drm/i915: Add contexts for HSW

Basic context support on HSW is no different than previous generations.
The size of the context object changes, but that's about it.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem_context.c

@@ -112,7 +112,10 @@ static int get_context_size(struct drm_device *dev)
 		break;
 	case 7:
 		reg = I915_READ(GEN7_CXT_SIZE);
-		ret = GEN7_CXT_TOTAL_SIZE(reg) * 64;
+		if (IS_HASWELL(dev))
+			ret = HSW_CXT_TOTAL_SIZE(reg) * 64;
+		else
+			ret = GEN7_CXT_TOTAL_SIZE(reg) * 64;
 		break;
 	default:
 		BUG();

drivers/gpu/drm/i915/i915_reg.h

@@ -1498,6 +1498,14 @@
 					 GEN7_CXT_EXTENDED_SIZE(ctx_reg) + \
 					 GEN7_CXT_GT1_SIZE(ctx_reg) + \
 					 GEN7_CXT_VFSTATE_SIZE(ctx_reg))
+#define HSW_CXT_POWER_SIZE(ctx_reg)	((ctx_reg >> 26) & 0x3f)
+#define HSW_CXT_RING_SIZE(ctx_reg)	((ctx_reg >> 23) & 0x7)
+#define HSW_CXT_RENDER_SIZE(ctx_reg)	((ctx_reg >> 15) & 0xff)
+#define HSW_CXT_TOTAL_SIZE(ctx_reg)	(HSW_CXT_POWER_SIZE(ctx_reg) + \
+					 HSW_CXT_RING_SIZE(ctx_reg) + \
+					 HSW_CXT_RENDER_SIZE(ctx_reg) + \
+					 GEN7_CXT_VFSTATE_SIZE(ctx_reg))
+
 
 /*
  * Overlay regs