|
@@ -0,0 +1,784 @@
|
|
|
+/*
|
|
|
+ * apb_timer.c: Driver for Langwell APB timers
|
|
|
+ *
|
|
|
+ * (C) Copyright 2009 Intel Corporation
|
|
|
+ * Author: Jacob Pan (jacob.jun.pan@intel.com)
|
|
|
+ *
|
|
|
+ * This program is free software; you can redistribute it and/or
|
|
|
+ * modify it under the terms of the GNU General Public License
|
|
|
+ * as published by the Free Software Foundation; version 2
|
|
|
+ * of the License.
|
|
|
+ *
|
|
|
+ * Note:
|
|
|
+ * Langwell is the south complex of Intel Moorestown MID platform. There are
|
|
|
+ * eight external timers in total that can be used by the operating system.
|
|
|
+ * The timer information, such as frequency and addresses, is provided to the
|
|
|
+ * OS via SFI tables.
|
|
|
+ * Timer interrupts are routed via FW/HW emulated IOAPIC independently via
|
|
|
+ * individual redirection table entries (RTE).
|
|
|
+ * Unlike HPET, there is no master counter, therefore one of the timers are
|
|
|
+ * used as clocksource. The overall allocation looks like:
|
|
|
+ * - timer 0 - NR_CPUs for per cpu timer
|
|
|
+ * - one timer for clocksource
|
|
|
+ * - one timer for watchdog driver.
|
|
|
+ * It is also worth notice that APB timer does not support true one-shot mode,
|
|
|
+ * free-running mode will be used here to emulate one-shot mode.
|
|
|
+ * APB timer can also be used as broadcast timer along with per cpu local APIC
|
|
|
+ * 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/errno.h>
|
|
|
+#include <linux/init.h>
|
|
|
+#include <linux/sysdev.h>
|
|
|
+#include <linux/pm.h>
|
|
|
+#include <linux/pci.h>
|
|
|
+#include <linux/sfi.h>
|
|
|
+#include <linux/interrupt.h>
|
|
|
+#include <linux/cpu.h>
|
|
|
+#include <linux/irq.h>
|
|
|
+
|
|
|
+#include <asm/fixmap.h>
|
|
|
+#include <asm/apb_timer.h>
|
|
|
+
|
|
|
+#define APBT_MASK CLOCKSOURCE_MASK(32)
|
|
|
+#define APBT_SHIFT 22
|
|
|
+#define APBT_CLOCKEVENT_RATING 150
|
|
|
+#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 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);
|
|
|
+
|
|
|
+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];
|
|
|
+};
|
|
|
+
|
|
|
+int disable_apbt_percpu __cpuinitdata;
|
|
|
+
|
|
|
+static DEFINE_PER_CPU(struct apbt_dev, cpu_apbt_dev);
|
|
|
+
|
|
|
+#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)
|
|
|
+{
|
|
|
+ return readl(apbt_virt_address + a);
|
|
|
+}
|
|
|
+
|
|
|
+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 inline void apbt_writel(int n, unsigned long d, unsigned long a)
|
|
|
+{
|
|
|
+ writel(d, apbt_virt_address + a + n * APBTMRS_REG_SIZE);
|
|
|
+}
|
|
|
+
|
|
|
+static inline void apbt_set_mapping(void)
|
|
|
+{
|
|
|
+ struct sfi_timer_table_entry *mtmr;
|
|
|
+
|
|
|
+ if (apbt_virt_address) {
|
|
|
+ pr_debug("APBT base already mapped\n");
|
|
|
+ return;
|
|
|
+ }
|
|
|
+ mtmr = sfi_get_mtmr(APBT_CLOCKEVENT0_NUM);
|
|
|
+ if (mtmr == NULL) {
|
|
|
+ printk(KERN_ERR "Failed to get MTMR %d from SFI\n",
|
|
|
+ APBT_CLOCKEVENT0_NUM);
|
|
|
+ return;
|
|
|
+ }
|
|
|
+ apbt_address = (unsigned long)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);
|
|
|
+ goto panic_noapbt;
|
|
|
+ }
|
|
|
+ apbt_freq = mtmr->freq_hz / USEC_PER_SEC;
|
|
|
+ sfi_free_mtmr(mtmr);
|
|
|
+
|
|
|
+ /* Now figure out the physical timer id for clocksource device */
|
|
|
+ mtmr = sfi_get_mtmr(APBT_CLOCKSOURCE_NUM);
|
|
|
+ if (mtmr == NULL)
|
|
|
+ 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);
|
|
|
+ return;
|
|
|
+
|
|
|
+panic_noapbt:
|
|
|
+ panic("Failed to setup APB system timer\n");
|
|
|
+
|
|
|
+}
|
|
|
+
|
|
|
+static inline void apbt_clear_mapping(void)
|
|
|
+{
|
|
|
+ iounmap(apbt_virt_address);
|
|
|
+ apbt_virt_address = NULL;
|
|
|
+}
|
|
|
+
|
|
|
+/*
|
|
|
+ * APBT timer interrupt enable / disable
|
|
|
+ */
|
|
|
+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,
|
|
|
+ .shift = APBT_SHIFT,
|
|
|
+ .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,
|
|
|
+};
|
|
|
+
|
|
|
+/*
|
|
|
+ * if user does not want to use per CPU apb timer, just give it a lower rating
|
|
|
+ * than local apic timer and skip the late per cpu timer init.
|
|
|
+ */
|
|
|
+static inline int __init setup_x86_mrst_timer(char *arg)
|
|
|
+{
|
|
|
+ if (!arg)
|
|
|
+ return -EINVAL;
|
|
|
+
|
|
|
+ if (strcmp("apbt_only", arg) == 0)
|
|
|
+ disable_apbt_percpu = 0;
|
|
|
+ else if (strcmp("lapic_and_apbt", arg) == 0)
|
|
|
+ disable_apbt_percpu = 1;
|
|
|
+ else {
|
|
|
+ pr_warning("X86 MRST timer option %s not recognised"
|
|
|
+ " use x86_mrst_timer=apbt_only or lapic_and_apbt\n",
|
|
|
+ arg);
|
|
|
+ return -EINVAL;
|
|
|
+ }
|
|
|
+ return 0;
|
|
|
+}
|
|
|
+__setup("x86_mrst_timer=", setup_x86_mrst_timer);
|
|
|
+
|
|
|
+/*
|
|
|
+ * 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);
|
|
|
+}
|
|
|
+
|
|
|
+/* Setup IRQ routing via IOAPIC */
|
|
|
+#ifdef CONFIG_SMP
|
|
|
+static void apbt_setup_irq(struct apbt_dev *adev)
|
|
|
+{
|
|
|
+ struct irq_chip *chip;
|
|
|
+ struct irq_desc *desc;
|
|
|
+
|
|
|
+ /* timer0 irq has been setup early */
|
|
|
+ if (adev->irq == 0)
|
|
|
+ return;
|
|
|
+ desc = irq_to_desc(adev->irq);
|
|
|
+ chip = get_irq_chip(adev->irq);
|
|
|
+ disable_irq(adev->irq);
|
|
|
+ desc->status |= IRQ_MOVE_PCNTXT;
|
|
|
+ irq_set_affinity(adev->irq, cpumask_of(adev->cpu));
|
|
|
+ /* APB timer irqs are set up as mp_irqs, timer is edge triggerred */
|
|
|
+ set_irq_chip_and_handler_name(adev->irq, chip, handle_edge_irq, "edge");
|
|
|
+ enable_irq(adev->irq);
|
|
|
+ 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);
|
|
|
+ }
|
|
|
+}
|
|
|
+#endif
|
|
|
+
|
|
|
+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;
|
|
|
+ struct apbt_dev *adev = &__get_cpu_var(cpu_apbt_dev);
|
|
|
+
|
|
|
+ mtmr = sfi_get_mtmr(APBT_CLOCKEVENT0_NUM);
|
|
|
+ if (mtmr == NULL) {
|
|
|
+ printk(KERN_ERR "Failed to get MTMR %d from SFI\n",
|
|
|
+ APBT_CLOCKEVENT0_NUM);
|
|
|
+ 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));
|
|
|
+
|
|
|
+ if (disable_apbt_percpu) {
|
|
|
+ apbt_clockevent.rating = APBT_CLOCKEVENT_RATING - 100;
|
|
|
+ global_clock_event = &adev->evt;
|
|
|
+ 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);
|
|
|
+
|
|
|
+ sfi_free_mtmr(mtmr);
|
|
|
+ return 0;
|
|
|
+}
|
|
|
+
|
|
|
+#ifdef CONFIG_SMP
|
|
|
+/* 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 == boot_cpu_id)
|
|
|
+ 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;
|
|
|
+
|
|
|
+ printk(KERN_INFO "Registering CPU %d clockevent device %s, mask %08x\n",
|
|
|
+ cpu, aevt->name, *(u32 *)aevt->cpumask);
|
|
|
+
|
|
|
+ apbt_setup_irq(adev);
|
|
|
+
|
|
|
+ clockevents_register_device(aevt);
|
|
|
+
|
|
|
+ apbt_enable_int(cpu);
|
|
|
+
|
|
|
+ return;
|
|
|
+}
|
|
|
+
|
|
|
+/*
|
|
|
+ * this notify handler process CPU hotplug events. in case of S0i3, nonboot
|
|
|
+ * cpus are disabled/enabled frequently, for performance reasons, we keep the
|
|
|
+ * per cpu timer irq registered so that we do need to do free_irq/request_irq.
|
|
|
+ *
|
|
|
+ * TODO: it might be more reliable to directly disable percpu clockevent device
|
|
|
+ * without the notifier chain. currently, cpu 0 may get interrupts from other
|
|
|
+ * cpu timers during the offline process due to the ordering of notification.
|
|
|
+ * the extra interrupt is harmless.
|
|
|
+ */
|
|
|
+static int apbt_cpuhp_notify(struct notifier_block *n,
|
|
|
+ unsigned long action, void *hcpu)
|
|
|
+{
|
|
|
+ unsigned long cpu = (unsigned long)hcpu;
|
|
|
+ struct apbt_dev *adev = &per_cpu(cpu_apbt_dev, cpu);
|
|
|
+
|
|
|
+ switch (action & 0xf) {
|
|
|
+ case CPU_DEAD:
|
|
|
+ apbt_disable_int(cpu);
|
|
|
+ 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);
|
|
|
+ }
|
|
|
+ break;
|
|
|
+ default:
|
|
|
+ pr_debug(KERN_INFO "APBT notified %lu, no action\n", action);
|
|
|
+ }
|
|
|
+ return NOTIFY_OK;
|
|
|
+}
|
|
|
+
|
|
|
+static __init int apbt_late_init(void)
|
|
|
+{
|
|
|
+ if (disable_apbt_percpu)
|
|
|
+ return 0;
|
|
|
+ /* This notifier should be called after workqueue is ready */
|
|
|
+ hotcpu_notifier(apbt_cpuhp_notify, -20);
|
|
|
+ return 0;
|
|
|
+}
|
|
|
+fs_initcall(apbt_late_init);
|
|
|
+#else
|
|
|
+
|
|
|
+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);
|
|
|
+
|
|
|
+ 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;
|
|
|
+}
|
|
|
+
|
|
|
+/*
|
|
|
+ * APB timer clock is not in sync with pclk on Langwell, which translates to
|
|
|
+ * unreliable read value caused by sampling error. the error does not add up
|
|
|
+ * overtime and only happens when sampling a 0 as a 1 by mistake. so the time
|
|
|
+ * would go backwards. the following code is trying to prevent time traveling
|
|
|
+ * backwards. little bit paranoid.
|
|
|
+ */
|
|
|
+static cycle_t apbt_read_clocksource(struct clocksource *cs)
|
|
|
+{
|
|
|
+ unsigned long t0, t1, t2;
|
|
|
+ static unsigned long last_read;
|
|
|
+
|
|
|
+bad_count:
|
|
|
+ t1 = apbt_readl(phy_cs_timer_id,
|
|
|
+ APBTMR_N_CURRENT_VALUE);
|
|
|
+ t2 = apbt_readl(phy_cs_timer_id,
|
|
|
+ APBTMR_N_CURRENT_VALUE);
|
|
|
+ if (unlikely(t1 < t2)) {
|
|
|
+ pr_debug("APBT: read current count error %lx:%lx:%lx\n",
|
|
|
+ t1, t2, t2 - t1);
|
|
|
+ goto bad_count;
|
|
|
+ }
|
|
|
+ /*
|
|
|
+ * check against cached last read, makes sure time does not go back.
|
|
|
+ * it could be a normal rollover but we will do tripple check anyway
|
|
|
+ */
|
|
|
+ if (unlikely(t2 > last_read)) {
|
|
|
+ /* check if we have a normal rollover */
|
|
|
+ unsigned long raw_intr_status =
|
|
|
+ apbt_readl_reg(APBTMRS_RAW_INT_STATUS);
|
|
|
+ /*
|
|
|
+ * cs timer interrupt is masked but raw intr bit is set if
|
|
|
+ * rollover occurs. then we read EOI reg to clear it.
|
|
|
+ */
|
|
|
+ if (raw_intr_status & (1 << phy_cs_timer_id)) {
|
|
|
+ apbt_readl(phy_cs_timer_id, APBTMR_N_EOI);
|
|
|
+ goto out;
|
|
|
+ }
|
|
|
+ pr_debug("APB CS going back %lx:%lx:%lx ",
|
|
|
+ t2, last_read, t2 - last_read);
|
|
|
+bad_count_x3:
|
|
|
+ pr_debug(KERN_INFO "tripple check enforced\n");
|
|
|
+ t0 = apbt_readl(phy_cs_timer_id,
|
|
|
+ APBTMR_N_CURRENT_VALUE);
|
|
|
+ udelay(1);
|
|
|
+ t1 = apbt_readl(phy_cs_timer_id,
|
|
|
+ APBTMR_N_CURRENT_VALUE);
|
|
|
+ udelay(1);
|
|
|
+ t2 = apbt_readl(phy_cs_timer_id,
|
|
|
+ APBTMR_N_CURRENT_VALUE);
|
|
|
+ if ((t2 > t1) || (t1 > t0)) {
|
|
|
+ printk(KERN_ERR "Error: APB CS tripple check failed\n");
|
|
|
+ goto bad_count_x3;
|
|
|
+ }
|
|
|
+ }
|
|
|
+out:
|
|
|
+ last_read = t2;
|
|
|
+ return (cycle_t)~t2;
|
|
|
+}
|
|
|
+
|
|
|
+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);
|
|
|
+
|
|
|
+ /* Verify whether apbt counter works */
|
|
|
+ t1 = apbt_read_clocksource(&clocksource_apbt);
|
|
|
+ rdtscll(start);
|
|
|
+
|
|
|
+ /*
|
|
|
+ * We don't know the TSC frequency yet, but waiting for
|
|
|
+ * 200000 TSC cycles is safe:
|
|
|
+ * 4 GHz == 50us
|
|
|
+ * 1 GHz == 200us
|
|
|
+ */
|
|
|
+ do {
|
|
|
+ rep_nop();
|
|
|
+ rdtscll(now);
|
|
|
+ } while ((now - start) < 200000UL);
|
|
|
+
|
|
|
+ /* APBT is the only always on clocksource, it has to work! */
|
|
|
+ if (t1 == apbt_read_clocksource(&clocksource_apbt))
|
|
|
+ panic("APBT counter not counting. APBT disabled\n");
|
|
|
+
|
|
|
+ /*
|
|
|
+ * initialize and register APBT clocksource
|
|
|
+ * convert that to ns/clock cycle
|
|
|
+ * mult = (ns/c) * 2^APBT_SHIFT
|
|
|
+ */
|
|
|
+ clocksource_apbt.mult = div_sc(MSEC_PER_SEC,
|
|
|
+ (unsigned long) apbt_freq, APBT_SHIFT);
|
|
|
+ clocksource_register(&clocksource_apbt);
|
|
|
+
|
|
|
+ return 0;
|
|
|
+}
|
|
|
+
|
|
|
+/*
|
|
|
+ * Early setup the APBT timer, only use timer 0 for booting then switch to
|
|
|
+ * per CPU timer if possible.
|
|
|
+ * returns 1 if per cpu apbt is setup
|
|
|
+ * returns 0 if no per cpu apbt is chosen
|
|
|
+ * panic if set up failed, this is the only platform timer on Moorestown.
|
|
|
+ */
|
|
|
+void __init apbt_time_init(void)
|
|
|
+{
|
|
|
+#ifdef CONFIG_SMP
|
|
|
+ int i;
|
|
|
+ struct sfi_timer_table_entry *p_mtmr;
|
|
|
+ unsigned int percpu_timer;
|
|
|
+ struct apbt_dev *adev;
|
|
|
+#endif
|
|
|
+
|
|
|
+ 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
|
|
|
+ goto out_noapbt;
|
|
|
+ /*
|
|
|
+ * Read the frequency and check for a sane value, for ESL model
|
|
|
+ * we extend the possible clock range to allow time scaling.
|
|
|
+ */
|
|
|
+
|
|
|
+ if (apbt_freq < APBT_MIN_FREQ || apbt_freq > APBT_MAX_FREQ) {
|
|
|
+ pr_debug("APBT has invalid freq 0x%llx\n", apbt_freq);
|
|
|
+ goto out_noapbt;
|
|
|
+ }
|
|
|
+ if (apbt_clocksource_register()) {
|
|
|
+ pr_debug("APBT has failed to register clocksource\n");
|
|
|
+ goto out_noapbt;
|
|
|
+ }
|
|
|
+ if (!apbt_clockevent_register())
|
|
|
+ apb_timer_block_enabled = 1;
|
|
|
+ else {
|
|
|
+ pr_debug("APBT has failed to register clockevent\n");
|
|
|
+ goto out_noapbt;
|
|
|
+ }
|
|
|
+#ifdef CONFIG_SMP
|
|
|
+ /* kernel cmdline disable apb timer, so we will use lapic timers */
|
|
|
+ if (disable_apbt_percpu) {
|
|
|
+ printk(KERN_INFO "apbt: disabled per cpu timer\n");
|
|
|
+ return;
|
|
|
+ }
|
|
|
+ pr_debug("%s: %d CPUs online\n", __func__, num_online_cpus());
|
|
|
+ if (num_possible_cpus() <= sfi_mtimer_num) {
|
|
|
+ percpu_timer = 1;
|
|
|
+ apbt_num_timers_used = num_possible_cpus();
|
|
|
+ } 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;
|
|
|
+ adev->irq = p_mtmr->irq;
|
|
|
+ } else
|
|
|
+ printk(KERN_ERR "Failed to get timer for cpu %d\n", i);
|
|
|
+ adev->count = 0;
|
|
|
+ sprintf(adev->name, "apbt%d", i);
|
|
|
+ }
|
|
|
+#endif
|
|
|
+
|
|
|
+ return;
|
|
|
+
|
|
|
+out_noapbt:
|
|
|
+ apbt_clear_mapping();
|
|
|
+ apb_timer_block_enabled = 0;
|
|
|
+ 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()
|
|
|
+{
|
|
|
+ int i, scale;
|
|
|
+ u64 old, new;
|
|
|
+ cycle_t t1, t2;
|
|
|
+ unsigned long khz = 0;
|
|
|
+ u32 loop, shift;
|
|
|
+
|
|
|
+ apbt_set_mapping();
|
|
|
+ apbt_start_counter(phy_cs_timer_id);
|
|
|
+
|
|
|
+ /* check if the timer can count down, otherwise return */
|
|
|
+ old = apbt_read_clocksource(&clocksource_apbt);
|
|
|
+ i = 10000;
|
|
|
+ while (--i) {
|
|
|
+ if (old != apbt_read_clocksource(&clocksource_apbt))
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ if (!i)
|
|
|
+ goto failed;
|
|
|
+
|
|
|
+ /* count 16 ms */
|
|
|
+ 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);
|
|
|
+
|
|
|
+ old = apbt_read_clocksource(&clocksource_apbt);
|
|
|
+ old += loop;
|
|
|
+
|
|
|
+ t1 = __native_read_tsc();
|
|
|
+
|
|
|
+ do {
|
|
|
+ new = apbt_read_clocksource(&clocksource_apbt);
|
|
|
+ } while (new < old);
|
|
|
+
|
|
|
+ t2 = __native_read_tsc();
|
|
|
+
|
|
|
+ shift = 5;
|
|
|
+ if (unlikely(loop >> shift == 0)) {
|
|
|
+ printk(KERN_INFO
|
|
|
+ "APBT TSC calibration failed, not enough resolution\n");
|
|
|
+ return 0;
|
|
|
+ }
|
|
|
+ scale = (int)div_u64((t2 - t1), loop >> shift);
|
|
|
+ khz = (scale * apbt_freq * 1000) >> shift;
|
|
|
+ printk(KERN_INFO "TSC freq calculated by APB timer is %lu khz\n", khz);
|
|
|
+ return khz;
|
|
|
+failed:
|
|
|
+ return 0;
|
|
|
+}
|