[PATCH v4 3/5] drm/i915: Watchdog timeout: Ringbuffer command emission for gen8+

Carlos Santa
2019-02-21T02:59:09Z

From: Michel Thierry <michel.thierry@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)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Antonio Argenziano <antonio.argenziano@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Signed-off-by: Carlos Santa <carlos.santa@intel.com>
---
drivers/gpu/drm/i915/i915_gem_context.h | 4 ++
drivers/gpu/drm/i915/intel_engine_cs.c | 2 +
drivers/gpu/drm/i915/intel_lrc.c | 79 +++++++++++++++++++++++--
drivers/gpu/drm/i915/intel_lrc.h | 2 +
drivers/gpu/drm/i915/intel_ringbuffer.h | 18 ++++--
5 files changed, 97 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.h b/drivers/gpu/drm/i915/i915_gem_context.h
index b1eeac64da8b..dcf4e98666a6 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/i915_gem_context.h
@@ -183,6 +183,10 @@ struct i915_gem_context {
u32 *lrc_reg_state;
u64 lrc_desc;
int pin_count;
+ /** watchdog_threshold: hw watchdog threshold value,
+ * in clock counts
+ */
+ u32 watchdog_threshold;

/**
* active_tracker: Active tracker for the external rq activity
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 74f563d23cc8..438bf93a4340 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_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index c38b239ab39e..9406d3f2b789 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -2193,16 +2193,75 @@ 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 = to_intel_context(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;
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 (to_intel_context(rq->gem_context, engine)->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);
+ engine->current_seqno = intel_engine_get_hangcheck_seqno(engine);
+ }
+
/*
* WaDisableCtxRestoreArbitration:bdw,chv
*
@@ -2229,10 +2288,16 @@ 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;
}

@@ -2353,7 +2418,7 @@ static int gen8_emit_flush_render(struct i915_request *request,
}

/* From GEN9 onwards, all engines use the same RING_CNTR format */
-static inline u32 get_watchdog_disable(struct intel_engine_cs *engine)
+u32 get_watchdog_disable(struct intel_engine_cs *engine)
{
if (engine->id == RCS || INTEL_GEN(engine->i915) >= 9)
return GEN8_WATCHDOG_DISABLE;
@@ -2532,6 +2597,9 @@ void intel_execlists_set_default_submission(struct intel_engine_cs *engine)
I915_SCHEDULER_CAP_PRIORITY;
if (intel_engine_has_preemption(engine))
engine->i915->caps.scheduler |= I915_SCHEDULER_CAP_PREEMPTION;
+
+ if(engine->id != BCS)
+ engine->flags |= I915_ENGINE_SUPPORTS_WATCHDOG;
}

static void
@@ -2710,6 +2778,9 @@ 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);
}

diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
index 5779e776cc3f..9db4f6369574 100644
--- a/drivers/gpu/drm/i915/intel_lrc.h
+++ b/drivers/gpu/drm/i915/intel_lrc.h
@@ -120,4 +120,6 @@ void intel_virtual_engine_put(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_ */
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 17250ba0246f..ec0b7d3c6315 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -360,6 +360,7 @@ struct intel_engine_cs {
unsigned int guc_id;
unsigned long mask;
u32 current_seqno;
+ u32 watchdog_disable_id;

u8 uabi_class;

@@ -463,6 +464,7 @@ struct intel_engine_cs {
int (*init_context)(struct i915_request *rq);

int (*emit_flush)(struct i915_request *request, u32 mode);
+
#define EMIT_INVALIDATE BIT(0)
#define EMIT_FLUSH BIT(1)
#define EMIT_BARRIER (EMIT_INVALIDATE | EMIT_FLUSH)
@@ -520,10 +522,12 @@ 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_IS_VIRTUAL 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_IS_VIRTUAL BIT(3)
+#define I915_ENGINE_SUPPORTS_WATCHDOG BIT(4)
+
unsigned int flags;

/*
@@ -612,6 +616,12 @@ intel_engine_is_virtual(const struct intel_engine_cs *engine)
return engine->flags & I915_ENGINE_IS_VIRTUAL;
}

+static inline bool
+intel_engine_supports_watchdog(const struct intel_engine_cs *engine)
+{
+ return engine->flags & I915_ENGINE_SUPPORTS_WATCHDOG;
+}
+
static inline void
execlists_set_active(struct intel_engine_execlists *execlists,
unsigned int bit)
--
2.17.1