| /* |
| * 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 <asm/i8253.h> |
| |
| #include <irq_vectors.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.sched_clock = vmi_sched_clock */ |
| unsigned long long vmi_sched_clock(void) |
| { |
| return cycles_2_ns(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: |
| case CLOCK_EVT_MODE_RESUME: |
| 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); |