntp_ctl_el0);
138 default:
139 BUILD_BUG();
140 }
141 } else if (access == ARCH_TIMER_VIRT_ACCESS) {
142 switch (reg) {
143 case ARCH_TIMER_REG_CTRL:
144 return read_sysreg(cntv_ctl_el0);
145 default:
146 BUILD_BUG();
147 }
148 }
149
150 BUILD_BUG();
151 unreachable();
152 }
153
154 static inline u32 arch_timer_get_cntfrq(void)
155 {
156 return read_sysreg(cntfrq_el0);
157 }
158
159 static inline u32 arch_timer_get_cntkctl(void)
160 {
161 return read_sysreg(cntkctl_el1);
162 }
163
164 static inline void arch_timer_set_cntkctl(u32 cntkctl)
165 {
166 write_sysreg(cntkctl, cntkctl_el1);
167 isb();
168 }
169
170 static __always_inline u64 __arch_counter_get_cntpct_stable(void)
171 {
172 u64 cnt;
173
174 cnt = arch_timer_reg_read_stable(cntpct_el0);
175 arch_counter_enforce_ordering(cnt);
176 return cnt;
177 }
178
179 static __always_inline u64 __arch_counter_get_cntpct(void)
180 {
181 u64 cnt;
182
183 asm volatile(ALTERNATIVE("isb\n mrs %0, cntpct_el0",
184 "nop\n" __mrs_s("%0", SYS_CNTPCTSS_EL0),
185 ARM64_HAS_ECV)
186 : "=r" (cnt));
187 arch_counter_enforce_ordering(cnt);
188 return cnt;
189 }
190
191 static __always_inline u64 __arch_counter_get_cntvct_stable(void)
192 {
193 u64 cnt;
194
195 cnt = arch_timer_reg_read_stable(cntvct_el0);
196 arch_counter_enforce_ordering(cnt);
197 return cnt;
198 }
199
200 static __always_inline u64 __arch_counter_get_cntvct(void)
201 {
202 u64 cnt;
203
204 asm volatile(ALTERNATIVE("isb\n mrs %0, cntvct_el0",
205 "nop\n" __mrs_s("%0", SYS_CNTVCTSS_EL0),
206 ARM64_HAS_ECV)
207 : "=r" (cnt));
208 arch_counter_enforce_ordering(cnt);
209 return cnt;
210 }
211
212 static inline int arch_timer_arch_init(void)
213 {
214 return 0;
215 }
216
217 static inline void arch_timer_set_evtstrm_feature(void)
218 {
219 cpu_set_named_feature(EVTSTRM);
220 #ifdef CONFIG_COMPAT
221 compat_elf_hwcap |= COMPAT_HWCAP_EVTSTRM;
222 #endif
223 }
224
225 static inline bool arch_timer_have_evtstrm_feature(void)
226 {
227 return cpu_have_named_feature(EVTSTRM);
228 }
229 #endif
230
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