gpu: host1x: Implement syncpoint wait using DMA fences

In anticipation of removal of the intr API, move host1x_syncpt_wait
to use DMA fences instead. As of this patch, this means that waits
have a 30 second maximum timeout because of the implicit timeout
we have with fences, but that will be lifted in a follow-up patch.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --git a/drivers/gpu/host1x/syncpt.c b/drivers/gpu/host1x/syncpt.c
index f87a870..75f58ec 100644 (file)
--- a/drivers/gpu/host1x/syncpt.c
+++ b/drivers/gpu/host1x/syncpt.c
@@ -7,6 +7,7 @@
 
 #include <linux/module.h>
 #include <linux/device.h>
+#include <linux/dma-fence.h>
 #include <linux/slab.h>
 
 #include <trace/events/host1x.h>
@@ -209,17 +210,6 @@ int host1x_syncpt_incr(struct host1x_syncpt *sp)
 }
 EXPORT_SYMBOL(host1x_syncpt_incr);
 
-/*
- * Updated sync point form hardware, and returns true if syncpoint is expired,
- * false if we may need to wait
- */
-static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
-{
-       host1x_hw_syncpt_load(sp->host, sp);
-
-       return host1x_syncpt_is_expired(sp, thresh);
-}
-
 /**
  * host1x_syncpt_wait() - wait for a syncpoint to reach a given value
  * @sp: host1x syncpoint
@@ -230,10 +220,10 @@ static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
 int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
                       u32 *value)
 {
-       DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
-       void *ref;
-       struct host1x_waitlist *waiter;
-       int err = 0, check_count = 0;
+       struct dma_fence *fence;
+       long wait_err;
+
+       host1x_hw_syncpt_load(sp->host, sp);
 
        if (value)
                *value = host1x_syncpt_load(sp);
@@ -241,73 +231,27 @@ int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
        if (host1x_syncpt_is_expired(sp, thresh))
                return 0;
 
-       if (!timeout) {
-               err = -EAGAIN;
-               goto done;
-       }
-
-       /* allocate a waiter */
-       waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
-       if (!waiter) {
-               err = -ENOMEM;
-               goto done;
-       }
-
-       /* schedule a wakeup when the syncpoint value is reached */
-       err = host1x_intr_add_action(sp->host, sp, thresh,
-                                    HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
-                                    &wq, waiter, &ref);
-       if (err)
-               goto done;
-
-       err = -EAGAIN;
-       /* Caller-specified timeout may be impractically low */
        if (timeout < 0)
                timeout = LONG_MAX;
+       else if (timeout == 0)
+               return -EAGAIN;
 
-       /* wait for the syncpoint, or timeout, or signal */
-       while (timeout) {
-               long check = min_t(long, SYNCPT_CHECK_PERIOD, timeout);
-               int remain;
-
-               remain = wait_event_interruptible_timeout(wq,
-                               syncpt_load_min_is_expired(sp, thresh),
-                               check);
-               if (remain > 0 || host1x_syncpt_is_expired(sp, thresh)) {
-                       if (value)
-                               *value = host1x_syncpt_load(sp);
+       fence = host1x_fence_create(sp, thresh);
+       if (IS_ERR(fence))
+               return PTR_ERR(fence);
 
-                       err = 0;
+       wait_err = dma_fence_wait_timeout(fence, true, timeout);
+       dma_fence_put(fence);
 
-                       break;
-               }
-
-               if (remain < 0) {
-                       err = remain;
-                       break;
-               }
-
-               timeout -= check;
-
-               if (timeout && check_count <= MAX_STUCK_CHECK_COUNT) {
-                       dev_warn(sp->host->dev,
-                               "%s: syncpoint id %u (%s) stuck waiting %d, timeout=%ld\n",
-                                current->comm, sp->id, sp->name,
-                                thresh, timeout);
-
-                       host1x_debug_dump_syncpts(sp->host);
-
-                       if (check_count == MAX_STUCK_CHECK_COUNT)
-                               host1x_debug_dump(sp->host);
-
-                       check_count++;
-               }
-       }
-
-       host1x_intr_put_ref(sp->host, sp->id, ref, true);
+       if (value)
+               *value = host1x_syncpt_load(sp);
 
-done:
-       return err;
+       if (wait_err == 0)
+               return -EAGAIN;
+       else if (wait_err < 0)
+               return wait_err;
+       else
+               return 0;
 }
 EXPORT_SYMBOL(host1x_syncpt_wait);