Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[pandora-kernel.git] / drivers / char / mmtimer.c

diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
index ea7c99f..e6d7562 100644 (file)
--- 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;
 }