In the discussions around commit 373701b1 (Jani Nikula)
drm: fix potential dangling else problems in for_each_ macros
Daniel Vetter mooted the idea of a for_each_engine(ring, dev_priv)
macro that didn't use or rely on having an integer index variable.
So here it is; and, for backwards compatibility, an updated version
of for_each_ring() implemented using the same internals. As an example
of the use of this new macro, the functions in intel_uncore.c have
been converted to use it in preference to for_each_ring() wherever
possible. A subsequent patch will convert many of the uses in other
source files.
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Dave Gordon <david.s.gordon@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 32 ++++++++++++++++++++++++++++----
drivers/gpu/drm/i915/intel_uncore.c | 5 ++---
2 files changed, 30 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index cf7e0fc..a6457ee 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1968,10 +1968,34 @@ static inline struct drm_i915_private *guc_to_i915(struct intel_guc *guc)
return container_of(guc, struct drm_i915_private, guc);
}
-/* Iterate over initialised rings */
-#define for_each_ring(ring__, dev_priv__, i__) \
- for ((i__) = 0; (i__) < I915_NUM_RINGS; (i__)++) \
- for_each_if ((((ring__) = &(dev_priv__)->ring[(i__)]), intel_ring_initialized((ring__))))
+/* Helpers for the for_each_* macros below */
+#define __INIT_ENGINE_PTR(engine, dev_priv) \
+ ({ \
+ struct intel_engine_cs *ep = (dev_priv)->ring; \
+ (engine) = --ep; \
+ })
+#define __NEXT_ACTIVE_ENGINE(engine, dev_priv, nr) \
+ ({ \
+ struct intel_engine_cs *end = &(dev_priv)->ring[nr]; \
+ struct intel_engine_cs *ep = (engine); \
+ bool in_range; \
+ do { \
+ in_range = ++(ep) < end; \
+ } while (in_range && !intel_ring_initialized(ep)); \
+ (engine) = ep; \
+ in_range; \
+ })
+
+/* Iterate over initialised engines */
+#define for_each_engine(engine, dev_priv) \
+ for (__INIT_ENGINE_PTR(engine, dev_priv); \
+ __NEXT_ACTIVE_ENGINE(engine, dev_priv, I915_NUM_RINGS); )
+
+/* Backwards compatibility: iterate over initialised "rings" */
+#define for_each_ring(engine, dev_priv, ring_id) \
+ for (__INIT_ENGINE_PTR(engine, dev_priv); \
+ __NEXT_ACTIVE_ENGINE(engine, dev_priv, I915_NUM_RINGS) && \
+ ((ring_id) = (engine)->id, true); )
enum hdmi_force_audio {
HDMI_AUDIO_OFF_DVI = -2, /* no aux data for HDMI-DVI converter */
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 277e60a..240c244 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1508,9 +1508,8 @@ static int gen8_do_reset(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
struct intel_engine_cs *engine;
- int i;
- for_each_ring(engine, dev_priv, i) {
+ for_each_engine(engine, dev_priv) {
I915_WRITE(RING_RESET_CTL(engine->mmio_base),
_MASKED_BIT_ENABLE(RESET_CTL_REQUEST_RESET));
@@ -1527,7 +1526,7 @@ static int gen8_do_reset(struct drm_device *dev)
return gen6_do_reset(dev);
not_ready:
- for_each_ring(engine, dev_priv, i)
+ for_each_engine(engine, dev_priv)
I915_WRITE(RING_RESET_CTL(engine->mmio_base),
_MASKED_BIT_DISABLE(RESET_CTL_REQUEST_RESET));
--
1.9.1
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