drm/i915: Make addressing mode bits in context descriptor configurable

Currently the addressing mode bit in context descriptor is statically
generated from the configuration of system-wide PPGTT usage model.

GVT-g will load the PPGTT shadow page table by itself and probably one
guest is using a different addressing mode with i915 host. The addressing
mode bits of a LRC context should be configurable under this case.

v10:

- Fix the identation. (Joonas)

v9:
- Rename the data member in struct i915_gem_context. (Chris)

v8:
- Rename the data member in struct i915_gem_context. (Chris)

v7:
- Move context addressing mode bit into i915_reg.h. (Joonas/Chris)
- Add prefix "INTEL_" for related definitions. (Joonas)

v6:
- Directly save the addressing mode bits inside i915_gem_context. (Chris)
- Move the LRC context addressing mode bits into intel_lrc.h. (Chris)

v5:
- Change USES_FULL_48BIT(dev) to USES_FULL_48BIT(dev_priv) (Tvrtko)

Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> (v9)
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1466078825-6662-7-git-send-email-zhi.a.wang@intel.com
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 177b61d..2116f86 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -208,16 +208,6 @@
 } while (0)
 
 enum {
-	ADVANCED_CONTEXT = 0,
-	LEGACY_32B_CONTEXT,
-	ADVANCED_AD_CONTEXT,
-	LEGACY_64B_CONTEXT
-};
-#define GEN8_CTX_ADDRESSING_MODE_SHIFT 3
-#define GEN8_CTX_ADDRESSING_MODE(dev)  (USES_FULL_48BIT_PPGTT(dev) ?\
-		LEGACY_64B_CONTEXT :\
-		LEGACY_32B_CONTEXT)
-enum {
 	FAULT_AND_HANG = 0,
 	FAULT_AND_HALT, /* Debug only */
 	FAULT_AND_STREAM,
@@ -281,8 +271,6 @@
 					(engine->id == VCS || engine->id == VCS2);
 
 	engine->ctx_desc_template = GEN8_CTX_VALID;
-	engine->ctx_desc_template |= GEN8_CTX_ADDRESSING_MODE(dev_priv) <<
-				   GEN8_CTX_ADDRESSING_MODE_SHIFT;
 	if (IS_GEN8(dev_priv))
 		engine->ctx_desc_template |= GEN8_CTX_L3LLC_COHERENT;
 	engine->ctx_desc_template |= GEN8_CTX_PRIVILEGE;
@@ -325,7 +313,8 @@
 
 	BUILD_BUG_ON(MAX_CONTEXT_HW_ID > (1<<GEN8_CTX_ID_WIDTH));
 
-	desc = engine->ctx_desc_template;			/* bits  0-11 */
+	desc = ctx->desc_template;				/* bits  3-4  */
+	desc |= engine->ctx_desc_template;			/* bits  0-11 */
 	desc |= ce->lrc_vma->node.start + LRC_PPHWSP_PN * PAGE_SIZE;
 								/* bits 12-31 */
 	desc |= (u64)ctx->hw_id << GEN8_CTX_ID_SHIFT;		/* bits 32-52 */