drm/i915: Introduce IS_GEN macro

To be used for more efficient Gen range checking.

v2: Remove spurious chunk. (Chris Wilson)
v3: Rebase.
v4: Renamed from INTEL_GEN_RANGE and added GEN_FOREVER.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v3)
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1462874228-6601-1-git-send-email-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -2519,9 +2519,29 @@ struct drm_i915_cmd_table {
 #define INTEL_INFO(p) 	(&__I915__(p)->info)
 #define INTEL_GEN(p)	(INTEL_INFO(p)->gen)
 #define INTEL_DEVID(p)	(INTEL_INFO(p)->device_id)
-#define INTEL_REVID(p)	(__I915__(p)->dev->pdev->revision)
 
 #define REVID_FOREVER		0xff
+#define INTEL_REVID(p)	(__I915__(p)->dev->pdev->revision)
+
+#define GEN_FOREVER (0)
+/*
+ * Returns true if Gen is in inclusive range [Start, End].
+ *
+ * Use GEN_FOREVER for unbound start and or end.
+ */
+#define IS_GEN(p, s, e) ({ \
+	unsigned int __s = (s), __e = (e); \
+	BUILD_BUG_ON(!__builtin_constant_p(s)); \
+	BUILD_BUG_ON(!__builtin_constant_p(e)); \
+	if ((__s) != GEN_FOREVER) \
+		__s = (s) - 1; \
+	if ((__e) == GEN_FOREVER) \
+		__e = BITS_PER_LONG - 1; \
+	else \
+		__e = (e) - 1; \
+	!!(INTEL_INFO(p)->gen_mask & GENMASK((__e), (__s))); \
+})
+
 /*
  * Return true if revision is in range [since,until] inclusive.
  *

drivers/gpu/drm/i915/intel_fbc.c

@@ -740,7 +740,7 @@ static void intel_fbc_update_state_cache(struct intel_crtc *crtc)
 
 	/* FIXME: We lack the proper locking here, so only run this on the
 	 * platforms that need. */
-	if (INTEL_INFO(dev_priv)->gen >= 5 && INTEL_INFO(dev_priv)->gen < 7)
+	if (IS_GEN(dev_priv, 5, 6))
 		cache->fb.ilk_ggtt_offset = i915_gem_obj_ggtt_offset(obj);
 	cache->fb.pixel_format = fb->pixel_format;
 	cache->fb.stride = fb->pitches[0];

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -506,7 +506,7 @@ static void intel_ring_setup_status_page(struct intel_engine_cs *engine)
 	 * arises: do we still need this and if so how should we go about
 	 * invalidating the TLB?
 	 */
-	if (INTEL_GEN(dev_priv) >= 6 && INTEL_GEN(dev_priv) < 8) {
+	if (IS_GEN(dev_priv, 6, 7)) {
 		i915_reg_t reg = RING_INSTPM(engine->mmio_base);
 
 		/* ring should be idle before issuing a sync flush*/
@@ -1206,7 +1206,7 @@ static int init_render_ring(struct intel_engine_cs *engine)
 		return ret;
 
 	/* WaTimedSingleVertexDispatch:cl,bw,ctg,elk,ilk,snb */
-	if (INTEL_GEN(dev_priv) >= 4 && INTEL_GEN(dev_priv) < 7)
+	if (IS_GEN(dev_priv, 4, 6))
 		I915_WRITE(MI_MODE, _MASKED_BIT_ENABLE(VS_TIMER_DISPATCH));
 
 	/* We need to disable the AsyncFlip performance optimisations in order
@@ -1215,7 +1215,7 @@ static int init_render_ring(struct intel_engine_cs *engine)
 	 *
 	 * WaDisableAsyncFlipPerfMode:snb,ivb,hsw,vlv
 	 */
-	if (INTEL_GEN(dev_priv) >= 6 && INTEL_GEN(dev_priv) < 8)
+	if (IS_GEN(dev_priv, 6, 7))
 		I915_WRITE(MI_MODE, _MASKED_BIT_ENABLE(ASYNC_FLIP_PERF_DISABLE));
 
 	/* Required for the hardware to program scanline values for waiting */
@@ -1240,7 +1240,7 @@ static int init_render_ring(struct intel_engine_cs *engine)
 			   _MASKED_BIT_DISABLE(CM0_STC_EVICT_DISABLE_LRA_SNB));
 	}
 
-	if (INTEL_GEN(dev_priv) >= 6 && INTEL_GEN(dev_priv) < 8)
+	if (IS_GEN(dev_priv, 6, 7))
 		I915_WRITE(INSTPM, _MASKED_BIT_ENABLE(INSTPM_FORCE_ORDERING));
 
 	if (HAS_L3_DPF(dev_priv))