arm: arch_timer: move core to drivers/clocksource

The core functionality of the arch_timer driver is not directly tied to
anything under arch/arm, and can be split out.

This patch factors out the core of the arch_timer driver, so it can be
shared with other architectures. A couple of functions are added so
that architecture-specific code can interact with the driver without
needing to touch its internals.

The ARM_ARCH_TIMER config variable is moved out to
drivers/clocksource/Kconfig, existing uses in arch/arm are replaced with
HAVE_ARM_ARCH_TIMER, which selects it.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 18 insertions, 368 deletions

diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c
index 94f503394c5c..36ebcf4b516f 100644
--- a/arch/arm/kernel/arch_timer.c
+++ b/arch/arm/kernel/arch_timer.c
@@ -9,402 +9,52 @@
  * published by the Free Software Foundation.
  */
 #include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/delay.h>
-#include <linux/device.h>
-#include <linux/smp.h>
-#include <linux/cpu.h>
-#include <linux/jiffies.h>
-#include <linux/clockchips.h>
-#include <linux/interrupt.h>
-#include <linux/of_irq.h>
-#include <linux/io.h>
+#include <linux/types.h>
 
 #include <asm/delay.h>
-#include <asm/arch_timer.h>
 #include <asm/sched_clock.h>
 
-static u32 arch_timer_rate;
+#include <clocksource/arm_arch_timer.h>
 
-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 struct delay_timer arch_delay_timer;
-
-static bool arch_timer_use_virtual = true;
-
-/*
- * Architected system timer support.
- */
-
-static irqreturn_t inline timer_handler(const int access,
-					struct clock_event_device *evt)
-{
-	unsigned long ctrl;
-	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL);
-	if (ctrl & ARCH_TIMER_CTRL_IT_STAT) {
-		ctrl |= ARCH_TIMER_CTRL_IT_MASK;
-		arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);
-		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 inline void timer_set_mode(const int access, int mode)
-{
-	unsigned long ctrl;
-	switch (mode) {
-	case CLOCK_EVT_MODE_UNUSED:
-	case CLOCK_EVT_MODE_SHUTDOWN:
-		ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL);
-		ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
-		arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);
-		break;
-	default:
-		break;
-	}
-}
-
-static void arch_timer_set_mode_virt(enum clock_event_mode mode,
-				     struct clock_event_device *clk)
-{
-	timer_set_mode(ARCH_TIMER_VIRT_ACCESS, mode);
-}
-
-static void arch_timer_set_mode_phys(enum clock_event_mode mode,
-				     struct clock_event_device *clk)
-{
-	timer_set_mode(ARCH_TIMER_PHYS_ACCESS, mode);
-}
-
-static inline void set_next_event(const int access, unsigned long evt)
-{
-	unsigned long ctrl;
-	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL);
-	ctrl |= ARCH_TIMER_CTRL_ENABLE;
-	ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
-	arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt);
-	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);
-}
-
-static int arch_timer_set_next_event_virt(unsigned long evt,
-					  struct clock_event_device *unused)
-{
-	set_next_event(ARCH_TIMER_VIRT_ACCESS, evt);
-	return 0;
-}
-
-static int arch_timer_set_next_event_phys(unsigned long evt,
-					  struct clock_event_device *unused)
-{
-	set_next_event(ARCH_TIMER_PHYS_ACCESS, evt);
-	return 0;
-}
-
-static int __cpuinit arch_timer_setup(struct clock_event_device *clk)
-{
-	clk->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP;
-	clk->name = "arch_sys_timer";
-	clk->rating = 450;
-	if (arch_timer_use_virtual) {
-		clk->irq = arch_timer_ppi[VIRT_PPI];
-		clk->set_mode = arch_timer_set_mode_virt;
-		clk->set_next_event = arch_timer_set_next_event_virt;
-	} else {
-		clk->irq = arch_timer_ppi[PHYS_SECURE_PPI];
-		clk->set_mode = arch_timer_set_mode_phys;
-		clk->set_next_event = arch_timer_set_next_event_phys;
-	}
-
-	clk->cpumask = cpumask_of(smp_processor_id());
-
-	clk->set_mode(CLOCK_EVT_MODE_SHUTDOWN, NULL);
-
-	clockevents_config_and_register(clk, arch_timer_rate,
-					0xf, 0x7fffffff);
-
-	if (arch_timer_use_virtual)
-		enable_percpu_irq(arch_timer_ppi[VIRT_PPI], 0);
-	else {
-		enable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI], 0);
-		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
-			enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], 0);
-	}
-
-	arch_counter_set_user_access();
-
-	return 0;
-}
-
-static int arch_timer_available(void)
-{
-	u32 freq;
-
-	if (arch_timer_rate == 0) {
-		freq = arch_timer_get_cntfrq();
-
-		/* Check the timer frequency. */
-		if (freq == 0) {
-			pr_warn("Architected timer frequency not available\n");
-			return -EINVAL;
-		}
-
-		arch_timer_rate = freq;
-	}
-
-	pr_info_once("Architected local timer running at %lu.%02luMHz (%s).\n",
-		     (unsigned long)arch_timer_rate / 1000000,
-		     (unsigned long)(arch_timer_rate / 10000) % 100,
-		     arch_timer_use_virtual ? "virt" : "phys");
-	return 0;
-}
-
-/*
- * Some external users of arch_timer_read_counter (e.g. sched_clock) may try to
- * call it before it has been initialised. Rather than incur a performance
- * penalty checking for initialisation, provide a default implementation that
- * won't lead to time appearing to jump backwards.
- */
-static u64 arch_timer_read_zero(void)
-{
-	return 0;
-}
-
-u64 (*arch_timer_read_counter)(void) = arch_timer_read_zero;
-
-static u32 arch_timer_read_counter32(void)
-{
-	return arch_timer_read_counter();
-}
-
-static cycle_t arch_counter_read(struct clocksource *cs)
+static unsigned long arch_timer_read_counter_long(void)
 {
 	return arch_timer_read_counter();
 }
 
-static unsigned long arch_timer_read_current_timer(void)
+static u32 arch_timer_read_counter_u32(void)
 {
 	return arch_timer_read_counter();
 }
 
-static cycle_t 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 timecounter timecounter;
-
-struct timecounter *arch_timer_get_timecounter(void)
-{
-	return &timecounter;
-}
-
-static void __cpuinit arch_timer_stop(struct clock_event_device *clk)
-{
-	pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n",
-		 clk->irq, smp_processor_id());
-
-	if (arch_timer_use_virtual)
-		disable_percpu_irq(arch_timer_ppi[VIRT_PPI]);
-	else {
-		disable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI]);
-		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
-			disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]);
-	}
-
-	clk->set_mode(CLOCK_EVT_MODE_UNUSED, clk);
-}
-
-static int __cpuinit arch_timer_cpu_notify(struct notifier_block *self,
-					   unsigned long action, void *hcpu)
-{
-	struct clock_event_device *evt = this_cpu_ptr(arch_timer_evt);
-
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_STARTING:
-		arch_timer_setup(evt);
-		break;
-	case CPU_DYING:
-		arch_timer_stop(evt);
-		break;
-	}
-
-	return NOTIFY_OK;
-}
-
-static struct notifier_block arch_timer_cpu_nb __cpuinitdata = {
-	.notifier_call = arch_timer_cpu_notify,
-};
+static struct delay_timer arch_delay_timer;
 
-static int __init arch_timer_register(void)
+static void __init arch_timer_delay_timer_register(void)
 {
-	int err;
-	int ppi;
-
-	err = arch_timer_available();
-	if (err)
-		goto out;
-
-	arch_timer_evt = alloc_percpu(struct clock_event_device);
-	if (!arch_timer_evt) {
-		err = -ENOMEM;
-		goto out;
-	}
-
-	clocksource_register_hz(&clocksource_counter, arch_timer_rate);
-	cyclecounter.mult = clocksource_counter.mult;
-	cyclecounter.shift = clocksource_counter.shift;
-	timecounter_init(&timecounter, &cyclecounter,
-			 arch_counter_get_cntpct());
-
-	if (arch_timer_use_virtual) {
-		ppi = arch_timer_ppi[VIRT_PPI];
-		err = request_percpu_irq(ppi, arch_timer_handler_virt,
-					 "arch_timer", arch_timer_evt);
-	} else {
-		ppi = arch_timer_ppi[PHYS_SECURE_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);
-		}
-	}
-
-	if (err) {
-		pr_err("arch_timer: can't register interrupt %d (%d)\n",
-		       ppi, err);
-		goto out_free;
-	}
-
-	err = register_cpu_notifier(&arch_timer_cpu_nb);
-	if (err)
-		goto out_free_irq;
-
-	/* Immediately configure the timer on the boot CPU */
-	arch_timer_setup(this_cpu_ptr(arch_timer_evt));
-
 	/* Use the architected timer for the delay loop. */
-	arch_delay_timer.read_current_timer = &arch_timer_read_current_timer;
-	arch_delay_timer.freq = arch_timer_rate;
+	arch_delay_timer.read_current_timer = arch_timer_read_counter_long;
+	arch_delay_timer.freq = arch_timer_get_rate();
 	register_current_timer_delay(&arch_delay_timer);
-	return 0;
-
-out_free_irq:
-	if (arch_timer_use_virtual)
-		free_percpu_irq(arch_timer_ppi[VIRT_PPI], arch_timer_evt);
-	else {
-		free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
-				arch_timer_evt);
-		if (arch_timer_ppi[PHYS_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 const struct of_device_id arch_timer_of_match[] __initconst = {
-	{ .compatible	= "arm,armv7-timer",	},
-	{},
-};
-
 int __init arch_timer_of_register(void)
 {
-	struct device_node *np;
-	u32 freq;
-	int i;
-
-	np = of_find_matching_node(NULL, arch_timer_of_match);
-	if (!np) {
-		pr_err("arch_timer: can't find DT node\n");
-		return -ENODEV;
-	}
+	int ret;
 
-	/* Try to determine the frequency from the device tree or CNTFRQ */
-	if (!of_property_read_u32(np, "clock-frequency", &freq))
-		arch_timer_rate = freq;
+	ret = arch_timer_init();
+	if (ret)
+		return ret;
 
-	for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
-		arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
+	arch_timer_delay_timer_register();
 
-	of_node_put(np);
-
-	/*
-	 * If no interrupt provided for virtual timer, we'll have to
-	 * stick to the physical timer. It'd better be accessible...
-	 */
-	if (!arch_timer_ppi[VIRT_PPI]) {
-		arch_timer_use_virtual = false;
-
-		if (!arch_timer_ppi[PHYS_SECURE_PPI] ||
-		    !arch_timer_ppi[PHYS_NONSECURE_PPI]) {
-			pr_warn("arch_timer: No interrupt available, giving up\n");
-			return -EINVAL;
-		}
-	}
-
-	if (arch_timer_use_virtual)
-		arch_timer_read_counter = arch_counter_get_cntvct;
-	else
-		arch_timer_read_counter = arch_counter_get_cntpct;
-
-	return arch_timer_register();
+	return 0;
 }
 
 int __init arch_timer_sched_clock_init(void)
 {
-	int err;
-
-	err = arch_timer_available();
-	if (err)
-		return err;
+	if (arch_timer_get_rate() == 0)
+		return -ENXIO;
 
-	setup_sched_clock(arch_timer_read_counter32,
-			  32, arch_timer_rate);
+	setup_sched_clock(arch_timer_read_counter_u32,
+			  32, arch_timer_get_rate());
 	return 0;
 }