linux/drivers/clocksource/arm_arch_timer.c
Ding Tianhong bb42ca4740 clocksource/drivers/arm_arch_timer: Work around Hisilicon erratum 161010101
Erratum Hisilicon-161010101 says that the ARM generic timer counter "has
the potential to contain an erroneous value when the timer value
changes". Accesses to TVAL (both read and write) are also affected due
to the implicit counter read. Accesses to CVAL are not affected.

The workaround is to reread the system count registers until the value
of the second read is larger than the first one by less than 32, the
system counter can be guaranteed not to return wrong value twice by
back-to-back read and the error value is always larger than the correct
one by 32. Writes to TVAL are replaced with an equivalent write to CVAL.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[Mark: split patch, fix Kconfig, reword commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2017-02-08 00:14:04 +01:00

1134 lines
29 KiB
C

/*
* linux/drivers/clocksource/arm_arch_timer.c
*
* Copyright (C) 2011 ARM Ltd.
* All Rights Reserved
*
* 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.
*/
#define pr_fmt(fmt) "arm_arch_timer: " fmt
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/smp.h>
#include <linux/cpu.h>
#include <linux/cpu_pm.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/interrupt.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/sched_clock.h>
#include <linux/acpi.h>
#include <asm/arch_timer.h>
#include <asm/virt.h>
#include <clocksource/arm_arch_timer.h>
#define CNTTIDR 0x08
#define CNTTIDR_VIRT(n) (BIT(1) << ((n) * 4))
#define CNTACR(n) (0x40 + ((n) * 4))
#define CNTACR_RPCT BIT(0)
#define CNTACR_RVCT BIT(1)
#define CNTACR_RFRQ BIT(2)
#define CNTACR_RVOFF BIT(3)
#define CNTACR_RWVT BIT(4)
#define CNTACR_RWPT BIT(5)
#define CNTVCT_LO 0x08
#define CNTVCT_HI 0x0c
#define CNTFRQ 0x10
#define CNTP_TVAL 0x28
#define CNTP_CTL 0x2c
#define CNTV_TVAL 0x38
#define CNTV_CTL 0x3c
#define ARCH_CP15_TIMER BIT(0)
#define ARCH_MEM_TIMER BIT(1)
static unsigned arch_timers_present __initdata;
static void __iomem *arch_counter_base;
struct arch_timer {
void __iomem *base;
struct clock_event_device evt;
};
#define to_arch_timer(e) container_of(e, struct arch_timer, evt)
static u32 arch_timer_rate;
enum ppi_nr {
PHYS_SECURE_PPI,
PHYS_NONSECURE_PPI,
VIRT_PPI,
HYP_PPI,
MAX_TIMER_PPI
};
static int arch_timer_ppi[MAX_TIMER_PPI];
static struct clock_event_device __percpu *arch_timer_evt;
static enum ppi_nr arch_timer_uses_ppi = VIRT_PPI;
static bool arch_timer_c3stop;
static bool arch_timer_mem_use_virtual;
static bool arch_counter_suspend_stop;
static bool evtstrm_enable = IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM);
static int __init early_evtstrm_cfg(char *buf)
{
return strtobool(buf, &evtstrm_enable);
}
early_param("clocksource.arm_arch_timer.evtstrm", early_evtstrm_cfg);
/*
* Architected system timer support.
*/
#ifdef CONFIG_FSL_ERRATUM_A008585
/*
* The number of retries is an arbitrary value well beyond the highest number
* of iterations the loop has been observed to take.
*/
#define __fsl_a008585_read_reg(reg) ({ \
u64 _old, _new; \
int _retries = 200; \
\
do { \
_old = read_sysreg(reg); \
_new = read_sysreg(reg); \
_retries--; \
} while (unlikely(_old != _new) && _retries); \
\
WARN_ON_ONCE(!_retries); \
_new; \
})
static u32 notrace fsl_a008585_read_cntp_tval_el0(void)
{
return __fsl_a008585_read_reg(cntp_tval_el0);
}
static u32 notrace fsl_a008585_read_cntv_tval_el0(void)
{
return __fsl_a008585_read_reg(cntv_tval_el0);
}
static u64 notrace fsl_a008585_read_cntvct_el0(void)
{
return __fsl_a008585_read_reg(cntvct_el0);
}
#endif
#ifdef CONFIG_HISILICON_ERRATUM_161010101
/*
* Verify whether the value of the second read is larger than the first by
* less than 32 is the only way to confirm the value is correct, so clear the
* lower 5 bits to check whether the difference is greater than 32 or not.
* Theoretically the erratum should not occur more than twice in succession
* when reading the system counter, but it is possible that some interrupts
* may lead to more than twice read errors, triggering the warning, so setting
* the number of retries far beyond the number of iterations the loop has been
* observed to take.
*/
#define __hisi_161010101_read_reg(reg) ({ \
u64 _old, _new; \
int _retries = 50; \
\
do { \
_old = read_sysreg(reg); \
_new = read_sysreg(reg); \
_retries--; \
} while (unlikely((_new - _old) >> 5) && _retries); \
\
WARN_ON_ONCE(!_retries); \
_new; \
})
static u32 notrace hisi_161010101_read_cntp_tval_el0(void)
{
return __hisi_161010101_read_reg(cntp_tval_el0);
}
static u32 notrace hisi_161010101_read_cntv_tval_el0(void)
{
return __hisi_161010101_read_reg(cntv_tval_el0);
}
static u64 notrace hisi_161010101_read_cntvct_el0(void)
{
return __hisi_161010101_read_reg(cntvct_el0);
}
#endif
#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
const struct arch_timer_erratum_workaround *timer_unstable_counter_workaround = NULL;
EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround);
DEFINE_STATIC_KEY_FALSE(arch_timer_read_ool_enabled);
EXPORT_SYMBOL_GPL(arch_timer_read_ool_enabled);
static const struct arch_timer_erratum_workaround ool_workarounds[] = {
#ifdef CONFIG_FSL_ERRATUM_A008585
{
.id = "fsl,erratum-a008585",
.read_cntp_tval_el0 = fsl_a008585_read_cntp_tval_el0,
.read_cntv_tval_el0 = fsl_a008585_read_cntv_tval_el0,
.read_cntvct_el0 = fsl_a008585_read_cntvct_el0,
},
#endif
#ifdef CONFIG_HISILICON_ERRATUM_161010101
{
.id = "hisilicon,erratum-161010101",
.read_cntp_tval_el0 = hisi_161010101_read_cntp_tval_el0,
.read_cntv_tval_el0 = hisi_161010101_read_cntv_tval_el0,
.read_cntvct_el0 = hisi_161010101_read_cntvct_el0,
},
#endif
};
#endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */
static __always_inline
void arch_timer_reg_write(int access, enum arch_timer_reg reg, u32 val,
struct clock_event_device *clk)
{
if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
struct arch_timer *timer = to_arch_timer(clk);
switch (reg) {
case ARCH_TIMER_REG_CTRL:
writel_relaxed(val, timer->base + CNTP_CTL);
break;
case ARCH_TIMER_REG_TVAL:
writel_relaxed(val, timer->base + CNTP_TVAL);
break;
}
} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
struct arch_timer *timer = to_arch_timer(clk);
switch (reg) {
case ARCH_TIMER_REG_CTRL:
writel_relaxed(val, timer->base + CNTV_CTL);
break;
case ARCH_TIMER_REG_TVAL:
writel_relaxed(val, timer->base + CNTV_TVAL);
break;
}
} else {
arch_timer_reg_write_cp15(access, reg, val);
}
}
static __always_inline
u32 arch_timer_reg_read(int access, enum arch_timer_reg reg,
struct clock_event_device *clk)
{
u32 val;
if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
struct arch_timer *timer = to_arch_timer(clk);
switch (reg) {
case ARCH_TIMER_REG_CTRL:
val = readl_relaxed(timer->base + CNTP_CTL);
break;
case ARCH_TIMER_REG_TVAL:
val = readl_relaxed(timer->base + CNTP_TVAL);
break;
}
} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
struct arch_timer *timer = to_arch_timer(clk);
switch (reg) {
case ARCH_TIMER_REG_CTRL:
val = readl_relaxed(timer->base + CNTV_CTL);
break;
case ARCH_TIMER_REG_TVAL:
val = readl_relaxed(timer->base + CNTV_TVAL);
break;
}
} else {
val = arch_timer_reg_read_cp15(access, reg);
}
return val;
}
static __always_inline irqreturn_t timer_handler(const int access,
struct clock_event_device *evt)
{
unsigned long ctrl;
ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, evt);
if (ctrl & ARCH_TIMER_CTRL_IT_STAT) {
ctrl |= ARCH_TIMER_CTRL_IT_MASK;
arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, evt);
evt->event_handler(evt);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
static irqreturn_t arch_timer_handler_virt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
return timer_handler(ARCH_TIMER_VIRT_ACCESS, evt);
}
static irqreturn_t arch_timer_handler_phys(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
return timer_handler(ARCH_TIMER_PHYS_ACCESS, evt);
}
static irqreturn_t arch_timer_handler_phys_mem(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
return timer_handler(ARCH_TIMER_MEM_PHYS_ACCESS, evt);
}
static irqreturn_t arch_timer_handler_virt_mem(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
return timer_handler(ARCH_TIMER_MEM_VIRT_ACCESS, evt);
}
static __always_inline int timer_shutdown(const int access,
struct clock_event_device *clk)
{
unsigned long ctrl;
ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
return 0;
}
static int arch_timer_shutdown_virt(struct clock_event_device *clk)
{
return timer_shutdown(ARCH_TIMER_VIRT_ACCESS, clk);
}
static int arch_timer_shutdown_phys(struct clock_event_device *clk)
{
return timer_shutdown(ARCH_TIMER_PHYS_ACCESS, clk);
}
static int arch_timer_shutdown_virt_mem(struct clock_event_device *clk)
{
return timer_shutdown(ARCH_TIMER_MEM_VIRT_ACCESS, clk);
}
static int arch_timer_shutdown_phys_mem(struct clock_event_device *clk)
{
return timer_shutdown(ARCH_TIMER_MEM_PHYS_ACCESS, clk);
}
static __always_inline void set_next_event(const int access, unsigned long evt,
struct clock_event_device *clk)
{
unsigned long ctrl;
ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
ctrl |= ARCH_TIMER_CTRL_ENABLE;
ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt, clk);
arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
}
#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
static __always_inline void erratum_set_next_event_generic(const int access,
unsigned long evt, struct clock_event_device *clk)
{
unsigned long ctrl;
u64 cval = evt + arch_counter_get_cntvct();
ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
ctrl |= ARCH_TIMER_CTRL_ENABLE;
ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
if (access == ARCH_TIMER_PHYS_ACCESS)
write_sysreg(cval, cntp_cval_el0);
else if (access == ARCH_TIMER_VIRT_ACCESS)
write_sysreg(cval, cntv_cval_el0);
arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
}
static int erratum_set_next_event_virt(unsigned long evt,
struct clock_event_device *clk)
{
erratum_set_next_event_generic(ARCH_TIMER_VIRT_ACCESS, evt, clk);
return 0;
}
static int erratum_set_next_event_phys(unsigned long evt,
struct clock_event_device *clk)
{
erratum_set_next_event_generic(ARCH_TIMER_PHYS_ACCESS, evt, clk);
return 0;
}
#endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */
static int arch_timer_set_next_event_virt(unsigned long evt,
struct clock_event_device *clk)
{
set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk);
return 0;
}
static int arch_timer_set_next_event_phys(unsigned long evt,
struct clock_event_device *clk)
{
set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk);
return 0;
}
static int arch_timer_set_next_event_virt_mem(unsigned long evt,
struct clock_event_device *clk)
{
set_next_event(ARCH_TIMER_MEM_VIRT_ACCESS, evt, clk);
return 0;
}
static int arch_timer_set_next_event_phys_mem(unsigned long evt,
struct clock_event_device *clk)
{
set_next_event(ARCH_TIMER_MEM_PHYS_ACCESS, evt, clk);
return 0;
}
static void erratum_workaround_set_sne(struct clock_event_device *clk)
{
#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
if (!static_branch_unlikely(&arch_timer_read_ool_enabled))
return;
if (arch_timer_uses_ppi == VIRT_PPI)
clk->set_next_event = erratum_set_next_event_virt;
else
clk->set_next_event = erratum_set_next_event_phys;
#endif
}
static void __arch_timer_setup(unsigned type,
struct clock_event_device *clk)
{
clk->features = CLOCK_EVT_FEAT_ONESHOT;
if (type == ARCH_CP15_TIMER) {
if (arch_timer_c3stop)
clk->features |= CLOCK_EVT_FEAT_C3STOP;
clk->name = "arch_sys_timer";
clk->rating = 450;
clk->cpumask = cpumask_of(smp_processor_id());
clk->irq = arch_timer_ppi[arch_timer_uses_ppi];
switch (arch_timer_uses_ppi) {
case VIRT_PPI:
clk->set_state_shutdown = arch_timer_shutdown_virt;
clk->set_state_oneshot_stopped = arch_timer_shutdown_virt;
clk->set_next_event = arch_timer_set_next_event_virt;
break;
case PHYS_SECURE_PPI:
case PHYS_NONSECURE_PPI:
case HYP_PPI:
clk->set_state_shutdown = arch_timer_shutdown_phys;
clk->set_state_oneshot_stopped = arch_timer_shutdown_phys;
clk->set_next_event = arch_timer_set_next_event_phys;
break;
default:
BUG();
}
erratum_workaround_set_sne(clk);
} else {
clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
clk->name = "arch_mem_timer";
clk->rating = 400;
clk->cpumask = cpu_all_mask;
if (arch_timer_mem_use_virtual) {
clk->set_state_shutdown = arch_timer_shutdown_virt_mem;
clk->set_state_oneshot_stopped = arch_timer_shutdown_virt_mem;
clk->set_next_event =
arch_timer_set_next_event_virt_mem;
} else {
clk->set_state_shutdown = arch_timer_shutdown_phys_mem;
clk->set_state_oneshot_stopped = arch_timer_shutdown_phys_mem;
clk->set_next_event =
arch_timer_set_next_event_phys_mem;
}
}
clk->set_state_shutdown(clk);
clockevents_config_and_register(clk, arch_timer_rate, 0xf, 0x7fffffff);
}
static void arch_timer_evtstrm_enable(int divider)
{
u32 cntkctl = arch_timer_get_cntkctl();
cntkctl &= ~ARCH_TIMER_EVT_TRIGGER_MASK;
/* Set the divider and enable virtual event stream */
cntkctl |= (divider << ARCH_TIMER_EVT_TRIGGER_SHIFT)
| ARCH_TIMER_VIRT_EVT_EN;
arch_timer_set_cntkctl(cntkctl);
elf_hwcap |= HWCAP_EVTSTRM;
#ifdef CONFIG_COMPAT
compat_elf_hwcap |= COMPAT_HWCAP_EVTSTRM;
#endif
}
static void arch_timer_configure_evtstream(void)
{
int evt_stream_div, pos;
/* Find the closest power of two to the divisor */
evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ;
pos = fls(evt_stream_div);
if (pos > 1 && !(evt_stream_div & (1 << (pos - 2))))
pos--;
/* enable event stream */
arch_timer_evtstrm_enable(min(pos, 15));
}
static void arch_counter_set_user_access(void)
{
u32 cntkctl = arch_timer_get_cntkctl();
/* Disable user access to the timers and the physical counter */
/* Also disable virtual event stream */
cntkctl &= ~(ARCH_TIMER_USR_PT_ACCESS_EN
| ARCH_TIMER_USR_VT_ACCESS_EN
| ARCH_TIMER_VIRT_EVT_EN
| ARCH_TIMER_USR_PCT_ACCESS_EN);
/* Enable user access to the virtual counter */
cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN;
arch_timer_set_cntkctl(cntkctl);
}
static bool arch_timer_has_nonsecure_ppi(void)
{
return (arch_timer_uses_ppi == PHYS_SECURE_PPI &&
arch_timer_ppi[PHYS_NONSECURE_PPI]);
}
static u32 check_ppi_trigger(int irq)
{
u32 flags = irq_get_trigger_type(irq);
if (flags != IRQF_TRIGGER_HIGH && flags != IRQF_TRIGGER_LOW) {
pr_warn("WARNING: Invalid trigger for IRQ%d, assuming level low\n", irq);
pr_warn("WARNING: Please fix your firmware\n");
flags = IRQF_TRIGGER_LOW;
}
return flags;
}
static int arch_timer_starting_cpu(unsigned int cpu)
{
struct clock_event_device *clk = this_cpu_ptr(arch_timer_evt);
u32 flags;
__arch_timer_setup(ARCH_CP15_TIMER, clk);
flags = check_ppi_trigger(arch_timer_ppi[arch_timer_uses_ppi]);
enable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], flags);
if (arch_timer_has_nonsecure_ppi()) {
flags = check_ppi_trigger(arch_timer_ppi[PHYS_NONSECURE_PPI]);
enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], flags);
}
arch_counter_set_user_access();
if (evtstrm_enable)
arch_timer_configure_evtstream();
return 0;
}
static void
arch_timer_detect_rate(void __iomem *cntbase, struct device_node *np)
{
/* Who has more than one independent system counter? */
if (arch_timer_rate)
return;
/*
* Try to determine the frequency from the device tree or CNTFRQ,
* if ACPI is enabled, get the frequency from CNTFRQ ONLY.
*/
if (!acpi_disabled ||
of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) {
if (cntbase)
arch_timer_rate = readl_relaxed(cntbase + CNTFRQ);
else
arch_timer_rate = arch_timer_get_cntfrq();
}
/* Check the timer frequency. */
if (arch_timer_rate == 0)
pr_warn("Architected timer frequency not available\n");
}
static void arch_timer_banner(unsigned type)
{
pr_info("Architected %s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n",
type & ARCH_CP15_TIMER ? "cp15" : "",
type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ? " and " : "",
type & ARCH_MEM_TIMER ? "mmio" : "",
(unsigned long)arch_timer_rate / 1000000,
(unsigned long)(arch_timer_rate / 10000) % 100,
type & ARCH_CP15_TIMER ?
(arch_timer_uses_ppi == VIRT_PPI) ? "virt" : "phys" :
"",
type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ? "/" : "",
type & ARCH_MEM_TIMER ?
arch_timer_mem_use_virtual ? "virt" : "phys" :
"");
}
u32 arch_timer_get_rate(void)
{
return arch_timer_rate;
}
static u64 arch_counter_get_cntvct_mem(void)
{
u32 vct_lo, vct_hi, tmp_hi;
do {
vct_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
vct_lo = readl_relaxed(arch_counter_base + CNTVCT_LO);
tmp_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
} while (vct_hi != tmp_hi);
return ((u64) vct_hi << 32) | vct_lo;
}
/*
* Default to cp15 based access because arm64 uses this function for
* sched_clock() before DT is probed and the cp15 method is guaranteed
* to exist on arm64. arm doesn't use this before DT is probed so even
* if we don't have the cp15 accessors we won't have a problem.
*/
u64 (*arch_timer_read_counter)(void) = arch_counter_get_cntvct;
static u64 arch_counter_read(struct clocksource *cs)
{
return arch_timer_read_counter();
}
static u64 arch_counter_read_cc(const struct cyclecounter *cc)
{
return arch_timer_read_counter();
}
static struct clocksource clocksource_counter = {
.name = "arch_sys_counter",
.rating = 400,
.read = arch_counter_read,
.mask = CLOCKSOURCE_MASK(56),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static struct cyclecounter cyclecounter = {
.read = arch_counter_read_cc,
.mask = CLOCKSOURCE_MASK(56),
};
static struct arch_timer_kvm_info arch_timer_kvm_info;
struct arch_timer_kvm_info *arch_timer_get_kvm_info(void)
{
return &arch_timer_kvm_info;
}
static void __init arch_counter_register(unsigned type)
{
u64 start_count;
/* Register the CP15 based counter if we have one */
if (type & ARCH_CP15_TIMER) {
if (IS_ENABLED(CONFIG_ARM64) || arch_timer_uses_ppi == VIRT_PPI)
arch_timer_read_counter = arch_counter_get_cntvct;
else
arch_timer_read_counter = arch_counter_get_cntpct;
clocksource_counter.archdata.vdso_direct = true;
#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
/*
* Don't use the vdso fastpath if errata require using
* the out-of-line counter accessor.
*/
if (static_branch_unlikely(&arch_timer_read_ool_enabled))
clocksource_counter.archdata.vdso_direct = false;
#endif
} else {
arch_timer_read_counter = arch_counter_get_cntvct_mem;
}
if (!arch_counter_suspend_stop)
clocksource_counter.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP;
start_count = arch_timer_read_counter();
clocksource_register_hz(&clocksource_counter, arch_timer_rate);
cyclecounter.mult = clocksource_counter.mult;
cyclecounter.shift = clocksource_counter.shift;
timecounter_init(&arch_timer_kvm_info.timecounter,
&cyclecounter, start_count);
/* 56 bits minimum, so we assume worst case rollover */
sched_clock_register(arch_timer_read_counter, 56, arch_timer_rate);
}
static void arch_timer_stop(struct clock_event_device *clk)
{
pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n",
clk->irq, smp_processor_id());
disable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi]);
if (arch_timer_has_nonsecure_ppi())
disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]);
clk->set_state_shutdown(clk);
}
static int arch_timer_dying_cpu(unsigned int cpu)
{
struct clock_event_device *clk = this_cpu_ptr(arch_timer_evt);
arch_timer_stop(clk);
return 0;
}
#ifdef CONFIG_CPU_PM
static unsigned int saved_cntkctl;
static int arch_timer_cpu_pm_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
if (action == CPU_PM_ENTER)
saved_cntkctl = arch_timer_get_cntkctl();
else if (action == CPU_PM_ENTER_FAILED || action == CPU_PM_EXIT)
arch_timer_set_cntkctl(saved_cntkctl);
return NOTIFY_OK;
}
static struct notifier_block arch_timer_cpu_pm_notifier = {
.notifier_call = arch_timer_cpu_pm_notify,
};
static int __init arch_timer_cpu_pm_init(void)
{
return cpu_pm_register_notifier(&arch_timer_cpu_pm_notifier);
}
static void __init arch_timer_cpu_pm_deinit(void)
{
WARN_ON(cpu_pm_unregister_notifier(&arch_timer_cpu_pm_notifier));
}
#else
static int __init arch_timer_cpu_pm_init(void)
{
return 0;
}
static void __init arch_timer_cpu_pm_deinit(void)
{
}
#endif
static int __init arch_timer_register(void)
{
int err;
int ppi;
arch_timer_evt = alloc_percpu(struct clock_event_device);
if (!arch_timer_evt) {
err = -ENOMEM;
goto out;
}
ppi = arch_timer_ppi[arch_timer_uses_ppi];
switch (arch_timer_uses_ppi) {
case VIRT_PPI:
err = request_percpu_irq(ppi, arch_timer_handler_virt,
"arch_timer", arch_timer_evt);
break;
case PHYS_SECURE_PPI:
case PHYS_NONSECURE_PPI:
err = request_percpu_irq(ppi, arch_timer_handler_phys,
"arch_timer", arch_timer_evt);
if (!err && arch_timer_ppi[PHYS_NONSECURE_PPI]) {
ppi = arch_timer_ppi[PHYS_NONSECURE_PPI];
err = request_percpu_irq(ppi, arch_timer_handler_phys,
"arch_timer", arch_timer_evt);
if (err)
free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
arch_timer_evt);
}
break;
case HYP_PPI:
err = request_percpu_irq(ppi, arch_timer_handler_phys,
"arch_timer", arch_timer_evt);
break;
default:
BUG();
}
if (err) {
pr_err("arch_timer: can't register interrupt %d (%d)\n",
ppi, err);
goto out_free;
}
err = arch_timer_cpu_pm_init();
if (err)
goto out_unreg_notify;
/* Register and immediately configure the timer on the boot CPU */
err = cpuhp_setup_state(CPUHP_AP_ARM_ARCH_TIMER_STARTING,
"clockevents/arm/arch_timer:starting",
arch_timer_starting_cpu, arch_timer_dying_cpu);
if (err)
goto out_unreg_cpupm;
return 0;
out_unreg_cpupm:
arch_timer_cpu_pm_deinit();
out_unreg_notify:
free_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], arch_timer_evt);
if (arch_timer_has_nonsecure_ppi())
free_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI],
arch_timer_evt);
out_free:
free_percpu(arch_timer_evt);
out:
return err;
}
static int __init arch_timer_mem_register(void __iomem *base, unsigned int irq)
{
int ret;
irq_handler_t func;
struct arch_timer *t;
t = kzalloc(sizeof(*t), GFP_KERNEL);
if (!t)
return -ENOMEM;
t->base = base;
t->evt.irq = irq;
__arch_timer_setup(ARCH_MEM_TIMER, &t->evt);
if (arch_timer_mem_use_virtual)
func = arch_timer_handler_virt_mem;
else
func = arch_timer_handler_phys_mem;
ret = request_irq(irq, func, IRQF_TIMER, "arch_mem_timer", &t->evt);
if (ret) {
pr_err("arch_timer: Failed to request mem timer irq\n");
kfree(t);
}
return ret;
}
static const struct of_device_id arch_timer_of_match[] __initconst = {
{ .compatible = "arm,armv7-timer", },
{ .compatible = "arm,armv8-timer", },
{},
};
static const struct of_device_id arch_timer_mem_of_match[] __initconst = {
{ .compatible = "arm,armv7-timer-mem", },
{},
};
static bool __init
arch_timer_needs_probing(int type, const struct of_device_id *matches)
{
struct device_node *dn;
bool needs_probing = false;
dn = of_find_matching_node(NULL, matches);
if (dn && of_device_is_available(dn) && !(arch_timers_present & type))
needs_probing = true;
of_node_put(dn);
return needs_probing;
}
static int __init arch_timer_common_init(void)
{
unsigned mask = ARCH_CP15_TIMER | ARCH_MEM_TIMER;
/* Wait until both nodes are probed if we have two timers */
if ((arch_timers_present & mask) != mask) {
if (arch_timer_needs_probing(ARCH_MEM_TIMER, arch_timer_mem_of_match))
return 0;
if (arch_timer_needs_probing(ARCH_CP15_TIMER, arch_timer_of_match))
return 0;
}
arch_timer_banner(arch_timers_present);
arch_counter_register(arch_timers_present);
return arch_timer_arch_init();
}
static int __init arch_timer_init(void)
{
int ret;
/*
* If HYP mode is available, we know that the physical timer
* has been configured to be accessible from PL1. Use it, so
* that a guest can use the virtual timer instead.
*
* If no interrupt provided for virtual timer, we'll have to
* stick to the physical timer. It'd better be accessible...
*
* On ARMv8.1 with VH extensions, the kernel runs in HYP. VHE
* accesses to CNTP_*_EL1 registers are silently redirected to
* their CNTHP_*_EL2 counterparts, and use a different PPI
* number.
*/
if (is_hyp_mode_available() || !arch_timer_ppi[VIRT_PPI]) {
bool has_ppi;
if (is_kernel_in_hyp_mode()) {
arch_timer_uses_ppi = HYP_PPI;
has_ppi = !!arch_timer_ppi[HYP_PPI];
} else {
arch_timer_uses_ppi = PHYS_SECURE_PPI;
has_ppi = (!!arch_timer_ppi[PHYS_SECURE_PPI] ||
!!arch_timer_ppi[PHYS_NONSECURE_PPI]);
}
if (!has_ppi) {
pr_warn("arch_timer: No interrupt available, giving up\n");
return -EINVAL;
}
}
ret = arch_timer_register();
if (ret)
return ret;
ret = arch_timer_common_init();
if (ret)
return ret;
arch_timer_kvm_info.virtual_irq = arch_timer_ppi[VIRT_PPI];
return 0;
}
static int __init arch_timer_of_init(struct device_node *np)
{
int i;
if (arch_timers_present & ARCH_CP15_TIMER) {
pr_warn("arch_timer: multiple nodes in dt, skipping\n");
return 0;
}
arch_timers_present |= ARCH_CP15_TIMER;
for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
arch_timer_detect_rate(NULL, np);
arch_timer_c3stop = !of_property_read_bool(np, "always-on");
#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
for (i = 0; i < ARRAY_SIZE(ool_workarounds); i++) {
if (of_property_read_bool(np, ool_workarounds[i].id)) {
timer_unstable_counter_workaround = &ool_workarounds[i];
static_branch_enable(&arch_timer_read_ool_enabled);
pr_info("arch_timer: Enabling workaround for %s\n",
timer_unstable_counter_workaround->id);
break;
}
}
#endif
/*
* If we cannot rely on firmware initializing the timer registers then
* we should use the physical timers instead.
*/
if (IS_ENABLED(CONFIG_ARM) &&
of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
arch_timer_uses_ppi = PHYS_SECURE_PPI;
/* On some systems, the counter stops ticking when in suspend. */
arch_counter_suspend_stop = of_property_read_bool(np,
"arm,no-tick-in-suspend");
return arch_timer_init();
}
CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_of_init);
CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_of_init);
static int __init arch_timer_mem_init(struct device_node *np)
{
struct device_node *frame, *best_frame = NULL;
void __iomem *cntctlbase, *base;
unsigned int irq, ret = -EINVAL;
u32 cnttidr;
arch_timers_present |= ARCH_MEM_TIMER;
cntctlbase = of_iomap(np, 0);
if (!cntctlbase) {
pr_err("arch_timer: Can't find CNTCTLBase\n");
return -ENXIO;
}
cnttidr = readl_relaxed(cntctlbase + CNTTIDR);
/*
* Try to find a virtual capable frame. Otherwise fall back to a
* physical capable frame.
*/
for_each_available_child_of_node(np, frame) {
int n;
u32 cntacr;
if (of_property_read_u32(frame, "frame-number", &n)) {
pr_err("arch_timer: Missing frame-number\n");
of_node_put(frame);
goto out;
}
/* Try enabling everything, and see what sticks */
cntacr = CNTACR_RFRQ | CNTACR_RWPT | CNTACR_RPCT |
CNTACR_RWVT | CNTACR_RVOFF | CNTACR_RVCT;
writel_relaxed(cntacr, cntctlbase + CNTACR(n));
cntacr = readl_relaxed(cntctlbase + CNTACR(n));
if ((cnttidr & CNTTIDR_VIRT(n)) &&
!(~cntacr & (CNTACR_RWVT | CNTACR_RVCT))) {
of_node_put(best_frame);
best_frame = frame;
arch_timer_mem_use_virtual = true;
break;
}
if (~cntacr & (CNTACR_RWPT | CNTACR_RPCT))
continue;
of_node_put(best_frame);
best_frame = of_node_get(frame);
}
ret= -ENXIO;
base = arch_counter_base = of_io_request_and_map(best_frame, 0,
"arch_mem_timer");
if (IS_ERR(base)) {
pr_err("arch_timer: Can't map frame's registers\n");
goto out;
}
if (arch_timer_mem_use_virtual)
irq = irq_of_parse_and_map(best_frame, 1);
else
irq = irq_of_parse_and_map(best_frame, 0);
ret = -EINVAL;
if (!irq) {
pr_err("arch_timer: Frame missing %s irq",
arch_timer_mem_use_virtual ? "virt" : "phys");
goto out;
}
arch_timer_detect_rate(base, np);
ret = arch_timer_mem_register(base, irq);
if (ret)
goto out;
return arch_timer_common_init();
out:
iounmap(cntctlbase);
of_node_put(best_frame);
return ret;
}
CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
arch_timer_mem_init);
#ifdef CONFIG_ACPI
static int __init map_generic_timer_interrupt(u32 interrupt, u32 flags)
{
int trigger, polarity;
if (!interrupt)
return 0;
trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
: ACPI_LEVEL_SENSITIVE;
polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
: ACPI_ACTIVE_HIGH;
return acpi_register_gsi(NULL, interrupt, trigger, polarity);
}
/* Initialize per-processor generic timer */
static int __init arch_timer_acpi_init(struct acpi_table_header *table)
{
struct acpi_table_gtdt *gtdt;
if (arch_timers_present & ARCH_CP15_TIMER) {
pr_warn("arch_timer: already initialized, skipping\n");
return -EINVAL;
}
gtdt = container_of(table, struct acpi_table_gtdt, header);
arch_timers_present |= ARCH_CP15_TIMER;
arch_timer_ppi[PHYS_SECURE_PPI] =
map_generic_timer_interrupt(gtdt->secure_el1_interrupt,
gtdt->secure_el1_flags);
arch_timer_ppi[PHYS_NONSECURE_PPI] =
map_generic_timer_interrupt(gtdt->non_secure_el1_interrupt,
gtdt->non_secure_el1_flags);
arch_timer_ppi[VIRT_PPI] =
map_generic_timer_interrupt(gtdt->virtual_timer_interrupt,
gtdt->virtual_timer_flags);
arch_timer_ppi[HYP_PPI] =
map_generic_timer_interrupt(gtdt->non_secure_el2_interrupt,
gtdt->non_secure_el2_flags);
/* Get the frequency from CNTFRQ */
arch_timer_detect_rate(NULL, NULL);
/* Always-on capability */
arch_timer_c3stop = !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);
arch_timer_init();
return 0;
}
CLOCKSOURCE_ACPI_DECLARE(arch_timer, ACPI_SIG_GTDT, arch_timer_acpi_init);
#endif