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path: root/drivers/char/mmtimer.c
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Diffstat (limited to 'drivers/char/mmtimer.c')
-rw-r--r--drivers/char/mmtimer.c104
1 files changed, 59 insertions, 45 deletions
diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
index 918711aa56f..3d6c0671e99 100644
--- a/drivers/char/mmtimer.c
+++ b/drivers/char/mmtimer.c
@@ -32,7 +32,8 @@
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/math64.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
#include <asm/uaccess.h>
#include <asm/sn/addrs.h>
@@ -52,12 +53,15 @@ MODULE_LICENSE("GPL");
#define RTC_BITS 55 /* 55 bits for this implementation */
+static struct k_clock sgi_clock;
+
extern unsigned long sn_rtc_cycles_per_second;
#define RTC_COUNTER_ADDR ((long *)LOCAL_MMR_ADDR(SH_RTC))
#define rtc_time() (*RTC_COUNTER_ADDR)
+static DEFINE_MUTEX(mmtimer_mutex);
static long mmtimer_ioctl(struct file *file, unsigned int cmd,
unsigned long arg);
static int mmtimer_mmap(struct file *file, struct vm_area_struct *vma);
@@ -71,6 +75,7 @@ static const struct file_operations mmtimer_fops = {
.owner = THIS_MODULE,
.mmap = mmtimer_mmap,
.unlocked_ioctl = mmtimer_ioctl,
+ .llseek = noop_llseek,
};
/*
@@ -173,9 +178,9 @@ static void mmtimer_setup_int_2(int cpu, u64 expires)
* in order to insure that the setup succeeds in a deterministic time frame.
* It will check if the interrupt setup succeeded.
*/
-static int mmtimer_setup(int cpu, int comparator, unsigned long expires)
+static int mmtimer_setup(int cpu, int comparator, unsigned long expires,
+ u64 *set_completion_time)
{
-
switch (comparator) {
case 0:
mmtimer_setup_int_0(cpu, expires);
@@ -188,7 +193,8 @@ static int mmtimer_setup(int cpu, int comparator, unsigned long expires)
break;
}
/* We might've missed our expiration time */
- if (rtc_time() <= expires)
+ *set_completion_time = rtc_time();
+ if (*set_completion_time <= expires)
return 1;
/*
@@ -224,6 +230,8 @@ static int mmtimer_disable_int(long nasid, int comparator)
#define TIMER_OFF 0xbadcabLL /* Timer is not setup */
#define TIMER_SET 0 /* Comparator is set for this timer */
+#define MMTIMER_INTERVAL_RETRY_INCREMENT_DEFAULT 40
+
/* There is one of these for each timer */
struct mmtimer {
struct rb_node list;
@@ -239,6 +247,11 @@ struct mmtimer_node {
};
static struct mmtimer_node *timers;
+static unsigned mmtimer_interval_retry_increment =
+ MMTIMER_INTERVAL_RETRY_INCREMENT_DEFAULT;
+module_param(mmtimer_interval_retry_increment, uint, 0644);
+MODULE_PARM_DESC(mmtimer_interval_retry_increment,
+ "RTC ticks to add to expiration on interval retry (default 40)");
/*
* Add a new mmtimer struct to the node's mmtimer list.
@@ -286,7 +299,8 @@ static void mmtimer_set_next_timer(int nodeid)
struct mmtimer_node *n = &timers[nodeid];
struct mmtimer *x;
struct k_itimer *t;
- int o;
+ u64 expires, exp, set_completion_time;
+ int i;
restart:
if (n->next == NULL)
@@ -297,7 +311,8 @@ restart:
if (!t->it.mmtimer.incr) {
/* Not an interval timer */
if (!mmtimer_setup(x->cpu, COMPARATOR,
- t->it.mmtimer.expires)) {
+ t->it.mmtimer.expires,
+ &set_completion_time)) {
/* Late setup, fire now */
tasklet_schedule(&n->tasklet);
}
@@ -305,14 +320,23 @@ restart:
}
/* Interval timer */
- o = 0;
- while (!mmtimer_setup(x->cpu, COMPARATOR, t->it.mmtimer.expires)) {
- unsigned long e, e1;
- struct rb_node *next;
- t->it.mmtimer.expires += t->it.mmtimer.incr << o;
- t->it_overrun += 1 << o;
- o++;
- if (o > 20) {
+ i = 0;
+ expires = exp = t->it.mmtimer.expires;
+ while (!mmtimer_setup(x->cpu, COMPARATOR, expires,
+ &set_completion_time)) {
+ int to;
+
+ i++;
+ expires = set_completion_time +
+ mmtimer_interval_retry_increment + (1 << i);
+ /* Calculate overruns as we go. */
+ to = ((u64)(expires - exp) / t->it.mmtimer.incr);
+ if (to) {
+ t->it_overrun += to;
+ t->it.mmtimer.expires += t->it.mmtimer.incr * to;
+ exp = t->it.mmtimer.expires;
+ }
+ if (i > 20) {
printk(KERN_ALERT "mmtimer: cannot reschedule timer\n");
t->it.mmtimer.clock = TIMER_OFF;
n->next = rb_next(&x->list);
@@ -320,21 +344,6 @@ restart:
kfree(x);
goto restart;
}
-
- e = t->it.mmtimer.expires;
- next = rb_next(&x->list);
-
- if (next == NULL)
- continue;
-
- e1 = rb_entry(next, struct mmtimer, list)->
- timer->it.mmtimer.expires;
- if (e > e1) {
- n->next = next;
- rb_erase(&x->list, &n->timer_head);
- mmtimer_add_list(x);
- goto restart;
- }
}
}
@@ -370,7 +379,7 @@ static long mmtimer_ioctl(struct file *file, unsigned int cmd,
{
int ret = 0;
- lock_kernel();
+ mutex_lock(&mmtimer_mutex);
switch (cmd) {
case MMTIMER_GETOFFSET: /* offset of the counter */
@@ -413,7 +422,7 @@ static long mmtimer_ioctl(struct file *file, unsigned int cmd,
ret = -ENOTTY;
break;
}
- unlock_kernel();
+ mutex_unlock(&mmtimer_mutex);
return ret;
}
@@ -480,7 +489,7 @@ static int sgi_clock_get(clockid_t clockid, struct timespec *tp)
return 0;
};
-static int sgi_clock_set(clockid_t clockid, struct timespec *tp)
+static int sgi_clock_set(const clockid_t clockid, const struct timespec *tp)
{
u64 nsec;
@@ -546,7 +555,7 @@ static void mmtimer_tasklet(unsigned long data)
{
int nodeid = data;
struct mmtimer_node *mn = &timers[nodeid];
- struct mmtimer *x = rb_entry(mn->next, struct mmtimer, list);
+ struct mmtimer *x;
struct k_itimer *t;
unsigned long flags;
@@ -756,15 +765,21 @@ static int sgi_timer_set(struct k_itimer *timr, int flags,
return err;
}
+static int sgi_clock_getres(const clockid_t which_clock, struct timespec *tp)
+{
+ tp->tv_sec = 0;
+ tp->tv_nsec = sgi_clock_period;
+ return 0;
+}
+
static struct k_clock sgi_clock = {
- .res = 0,
- .clock_set = sgi_clock_set,
- .clock_get = sgi_clock_get,
- .timer_create = sgi_timer_create,
- .nsleep = do_posix_clock_nonanosleep,
- .timer_set = sgi_timer_set,
- .timer_del = sgi_timer_del,
- .timer_get = sgi_timer_get
+ .clock_set = sgi_clock_set,
+ .clock_get = sgi_clock_get,
+ .clock_getres = sgi_clock_getres,
+ .timer_create = sgi_timer_create,
+ .timer_set = sgi_timer_set,
+ .timer_del = sgi_timer_del,
+ .timer_get = sgi_timer_get
};
/**
@@ -811,7 +826,7 @@ static int __init mmtimer_init(void)
/* Allocate list of node ptrs to mmtimer_t's */
timers = kzalloc(sizeof(struct mmtimer_node)*maxn, GFP_KERNEL);
- if (timers == NULL) {
+ if (!timers) {
printk(KERN_ERR "%s: failed to allocate memory for device\n",
MMTIMER_NAME);
goto out3;
@@ -824,8 +839,8 @@ static int __init mmtimer_init(void)
(unsigned long) node);
}
- sgi_clock_period = sgi_clock.res = NSEC_PER_SEC / sn_rtc_cycles_per_second;
- register_posix_clock(CLOCK_SGI_CYCLE, &sgi_clock);
+ sgi_clock_period = NSEC_PER_SEC / sn_rtc_cycles_per_second;
+ posix_timers_register_clock(CLOCK_SGI_CYCLE, &sgi_clock);
printk(KERN_INFO "%s: v%s, %ld MHz\n", MMTIMER_DESC, MMTIMER_VERSION,
sn_rtc_cycles_per_second/(unsigned long)1E6);
@@ -833,7 +848,6 @@ static int __init mmtimer_init(void)
return 0;
out3:
- kfree(timers);
misc_deregister(&mmtimer_miscdev);
out2:
free_irq(SGI_MMTIMER_VECTOR, NULL);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-09 13:59:58 +0000