drm/i915: Move a bunch of workaround-related code to its own file

This has grown to be a sizable amount of code, so move it to
its own file before we try to refactor anything. For the moment,
we are leaving behind the WA BB code and the WAs that get applied
(incorrectly) in init_clock_gating, but we will deal with it later.

v2: Use intel_ prefix for code that deals with the hardware (Chris)
v3: Rebased
v4:
  - Rebased
  - New license header
v5:
  - Rebased
  - Added some organisational notes to the file (Chris)
v6: Include DOC section in the documentation build (Jani)
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
[ickle: appease checkpatch, mostly]
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/1523376767-18480-1-git-send-email-oscar.mateo@intel.com

Documentation/gpu/i915.rst

@@ -58,6 +58,12 @@ Intel GVT-g Host Support(vGPU device model)
 .. kernel-doc:: drivers/gpu/drm/i915/intel_gvt.c
    :internal:
 
+Workarounds
+-----------
+
+.. kernel-doc:: drivers/gpu/drm/i915/intel_workarounds.c
+   :doc: Hardware workarounds
+
 Display Hardware Handling
 =========================
 

drivers/gpu/drm/i915/Makefile

@@ -43,7 +43,8 @@ i915-y := i915_drv.o \
 	  intel_csr.o \
 	  intel_device_info.o \
 	  intel_pm.o \
-	  intel_runtime_pm.o
+	  intel_runtime_pm.o \
+	  intel_workarounds.o
 
 i915-$(CONFIG_COMPAT)   += i915_ioc32.o
 i915-$(CONFIG_DEBUG_FS) += i915_debugfs.o intel_pipe_crc.o

drivers/gpu/drm/i915/intel_lrc.c

@@ -139,6 +139,7 @@
 #include "i915_gem_render_state.h"
 #include "intel_lrc_reg.h"
 #include "intel_mocs.h"
+#include "intel_workarounds.h"
 
 #define RING_EXECLIST_QFULL		(1 << 0x2)
 #define RING_EXECLIST1_VALID		(1 << 0x3)

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -36,6 +36,7 @@
 #include "i915_gem_render_state.h"
 #include "i915_trace.h"
 #include "intel_drv.h"
+#include "intel_workarounds.h"
 
 /* Rough estimate of the typical request size, performing a flush,
  * set-context and then emitting the batch.

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -885,9 +885,6 @@ static inline u32 intel_engine_last_submit(struct intel_engine_cs *engine)
 	return READ_ONCE(engine->timeline->seqno);
 }
 
-int init_workarounds_ring(struct intel_engine_cs *engine);
-int intel_ring_workarounds_emit(struct i915_request *rq);
-
 void intel_engine_get_instdone(struct intel_engine_cs *engine,
 			       struct intel_instdone *instdone);
 

drivers/gpu/drm/i915/intel_workarounds.h

+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2014-2018 Intel Corporation
+ */
+
+#ifndef _I915_WORKAROUNDS_H_
+#define _I915_WORKAROUNDS_H_
+
+int init_workarounds_ring(struct intel_engine_cs *engine);
+int intel_ring_workarounds_emit(struct i915_request *rq);
+
+#endif