/*
* SGI RTC clock/timer routines.
*
* 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. 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Copyright (c) 2009 Silicon Graphics, Inc. All Rights Reserved.
* Copyright (c) Dimitri Sivanich
*/
#include <linux/clockchips.h>
#include <linux/slab.h>
#include <asm/uv/uv_mmrs.h>
#include <asm/uv/uv_hub.h>
#include <asm/uv/bios.h>
#include <asm/uv/uv.h>
#include <asm/apic.h>
#include <asm/cpu.h>
#define RTC_NAME "sgi_rtc"
static cycle_t uv_read_rtc(struct clocksource *cs);
static int uv_rtc_next_event(unsigned long, struct clock_event_device *);
static void uv_rtc_timer_setup(enum clock_event_mode,
struct clock_event_device *);
static struct clocksource clocksource_uv = {
.name = RTC_NAME,
.rating = 400,
.read = uv_read_rtc,
.mask = (cycle_t)UVH_RTC_REAL_TIME_CLOCK_MASK,
.shift = 10,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static struct clock_event_device clock_event_device_uv = {
.name = RTC_NAME,
.features = CLOCK_EVT_FEAT_ONESHOT,
.shift = 20,
.rating = 400,
.irq = -1,
.set_next_event = uv_rtc_next_event,
.set_mode = uv_rtc_timer_setup,
.event_handler = NULL,
};
static DEFINE_PER_CPU(struct clock_event_device, cpu_ced);
/* There is one of these allocated per node */
struct uv_rtc_timer_head {
spinlock_t lock;
/* next cpu waiting for timer, local node relative: */
int next_cpu;
/* number of cpus on this node: */
int ncpus;
struct {
int lcpu; /* systemwide logical cpu number */
u64 expires; /* next timer expiration for this cpu */
} cpu[1];
};
/*
* Access to uv_rtc_timer_head via blade id.
*/
static struct uv_rtc_timer_head **blade_info __read_mostly;
static int uv_rtc_evt_enable;
/*
* Hardware interface routines
*/
/* Send IPIs to another node */
static void uv_rtc_send_IPI(int cpu)
{
unsigned long apicid, val;
int pnode;
apicid = cpu_physical_id(cpu);
pnode = uv_apicid_to_pnode(apicid);
val = (1UL << UVH_IPI_INT_SEND_SHFT) |
(apicid << UVH_IPI_INT_APIC_ID_SHFT) |
(X86_PLATFORM_IPI_VECTOR << UVH_IPI_INT_VECTOR_SHFT);
uv_write_global_mmr64(pnode, UVH_IPI_INT, val);
}
/* Check for an RTC interrupt pending */
static int uv_intr_pending(int pnode)
{
return uv_read_global_mmr64(pnode, UVH_EVENT_OCCURRED0) &
UVH_EVENT_OCCURRED0_RTC1_MASK;
}
/* Setup interrupt and return non-zero if early expiration occurred. */
static int uv_setup_intr(int cpu, u64 expires)
{
u64 val;
int pnode = uv_cpu_to_pnode(cpu);
uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG,
UVH_RTC1_INT_CONFIG_M_MASK);
uv_write_global_mmr64(pnode, UVH_INT_CMPB, -1L);
uv_write_global_mmr64(pnode, UVH_EVENT_OCCURRED0_ALIAS,
UVH_EVENT_OCCURRED0_RTC1_MASK);
val = (X86_PLATFORM_IPI_VECTOR << UVH_RTC1_INT_CONFIG_VECTOR_SHFT) |
((u64)cpu_physical_id(cpu) << UVH_RTC1_INT_CONFIG_APIC_ID_SHFT);
/* Set configuration */
uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG, val);
/* Initialize comparator value */
uv_write_global_mmr64(pnode, UVH_INT_CMPB, expires);
if (uv_read_rtc(NULL) <= expires)
return 0;
return !uv_intr_pending(pnode);
}
/*
* Per-cpu timer tracking routines
*/
static __init void uv_rtc_deallocate_timers(void)
{
int bid;
for_each_possible_blade(bid) {
kfree(blade_info[bid]);
}
kfree(blade_info);
}
/* Allocate per-node list of cpu timer expiration times. */
static __init int uv_rtc_allocate_timers(void)
{
int cpu;
blade_info = kmalloc(uv_possible_blades * sizeof(void *), GFP_KERNEL);
if (!blade_info)
return -ENOMEM;
memset(blade_info, 0, uv_possible_blades * sizeof(void *));
for_each_present_cpu(cpu) {
int nid = cpu_to_node(cpu);
int bid = uv_cpu_to_blade_id(cpu);
int bcpu = uv_cpu_hub_info(cpu)->blade_processor_id;
struct uv_rtc_timer_head *head = blade_info[bid];
if (!head) {
head = kmalloc_node(sizeof(struct uv_rtc_timer_head) +
(uv_blade_nr_possible_cpus(bid) *
2 * sizeof(u64)),
GFP_KERNEL, nid);
if (!head) {
uv_rtc_deallocate_timers();
return -ENOMEM;
}
spin_lock_init(&head->lock);
head->ncpus = uv_blade_nr_possible_cpus(bid);
head->next_cpu = -1;
blade_info[bid] = head;
}
head->cpu[bcpu].lcpu = cpu;
head->cpu[bcpu].expires = ULLONG_MAX;
}
return 0;
}
/* Find and set the next expiring timer. */
static void uv_rtc_find_next_timer(struct uv_rtc_timer_head *head, int pnode)
{
u64 lowest = ULLONG_MAX;
int c, bcpu = -1;
head->next_cpu = -1;
for (c = 0; c < head->ncpus; c++) {
u64 exp = head->cpu[c].expires;
if (exp < lowest) {
bcpu = c;
lowest = exp;
}
}
if (bcpu >= 0) {
head->next_cpu = bcpu;
c = head->cpu[bcpu].lcpu;
if (uv_setup_intr(c, lowest))
/* If we didn't set it up in time, trigger */
uv_rtc_send_IPI(c);
} else {
uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG,
UVH_RTC1_INT_CONFIG_M_MASK);
}
}
/*
* Set expiration time for current cpu.
*
* Returns 1 if we missed the expiration time.
*/
static int uv_rtc_set_timer(int cpu, u64 expires)
{
int pnode = uv_cpu_to_pnode(cpu);
int bid = uv_cpu_to_blade_id(cpu);
struct uv_rtc_timer_head *head = blade_info[bid];
int bcpu = uv_cpu_hub_info(cpu)->blade_processor_id;
u64 *t = &head->cpu[bcpu].expires;
unsigned long flags;
int next_cpu;
spin_lock_irqsave(&head->lock, flags);
next_cpu = head->next_cpu;
*t = expires;
/* Will this one be next to go off? */
if (next_cpu < 0 || bcpu == next_cpu ||
expires < head->cpu[next_cpu].expires) {
head->next_cpu = bcpu;
if (uv_setup_intr(cpu, expires)) {
*t = ULLONG_MAX;
uv_rtc_find_next_timer(head, pnode);
spin_unlock_irqrestore(&head->lock, flags);
return -ETIME;
}
}
spin_unlock_irqrestore(&head->lock, flags);
return 0;
}
/*
* Unset expiration time for current cpu.
*
* Returns 1 if this timer was pending.
*/
static int uv_rtc_unset_timer(int cpu, int force)
{
int pnode = uv_cpu_to_pnode(cpu);
int bid = uv_cpu_to_blade_id(cpu);
struct uv_rtc_timer_head *head = blade_info[bid];
int bcpu = uv_cpu_hub_info(cpu)->blade_processor_id;
u64 *t = &head->cpu[bcpu].expires;
unsigned long flags;
int rc = 0;
spin_lock_irqsave(&head->lock, flags);
if ((head->next_cpu == bcpu && uv_read_rtc(NULL) >= *t) || force)
rc = 1;
if (rc) {
*t = ULLONG_MAX;
/* Was the hardware setup for this timer? */
if (head->next_cpu == bcpu)
uv_rtc_find_next_timer(head, pnode);
}
spin_unlock_irqrestore(&head->lock, flags);
return rc;
}
/*
* Kernel interface routines.
*/
/*
* Read the RTC.
*
* Starting with HUB rev 2.0, the UV RTC register is replicated across all
* cachelines of it's own page. This allows faster simultaneous reads
* from a given socket.
*/
static cycle_t uv_read_rtc(struct clocksource *cs)
{
unsigned long offset;
if (uv_get_min_hub_revision_id() == 1)
offset = 0;
else
offset = (uv_blade_processor_id() * L1_CACHE_BYTES) % PAGE_SIZE;
return (cycle_t)uv_read_local_mmr(UVH_RTC | offset);
}
/*
* Program the next event, relative to now
*/
static int uv_rtc_next_event(unsigned long delta,
struct clock_event_device *ced)
{
int ced_cpu = cpumask_first(ced->cpumask);
return uv_rtc_set_timer(ced_cpu, delta + uv_read_rtc(NULL));
}
/*
* Setup the RTC timer in oneshot mode
*/
static void uv_rtc_timer_setup(enum clock_event_mode mode,
struct clock_event_device *evt)
{
int ced_cpu = cpumask_first(evt->cpumask);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_RESUME:
/* Nothing to do here yet */
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
uv_rtc_unset_timer(ced_cpu, 1);
break;
}
}
static void uv_rtc_interrupt(void)
{
int cpu = smp_processor_id();
struct clock_event_device *ced = &per_cpu(cpu_ced, cpu);
if (!ced || !ced->event_handler)
return;
if (uv_rtc_unset_timer(cpu, 0) != 1)
return;
ced->event_handler(ced);
}
static int __init uv_enable_evt_rtc(char *str)
{
uv_rtc_evt_enable = 1;
return 1;
}
__setup("uvrtcevt", uv_enable_evt_rtc);
static __init void uv_rtc_register_clockevents(struct work_struct *dummy)
{
struct clock_event_device *ced = &__get_cpu_var(cpu_ced);
*ced = clock_event_device_uv;
ced->cpumask = cpumask_of(smp_processor_id());
clockevents_register_device(ced);
}
static __init int uv_rtc_setup_clock(void)
{
int rc;
if (!is_uv_system())
return -ENODEV;
clocksource_uv.mult = clocksource_hz2mult(sn_rtc_cycles_per_second,
clocksource_uv.shift);
/* If single blade, prefer tsc */
if (uv_num_possible_blades() == 1)
clocksource_uv.rating = 250;
rc = clocksource_register(&clocksource_uv);
if (rc)
printk(KERN_INFO "UV RTC clocksource failed rc %d\n", rc);
else
printk(KERN_INFO "UV RTC clocksource registered freq %lu MHz\n",
sn_rtc_cycles_per_second/(unsigned long)1E6);
if (rc || !uv_rtc_evt_enable || x86_platform_ipi_callback)
return rc;
/* Setup and register clockevents */
rc = uv_rtc_allocate_timers();
if (rc)
goto error;
x86_platform_ipi_callback = uv_rtc_interrupt;
clock_event_device_uv.mult = div_sc(sn_rtc_cycles_per_second,
NSEC_PER_SEC, clock_event_device_uv.shift);
clock_event_device_uv.min_delta_ns = NSEC_PER_SEC /
sn_rtc_cycles_per_second;
clock_event_device_uv.max_delta_ns = clocksource_uv.mask *
(NSEC_PER_SEC / sn_rtc_cycles_per_second);
rc = schedule_on_each_cpu(uv_rtc_register_clockevents);
if (rc) {
x86_platform_ipi_callback = NULL;
uv_rtc_deallocate_timers();
goto error;
}
printk(KERN_INFO "UV RTC clockevents registered\n");
return 0;
error:
clocksource_unregister(&clocksource_uv);
printk(KERN_INFO "UV RTC clockevents failed rc %d\n", rc);
return rc;
}
arch_initcall(uv_rtc_setup_clock);
