Merge branch 'timers-clocksource-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'timers-clocksource-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  clocksource: apb: Share APB timer code with other platforms

7 files changed, 533 insertions, 360 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5f60ea190d5b..c3e03e46bc64 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -623,6 +623,7 @@ config HPET_EMULATE_RTC
 config APB_TIMER
        def_bool y if MRST
        prompt "Langwell APB Timer Support" if X86_MRST
+       select DW_APB_TIMER
        help
          APB timer is the replacement for 8254, HPET on X86 MID platforms.
          The APBT provides a stable time base on SMP
diff --git a/arch/x86/include/asm/apb_timer.h b/arch/x86/include/asm/apb_timer.h
index 082cf8184935..0acbac299e49 100644
--- a/arch/x86/include/asm/apb_timer.h
+++ b/arch/x86/include/asm/apb_timer.h
@@ -18,24 +18,6 @@
 
 #ifdef CONFIG_APB_TIMER
 
-/* Langwell DW APB timer registers */
-#define APBTMR_N_LOAD_COUNT    0x00
-#define APBTMR_N_CURRENT_VALUE 0x04
-#define APBTMR_N_CONTROL       0x08
-#define APBTMR_N_EOI           0x0c
-#define APBTMR_N_INT_STATUS    0x10
-
-#define APBTMRS_INT_STATUS     0xa0
-#define APBTMRS_EOI            0xa4
-#define APBTMRS_RAW_INT_STATUS 0xa8
-#define APBTMRS_COMP_VERSION   0xac
-#define APBTMRS_REG_SIZE       0x14
-
-/* register bits */
-#define APBTMR_CONTROL_ENABLE  (1<<0)
-#define APBTMR_CONTROL_MODE_PERIODIC   (1<<1) /*1: periodic 0:free running */
-#define APBTMR_CONTROL_INT     (1<<2)
-
 /* default memory mapped register base */
 #define LNW_SCU_ADDR           0xFF100000
 #define LNW_EXT_TIMER_OFFSET   0x1B800
@@ -43,8 +25,8 @@
 #define LNW_EXT_TIMER_PGOFFSET         0x800
 
 /* APBT clock speed range from PCLK to fabric base, 25-100MHz */
-#define APBT_MAX_FREQ          50
-#define APBT_MIN_FREQ          1
+#define APBT_MAX_FREQ          50000000
+#define APBT_MIN_FREQ          1000000
 #define APBT_MMAP_SIZE         1024
 
 #define APBT_DEV_USED  1
diff --git a/arch/x86/kernel/apb_timer.c b/arch/x86/kernel/apb_timer.c
index 2b6630d75e17..afdc3f756dea 100644
--- a/arch/x86/kernel/apb_timer.c
+++ b/arch/x86/kernel/apb_timer.c
@@ -27,15 +27,12 @@
  * timer, but by default APB timer has higher rating than local APIC timers.
  */
 
-#include <linux/clocksource.h>
-#include <linux/clockchips.h>
 #include <linux/delay.h>
+#include <linux/dw_apb_timer.h>
 #include <linux/errno.h>
 #include <linux/init.h>
-#include <linux/sysdev.h>
 #include <linux/slab.h>
 #include <linux/pm.h>
-#include <linux/pci.h>
 #include <linux/sfi.h>
 #include <linux/interrupt.h>
 #include <linux/cpu.h>
@@ -46,75 +43,46 @@
 #include <asm/mrst.h>
 #include <asm/time.h>
 
-#define APBT_MASK			CLOCKSOURCE_MASK(32)
-#define APBT_SHIFT			22
 #define APBT_CLOCKEVENT_RATING		110
 #define APBT_CLOCKSOURCE_RATING		250
-#define APBT_MIN_DELTA_USEC		200
 
-#define EVT_TO_APBT_DEV(evt) container_of(evt, struct apbt_dev, evt)
 #define APBT_CLOCKEVENT0_NUM   (0)
-#define APBT_CLOCKEVENT1_NUM   (1)
 #define APBT_CLOCKSOURCE_NUM   (2)
 
-static unsigned long apbt_address;
+static phys_addr_t apbt_address;
 static int apb_timer_block_enabled;
 static void __iomem *apbt_virt_address;
-static int phy_cs_timer_id;
 
 /*
  * Common DW APB timer info
  */
-static uint64_t apbt_freq;
-
-static void apbt_set_mode(enum clock_event_mode mode,
-			  struct clock_event_device *evt);
-static int apbt_next_event(unsigned long delta,
-			   struct clock_event_device *evt);
-static cycle_t apbt_read_clocksource(struct clocksource *cs);
-static void apbt_restart_clocksource(struct clocksource *cs);
+static unsigned long apbt_freq;
 
 struct apbt_dev {
-	struct clock_event_device evt;
-	unsigned int num;
-	int cpu;
-	unsigned int irq;
-	unsigned int tick;
-	unsigned int count;
-	unsigned int flags;
-	char name[10];
+	struct dw_apb_clock_event_device	*timer;
+	unsigned int				num;
+	int					cpu;
+	unsigned int				irq;
+	char					name[10];
 };
 
-static DEFINE_PER_CPU(struct apbt_dev, cpu_apbt_dev);
+static struct dw_apb_clocksource *clocksource_apbt;
 
-#ifdef CONFIG_SMP
-static unsigned int apbt_num_timers_used;
-static struct apbt_dev *apbt_devs;
-#endif
-
-static	inline unsigned long apbt_readl_reg(unsigned long a)
+static inline void __iomem *adev_virt_addr(struct apbt_dev *adev)
 {
-	return readl(apbt_virt_address + a);
+	return apbt_virt_address + adev->num * APBTMRS_REG_SIZE;
 }
 
-static inline void apbt_writel_reg(unsigned long d, unsigned long a)
-{
-	writel(d, apbt_virt_address + a);
-}
-
-static inline unsigned long apbt_readl(int n, unsigned long a)
-{
-	return readl(apbt_virt_address + a + n * APBTMRS_REG_SIZE);
-}
+static DEFINE_PER_CPU(struct apbt_dev, cpu_apbt_dev);
 
-static inline void apbt_writel(int n, unsigned long d, unsigned long a)
-{
-	writel(d, apbt_virt_address + a + n * APBTMRS_REG_SIZE);
-}
+#ifdef CONFIG_SMP
+static unsigned int apbt_num_timers_used;
+#endif
 
 static inline void apbt_set_mapping(void)
 {
 	struct sfi_timer_table_entry *mtmr;
+	int phy_cs_timer_id = 0;
 
 	if (apbt_virt_address) {
 		pr_debug("APBT base already mapped\n");
@@ -126,21 +94,18 @@ static inline void apbt_set_mapping(void)
 		       APBT_CLOCKEVENT0_NUM);
 		return;
 	}
-	apbt_address = (unsigned long)mtmr->phys_addr;
+	apbt_address = (phys_addr_t)mtmr->phys_addr;
 	if (!apbt_address) {
 		printk(KERN_WARNING "No timer base from SFI, use default\n");
 		apbt_address = APBT_DEFAULT_BASE;
 	}
 	apbt_virt_address = ioremap_nocache(apbt_address, APBT_MMAP_SIZE);
-	if (apbt_virt_address) {
-		pr_debug("Mapped APBT physical addr %p at virtual addr %p\n",\
-			 (void *)apbt_address, (void *)apbt_virt_address);
-	} else {
-		pr_debug("Failed mapping APBT phy address at %p\n",\
-			 (void *)apbt_address);
+	if (!apbt_virt_address) {
+		pr_debug("Failed mapping APBT phy address at %lu\n",\
+			 (unsigned long)apbt_address);
 		goto panic_noapbt;
 	}
-	apbt_freq = mtmr->freq_hz / USEC_PER_SEC;
+	apbt_freq = mtmr->freq_hz;
 	sfi_free_mtmr(mtmr);
 
 	/* Now figure out the physical timer id for clocksource device */
@@ -149,9 +114,14 @@ static inline void apbt_set_mapping(void)
 		goto panic_noapbt;
 
 	/* Now figure out the physical timer id */
-	phy_cs_timer_id = (unsigned int)(mtmr->phys_addr & 0xff)
-		/ APBTMRS_REG_SIZE;
-	pr_debug("Use timer %d for clocksource\n", phy_cs_timer_id);
+	pr_debug("Use timer %d for clocksource\n",
+		 (int)(mtmr->phys_addr & 0xff) / APBTMRS_REG_SIZE);
+	phy_cs_timer_id = (unsigned int)(mtmr->phys_addr & 0xff) /
+		APBTMRS_REG_SIZE;
+
+	clocksource_apbt = dw_apb_clocksource_init(APBT_CLOCKSOURCE_RATING,
+		"apbt0", apbt_virt_address + phy_cs_timer_id *
+		APBTMRS_REG_SIZE, apbt_freq);
 	return;
 
 panic_noapbt:
@@ -173,82 +143,6 @@ static inline int is_apbt_capable(void)
 	return apbt_virt_address ? 1 : 0;
 }
 
-static struct clocksource clocksource_apbt = {
-	.name		= "apbt",
-	.rating		= APBT_CLOCKSOURCE_RATING,
-	.read		= apbt_read_clocksource,
-	.mask		= APBT_MASK,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
-	.resume		= apbt_restart_clocksource,
-};
-
-/* boot APB clock event device */
-static struct clock_event_device apbt_clockevent = {
-	.name		= "apbt0",
-	.features	= CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
-	.set_mode	= apbt_set_mode,
-	.set_next_event = apbt_next_event,
-	.shift		= APBT_SHIFT,
-	.irq		= 0,
-	.rating		= APBT_CLOCKEVENT_RATING,
-};
-
-/*
- * start count down from 0xffff_ffff. this is done by toggling the enable bit
- * then load initial load count to ~0.
- */
-static void apbt_start_counter(int n)
-{
-	unsigned long ctrl = apbt_readl(n, APBTMR_N_CONTROL);
-
-	ctrl &= ~APBTMR_CONTROL_ENABLE;
-	apbt_writel(n, ctrl, APBTMR_N_CONTROL);
-	apbt_writel(n, ~0, APBTMR_N_LOAD_COUNT);
-	/* enable, mask interrupt */
-	ctrl &= ~APBTMR_CONTROL_MODE_PERIODIC;
-	ctrl |= (APBTMR_CONTROL_ENABLE | APBTMR_CONTROL_INT);
-	apbt_writel(n, ctrl, APBTMR_N_CONTROL);
-	/* read it once to get cached counter value initialized */
-	apbt_read_clocksource(&clocksource_apbt);
-}
-
-static irqreturn_t apbt_interrupt_handler(int irq, void *data)
-{
-	struct apbt_dev *dev = (struct apbt_dev *)data;
-	struct clock_event_device *aevt = &dev->evt;
-
-	if (!aevt->event_handler) {
-		printk(KERN_INFO "Spurious APBT timer interrupt on %d\n",
-		       dev->num);
-		return IRQ_NONE;
-	}
-	aevt->event_handler(aevt);
-	return IRQ_HANDLED;
-}
-
-static void apbt_restart_clocksource(struct clocksource *cs)
-{
-	apbt_start_counter(phy_cs_timer_id);
-}
-
-static void apbt_enable_int(int n)
-{
-	unsigned long ctrl = apbt_readl(n, APBTMR_N_CONTROL);
-	/* clear pending intr */
-	apbt_readl(n, APBTMR_N_EOI);
-	ctrl &= ~APBTMR_CONTROL_INT;
-	apbt_writel(n, ctrl, APBTMR_N_CONTROL);
-}
-
-static void apbt_disable_int(int n)
-{
-	unsigned long ctrl = apbt_readl(n, APBTMR_N_CONTROL);
-
-	ctrl |= APBTMR_CONTROL_INT;
-	apbt_writel(n, ctrl, APBTMR_N_CONTROL);
-}
-
-
 static int __init apbt_clockevent_register(void)
 {
 	struct sfi_timer_table_entry *mtmr;
@@ -261,45 +155,21 @@ static int __init apbt_clockevent_register(void)
 		return -ENODEV;
 	}
 
-	/*
-	 * We need to calculate the scaled math multiplication factor for
-	 * nanosecond to apbt tick conversion.
-	 * mult = (nsec/cycle)*2^APBT_SHIFT
-	 */
-	apbt_clockevent.mult = div_sc((unsigned long) mtmr->freq_hz
-				      , NSEC_PER_SEC, APBT_SHIFT);
-
-	/* Calculate the min / max delta */
-	apbt_clockevent.max_delta_ns = clockevent_delta2ns(0x7FFFFFFF,
-							   &apbt_clockevent);
-	apbt_clockevent.min_delta_ns = clockevent_delta2ns(
-		APBT_MIN_DELTA_USEC*apbt_freq,
-		&apbt_clockevent);
-	/*
-	 * Start apbt with the boot cpu mask and make it
-	 * global if not used for per cpu timer.
-	 */
-	apbt_clockevent.cpumask = cpumask_of(smp_processor_id());
 	adev->num = smp_processor_id();
-	memcpy(&adev->evt, &apbt_clockevent, sizeof(struct clock_event_device));
+	adev->timer = dw_apb_clockevent_init(smp_processor_id(), "apbt0",
+		mrst_timer_options == MRST_TIMER_LAPIC_APBT ?
+		APBT_CLOCKEVENT_RATING - 100 : APBT_CLOCKEVENT_RATING,
+		adev_virt_addr(adev), 0, apbt_freq);
+	/* Firmware does EOI handling for us. */
+	adev->timer->eoi = NULL;
 
 	if (mrst_timer_options == MRST_TIMER_LAPIC_APBT) {
-		adev->evt.rating = APBT_CLOCKEVENT_RATING - 100;
-		global_clock_event = &adev->evt;
+		global_clock_event = &adev->timer->ced;
 		printk(KERN_DEBUG "%s clockevent registered as global\n",
 		       global_clock_event->name);
 	}
 
-	if (request_irq(apbt_clockevent.irq, apbt_interrupt_handler,
-			IRQF_TIMER | IRQF_DISABLED | IRQF_NOBALANCING,
-			apbt_clockevent.name, adev)) {
-		printk(KERN_ERR "Failed request IRQ for APBT%d\n",
-		       apbt_clockevent.irq);
-	}
-
-	clockevents_register_device(&adev->evt);
-	/* Start APBT 0 interrupts */
-	apbt_enable_int(APBT_CLOCKEVENT0_NUM);
+	dw_apb_clockevent_register(adev->timer);
 
 	sfi_free_mtmr(mtmr);
 	return 0;
@@ -317,52 +187,34 @@ static void apbt_setup_irq(struct apbt_dev *adev)
 	irq_set_affinity(adev->irq, cpumask_of(adev->cpu));
 	/* APB timer irqs are set up as mp_irqs, timer is edge type */
 	__irq_set_handler(adev->irq, handle_edge_irq, 0, "edge");
-
-	if (system_state == SYSTEM_BOOTING) {
-		if (request_irq(adev->irq, apbt_interrupt_handler,
-					IRQF_TIMER | IRQF_DISABLED |
-					IRQF_NOBALANCING,
-					adev->name, adev)) {
-			printk(KERN_ERR "Failed request IRQ for APBT%d\n",
-			       adev->num);
-		}
-	} else
-		enable_irq(adev->irq);
 }
 
 /* Should be called with per cpu */
 void apbt_setup_secondary_clock(void)
 {
 	struct apbt_dev *adev;
-	struct clock_event_device *aevt;
 	int cpu;
 
 	/* Don't register boot CPU clockevent */
 	cpu = smp_processor_id();
 	if (!cpu)
 		return;
-	/*
-	 * We need to calculate the scaled math multiplication factor for
-	 * nanosecond to apbt tick conversion.
-	 * mult = (nsec/cycle)*2^APBT_SHIFT
-	 */
-	printk(KERN_INFO "Init per CPU clockevent %d\n", cpu);
-	adev = &per_cpu(cpu_apbt_dev, cpu);
-	aevt = &adev->evt;
 
-	memcpy(aevt, &apbt_clockevent, sizeof(*aevt));
-	aevt->cpumask = cpumask_of(cpu);
-	aevt->name = adev->name;
-	aevt->mode = CLOCK_EVT_MODE_UNUSED;
+	adev = &__get_cpu_var(cpu_apbt_dev);
+	if (!adev->timer) {
+		adev->timer = dw_apb_clockevent_init(cpu, adev->name,
+			APBT_CLOCKEVENT_RATING, adev_virt_addr(adev),
+			adev->irq, apbt_freq);
+		adev->timer->eoi = NULL;
+	} else {
+		dw_apb_clockevent_resume(adev->timer);
+	}
 
-	printk(KERN_INFO "Registering CPU %d clockevent device %s, mask %08x\n",
-	       cpu, aevt->name, *(u32 *)aevt->cpumask);
+	printk(KERN_INFO "Registering CPU %d clockevent device %s, cpu %08x\n",
+	       cpu, adev->name, adev->cpu);
 
 	apbt_setup_irq(adev);
-
-	clockevents_register_device(aevt);
-
-	apbt_enable_int(cpu);
+	dw_apb_clockevent_register(adev->timer);
 
 	return;
 }
@@ -385,13 +237,12 @@ static int apbt_cpuhp_notify(struct notifier_block *n,
 
 	switch (action & 0xf) {
 	case CPU_DEAD:
-		disable_irq(adev->irq);
-		apbt_disable_int(cpu);
+		dw_apb_clockevent_pause(adev->timer);
 		if (system_state == SYSTEM_RUNNING) {
 			pr_debug("skipping APBT CPU %lu offline\n", cpu);
 		} else if (adev) {
 			pr_debug("APBT clockevent for cpu %lu offline\n", cpu);
-			free_irq(adev->irq, adev);
+			dw_apb_clockevent_stop(adev->timer);
 		}
 		break;
 	default:
@@ -416,116 +267,16 @@ void apbt_setup_secondary_clock(void) {}
 
 #endif /* CONFIG_SMP */
 
-static void apbt_set_mode(enum clock_event_mode mode,
-			  struct clock_event_device *evt)
-{
-	unsigned long ctrl;
-	uint64_t delta;
-	int timer_num;
-	struct apbt_dev *adev = EVT_TO_APBT_DEV(evt);
-
-	BUG_ON(!apbt_virt_address);
-
-	timer_num = adev->num;
-	pr_debug("%s CPU %d timer %d mode=%d\n",
-		 __func__, first_cpu(*evt->cpumask), timer_num, mode);
-
-	switch (mode) {
-	case CLOCK_EVT_MODE_PERIODIC:
-		delta = ((uint64_t)(NSEC_PER_SEC/HZ)) * apbt_clockevent.mult;
-		delta >>= apbt_clockevent.shift;
-		ctrl = apbt_readl(timer_num, APBTMR_N_CONTROL);
-		ctrl |= APBTMR_CONTROL_MODE_PERIODIC;
-		apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
-		/*
-		 * DW APB p. 46, have to disable timer before load counter,
-		 * may cause sync problem.
-		 */
-		ctrl &= ~APBTMR_CONTROL_ENABLE;
-		apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
-		udelay(1);
-		pr_debug("Setting clock period %d for HZ %d\n", (int)delta, HZ);
-		apbt_writel(timer_num, delta, APBTMR_N_LOAD_COUNT);
-		ctrl |= APBTMR_CONTROL_ENABLE;
-		apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
-		break;
-		/* APB timer does not have one-shot mode, use free running mode */
-	case CLOCK_EVT_MODE_ONESHOT:
-		ctrl = apbt_readl(timer_num, APBTMR_N_CONTROL);
-		/*
-		 * set free running mode, this mode will let timer reload max
-		 * timeout which will give time (3min on 25MHz clock) to rearm
-		 * the next event, therefore emulate the one-shot mode.
-		 */
-		ctrl &= ~APBTMR_CONTROL_ENABLE;
-		ctrl &= ~APBTMR_CONTROL_MODE_PERIODIC;
-
-		apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
-		/* write again to set free running mode */
-		apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
-
-		/*
-		 * DW APB p. 46, load counter with all 1s before starting free
-		 * running mode.
-		 */
-		apbt_writel(timer_num, ~0, APBTMR_N_LOAD_COUNT);
-		ctrl &= ~APBTMR_CONTROL_INT;
-		ctrl |= APBTMR_CONTROL_ENABLE;
-		apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
-		break;
-
-	case CLOCK_EVT_MODE_UNUSED:
-	case CLOCK_EVT_MODE_SHUTDOWN:
-		apbt_disable_int(timer_num);
-		ctrl = apbt_readl(timer_num, APBTMR_N_CONTROL);
-		ctrl &= ~APBTMR_CONTROL_ENABLE;
-		apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
-		break;
-
-	case CLOCK_EVT_MODE_RESUME:
-		apbt_enable_int(timer_num);
-		break;
-	}
-}
-
-static int apbt_next_event(unsigned long delta,
-			   struct clock_event_device *evt)
-{
-	unsigned long ctrl;
-	int timer_num;
-
-	struct apbt_dev *adev = EVT_TO_APBT_DEV(evt);
-
-	timer_num = adev->num;
-	/* Disable timer */
-	ctrl = apbt_readl(timer_num, APBTMR_N_CONTROL);
-	ctrl &= ~APBTMR_CONTROL_ENABLE;
-	apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
-	/* write new count */
-	apbt_writel(timer_num, delta, APBTMR_N_LOAD_COUNT);
-	ctrl |= APBTMR_CONTROL_ENABLE;
-	apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
-	return 0;
-}
-
-static cycle_t apbt_read_clocksource(struct clocksource *cs)
-{
-	unsigned long current_count;
-
-	current_count = apbt_readl(phy_cs_timer_id, APBTMR_N_CURRENT_VALUE);
-	return (cycle_t)~current_count;
-}
-
 static int apbt_clocksource_register(void)
 {
 	u64 start, now;
 	cycle_t t1;
 
 	/* Start the counter, use timer 2 as source, timer 0/1 for event */
-	apbt_start_counter(phy_cs_timer_id);
+	dw_apb_clocksource_start(clocksource_apbt);
 
 	/* Verify whether apbt counter works */
-	t1 = apbt_read_clocksource(&clocksource_apbt);
+	t1 = dw_apb_clocksource_read(clocksource_apbt);
 	rdtscll(start);
 
 	/*
@@ -540,10 +291,10 @@ static int apbt_clocksource_register(void)
 	} while ((now - start) < 200000UL);
 
 	/* APBT is the only always on clocksource, it has to work! */
-	if (t1 == apbt_read_clocksource(&clocksource_apbt))
+	if (t1 == dw_apb_clocksource_read(clocksource_apbt))
 		panic("APBT counter not counting. APBT disabled\n");
 
-	clocksource_register_khz(&clocksource_apbt, (u32)apbt_freq*1000);
+	dw_apb_clocksource_register(clocksource_apbt);
 
 	return 0;
 }
@@ -567,10 +318,7 @@ void __init apbt_time_init(void)
 	if (apb_timer_block_enabled)
 		return;
 	apbt_set_mapping();
-	if (apbt_virt_address) {
-		pr_debug("Found APBT version 0x%lx\n",\
-			 apbt_readl_reg(APBTMRS_COMP_VERSION));
-	} else
+	if (!apbt_virt_address)
 		goto out_noapbt;
 	/*
 	 * Read the frequency and check for a sane value, for ESL model
@@ -578,7 +326,7 @@ void __init apbt_time_init(void)
 	 */
 
 	if (apbt_freq < APBT_MIN_FREQ || apbt_freq > APBT_MAX_FREQ) {
-		pr_debug("APBT has invalid freq 0x%llx\n", apbt_freq);
+		pr_debug("APBT has invalid freq 0x%lx\n", apbt_freq);
 		goto out_noapbt;
 	}
 	if (apbt_clocksource_register()) {
@@ -604,30 +352,20 @@ void __init apbt_time_init(void)
 	} else {
 		percpu_timer = 0;
 		apbt_num_timers_used = 1;
-		adev = &per_cpu(cpu_apbt_dev, 0);
-		adev->flags &= ~APBT_DEV_USED;
 	}
 	pr_debug("%s: %d APB timers used\n", __func__, apbt_num_timers_used);
 
 	/* here we set up per CPU timer data structure */
-	apbt_devs = kzalloc(sizeof(struct apbt_dev) * apbt_num_timers_used,
-			    GFP_KERNEL);
-	if (!apbt_devs) {
-		printk(KERN_ERR "Failed to allocate APB timer devices\n");
-		return;
-	}
 	for (i = 0; i < apbt_num_timers_used; i++) {
 		adev = &per_cpu(cpu_apbt_dev, i);
 		adev->num = i;
 		adev->cpu = i;
 		p_mtmr = sfi_get_mtmr(i);
-		if (p_mtmr) {
-			adev->tick = p_mtmr->freq_hz;
+		if (p_mtmr)
 			adev->irq = p_mtmr->irq;
-		} else
+		else
 			printk(KERN_ERR "Failed to get timer for cpu %d\n", i);
-		adev->count = 0;
-		sprintf(adev->name, "apbt%d", i);
+		snprintf(adev->name, sizeof(adev->name) - 1, "apbt%d", i);
 	}
 #endif
 
@@ -639,17 +377,8 @@ out_noapbt:
 	panic("failed to enable APB timer\n");
 }
 
-static inline void apbt_disable(int n)
-{
-	if (is_apbt_capable()) {
-		unsigned long ctrl =  apbt_readl(n, APBTMR_N_CONTROL);
-		ctrl &= ~APBTMR_CONTROL_ENABLE;
-		apbt_writel(n, ctrl, APBTMR_N_CONTROL);
-	}
-}
-
 /* called before apb_timer_enable, use early map */
-unsigned long apbt_quick_calibrate()
+unsigned long apbt_quick_calibrate(void)
 {
 	int i, scale;
 	u64 old, new;
@@ -658,31 +387,31 @@ unsigned long apbt_quick_calibrate()
 	u32 loop, shift;
 
 	apbt_set_mapping();
-	apbt_start_counter(phy_cs_timer_id);
+	dw_apb_clocksource_start(clocksource_apbt);
 
 	/* check if the timer can count down, otherwise return */
-	old = apbt_read_clocksource(&clocksource_apbt);
+	old = dw_apb_clocksource_read(clocksource_apbt);
 	i = 10000;
 	while (--i) {
-		if (old != apbt_read_clocksource(&clocksource_apbt))
+		if (old != dw_apb_clocksource_read(clocksource_apbt))
 			break;
 	}
 	if (!i)
 		goto failed;
 
 	/* count 16 ms */
-	loop = (apbt_freq * 1000) << 4;
+	loop = (apbt_freq / 1000) << 4;
 
 	/* restart the timer to ensure it won't get to 0 in the calibration */
-	apbt_start_counter(phy_cs_timer_id);
+	dw_apb_clocksource_start(clocksource_apbt);
 
-	old = apbt_read_clocksource(&clocksource_apbt);
+	old = dw_apb_clocksource_read(clocksource_apbt);
 	old += loop;
 
 	t1 = __native_read_tsc();
 
 	do {
-		new = apbt_read_clocksource(&clocksource_apbt);
+		new = dw_apb_clocksource_read(clocksource_apbt);
 	} while (new < old);
 
 	t2 = __native_read_tsc();
@@ -694,7 +423,7 @@ unsigned long apbt_quick_calibrate()
 		return 0;
 	}
 	scale = (int)div_u64((t2 - t1), loop >> shift);
-	khz = (scale * apbt_freq * 1000) >> shift;
+	khz = (scale * (apbt_freq / 1000)) >> shift;
 	printk(KERN_INFO "TSC freq calculated by APB timer is %lu khz\n", khz);
 	return khz;
 failed:
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index d8d3e02b912c..34e9c4f88926 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -12,3 +12,6 @@ config CLKBLD_I8253
 
 config CLKSRC_MMIO
 	bool
+
+config DW_APB_TIMER
+	bool
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 7922a0cfc99f..85ad1646a7b7 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_SH_TIMER_MTU2)	+= sh_mtu2.o
 obj-$(CONFIG_SH_TIMER_TMU)	+= sh_tmu.o
 obj-$(CONFIG_CLKBLD_I8253)	+= i8253.o
 obj-$(CONFIG_CLKSRC_MMIO)	+= mmio.o
+obj-$(CONFIG_DW_APB_TIMER)	+= dw_apb_timer.o
diff --git a/drivers/clocksource/dw_apb_timer.c b/drivers/clocksource/dw_apb_timer.c
new file mode 100644
index 000000000000..580f870541a3
--- /dev/null
+++ b/drivers/clocksource/dw_apb_timer.c
@@ -0,0 +1,401 @@
+/*
+ * (C) Copyright 2009 Intel Corporation
+ * Author: Jacob Pan (jacob.jun.pan@intel.com)
+ *
+ * Shared with ARM platforms, Jamie Iles, Picochip 2011
+ *
+ * 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.
+ *
+ * Support for the Synopsys DesignWare APB Timers.
+ */
+#include <linux/dw_apb_timer.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+
+#define APBT_MIN_PERIOD			4
+#define APBT_MIN_DELTA_USEC		200
+
+#define APBTMR_N_LOAD_COUNT		0x00
+#define APBTMR_N_CURRENT_VALUE		0x04
+#define APBTMR_N_CONTROL		0x08
+#define APBTMR_N_EOI			0x0c
+#define APBTMR_N_INT_STATUS		0x10
+
+#define APBTMRS_INT_STATUS		0xa0
+#define APBTMRS_EOI			0xa4
+#define APBTMRS_RAW_INT_STATUS		0xa8
+#define APBTMRS_COMP_VERSION		0xac
+
+#define APBTMR_CONTROL_ENABLE		(1 << 0)
+/* 1: periodic, 0:free running. */
+#define APBTMR_CONTROL_MODE_PERIODIC	(1 << 1)
+#define APBTMR_CONTROL_INT		(1 << 2)
+
+static inline struct dw_apb_clock_event_device *
+ced_to_dw_apb_ced(struct clock_event_device *evt)
+{
+	return container_of(evt, struct dw_apb_clock_event_device, ced);
+}
+
+static inline struct dw_apb_clocksource *
+clocksource_to_dw_apb_clocksource(struct clocksource *cs)
+{
+	return container_of(cs, struct dw_apb_clocksource, cs);
+}
+
+static unsigned long apbt_readl(struct dw_apb_timer *timer, unsigned long offs)
+{
+	return readl(timer->base + offs);
+}
+
+static void apbt_writel(struct dw_apb_timer *timer, unsigned long val,
+		 unsigned long offs)
+{
+	writel(val, timer->base + offs);
+}
+
+static void apbt_disable_int(struct dw_apb_timer *timer)
+{
+	unsigned long ctrl = apbt_readl(timer, APBTMR_N_CONTROL);
+
+	ctrl |= APBTMR_CONTROL_INT;
+	apbt_writel(timer, ctrl, APBTMR_N_CONTROL);
+}
+
+/**
+ * dw_apb_clockevent_pause() - stop the clock_event_device from running
+ *
+ * @dw_ced:	The APB clock to stop generating events.
+ */
+void dw_apb_clockevent_pause(struct dw_apb_clock_event_device *dw_ced)
+{
+	disable_irq(dw_ced->timer.irq);
+	apbt_disable_int(&dw_ced->timer);
+}
+
+static void apbt_eoi(struct dw_apb_timer *timer)
+{
+	apbt_readl(timer, APBTMR_N_EOI);
+}
+
+static irqreturn_t dw_apb_clockevent_irq(int irq, void *data)
+{
+	struct clock_event_device *evt = data;
+	struct dw_apb_clock_event_device *dw_ced = ced_to_dw_apb_ced(evt);
+
+	if (!evt->event_handler) {
+		pr_info("Spurious APBT timer interrupt %d", irq);
+		return IRQ_NONE;
+	}
+
+	if (dw_ced->eoi)
+		dw_ced->eoi(&dw_ced->timer);
+
+	evt->event_handler(evt);
+	return IRQ_HANDLED;
+}
+
+static void apbt_enable_int(struct dw_apb_timer *timer)
+{
+	unsigned long ctrl = apbt_readl(timer, APBTMR_N_CONTROL);
+	/* clear pending intr */
+	apbt_readl(timer, APBTMR_N_EOI);
+	ctrl &= ~APBTMR_CONTROL_INT;
+	apbt_writel(timer, ctrl, APBTMR_N_CONTROL);
+}
+
+static void apbt_set_mode(enum clock_event_mode mode,
+			  struct clock_event_device *evt)
+{
+	unsigned long ctrl;
+	unsigned long period;
+	struct dw_apb_clock_event_device *dw_ced = ced_to_dw_apb_ced(evt);
+
+	pr_debug("%s CPU %d mode=%d\n", __func__, first_cpu(*evt->cpumask),
+		 mode);
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		period = DIV_ROUND_UP(dw_ced->timer.freq, HZ);
+		ctrl = apbt_readl(&dw_ced->timer, APBTMR_N_CONTROL);
+		ctrl |= APBTMR_CONTROL_MODE_PERIODIC;
+		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
+		/*
+		 * DW APB p. 46, have to disable timer before load counter,
+		 * may cause sync problem.
+		 */
+		ctrl &= ~APBTMR_CONTROL_ENABLE;
+		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
+		udelay(1);
+		pr_debug("Setting clock period %lu for HZ %d\n", period, HZ);
+		apbt_writel(&dw_ced->timer, period, APBTMR_N_LOAD_COUNT);
+		ctrl |= APBTMR_CONTROL_ENABLE;
+		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
+		break;
+
+	case CLOCK_EVT_MODE_ONESHOT:
+		ctrl = apbt_readl(&dw_ced->timer, APBTMR_N_CONTROL);
+		/*
+		 * set free running mode, this mode will let timer reload max
+		 * timeout which will give time (3min on 25MHz clock) to rearm
+		 * the next event, therefore emulate the one-shot mode.
+		 */
+		ctrl &= ~APBTMR_CONTROL_ENABLE;
+		ctrl &= ~APBTMR_CONTROL_MODE_PERIODIC;
+
+		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
+		/* write again to set free running mode */
+		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
+
+		/*
+		 * DW APB p. 46, load counter with all 1s before starting free
+		 * running mode.
+		 */
+		apbt_writel(&dw_ced->timer, ~0, APBTMR_N_LOAD_COUNT);
+		ctrl &= ~APBTMR_CONTROL_INT;
+		ctrl |= APBTMR_CONTROL_ENABLE;
+		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
+		break;
+
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+		ctrl = apbt_readl(&dw_ced->timer, APBTMR_N_CONTROL);
+		ctrl &= ~APBTMR_CONTROL_ENABLE;
+		apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
+		break;
+
+	case CLOCK_EVT_MODE_RESUME:
+		apbt_enable_int(&dw_ced->timer);
+		break;
+	}
+}
+
+static int apbt_next_event(unsigned long delta,
+			   struct clock_event_device *evt)
+{
+	unsigned long ctrl;
+	struct dw_apb_clock_event_device *dw_ced = ced_to_dw_apb_ced(evt);
+
+	/* Disable timer */
+	ctrl = apbt_readl(&dw_ced->timer, APBTMR_N_CONTROL);
+	ctrl &= ~APBTMR_CONTROL_ENABLE;
+	apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
+	/* write new count */
+	apbt_writel(&dw_ced->timer, delta, APBTMR_N_LOAD_COUNT);
+	ctrl |= APBTMR_CONTROL_ENABLE;
+	apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
+
+	return 0;
+}
+
+/**
+ * dw_apb_clockevent_init() - use an APB timer as a clock_event_device
+ *
+ * @cpu:	The CPU the events will be targeted at.
+ * @name:	The name used for the timer and the IRQ for it.
+ * @rating:	The rating to give the timer.
+ * @base:	I/O base for the timer registers.
+ * @irq:	The interrupt number to use for the timer.
+ * @freq:	The frequency that the timer counts at.
+ *
+ * This creates a clock_event_device for using with the generic clock layer
+ * but does not start and register it.  This should be done with
+ * dw_apb_clockevent_register() as the next step.  If this is the first time
+ * it has been called for a timer then the IRQ will be requested, if not it
+ * just be enabled to allow CPU hotplug to avoid repeatedly requesting and
+ * releasing the IRQ.
+ */
+struct dw_apb_clock_event_device *
+dw_apb_clockevent_init(int cpu, const char *name, unsigned rating,
+		       void __iomem *base, int irq, unsigned long freq)
+{
+	struct dw_apb_clock_event_device *dw_ced =
+		kzalloc(sizeof(*dw_ced), GFP_KERNEL);
+	int err;
+
+	if (!dw_ced)
+		return NULL;
+
+	dw_ced->timer.base = base;
+	dw_ced->timer.irq = irq;
+	dw_ced->timer.freq = freq;
+
+	clockevents_calc_mult_shift(&dw_ced->ced, freq, APBT_MIN_PERIOD);
+	dw_ced->ced.max_delta_ns = clockevent_delta2ns(0x7fffffff,
+						       &dw_ced->ced);
+	dw_ced->ced.min_delta_ns = clockevent_delta2ns(5000, &dw_ced->ced);
+	dw_ced->ced.cpumask = cpumask_of(cpu);
+	dw_ced->ced.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+	dw_ced->ced.set_mode = apbt_set_mode;
+	dw_ced->ced.set_next_event = apbt_next_event;
+	dw_ced->ced.irq = dw_ced->timer.irq;
+	dw_ced->ced.rating = rating;
+	dw_ced->ced.name = name;
+
+	dw_ced->irqaction.name		= dw_ced->ced.name;
+	dw_ced->irqaction.handler	= dw_apb_clockevent_irq;
+	dw_ced->irqaction.dev_id	= &dw_ced->ced;
+	dw_ced->irqaction.irq		= irq;
+	dw_ced->irqaction.flags		= IRQF_TIMER | IRQF_IRQPOLL |
+					  IRQF_NOBALANCING |
+					  IRQF_DISABLED;
+
+	dw_ced->eoi = apbt_eoi;
+	err = setup_irq(irq, &dw_ced->irqaction);
+	if (err) {
+		pr_err("failed to request timer irq\n");
+		kfree(dw_ced);
+		dw_ced = NULL;
+	}
+
+	return dw_ced;
+}
+
+/**
+ * dw_apb_clockevent_resume() - resume a clock that has been paused.
+ *
+ * @dw_ced:	The APB clock to resume.
+ */
+void dw_apb_clockevent_resume(struct dw_apb_clock_event_device *dw_ced)
+{
+	enable_irq(dw_ced->timer.irq);
+}
+
+/**
+ * dw_apb_clockevent_stop() - stop the clock_event_device and release the IRQ.
+ *
+ * @dw_ced:	The APB clock to stop generating the events.
+ */
+void dw_apb_clockevent_stop(struct dw_apb_clock_event_device *dw_ced)
+{
+	free_irq(dw_ced->timer.irq, &dw_ced->ced);
+}
+
+/**
+ * dw_apb_clockevent_register() - register the clock with the generic layer
+ *
+ * @dw_ced:	The APB clock to register as a clock_event_device.
+ */
+void dw_apb_clockevent_register(struct dw_apb_clock_event_device *dw_ced)
+{
+	apbt_writel(&dw_ced->timer, 0, APBTMR_N_CONTROL);
+	clockevents_register_device(&dw_ced->ced);
+	apbt_enable_int(&dw_ced->timer);
+}
+
+/**
+ * dw_apb_clocksource_start() - start the clocksource counting.
+ *
+ * @dw_cs:	The clocksource to start.
+ *
+ * This is used to start the clocksource before registration and can be used
+ * to enable calibration of timers.
+ */
+void dw_apb_clocksource_start(struct dw_apb_clocksource *dw_cs)
+{
+	/*
+	 * start count down from 0xffff_ffff. this is done by toggling the
+	 * enable bit then load initial load count to ~0.
+	 */
+	unsigned long ctrl = apbt_readl(&dw_cs->timer, APBTMR_N_CONTROL);
+
+	ctrl &= ~APBTMR_CONTROL_ENABLE;
+	apbt_writel(&dw_cs->timer, ctrl, APBTMR_N_CONTROL);
+	apbt_writel(&dw_cs->timer, ~0, APBTMR_N_LOAD_COUNT);
+	/* enable, mask interrupt */
+	ctrl &= ~APBTMR_CONTROL_MODE_PERIODIC;
+	ctrl |= (APBTMR_CONTROL_ENABLE | APBTMR_CONTROL_INT);
+	apbt_writel(&dw_cs->timer, ctrl, APBTMR_N_CONTROL);
+	/* read it once to get cached counter value initialized */
+	dw_apb_clocksource_read(dw_cs);
+}
+
+static cycle_t __apbt_read_clocksource(struct clocksource *cs)
+{
+	unsigned long current_count;
+	struct dw_apb_clocksource *dw_cs =
+		clocksource_to_dw_apb_clocksource(cs);
+
+	current_count = apbt_readl(&dw_cs->timer, APBTMR_N_CURRENT_VALUE);
+
+	return (cycle_t)~current_count;
+}
+
+static void apbt_restart_clocksource(struct clocksource *cs)
+{
+	struct dw_apb_clocksource *dw_cs =
+		clocksource_to_dw_apb_clocksource(cs);
+
+	dw_apb_clocksource_start(dw_cs);
+}
+
+/**
+ * dw_apb_clocksource_init() - use an APB timer as a clocksource.
+ *
+ * @rating:	The rating to give the clocksource.
+ * @name:	The name for the clocksource.
+ * @base:	The I/O base for the timer registers.
+ * @freq:	The frequency that the timer counts at.
+ *
+ * This creates a clocksource using an APB timer but does not yet register it
+ * with the clocksource system.  This should be done with
+ * dw_apb_clocksource_register() as the next step.
+ */
+struct dw_apb_clocksource *
+dw_apb_clocksource_init(unsigned rating, char *name, void __iomem *base,
+			unsigned long freq)
+{
+	struct dw_apb_clocksource *dw_cs = kzalloc(sizeof(*dw_cs), GFP_KERNEL);
+
+	if (!dw_cs)
+		return NULL;
+
+	dw_cs->timer.base = base;
+	dw_cs->timer.freq = freq;
+	dw_cs->cs.name = name;
+	dw_cs->cs.rating = rating;
+	dw_cs->cs.read = __apbt_read_clocksource;
+	dw_cs->cs.mask = CLOCKSOURCE_MASK(32);
+	dw_cs->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+	dw_cs->cs.resume = apbt_restart_clocksource;
+
+	return dw_cs;
+}
+
+/**
+ * dw_apb_clocksource_register() - register the APB clocksource.
+ *
+ * @dw_cs:	The clocksource to register.
+ */
+void dw_apb_clocksource_register(struct dw_apb_clocksource *dw_cs)
+{
+	clocksource_register_hz(&dw_cs->cs, dw_cs->timer.freq);
+}
+
+/**
+ * dw_apb_clocksource_read() - read the current value of a clocksource.
+ *
+ * @dw_cs:	The clocksource to read.
+ */
+cycle_t dw_apb_clocksource_read(struct dw_apb_clocksource *dw_cs)
+{
+	return (cycle_t)~apbt_readl(&dw_cs->timer, APBTMR_N_CURRENT_VALUE);
+}
+
+/**
+ * dw_apb_clocksource_unregister() - unregister and free a clocksource.
+ *
+ * @dw_cs:	The clocksource to unregister/free.
+ */
+void dw_apb_clocksource_unregister(struct dw_apb_clocksource *dw_cs)
+{
+	clocksource_unregister(&dw_cs->cs);
+
+	kfree(dw_cs);
+}
diff --git a/include/linux/dw_apb_timer.h b/include/linux/dw_apb_timer.h
new file mode 100644
index 000000000000..49638ea3b776
--- /dev/null
+++ b/include/linux/dw_apb_timer.h
@@ -0,0 +1,56 @@
+/*
+ * (C) Copyright 2009 Intel Corporation
+ * Author: Jacob Pan (jacob.jun.pan@intel.com)
+ *
+ * Shared with ARM platforms, Jamie Iles, Picochip 2011
+ *
+ * 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.
+ *
+ * Support for the Synopsys DesignWare APB Timers.
+ */
+#ifndef __DW_APB_TIMER_H__
+#define __DW_APB_TIMER_H__
+
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/interrupt.h>
+
+#define APBTMRS_REG_SIZE       0x14
+
+struct dw_apb_timer {
+	void __iomem				*base;
+	unsigned long				freq;
+	int					irq;
+};
+
+struct dw_apb_clock_event_device {
+	struct clock_event_device		ced;
+	struct dw_apb_timer			timer;
+	struct irqaction			irqaction;
+	void					(*eoi)(struct dw_apb_timer *);
+};
+
+struct dw_apb_clocksource {
+	struct dw_apb_timer			timer;
+	struct clocksource			cs;
+};
+
+void dw_apb_clockevent_register(struct dw_apb_clock_event_device *dw_ced);
+void dw_apb_clockevent_pause(struct dw_apb_clock_event_device *dw_ced);
+void dw_apb_clockevent_resume(struct dw_apb_clock_event_device *dw_ced);
+void dw_apb_clockevent_stop(struct dw_apb_clock_event_device *dw_ced);
+
+struct dw_apb_clock_event_device *
+dw_apb_clockevent_init(int cpu, const char *name, unsigned rating,
+		       void __iomem *base, int irq, unsigned long freq);
+struct dw_apb_clocksource *
+dw_apb_clocksource_init(unsigned rating, char *name, void __iomem *base,
+			unsigned long freq);
+void dw_apb_clocksource_register(struct dw_apb_clocksource *dw_cs);
+void dw_apb_clocksource_start(struct dw_apb_clocksource *dw_cs);
+cycle_t dw_apb_clocksource_read(struct dw_apb_clocksource *dw_cs);
+void dw_apb_clocksource_unregister(struct dw_apb_clocksource *dw_cs);
+
+#endif /* __DW_APB_TIMER_H__ */