[PATCH] drm/i915: add a LLC feature flag in device description

[Eugeni Dodonov <eugeni@dodonov.net>]

From: Eugeni Dodonov <eugeni.dodonov@intel.com>

LLC is not SNB-specific, so we should check for it in a more generic way.

v2: export LLC support status via debugfs and DRM GETPARAM.

Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c |    1 +
 drivers/gpu/drm/i915/i915_dma.c     |    3 +++
 drivers/gpu/drm/i915/i915_drv.c     |    2 ++
 drivers/gpu/drm/i915/i915_drv.h     |    2 ++
 drivers/gpu/drm/i915/i915_gem.c     |    4 ++--
 include/drm/i915_drm.h              |    1 +
 6 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 4f40f1c..070dbd9 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -82,6 +82,7 @@ static int i915_capabilities(struct seq_file *m, void *data)
 	B(supports_tv);
 	B(has_bsd_ring);
 	B(has_blt_ring);
+	B(has_llc);
 #undef B
 
 	return 0;
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index a9533c5..938ad57 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -781,6 +781,9 @@ static int i915_getparam(struct drm_device *dev, void *data,
 	case I915_PARAM_HAS_RELAXED_DELTA:
 		value = 1;
 		break;
+	case I915_PARAM_HAS_LLC:
+		value = HAS_LLC(dev);
+		break;
 	default:
 		DRM_DEBUG_DRIVER("Unknown parameter %d\n",
 				 param->param);
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index e9c2cfe..b7ac903 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -214,6 +214,7 @@ static const struct intel_device_info intel_sandybridge_d_info = {
 	.need_gfx_hws = 1, .has_hotplug = 1,
 	.has_bsd_ring = 1,
 	.has_blt_ring = 1,
+	.has_llc = 1,
 };
 
 static const struct intel_device_info intel_sandybridge_m_info = {
@@ -222,6 +223,7 @@ static const struct intel_device_info intel_sandybridge_m_info = {
 	.has_fbc = 1,
 	.has_bsd_ring = 1,
 	.has_blt_ring = 1,
+	.has_llc = 1,
 };
 
 static const struct intel_device_info intel_ivybridge_d_info = {
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 06a37f4..24969eb 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -247,6 +247,7 @@ struct intel_device_info {
 	u8 supports_tv:1;
 	u8 has_bsd_ring:1;
 	u8 has_blt_ring:1;
+	u8 has_llc:1;
 };
 
 enum no_fbc_reason {
@@ -960,6 +961,7 @@ struct drm_i915_file_private {
 
 #define HAS_BSD(dev)            (INTEL_INFO(dev)->has_bsd_ring)
 #define HAS_BLT(dev)            (INTEL_INFO(dev)->has_blt_ring)
+#define HAS_LLC(dev)            (INTEL_INFO(dev)->has_llc)
 #define I915_NEED_GFX_HWS(dev)	(INTEL_INFO(dev)->need_gfx_hws)
 
 #define HAS_OVERLAY(dev)		(INTEL_INFO(dev)->has_overlay)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index d18b07a..2c0fa78 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3613,8 +3613,8 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
 	obj->base.write_domain = I915_GEM_DOMAIN_CPU;
 	obj->base.read_domains = I915_GEM_DOMAIN_CPU;
 
-	if (IS_GEN6(dev)) {
-		/* On Gen6, we can have the GPU use the LLC (the CPU
+	if (HAS_LLC(dev)) {
+		/* On some devices, we can have the GPU use the LLC (the CPU
 		 * cache) for about a 10% performance improvement
 		 * compared to uncached.  Graphics requests other than
 		 * display scanout are coherent with the CPU in
diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
index 28c0d11..b34e630 100644
--- a/include/drm/i915_drm.h
+++ b/include/drm/i915_drm.h
@@ -291,6 +291,7 @@ typedef struct drm_i915_irq_wait {
 #define I915_PARAM_HAS_COHERENT_RINGS	 13
 #define I915_PARAM_HAS_EXEC_CONSTANTS	 14
 #define I915_PARAM_HAS_RELAXED_DELTA	 15
+#define I915_PARAM_HAS_LLC		 16
 
 typedef struct drm_i915_getparam {
 	int param;
-- 
1.7.7.4