diff options
Diffstat (limited to 'drivers/char/mmtimer.c')
| -rw-r--r-- | drivers/char/mmtimer.c | 68 |
1 files changed, 37 insertions, 31 deletions
diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c index ea7c99fa978f..e6d75627c6c8 100644 --- a/drivers/char/mmtimer.c +++ b/drivers/char/mmtimer.c @@ -32,7 +32,7 @@ #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> @@ -59,6 +59,7 @@ extern unsigned long sn_rtc_cycles_per_second; #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); @@ -72,6 +73,7 @@ static const struct file_operations mmtimer_fops = { .owner = THIS_MODULE, .mmap = mmtimer_mmap, .unlocked_ioctl = mmtimer_ioctl, + .llseek = noop_llseek, }; /* @@ -174,9 +176,9 @@ 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); @@ -189,7 +191,8 @@ 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; /* @@ -225,6 +228,8 @@ 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; @@ -240,6 +245,11 @@ 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. @@ -287,7 +297,8 @@ 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) @@ -298,7 +309,8 @@ 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); } @@ -306,14 +318,23 @@ 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); @@ -321,21 +342,6 @@ 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; - } } } @@ -371,7 +377,7 @@ 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 */ @@ -414,7 +420,7 @@ static long mmtimer_ioctl(struct file *file, unsigned int cmd, ret = -ENOTTY; break; } - unlock_kernel(); + mutex_unlock(&mmtimer_mutex); return ret; } |