diff options
Diffstat (limited to 'arch/i386/kernel/vmiclock.c')
| -rw-r--r-- | arch/i386/kernel/vmiclock.c | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/arch/i386/kernel/vmiclock.c b/arch/i386/kernel/vmiclock.c new file mode 100644 index 00000000000..26a37f8a876 --- /dev/null +++ b/arch/i386/kernel/vmiclock.c @@ -0,0 +1,318 @@ +/* + * VMI paravirtual timer support routines. + * + * Copyright (C) 2007, VMware, Inc. + * + * 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; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for more + * details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + */ + +#include <linux/smp.h> +#include <linux/interrupt.h> +#include <linux/cpumask.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> + +#include <asm/vmi.h> +#include <asm/vmi_time.h> +#include <asm/arch_hooks.h> +#include <asm/apicdef.h> +#include <asm/apic.h> +#include <asm/timer.h> + +#include <irq_vectors.h> +#include "io_ports.h" + +#define VMI_ONESHOT (VMI_ALARM_IS_ONESHOT | VMI_CYCLES_REAL | vmi_get_alarm_wiring()) +#define VMI_PERIODIC (VMI_ALARM_IS_PERIODIC | VMI_CYCLES_REAL | vmi_get_alarm_wiring()) + +static DEFINE_PER_CPU(struct clock_event_device, local_events); + +static inline u32 vmi_counter(u32 flags) +{ + /* Given VMI_ONESHOT or VMI_PERIODIC, return the corresponding + * cycle counter. */ + return flags & VMI_ALARM_COUNTER_MASK; +} + +/* paravirt_ops.get_wallclock = vmi_get_wallclock */ +unsigned long vmi_get_wallclock(void) +{ + unsigned long long wallclock; + wallclock = vmi_timer_ops.get_wallclock(); // nsec + (void)do_div(wallclock, 1000000000); // sec + + return wallclock; +} + +/* paravirt_ops.set_wallclock = vmi_set_wallclock */ +int vmi_set_wallclock(unsigned long now) +{ + return 0; +} + +/* paravirt_ops.get_scheduled_cycles = vmi_get_sched_cycles */ +unsigned long long vmi_get_sched_cycles(void) +{ + return vmi_timer_ops.get_cycle_counter(VMI_CYCLES_AVAILABLE); +} + +/* paravirt_ops.get_cpu_khz = vmi_cpu_khz */ +unsigned long vmi_cpu_khz(void) +{ + unsigned long long khz; + khz = vmi_timer_ops.get_cycle_frequency(); + (void)do_div(khz, 1000); + return khz; +} + +static inline unsigned int vmi_get_timer_vector(void) +{ +#ifdef CONFIG_X86_IO_APIC + return FIRST_DEVICE_VECTOR; +#else + return FIRST_EXTERNAL_VECTOR; +#endif +} + +/** vmi clockchip */ +#ifdef CONFIG_X86_LOCAL_APIC +static unsigned int startup_timer_irq(unsigned int irq) +{ + unsigned long val = apic_read(APIC_LVTT); + apic_write(APIC_LVTT, vmi_get_timer_vector()); + + return (val & APIC_SEND_PENDING); +} + +static void mask_timer_irq(unsigned int irq) +{ + unsigned long val = apic_read(APIC_LVTT); + apic_write(APIC_LVTT, val | APIC_LVT_MASKED); +} + +static void unmask_timer_irq(unsigned int irq) +{ + unsigned long val = apic_read(APIC_LVTT); + apic_write(APIC_LVTT, val & ~APIC_LVT_MASKED); +} + +static void ack_timer_irq(unsigned int irq) +{ + ack_APIC_irq(); +} + +static struct irq_chip vmi_chip __read_mostly = { + .name = "VMI-LOCAL", + .startup = startup_timer_irq, + .mask = mask_timer_irq, + .unmask = unmask_timer_irq, + .ack = ack_timer_irq +}; +#endif + +/** vmi clockevent */ +#define VMI_ALARM_WIRED_IRQ0 0x00000000 +#define VMI_ALARM_WIRED_LVTT 0x00010000 +static int vmi_wiring = VMI_ALARM_WIRED_IRQ0; + +static inline int vmi_get_alarm_wiring(void) +{ + return vmi_wiring; +} + +static void vmi_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + cycle_t now, cycles_per_hz; + BUG_ON(!irqs_disabled()); + + switch (mode) { + case CLOCK_EVT_MODE_ONESHOT: + break; + case CLOCK_EVT_MODE_PERIODIC: + cycles_per_hz = vmi_timer_ops.get_cycle_frequency(); + (void)do_div(cycles_per_hz, HZ); + now = vmi_timer_ops.get_cycle_counter(vmi_counter(VMI_PERIODIC)); + vmi_timer_ops.set_alarm(VMI_PERIODIC, now, cycles_per_hz); + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + switch (evt->mode) { + case CLOCK_EVT_MODE_ONESHOT: + vmi_timer_ops.cancel_alarm(VMI_ONESHOT); + break; + case CLOCK_EVT_MODE_PERIODIC: + vmi_timer_ops.cancel_alarm(VMI_PERIODIC); + break; + default: + break; + } + break; + default: + break; + } +} + +static int vmi_timer_next_event(unsigned long delta, + struct clock_event_device *evt) +{ + /* Unfortunately, set_next_event interface only passes relative + * expiry, but we want absolute expiry. It'd be better if were + * were passed an aboslute expiry, since a bunch of time may + * have been stolen between the time the delta is computed and + * when we set the alarm below. */ + cycle_t now = vmi_timer_ops.get_cycle_counter(vmi_counter(VMI_ONESHOT)); + + BUG_ON(evt->mode != CLOCK_EVT_MODE_ONESHOT); + vmi_timer_ops.set_alarm(VMI_ONESHOT, now + delta, 0); + return 0; +} + +static struct clock_event_device vmi_clockevent = { + .name = "vmi-timer", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .shift = 22, + .set_mode = vmi_timer_set_mode, + .set_next_event = vmi_timer_next_event, + .rating = 1000, + .irq = 0, +}; + +static irqreturn_t vmi_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = &__get_cpu_var(local_events); + evt->event_handler(evt); + return IRQ_HANDLED; +} + +static struct irqaction vmi_clock_action = { + .name = "vmi-timer", + .handler = vmi_timer_interrupt, + .flags = IRQF_DISABLED | IRQF_NOBALANCING, + .mask = CPU_MASK_ALL, +}; + +static void __devinit vmi_time_init_clockevent(void) +{ + cycle_t cycles_per_msec; + struct clock_event_device *evt; + + int cpu = smp_processor_id(); + evt = &__get_cpu_var(local_events); + + /* Use cycles_per_msec since div_sc params are 32-bits. */ + cycles_per_msec = vmi_timer_ops.get_cycle_frequency(); + (void)do_div(cycles_per_msec, 1000); + + memcpy(evt, &vmi_clockevent, sizeof(*evt)); + /* Must pick .shift such that .mult fits in 32-bits. Choosing + * .shift to be 22 allows 2^(32-22) cycles per nano-seconds + * before overflow. */ + evt->mult = div_sc(cycles_per_msec, NSEC_PER_MSEC, evt->shift); + /* Upper bound is clockevent's use of ulong for cycle deltas. */ + evt->max_delta_ns = clockevent_delta2ns(ULONG_MAX, evt); + evt->min_delta_ns = clockevent_delta2ns(1, evt); + evt->cpumask = cpumask_of_cpu(cpu); + + printk(KERN_WARNING "vmi: registering clock event %s. mult=%lu shift=%u\n", + evt->name, evt->mult, evt->shift); + clockevents_register_device(evt); +} + +void __init vmi_time_init(void) +{ + /* Disable PIT: BIOSes start PIT CH0 with 18.2hz peridic. */ + outb_p(0x3a, PIT_MODE); /* binary, mode 5, LSB/MSB, ch 0 */ + + vmi_time_init_clockevent(); + setup_irq(0, &vmi_clock_action); +} + +#ifdef CONFIG_X86_LOCAL_APIC +void __devinit vmi_time_bsp_init(void) +{ + /* + * On APIC systems, we want local timers to fire on each cpu. We do + * this by programming LVTT to deliver timer events to the IRQ handler + * for IRQ-0, since we can't re-use the APIC local timer handler + * without interfering with that code. + */ + clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); + local_irq_disable(); +#ifdef CONFIG_X86_SMP + /* + * XXX handle_percpu_irq only defined for SMP; we need to switch over + * to using it, since this is a local interrupt, which each CPU must + * handle individually without locking out or dropping simultaneous + * local timers on other CPUs. We also don't want to trigger the + * quirk workaround code for interrupts which gets invoked from + * handle_percpu_irq via eoi, so we use our own IRQ chip. + */ + set_irq_chip_and_handler_name(0, &vmi_chip, handle_percpu_irq, "lvtt"); +#else + set_irq_chip_and_handler_name(0, &vmi_chip, handle_edge_irq, "lvtt"); +#endif + vmi_wiring = VMI_ALARM_WIRED_LVTT; + apic_write(APIC_LVTT, vmi_get_timer_vector()); + local_irq_enable(); + clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); +} + +void __devinit vmi_time_ap_init(void) +{ + vmi_time_init_clockevent(); + apic_write(APIC_LVTT, vmi_get_timer_vector()); +} +#endif + +/** vmi clocksource */ + +static cycle_t read_real_cycles(void) +{ + return vmi_timer_ops.get_cycle_counter(VMI_CYCLES_REAL); +} + +static struct clocksource clocksource_vmi = { + .name = "vmi-timer", + .rating = 450, + .read = read_real_cycles, + .mask = CLOCKSOURCE_MASK(64), + .mult = 0, /* to be set */ + .shift = 22, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int __init init_vmi_clocksource(void) +{ + cycle_t cycles_per_msec; + + if (!vmi_timer_ops.get_cycle_frequency) + return 0; + /* Use khz2mult rather than hz2mult since hz arg is only 32-bits. */ + cycles_per_msec = vmi_timer_ops.get_cycle_frequency(); + (void)do_div(cycles_per_msec, 1000); + + /* Note that clocksource.{mult, shift} converts in the opposite direction + * as clockevents. */ + clocksource_vmi.mult = clocksource_khz2mult(cycles_per_msec, + clocksource_vmi.shift); + + printk(KERN_WARNING "vmi: registering clock source khz=%lld\n", cycles_per_msec); + return clocksource_register(&clocksource_vmi); + +} +module_init(init_vmi_clocksource); |