[Intel-gfx] [PATCH 1/2] drm/i915/tdr: Add helper function to perform Engine reset

[Arun Siluvery]

This patch only adds a function to reset an engine and it is in preparation
for the complete engine reset feature.

At the moment this is only made available from Gen8 onwards.

v2: use indexed initialization and keep everything under forcewake (Dave)

Cc: Dave Gordon <david.s.gordon at intel.com>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
Signed-off-by: Tomas Elf <tomas.elf at intel.com>
Signed-off-by: Arun Siluvery <arun.siluvery at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h     |  1 +
 drivers/gpu/drm/i915/i915_reg.h     |  2 ++
 drivers/gpu/drm/i915/intel_uncore.c | 67 +++++++++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 09b85b2..55dadfc 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2741,6 +2741,7 @@ extern long i915_compat_ioctl(struct file *filp, unsigned int cmd,
 			      unsigned long arg);
 #endif
 extern int intel_gpu_reset(struct drm_device *dev);
+extern int intel_engine_reset(struct intel_engine_cs *engine);
 extern bool intel_has_gpu_reset(struct drm_device *dev);
 extern int i915_reset(struct drm_device *dev);
 extern unsigned long i915_chipset_val(struct drm_i915_private *dev_priv);
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index f76cbf3..a798e40 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -164,6 +164,8 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
 #define  GEN6_GRDOM_RENDER		(1 << 1)
 #define  GEN6_GRDOM_MEDIA		(1 << 2)
 #define  GEN6_GRDOM_BLT			(1 << 3)
+#define  GEN6_GRDOM_VECS		(1 << 4)
+#define  GEN8_GRDOM_MEDIA2		(1 << 7)
 
 #define RING_PP_DIR_BASE(ring)		_MMIO((ring)->mmio_base+0x228)
 #define RING_PP_DIR_BASE_READ(ring)	_MMIO((ring)->mmio_base+0x518)
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 436d8f2..d003b78 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1616,6 +1616,73 @@ bool intel_has_gpu_reset(struct drm_device *dev)
 	return intel_get_gpu_reset(dev) != NULL;
 }
 
+static int wait_for_engine_reset(struct drm_i915_private *dev_priv,
+				 unsigned int grdom)
+{
+	int ret;
+
+#define _CND ((__raw_i915_read32(dev_priv, GEN6_GDRST) & grdom) == 0)
+
+	/*
+	 * Spin waiting for the device to ack the reset request.
+	 * Times out after 500 us
+	 */
+	ret = wait_for_atomic_us(_CND, 500);
+#undef _CND
+
+	return ret;
+}
+
+static int gen8_do_engine_reset(struct intel_engine_cs *engine)
+{
+	struct drm_device *dev = engine->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 reset_ctl;
+	int ret;
+	int engine_mask[I915_NUM_RINGS] = {
+		[RCS] = GEN6_GRDOM_RENDER,
+		[BCS] = GEN6_GRDOM_BLT,
+		[VCS] = GEN6_GRDOM_MEDIA,
+		[VCS2] = GEN8_GRDOM_MEDIA2,
+		[VECS] = GEN6_GRDOM_VECS,
+	};
+
+	if (WARN_ON_ONCE(!intel_ring_initialized(engine)))
+		return -EINVAL;
+
+	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
+
+	/* reset engine */
+	__raw_i915_write32(dev_priv, GEN6_GDRST, engine_mask[engine->id]);
+
+	ret = wait_for_engine_reset(dev_priv, engine_mask[engine->id]);
+	if (ret)
+		goto out;
+
+	/* Confirm that reset control register is back to normal after reset */
+	reset_ctl = I915_READ(RING_RESET_CTL(engine->mmio_base));
+	WARN((reset_ctl & (RESET_CTL_REQUEST_RESET | RESET_CTL_READY_TO_RESET)),
+	     "%s reset control still active after reset !! (0x%08x)\n",
+	     engine->name, reset_ctl);
+
+out:
+	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
+	return ret;
+}
+
+int intel_engine_reset(struct intel_engine_cs *engine)
+{
+	struct drm_device *dev = engine->dev;
+
+	if (INTEL_INFO(dev)->gen < 8) {
+		DRM_ERROR("Engine Reset not supported on Gen%d\n",
+			  INTEL_INFO(dev)->gen);
+		return -EINVAL;
+	}
+
+	return gen8_do_engine_reset(engine);
+}
+
 bool intel_uncore_unclaimed_mmio(struct drm_i915_private *dev_priv)
 {
 	return check_for_unclaimed_mmio(dev_priv);
-- 
1.9.1