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.

Signed-off-by: Tomas Elf <tomas....@intel.com>
Signed-off-by: Ian Lister <ian.lis...@intel.com>
Signed-off-by: Arun Siluvery <arun.siluv...@linux.intel.com>
Signed-off-by: Michel Thierry <michel.thie...@intel.com>
---
 drivers/gpu/drm/i915/i915_gem_context.h |  4 ++
 drivers/gpu/drm/i915/intel_lrc.c        | 81 ++++++++++++++++++++++++++++++++-
 drivers/gpu/drm/i915/intel_ringbuffer.h |  4 ++
 3 files changed, 87 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.h 
b/drivers/gpu/drm/i915/i915_gem_context.h
index 4af2ab94558b..88700bdbb4e1 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/i915_gem_context.h
@@ -150,6 +150,10 @@ 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;
                bool initialised;
        } engine[I915_NUM_ENGINES];
 
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 2263b9fb9b50..7a202e73ce9b 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1310,6 +1310,8 @@ static int gen8_emit_bb_start(struct drm_i915_gem_request 
*req,
                              const unsigned int flags)
 {
        u32 *cs;
+       u32 num_dwords;
+       bool watchdog_running = false;
        int ret;
 
        /* Don't rely in hw updating PDPs, specially in lite-restore.
@@ -1329,10 +1331,29 @@ static int gen8_emit_bb_start(struct 
drm_i915_gem_request *req,
                req->ctx->ppgtt->pd_dirty_rings &= 
~intel_engine_flag(req->engine);
        }
 
-       cs = intel_ring_begin(req, 4);
+       /* bb_start only */
+       num_dwords = 4;
+
+       /* check if watchdog will be required */
+       if (req->ctx->engine[req->engine->id].watchdog_threshold != 0) {
+               if (!req->engine->emit_start_watchdog ||
+                   !req->engine->emit_stop_watchdog)
+                       return -EINVAL;
+
+               /* + start_watchdog (6) + stop_watchdog (4) */
+               num_dwords += 10;
+               watchdog_running = true;
+       }
+
+       cs = intel_ring_begin(req, num_dwords);
        if (IS_ERR(cs))
                return PTR_ERR(cs);
 
+       if (watchdog_running) {
+               /* Start watchdog timer */
+               cs = req->engine->emit_start_watchdog(req, cs);
+       }
+
        /* FIXME(BDW): Address space and security selectors. */
        *cs++ = MI_BATCH_BUFFER_START_GEN8 |
                (flags & I915_DISPATCH_SECURE ? 0 : BIT(8)) |
@@ -1340,8 +1361,13 @@ static int gen8_emit_bb_start(struct 
drm_i915_gem_request *req,
        *cs++ = lower_32_bits(offset);
        *cs++ = upper_32_bits(offset);
        *cs++ = MI_NOOP;
-       intel_ring_advance(req, cs);
 
+       if (watchdog_running) {
+               /* Cancel watchdog timer */
+               cs = req->engine->emit_stop_watchdog(req, cs);
+       }
+
+       intel_ring_advance(req, cs);
        return 0;
 }
 
@@ -1508,6 +1534,49 @@ static void gen8_watchdog_irq_handler(unsigned long data)
        intel_uncore_forcewake_put(dev_priv, engine->fw_domains);
 }
 
+static u32 *gen8_emit_start_watchdog(struct drm_i915_gem_request *req, u32 *cs)
+{
+       struct intel_engine_cs *engine = req->engine;
+       struct i915_gem_context *ctx = req->ctx;
+       struct intel_context *ce = &ctx->engine[engine->id];
+
+       /* XXX: no watchdog support in BCS engine */
+       GEM_BUG_ON(engine->id == BCS);
+
+       /*
+        * 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;
+       *cs++ = MI_NOOP;
+
+       return cs;
+}
+
+static u32 *gen8_emit_stop_watchdog(struct drm_i915_gem_request *req, u32 *cs)
+{
+       struct intel_engine_cs *engine = req->engine;
+
+       /* XXX: no watchdog support in BCS engine */
+       GEM_BUG_ON(engine->id == BCS);
+
+       *cs++ = MI_LOAD_REGISTER_IMM(2);
+       *cs++ = i915_mmio_reg_offset(RING_CNTR(engine->mmio_base));
+       *cs++ = get_watchdog_disable(engine);
+       *cs++ = MI_NOOP;
+
+       return cs;
+}
+
 /*
  * Reserve space for 2 NOOPs at the end of each request to be
  * used as a workaround for not being allowed to do lite
@@ -1776,6 +1845,8 @@ int logical_render_ring_init(struct intel_engine_cs 
*engine)
        engine->emit_flush = gen8_emit_flush_render;
        engine->emit_breadcrumb = gen8_emit_breadcrumb_render;
        engine->emit_breadcrumb_sz = gen8_emit_breadcrumb_render_sz;
+       engine->emit_start_watchdog = gen8_emit_start_watchdog;
+       engine->emit_stop_watchdog = gen8_emit_stop_watchdog;
 
        ret = intel_engine_create_scratch(engine, PAGE_SIZE);
        if (ret)
@@ -1799,6 +1870,12 @@ int logical_xcs_ring_init(struct intel_engine_cs *engine)
 {
        logical_ring_setup(engine);
 
+       /* BCS engine does not have a watchdog-expired irq */
+       if (engine->id != BCS) {
+               engine->emit_start_watchdog = gen8_emit_start_watchdog;
+               engine->emit_stop_watchdog = gen8_emit_stop_watchdog;
+       }
+
        return logical_ring_init(engine);
 }
 
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h 
b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 927f0c06cbe6..0392bd5fd300 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -279,6 +279,10 @@ struct intel_engine_cs {
 
        int             (*emit_flush)(struct drm_i915_gem_request *request,
                                      u32 mode);
+       u32 *           (*emit_start_watchdog)(struct drm_i915_gem_request *req,
+                                              u32 *cs);
+       u32 *           (*emit_stop_watchdog)(struct drm_i915_gem_request *req,
+                                             u32 *cs);
 #define EMIT_INVALIDATE        BIT(0)
 #define EMIT_FLUSH     BIT(1)
 #define EMIT_BARRIER   (EMIT_INVALIDATE | EMIT_FLUSH)
-- 
2.11.0

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