drm/i915: Make IS_GENx macros work on a mask

If instead of numerical comparison me make these test a
bitmask, we enable the compiler to optimize all instances
of IS_GENx || IS_GENy.

v2: Make bit zero of gen mask mean gen 1.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_dma.c

@@ -1073,6 +1073,9 @@ static int i915_driver_init_early(struct drm_i915_private *dev_priv,
 	memcpy(device_info, info, sizeof(dev_priv->info));
 	device_info->device_id = dev->pdev->device;
 
+	BUG_ON(device_info->gen > sizeof(device_info->gen_mask) * BITS_PER_BYTE);
+	device_info->gen_mask = BIT(device_info->gen - 1);
+
 	spin_lock_init(&dev_priv->irq_lock);
 	spin_lock_init(&dev_priv->gpu_error.lock);
 	mutex_init(&dev_priv->backlight_lock);

drivers/gpu/drm/i915/i915_drv.h

@@ -760,6 +760,7 @@ struct intel_device_info {
 	u8 num_pipes:3;
 	u8 num_sprites[I915_MAX_PIPES];
 	u8 gen;
+	u16 gen_mask;
 	u8 ring_mask; /* Rings supported by the HW */
 	DEV_INFO_FOR_EACH_FLAG(DEFINE_FLAG, SEP_SEMICOLON);
 	/* Register offsets for the various display pipes and transcoders */
@@ -2620,14 +2621,14 @@ struct drm_i915_cmd_table {
  * have their own (e.g. HAS_PCH_SPLIT for ILK+ display, IS_foo for particular
  * chips, etc.).
  */
-#define IS_GEN2(dev)	(INTEL_INFO(dev)->gen == 2)
-#define IS_GEN3(dev)	(INTEL_INFO(dev)->gen == 3)
-#define IS_GEN4(dev)	(INTEL_INFO(dev)->gen == 4)
-#define IS_GEN5(dev)	(INTEL_INFO(dev)->gen == 5)
-#define IS_GEN6(dev)	(INTEL_INFO(dev)->gen == 6)
-#define IS_GEN7(dev)	(INTEL_INFO(dev)->gen == 7)
-#define IS_GEN8(dev)	(INTEL_INFO(dev)->gen == 8)
-#define IS_GEN9(dev)	(INTEL_INFO(dev)->gen == 9)
+#define IS_GEN2(dev)	(INTEL_INFO(dev)->gen_mask & BIT(1))
+#define IS_GEN3(dev)	(INTEL_INFO(dev)->gen_mask & BIT(2))
+#define IS_GEN4(dev)	(INTEL_INFO(dev)->gen_mask & BIT(3))
+#define IS_GEN5(dev)	(INTEL_INFO(dev)->gen_mask & BIT(4))
+#define IS_GEN6(dev)	(INTEL_INFO(dev)->gen_mask & BIT(5))
+#define IS_GEN7(dev)	(INTEL_INFO(dev)->gen_mask & BIT(6))
+#define IS_GEN8(dev)	(INTEL_INFO(dev)->gen_mask & BIT(7))
+#define IS_GEN9(dev)	(INTEL_INFO(dev)->gen_mask & BIT(8))
 
 #define RENDER_RING		(1<<RCS)
 #define BSD_RING		(1<<VCS)

drivers/gpu/drm/i915/intel_uncore.c

@@ -1391,7 +1391,7 @@ void intel_uncore_fini(struct drm_i915_private *dev_priv)
 	intel_uncore_forcewake_reset(dev_priv, false);
 }
 
-#define GEN_RANGE(l, h) GENMASK(h, l)
+#define GEN_RANGE(l, h) GENMASK((h) - 1, (l) - 1)
 
 static const struct register_whitelist {
 	i915_reg_t offset_ldw, offset_udw;
@@ -1416,7 +1416,7 @@ int i915_reg_read_ioctl(struct drm_device *dev,
 
 	for (i = 0; i < ARRAY_SIZE(whitelist); i++, entry++) {
 		if (i915_mmio_reg_offset(entry->offset_ldw) == (reg->offset & -entry->size) &&
-		    (1 << INTEL_INFO(dev)->gen & entry->gen_bitmask))
+		    (INTEL_INFO(dev)->gen_mask & entry->gen_bitmask))
 			break;
 	}