drm/nouveau: add function to wait until a callback returns true

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -833,6 +833,8 @@ extern bool nouveau_wait_eq(struct drm_device *, uint64_t timeout,
 			    uint32_t reg, uint32_t mask, uint32_t val);
 extern bool nouveau_wait_ne(struct drm_device *, uint64_t timeout,
 			    uint32_t reg, uint32_t mask, uint32_t val);
+extern bool nouveau_wait_cb(struct drm_device *, u64 timeout,
+			    bool (*cond)(void *), void *);
 extern bool nouveau_wait_for_idle(struct drm_device *);
 extern int  nouveau_card_init(struct drm_device *);
 
@@ -1457,6 +1459,8 @@ static inline void nv_wr08(struct drm_device *dev, unsigned reg, u8 val)
 	nouveau_wait_eq(dev, 2000000000ULL, (reg), (mask), (val))
 #define nv_wait_ne(dev, reg, mask, val) \
 	nouveau_wait_ne(dev, 2000000000ULL, (reg), (mask), (val))
+#define nv_wait_cb(dev, func, data) \
+	nouveau_wait_cb(dev, 2000000000ULL, (func), (data))
 
 /* PRAMIN access */
 static inline u32 nv_ri32(struct drm_device *dev, unsigned offset)

drivers/gpu/drm/nouveau/nouveau_state.c

@@ -1200,6 +1200,23 @@ nouveau_wait_ne(struct drm_device *dev, uint64_t timeout,
 	return false;
 }
 
+/* Wait until cond(data) == true, up until timeout has hit */
+bool
+nouveau_wait_cb(struct drm_device *dev, u64 timeout,
+		bool (*cond)(void *), void *data)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_timer_engine *ptimer = &dev_priv->engine.timer;
+	u64 start = ptimer->read(dev);
+
+	do {
+		if (cond(data) == true)
+			return true;
+	} while (ptimer->read(dev) - start < timeout);
+
+	return false;
+}
+
 /* Waits for PGRAPH to go completely idle */
 bool nouveau_wait_for_idle(struct drm_device *dev)
 {