nouveau: Add read() method to Engine.timer.

This is not called from anywhere, yet.

3 files changed, 31 insertions, 0 deletions

diff --git a/shared-core/nouveau_drv.h b/shared-core/nouveau_drv.h
index f68304c9..9e11f9b7 100644
--- a/shared-core/nouveau_drv.h
+++ b/shared-core/nouveau_drv.h
@@ -157,6 +157,7 @@ struct nouveau_engine_func {
 
 	struct {
 		int	(*init)(struct drm_device *dev);
+		uint64_t (*read)(struct drm_device *dev);
 		void	(*takedown)(struct drm_device *dev);
 	} timer;
 
@@ -469,6 +470,7 @@ extern void nv50_mc_takedown(struct drm_device *dev);
 
 /* nv04_timer.c */
 extern int  nv04_timer_init(struct drm_device *dev);
+extern uint64_t nv04_timer_read(struct drm_device *dev);
 extern void nv04_timer_takedown(struct drm_device *dev);
 
 extern long nouveau_compat_ioctl(struct file *filp, unsigned int cmd,
diff --git a/shared-core/nouveau_state.c b/shared-core/nouveau_state.c
index 4e3b39dd..5b67aea1 100644
--- a/shared-core/nouveau_state.c
+++ b/shared-core/nouveau_state.c
@@ -88,6 +88,8 @@ static int nouveau_init_card_mappings(struct drm_device *dev)
 
 static int nouveau_stub_init(struct drm_device *dev) { return 0; }
 static void nouveau_stub_takedown(struct drm_device *dev) {}
+static uint64_t nouveau_stub_timer_read(struct drm_device *dev) { return 0; }
+
 static int nouveau_init_engine_ptrs(struct drm_device *dev)
 {
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
@@ -104,6 +106,7 @@ static int nouveau_init_engine_ptrs(struct drm_device *dev)
 		engine->mc.init		= nv04_mc_init;
 		engine->mc.takedown	= nv04_mc_takedown;
 		engine->timer.init	= nv04_timer_init;
+		engine->timer.read	= nv04_timer_read;
 		engine->timer.takedown	= nv04_timer_takedown;
 		engine->fb.init		= nv04_fb_init;
 		engine->fb.takedown	= nv04_fb_takedown;
@@ -130,6 +133,7 @@ static int nouveau_init_engine_ptrs(struct drm_device *dev)
 		engine->mc.init		= nv04_mc_init;
 		engine->mc.takedown	= nv04_mc_takedown;
 		engine->timer.init	= nv04_timer_init;
+		engine->timer.read	= nv04_timer_read;
 		engine->timer.takedown	= nv04_timer_takedown;
 		engine->fb.init		= nv10_fb_init;
 		engine->fb.takedown	= nv10_fb_takedown;
@@ -156,6 +160,7 @@ static int nouveau_init_engine_ptrs(struct drm_device *dev)
 		engine->mc.init		= nv04_mc_init;
 		engine->mc.takedown	= nv04_mc_takedown;
 		engine->timer.init	= nv04_timer_init;
+		engine->timer.read	= nv04_timer_read;
 		engine->timer.takedown	= nv04_timer_takedown;
 		engine->fb.init		= nv10_fb_init;
 		engine->fb.takedown	= nv10_fb_takedown;
@@ -182,6 +187,7 @@ static int nouveau_init_engine_ptrs(struct drm_device *dev)
 		engine->mc.init		= nv04_mc_init;
 		engine->mc.takedown	= nv04_mc_takedown;
 		engine->timer.init	= nv04_timer_init;
+		engine->timer.read	= nv04_timer_read;
 		engine->timer.takedown	= nv04_timer_takedown;
 		engine->fb.init		= nv10_fb_init;
 		engine->fb.takedown	= nv10_fb_takedown;
@@ -208,6 +214,7 @@ static int nouveau_init_engine_ptrs(struct drm_device *dev)
 		engine->mc.init		= nv40_mc_init;
 		engine->mc.takedown	= nv40_mc_takedown;
 		engine->timer.init	= nv04_timer_init;
+		engine->timer.read	= nv04_timer_read;
 		engine->timer.takedown	= nv04_timer_takedown;
 		engine->fb.init		= nv40_fb_init;
 		engine->fb.takedown	= nv40_fb_takedown;
@@ -235,6 +242,7 @@ static int nouveau_init_engine_ptrs(struct drm_device *dev)
 		engine->mc.init		= nv50_mc_init;
 		engine->mc.takedown	= nv50_mc_takedown;
 		engine->timer.init	= nouveau_stub_init;
+		engine->timer.read	= nouveau_stub_timer_read;
 		engine->timer.takedown	= nouveau_stub_takedown;
 		engine->fb.init		= nouveau_stub_init;
 		engine->fb.takedown	= nouveau_stub_takedown;
diff --git a/shared-core/nv04_timer.c b/shared-core/nv04_timer.c
index efe78da7..08a27f4f 100644
--- a/shared-core/nv04_timer.c
+++ b/shared-core/nv04_timer.c
@@ -17,6 +17,27 @@ nv04_timer_init(struct drm_device *dev)
 	return 0;
 }
 
+uint64_t
+nv04_timer_read(struct drm_device *dev)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	uint32_t low;
+	/* From kmmio dumps on nv28 this looks like how the blob does this.
+	 * It reads the high dword twice, before and after.
+	 * The only explanation seems to be that the 64-bit timer counter
+	 * advances between high and low dword reads and may corrupt the
+	 * result. Not confirmed.
+	 */
+	uint32_t high2 = NV_READ(NV04_PTIMER_TIME_1);
+	uint32_t high1;
+	do {
+		high1 = high2;
+		low = NV_READ(NV04_PTIMER_TIME_0);
+		high2 = NV_READ(NV04_PTIMER_TIME_1);
+	} while(high1 != high2);
+	return (((uint64_t)high2) << 32) | (uint64_t)low;
+}
+
 void
 nv04_timer_takedown(struct drm_device *dev)
 {