/*
* 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 <asm/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_tsc_khz = vmi_tsc_khz */
unsigned long vmi_tsc_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_pit(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);
