2 * linux/drivers/clocksource/arm_arch_timer.c
4 * Copyright (C) 2011 ARM Ltd.
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 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/device.h>
14 #include <linux/smp.h>
15 #include <linux/cpu.h>
16 #include <linux/clockchips.h>
17 #include <linux/interrupt.h>
18 #include <linux/of_irq.h>
21 #include <asm/arch_timer.h>
24 #include <clocksource/arm_arch_timer.h>
26 static u32 arch_timer_rate
;
36 static int arch_timer_ppi
[MAX_TIMER_PPI
];
38 static struct clock_event_device __percpu
*arch_timer_evt
;
40 static bool arch_timer_use_virtual
= true;
43 * Architected system timer support.
46 static inline irqreturn_t
timer_handler(const int access
,
47 struct clock_event_device
*evt
)
50 ctrl
= arch_timer_reg_read(access
, ARCH_TIMER_REG_CTRL
);
51 if (ctrl
& ARCH_TIMER_CTRL_IT_STAT
) {
52 ctrl
|= ARCH_TIMER_CTRL_IT_MASK
;
53 arch_timer_reg_write(access
, ARCH_TIMER_REG_CTRL
, ctrl
);
54 evt
->event_handler(evt
);
61 static irqreturn_t
arch_timer_handler_virt(int irq
, void *dev_id
)
63 struct clock_event_device
*evt
= dev_id
;
65 return timer_handler(ARCH_TIMER_VIRT_ACCESS
, evt
);
68 static irqreturn_t
arch_timer_handler_phys(int irq
, void *dev_id
)
70 struct clock_event_device
*evt
= dev_id
;
72 return timer_handler(ARCH_TIMER_PHYS_ACCESS
, evt
);
75 static inline void timer_set_mode(const int access
, int mode
)
79 case CLOCK_EVT_MODE_UNUSED
:
80 case CLOCK_EVT_MODE_SHUTDOWN
:
81 ctrl
= arch_timer_reg_read(access
, ARCH_TIMER_REG_CTRL
);
82 ctrl
&= ~ARCH_TIMER_CTRL_ENABLE
;
83 arch_timer_reg_write(access
, ARCH_TIMER_REG_CTRL
, ctrl
);
90 static void arch_timer_set_mode_virt(enum clock_event_mode mode
,
91 struct clock_event_device
*clk
)
93 timer_set_mode(ARCH_TIMER_VIRT_ACCESS
, mode
);
96 static void arch_timer_set_mode_phys(enum clock_event_mode mode
,
97 struct clock_event_device
*clk
)
99 timer_set_mode(ARCH_TIMER_PHYS_ACCESS
, mode
);
102 static inline void set_next_event(const int access
, unsigned long evt
)
105 ctrl
= arch_timer_reg_read(access
, ARCH_TIMER_REG_CTRL
);
106 ctrl
|= ARCH_TIMER_CTRL_ENABLE
;
107 ctrl
&= ~ARCH_TIMER_CTRL_IT_MASK
;
108 arch_timer_reg_write(access
, ARCH_TIMER_REG_TVAL
, evt
);
109 arch_timer_reg_write(access
, ARCH_TIMER_REG_CTRL
, ctrl
);
112 static int arch_timer_set_next_event_virt(unsigned long evt
,
113 struct clock_event_device
*unused
)
115 set_next_event(ARCH_TIMER_VIRT_ACCESS
, evt
);
119 static int arch_timer_set_next_event_phys(unsigned long evt
,
120 struct clock_event_device
*unused
)
122 set_next_event(ARCH_TIMER_PHYS_ACCESS
, evt
);
126 static int __cpuinit
arch_timer_setup(struct clock_event_device
*clk
)
128 clk
->features
= CLOCK_EVT_FEAT_ONESHOT
| CLOCK_EVT_FEAT_C3STOP
;
129 clk
->name
= "arch_sys_timer";
131 if (arch_timer_use_virtual
) {
132 clk
->irq
= arch_timer_ppi
[VIRT_PPI
];
133 clk
->set_mode
= arch_timer_set_mode_virt
;
134 clk
->set_next_event
= arch_timer_set_next_event_virt
;
136 clk
->irq
= arch_timer_ppi
[PHYS_SECURE_PPI
];
137 clk
->set_mode
= arch_timer_set_mode_phys
;
138 clk
->set_next_event
= arch_timer_set_next_event_phys
;
141 clk
->cpumask
= cpumask_of(smp_processor_id());
143 clk
->set_mode(CLOCK_EVT_MODE_SHUTDOWN
, NULL
);
145 clockevents_config_and_register(clk
, arch_timer_rate
,
148 if (arch_timer_use_virtual
)
149 enable_percpu_irq(arch_timer_ppi
[VIRT_PPI
], 0);
151 enable_percpu_irq(arch_timer_ppi
[PHYS_SECURE_PPI
], 0);
152 if (arch_timer_ppi
[PHYS_NONSECURE_PPI
])
153 enable_percpu_irq(arch_timer_ppi
[PHYS_NONSECURE_PPI
], 0);
156 arch_counter_set_user_access();
161 static int arch_timer_available(void)
165 if (arch_timer_rate
== 0) {
166 freq
= arch_timer_get_cntfrq();
168 /* Check the timer frequency. */
170 pr_warn("Architected timer frequency not available\n");
174 arch_timer_rate
= freq
;
177 pr_info_once("Architected local timer running at %lu.%02luMHz (%s).\n",
178 (unsigned long)arch_timer_rate
/ 1000000,
179 (unsigned long)(arch_timer_rate
/ 10000) % 100,
180 arch_timer_use_virtual
? "virt" : "phys");
184 u32
arch_timer_get_rate(void)
186 return arch_timer_rate
;
190 * Some external users of arch_timer_read_counter (e.g. sched_clock) may try to
191 * call it before it has been initialised. Rather than incur a performance
192 * penalty checking for initialisation, provide a default implementation that
193 * won't lead to time appearing to jump backwards.
195 static u64
arch_timer_read_zero(void)
200 u64 (*arch_timer_read_counter
)(void) = arch_timer_read_zero
;
202 static cycle_t
arch_counter_read(struct clocksource
*cs
)
204 return arch_timer_read_counter();
207 static cycle_t
arch_counter_read_cc(const struct cyclecounter
*cc
)
209 return arch_timer_read_counter();
212 static struct clocksource clocksource_counter
= {
213 .name
= "arch_sys_counter",
215 .read
= arch_counter_read
,
216 .mask
= CLOCKSOURCE_MASK(56),
217 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
220 static struct cyclecounter cyclecounter
= {
221 .read
= arch_counter_read_cc
,
222 .mask
= CLOCKSOURCE_MASK(56),
225 static struct timecounter timecounter
;
227 struct timecounter
*arch_timer_get_timecounter(void)
232 static void __cpuinit
arch_timer_stop(struct clock_event_device
*clk
)
234 pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n",
235 clk
->irq
, smp_processor_id());
237 if (arch_timer_use_virtual
)
238 disable_percpu_irq(arch_timer_ppi
[VIRT_PPI
]);
240 disable_percpu_irq(arch_timer_ppi
[PHYS_SECURE_PPI
]);
241 if (arch_timer_ppi
[PHYS_NONSECURE_PPI
])
242 disable_percpu_irq(arch_timer_ppi
[PHYS_NONSECURE_PPI
]);
245 clk
->set_mode(CLOCK_EVT_MODE_UNUSED
, clk
);
248 static int __cpuinit
arch_timer_cpu_notify(struct notifier_block
*self
,
249 unsigned long action
, void *hcpu
)
252 * Grab cpu pointer in each case to avoid spurious
253 * preemptible warnings
255 switch (action
& ~CPU_TASKS_FROZEN
) {
257 arch_timer_setup(this_cpu_ptr(arch_timer_evt
));
260 arch_timer_stop(this_cpu_ptr(arch_timer_evt
));
267 static struct notifier_block arch_timer_cpu_nb __cpuinitdata
= {
268 .notifier_call
= arch_timer_cpu_notify
,
271 static int __init
arch_timer_register(void)
276 err
= arch_timer_available();
280 arch_timer_evt
= alloc_percpu(struct clock_event_device
);
281 if (!arch_timer_evt
) {
286 clocksource_register_hz(&clocksource_counter
, arch_timer_rate
);
287 cyclecounter
.mult
= clocksource_counter
.mult
;
288 cyclecounter
.shift
= clocksource_counter
.shift
;
289 timecounter_init(&timecounter
, &cyclecounter
,
290 arch_counter_get_cntpct());
292 if (arch_timer_use_virtual
) {
293 ppi
= arch_timer_ppi
[VIRT_PPI
];
294 err
= request_percpu_irq(ppi
, arch_timer_handler_virt
,
295 "arch_timer", arch_timer_evt
);
297 ppi
= arch_timer_ppi
[PHYS_SECURE_PPI
];
298 err
= request_percpu_irq(ppi
, arch_timer_handler_phys
,
299 "arch_timer", arch_timer_evt
);
300 if (!err
&& arch_timer_ppi
[PHYS_NONSECURE_PPI
]) {
301 ppi
= arch_timer_ppi
[PHYS_NONSECURE_PPI
];
302 err
= request_percpu_irq(ppi
, arch_timer_handler_phys
,
303 "arch_timer", arch_timer_evt
);
305 free_percpu_irq(arch_timer_ppi
[PHYS_SECURE_PPI
],
311 pr_err("arch_timer: can't register interrupt %d (%d)\n",
316 err
= register_cpu_notifier(&arch_timer_cpu_nb
);
320 /* Immediately configure the timer on the boot CPU */
321 arch_timer_setup(this_cpu_ptr(arch_timer_evt
));
326 if (arch_timer_use_virtual
)
327 free_percpu_irq(arch_timer_ppi
[VIRT_PPI
], arch_timer_evt
);
329 free_percpu_irq(arch_timer_ppi
[PHYS_SECURE_PPI
],
331 if (arch_timer_ppi
[PHYS_NONSECURE_PPI
])
332 free_percpu_irq(arch_timer_ppi
[PHYS_NONSECURE_PPI
],
337 free_percpu(arch_timer_evt
);
342 static void __init
arch_timer_init(struct device_node
*np
)
347 if (arch_timer_get_rate()) {
348 pr_warn("arch_timer: multiple nodes in dt, skipping\n");
352 /* Try to determine the frequency from the device tree or CNTFRQ */
353 if (!of_property_read_u32(np
, "clock-frequency", &freq
))
354 arch_timer_rate
= freq
;
356 for (i
= PHYS_SECURE_PPI
; i
< MAX_TIMER_PPI
; i
++)
357 arch_timer_ppi
[i
] = irq_of_parse_and_map(np
, i
);
362 * If HYP mode is available, we know that the physical timer
363 * has been configured to be accessible from PL1. Use it, so
364 * that a guest can use the virtual timer instead.
366 * If no interrupt provided for virtual timer, we'll have to
367 * stick to the physical timer. It'd better be accessible...
369 if (is_hyp_mode_available() || !arch_timer_ppi
[VIRT_PPI
]) {
370 arch_timer_use_virtual
= false;
372 if (!arch_timer_ppi
[PHYS_SECURE_PPI
] ||
373 !arch_timer_ppi
[PHYS_NONSECURE_PPI
]) {
374 pr_warn("arch_timer: No interrupt available, giving up\n");
379 if (arch_timer_use_virtual
)
380 arch_timer_read_counter
= arch_counter_get_cntvct
;
382 arch_timer_read_counter
= arch_counter_get_cntpct
;
384 arch_timer_register();
385 arch_timer_arch_init();
387 CLOCKSOURCE_OF_DECLARE(armv7_arch_timer
, "arm,armv7-timer", arch_timer_init
);
388 CLOCKSOURCE_OF_DECLARE(armv8_arch_timer
, "arm,armv8-timer", arch_timer_init
);