[Intel-gfx] [PATCH v5 3/5] drm/i915: Watchdog timeout: Ringbuffer command emission for gen8+

Carlos Santa carlos.santa at intel.com
Fri Mar 22 23:41:16 UTC 2019


From: Michel Thierry <michel.thierry at intel.com>

Emit the required commands into the ring buffer for starting and
stopping the watchdog timer before/after batch buffer start during
batch buffer submission.

v2: Support watchdog threshold per context engine, merge lri commands,
and move watchdog commands emission to emit_bb_start. Request space of
combined start_watchdog, bb_start and stop_watchdog to avoid any error
after emitting bb_start.

v3: There were too many req->engine in emit_bb_start.
Use GEM_BUG_ON instead of returning a very late EINVAL in the remote
case of watchdog misprogramming; set correct LRI cmd size in
emit_stop_watchdog. (Chris)

v4: Rebase.
v5: use to_intel_context instead of ctx->engine.
v6: Rebase.
v7: Rebase,
    Store gpu watchdog capability in engine flag (Tvrtko)
    Store WATCHDOG_DISABLE magic # in engine (Tvrtko)
    No need to declare emit_{start|stop}_watchdog as vfuncs (Tvrtko)
    Replace flag watchdog_running with enable_watchdog (Tvrtko)
    Emit a single MI_NOOP by conditionally checking whether the #
    of emitted OPs is odd (Tvrtko)
v8: Rebase

Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Antonio Argenziano <antonio.argenziano at intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
Signed-off-by: Michel Thierry <michel.thierry at intel.com>
Signed-off-by: Carlos Santa <carlos.santa at intel.com>
---
 drivers/gpu/drm/i915/intel_context_types.h |  4 +
 drivers/gpu/drm/i915/intel_engine_cs.c     |  2 +
 drivers/gpu/drm/i915/intel_engine_types.h  | 17 ++++-
 drivers/gpu/drm/i915/intel_lrc.c           | 89 +++++++++++++++++++++-
 drivers/gpu/drm/i915/intel_lrc.h           |  2 +
 5 files changed, 106 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_context_types.h b/drivers/gpu/drm/i915/intel_context_types.h
index 6dc9b4b9067b..e56fc263568e 100644
--- a/drivers/gpu/drm/i915/intel_context_types.h
+++ b/drivers/gpu/drm/i915/intel_context_types.h
@@ -51,6 +51,10 @@ struct intel_context {
 	u64 lrc_desc;
 
 	atomic_t pin_count;
+	/** watchdog_threshold: hw watchdog threshold value,
+	 * in clock counts
+	 */
+	u32 watchdog_threshold;
 	struct mutex pin_mutex; /* guards pinning and associated on-gpuing */
 
 	/**
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 88cf0fc07623..d4ea07b70904 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -324,6 +324,8 @@ intel_engine_setup(struct drm_i915_private *dev_priv,
 	if (engine->context_size)
 		DRIVER_CAPS(dev_priv)->has_logical_contexts = true;
 
+	engine->watchdog_disable_id = get_watchdog_disable(engine);
+
 	/* Nothing to do here, execute in order of dependencies */
 	engine->schedule = NULL;
 
diff --git a/drivers/gpu/drm/i915/intel_engine_types.h b/drivers/gpu/drm/i915/intel_engine_types.h
index c4f66b774e7c..1f99b536471d 100644
--- a/drivers/gpu/drm/i915/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/intel_engine_types.h
@@ -260,6 +260,7 @@ struct intel_engine_cs {
 	unsigned int guc_id;
 	intel_engine_mask_t mask;
 
+	u32 watchdog_disable_id;
 	u8 uabi_class;
 
 	u8 class;
@@ -422,10 +423,12 @@ struct intel_engine_cs {
 
 	struct intel_engine_hangcheck hangcheck;
 
-#define I915_ENGINE_NEEDS_CMD_PARSER BIT(0)
-#define I915_ENGINE_SUPPORTS_STATS   BIT(1)
-#define I915_ENGINE_HAS_PREEMPTION   BIT(2)
-#define I915_ENGINE_HAS_SEMAPHORES   BIT(3)
+#define I915_ENGINE_NEEDS_CMD_PARSER  BIT(0)
+#define I915_ENGINE_SUPPORTS_STATS    BIT(1)
+#define I915_ENGINE_HAS_PREEMPTION    BIT(2)
+#define I915_ENGINE_HAS_SEMAPHORES    BIT(3)
+#define I915_ENGINE_SUPPORTS_WATCHDOG BIT(4)
+
 	unsigned int flags;
 
 	/*
@@ -509,6 +512,12 @@ intel_engine_has_semaphores(const struct intel_engine_cs *engine)
 	return engine->flags & I915_ENGINE_HAS_SEMAPHORES;
 }
 
+static inline bool
+intel_engine_supports_watchdog(const struct intel_engine_cs *engine)
+{
+	return engine->flags & I915_ENGINE_SUPPORTS_WATCHDOG;
+}
+
 #define instdone_slice_mask(dev_priv__) \
 	(IS_GEN(dev_priv__, 7) ? \
 	 1 : RUNTIME_INFO(dev_priv__)->sseu.slice_mask)
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 85785a94f6ae..78ea54a5dbc3 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -2036,16 +2036,75 @@ static void execlists_reset_finish(struct intel_engine_cs *engine)
 		  atomic_read(&execlists->tasklet.count));
 }
 
+static u32 *gen8_emit_start_watchdog(struct i915_request *rq, u32 *cs)
+{
+	struct intel_engine_cs *engine = rq->engine;
+	struct i915_gem_context *ctx = rq->gem_context;
+	struct intel_context *ce = intel_context_lookup(ctx, engine);
+
+	GEM_BUG_ON(!intel_engine_supports_watchdog(engine));
+
+	/*
+	 * watchdog register must never be programmed to zero. This would
+	 * cause the watchdog counter to exceed and not allow the engine to
+	 * go into IDLE state
+	 */
+	GEM_BUG_ON(ce->watchdog_threshold == 0);
+
+	/* Set counter period */
+	*cs++ = MI_LOAD_REGISTER_IMM(2);
+	*cs++ = i915_mmio_reg_offset(RING_THRESH(engine->mmio_base));
+	*cs++ = ce->watchdog_threshold;
+	/* Start counter */
+	*cs++ = i915_mmio_reg_offset(RING_CNTR(engine->mmio_base));
+	*cs++ = GEN8_WATCHDOG_ENABLE;
+
+	return cs;
+}
+
+static u32 *gen8_emit_stop_watchdog(struct i915_request *rq, u32 *cs)
+{
+	struct intel_engine_cs *engine = rq->engine;
+
+	GEM_BUG_ON(!intel_engine_supports_watchdog(engine));
+
+	*cs++ = MI_LOAD_REGISTER_IMM(1);
+	*cs++ = i915_mmio_reg_offset(RING_CNTR(engine->mmio_base));
+	*cs++ = engine->watchdog_disable_id;
+
+	return cs;
+}
+
 static int gen8_emit_bb_start(struct i915_request *rq,
 			      u64 offset, u32 len,
 			      const unsigned int flags)
 {
+	struct intel_engine_cs *engine = rq->engine;
+	struct i915_gem_context *ctx = rq->gem_context;
+	struct intel_context *ce = intel_context_lookup(ctx, engine);
 	u32 *cs;
+	u32 num_dwords;
+	bool enable_watchdog = false;
 
-	cs = intel_ring_begin(rq, 6);
+	/* bb_start only */
+	num_dwords = 6;
+
+	/* check if watchdog will be required */
+	if (ce->watchdog_threshold != 0) {
+		/* + start_watchdog (6) + stop_watchdog (4) */
+		num_dwords += 10;
+		enable_watchdog = true;
+	}
+
+	cs = intel_ring_begin(rq, num_dwords);
 	if (IS_ERR(cs))
 		return PTR_ERR(cs);
 
+	if (enable_watchdog) {
+		/* Start watchdog timer */
+		cs = gen8_emit_start_watchdog(rq, cs);
+	}
+
 	/*
 	 * WaDisableCtxRestoreArbitration:bdw,chv
 	 *
@@ -2072,10 +2131,16 @@ static int gen8_emit_bb_start(struct i915_request *rq,
 	*cs++ = upper_32_bits(offset);
 
 	*cs++ = MI_ARB_ON_OFF | MI_ARB_DISABLE;
-	*cs++ = MI_NOOP;
 
-	intel_ring_advance(rq, cs);
+	if (enable_watchdog) {
+		/* Cancel watchdog timer */
+		cs = gen8_emit_stop_watchdog(rq, cs);
+	}
+
+	if (*cs%2 != 0)
+		*cs++ = MI_NOOP;
 
+	intel_ring_advance(rq, cs);
 	return 0;
 }
 
@@ -2195,6 +2260,15 @@ static int gen8_emit_flush_render(struct i915_request *request,
 	return 0;
 }
 
+/* From GEN9 onwards, all engines use the same RING_CNTR format */
+u32 get_watchdog_disable(struct intel_engine_cs *engine)
+{
+	if (engine->id == RCS0 || INTEL_GEN(engine->i915) >= 9)
+		return GEN8_WATCHDOG_DISABLE;
+	else
+		return GEN8_XCS_WATCHDOG_DISABLE;
+}
+
 static void gen8_watchdog_tasklet(unsigned long data)
 {
 	struct intel_engine_cs *engine = (struct intel_engine_cs *)data;
@@ -2357,6 +2431,9 @@ void intel_execlists_set_default_submission(struct intel_engine_cs *engine)
 	engine->flags |= I915_ENGINE_SUPPORTS_STATS;
 	if (engine->preempt_context)
 		engine->flags |= I915_ENGINE_HAS_PREEMPTION;
+
+	if(engine->id != BCS0)
+		engine->flags |= I915_ENGINE_SUPPORTS_WATCHDOG;
 }
 
 static void
@@ -2531,6 +2608,9 @@ int logical_xcs_ring_init(struct intel_engine_cs *engine)
 	if (err)
 		return err;
 
+	/* BCS engine does not have a watchdog-expired irq */
+	GEM_BUG_ON(!intel_engine_supports_watchdog(engine));
+
 	return logical_ring_init(engine);
 }
 
@@ -2666,7 +2746,7 @@ u32 gen8_make_rpcs(struct drm_i915_private *i915, struct intel_sseu *req_sseu)
 	return rpcs;
 }
 
-static u32 intel_lr_indirect_ctx_offset(struct intel_engine_cs *engine)
+u32 intel_lr_indirect_ctx_offset(struct intel_engine_cs *engine)
 {
 	u32 indirect_ctx_offset;
 
@@ -2693,6 +2773,7 @@ static u32 intel_lr_indirect_ctx_offset(struct intel_engine_cs *engine)
 	}
 
 	return indirect_ctx_offset;
+
 }
 
 static void execlists_init_reg_state(u32 *regs,
diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
index f1aec8a6986f..4ce97fd5bb2e 100644
--- a/drivers/gpu/drm/i915/intel_lrc.h
+++ b/drivers/gpu/drm/i915/intel_lrc.h
@@ -114,4 +114,6 @@ void intel_execlists_show_requests(struct intel_engine_cs *engine,
 
 u32 gen8_make_rpcs(struct drm_i915_private *i915, struct intel_sseu *ctx_sseu);
 
+u32 get_watchdog_disable(struct intel_engine_cs *engine);
+
 #endif /* _INTEL_LRC_H_ */
-- 
2.17.1



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