xref: /dragonfly/sys/dev/drm/i915/intel_lrc.c (revision 0720b42f)
1 /*
2  * Copyright © 2014 Intel Corporation
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice (including the next
12  * paragraph) shall be included in all copies or substantial portions of the
13  * Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21  * IN THE SOFTWARE.
22  *
23  * Authors:
24  *    Ben Widawsky <ben@bwidawsk.net>
25  *    Michel Thierry <michel.thierry@intel.com>
26  *    Thomas Daniel <thomas.daniel@intel.com>
27  *    Oscar Mateo <oscar.mateo@intel.com>
28  *
29  */
30 
31 /**
32  * DOC: Logical Rings, Logical Ring Contexts and Execlists
33  *
34  * Motivation:
35  * GEN8 brings an expansion of the HW contexts: "Logical Ring Contexts".
36  * These expanded contexts enable a number of new abilities, especially
37  * "Execlists" (also implemented in this file).
38  *
39  * One of the main differences with the legacy HW contexts is that logical
40  * ring contexts incorporate many more things to the context's state, like
41  * PDPs or ringbuffer control registers:
42  *
43  * The reason why PDPs are included in the context is straightforward: as
44  * PPGTTs (per-process GTTs) are actually per-context, having the PDPs
45  * contained there mean you don't need to do a ppgtt->switch_mm yourself,
46  * instead, the GPU will do it for you on the context switch.
47  *
48  * But, what about the ringbuffer control registers (head, tail, etc..)?
49  * shouldn't we just need a set of those per engine command streamer? This is
50  * where the name "Logical Rings" starts to make sense: by virtualizing the
51  * rings, the engine cs shifts to a new "ring buffer" with every context
52  * switch. When you want to submit a workload to the GPU you: A) choose your
53  * context, B) find its appropriate virtualized ring, C) write commands to it
54  * and then, finally, D) tell the GPU to switch to that context.
55  *
56  * Instead of the legacy MI_SET_CONTEXT, the way you tell the GPU to switch
57  * to a contexts is via a context execution list, ergo "Execlists".
58  *
59  * LRC implementation:
60  * Regarding the creation of contexts, we have:
61  *
62  * - One global default context.
63  * - One local default context for each opened fd.
64  * - One local extra context for each context create ioctl call.
65  *
66  * Now that ringbuffers belong per-context (and not per-engine, like before)
67  * and that contexts are uniquely tied to a given engine (and not reusable,
68  * like before) we need:
69  *
70  * - One ringbuffer per-engine inside each context.
71  * - One backing object per-engine inside each context.
72  *
73  * The global default context starts its life with these new objects fully
74  * allocated and populated. The local default context for each opened fd is
75  * more complex, because we don't know at creation time which engine is going
76  * to use them. To handle this, we have implemented a deferred creation of LR
77  * contexts:
78  *
79  * The local context starts its life as a hollow or blank holder, that only
80  * gets populated for a given engine once we receive an execbuffer. If later
81  * on we receive another execbuffer ioctl for the same context but a different
82  * engine, we allocate/populate a new ringbuffer and context backing object and
83  * so on.
84  *
85  * Finally, regarding local contexts created using the ioctl call: as they are
86  * only allowed with the render ring, we can allocate & populate them right
87  * away (no need to defer anything, at least for now).
88  *
89  * Execlists implementation:
90  * Execlists are the new method by which, on gen8+ hardware, workloads are
91  * submitted for execution (as opposed to the legacy, ringbuffer-based, method).
92  * This method works as follows:
93  *
94  * When a request is committed, its commands (the BB start and any leading or
95  * trailing commands, like the seqno breadcrumbs) are placed in the ringbuffer
96  * for the appropriate context. The tail pointer in the hardware context is not
97  * updated at this time, but instead, kept by the driver in the ringbuffer
98  * structure. A structure representing this request is added to a request queue
99  * for the appropriate engine: this structure contains a copy of the context's
100  * tail after the request was written to the ring buffer and a pointer to the
101  * context itself.
102  *
103  * If the engine's request queue was empty before the request was added, the
104  * queue is processed immediately. Otherwise the queue will be processed during
105  * a context switch interrupt. In any case, elements on the queue will get sent
106  * (in pairs) to the GPU's ExecLists Submit Port (ELSP, for short) with a
107  * globally unique 20-bits submission ID.
108  *
109  * When execution of a request completes, the GPU updates the context status
110  * buffer with a context complete event and generates a context switch interrupt.
111  * During the interrupt handling, the driver examines the events in the buffer:
112  * for each context complete event, if the announced ID matches that on the head
113  * of the request queue, then that request is retired and removed from the queue.
114  *
115  * After processing, if any requests were retired and the queue is not empty
116  * then a new execution list can be submitted. The two requests at the front of
117  * the queue are next to be submitted but since a context may not occur twice in
118  * an execution list, if subsequent requests have the same ID as the first then
119  * the two requests must be combined. This is done simply by discarding requests
120  * at the head of the queue until either only one requests is left (in which case
121  * we use a NULL second context) or the first two requests have unique IDs.
122  *
123  * By always executing the first two requests in the queue the driver ensures
124  * that the GPU is kept as busy as possible. In the case where a single context
125  * completes but a second context is still executing, the request for this second
126  * context will be at the head of the queue when we remove the first one. This
127  * request will then be resubmitted along with a new request for a different context,
128  * which will cause the hardware to continue executing the second request and queue
129  * the new request (the GPU detects the condition of a context getting preempted
130  * with the same context and optimizes the context switch flow by not doing
131  * preemption, but just sampling the new tail pointer).
132  *
133  */
134 
135 #include <drm/drmP.h>
136 #include <drm/i915_drm.h>
137 #include "i915_drv.h"
138 #include "intel_drv.h"
139 
140 #define GEN9_LR_CONTEXT_RENDER_SIZE (22 * PAGE_SIZE)
141 #define GEN8_LR_CONTEXT_RENDER_SIZE (20 * PAGE_SIZE)
142 #define GEN8_LR_CONTEXT_OTHER_SIZE (2 * PAGE_SIZE)
143 
144 #define RING_EXECLIST_QFULL		(1 << 0x2)
145 #define RING_EXECLIST1_VALID		(1 << 0x3)
146 #define RING_EXECLIST0_VALID		(1 << 0x4)
147 #define RING_EXECLIST_ACTIVE_STATUS	(3 << 0xE)
148 #define RING_EXECLIST1_ACTIVE		(1 << 0x11)
149 #define RING_EXECLIST0_ACTIVE		(1 << 0x12)
150 
151 #define GEN8_CTX_STATUS_IDLE_ACTIVE	(1 << 0)
152 #define GEN8_CTX_STATUS_PREEMPTED	(1 << 1)
153 #define GEN8_CTX_STATUS_ELEMENT_SWITCH	(1 << 2)
154 #define GEN8_CTX_STATUS_ACTIVE_IDLE	(1 << 3)
155 #define GEN8_CTX_STATUS_COMPLETE	(1 << 4)
156 #define GEN8_CTX_STATUS_LITE_RESTORE	(1 << 15)
157 
158 #define CTX_LRI_HEADER_0		0x01
159 #define CTX_CONTEXT_CONTROL		0x02
160 #define CTX_RING_HEAD			0x04
161 #define CTX_RING_TAIL			0x06
162 #define CTX_RING_BUFFER_START		0x08
163 #define CTX_RING_BUFFER_CONTROL		0x0a
164 #define CTX_BB_HEAD_U			0x0c
165 #define CTX_BB_HEAD_L			0x0e
166 #define CTX_BB_STATE			0x10
167 #define CTX_SECOND_BB_HEAD_U		0x12
168 #define CTX_SECOND_BB_HEAD_L		0x14
169 #define CTX_SECOND_BB_STATE		0x16
170 #define CTX_BB_PER_CTX_PTR		0x18
171 #define CTX_RCS_INDIRECT_CTX		0x1a
172 #define CTX_RCS_INDIRECT_CTX_OFFSET	0x1c
173 #define CTX_LRI_HEADER_1		0x21
174 #define CTX_CTX_TIMESTAMP		0x22
175 #define CTX_PDP3_UDW			0x24
176 #define CTX_PDP3_LDW			0x26
177 #define CTX_PDP2_UDW			0x28
178 #define CTX_PDP2_LDW			0x2a
179 #define CTX_PDP1_UDW			0x2c
180 #define CTX_PDP1_LDW			0x2e
181 #define CTX_PDP0_UDW			0x30
182 #define CTX_PDP0_LDW			0x32
183 #define CTX_LRI_HEADER_2		0x41
184 #define CTX_R_PWR_CLK_STATE		0x42
185 #define CTX_GPGPU_CSR_BASE_ADDRESS	0x44
186 
187 #define GEN8_CTX_VALID (1<<0)
188 #define GEN8_CTX_FORCE_PD_RESTORE (1<<1)
189 #define GEN8_CTX_FORCE_RESTORE (1<<2)
190 #define GEN8_CTX_L3LLC_COHERENT (1<<5)
191 #define GEN8_CTX_PRIVILEGE (1<<8)
192 enum {
193 	ADVANCED_CONTEXT = 0,
194 	LEGACY_CONTEXT,
195 	ADVANCED_AD_CONTEXT,
196 	LEGACY_64B_CONTEXT
197 };
198 #define GEN8_CTX_MODE_SHIFT 3
199 enum {
200 	FAULT_AND_HANG = 0,
201 	FAULT_AND_HALT, /* Debug only */
202 	FAULT_AND_STREAM,
203 	FAULT_AND_CONTINUE /* Unsupported */
204 };
205 #define GEN8_CTX_ID_SHIFT 32
206 
207 static int intel_lr_context_pin(struct intel_engine_cs *ring,
208 		struct intel_context *ctx);
209 
210 /**
211  * intel_sanitize_enable_execlists() - sanitize i915.enable_execlists
212  * @dev: DRM device.
213  * @enable_execlists: value of i915.enable_execlists module parameter.
214  *
215  * Only certain platforms support Execlists (the prerequisites being
216  * support for Logical Ring Contexts and Aliasing PPGTT or better).
217  *
218  * Return: 1 if Execlists is supported and has to be enabled.
219  */
220 int intel_sanitize_enable_execlists(struct drm_device *dev, int enable_execlists)
221 {
222 	WARN_ON(i915.enable_ppgtt == -1);
223 
224 	if (INTEL_INFO(dev)->gen >= 9)
225 		return 1;
226 
227 	if (enable_execlists == 0)
228 		return 0;
229 
230 	if (HAS_LOGICAL_RING_CONTEXTS(dev) && USES_PPGTT(dev) &&
231 	    i915.use_mmio_flip >= 0)
232 		return 1;
233 
234 	return 0;
235 }
236 
237 /**
238  * intel_execlists_ctx_id() - get the Execlists Context ID
239  * @ctx_obj: Logical Ring Context backing object.
240  *
241  * Do not confuse with ctx->id! Unfortunately we have a name overload
242  * here: the old context ID we pass to userspace as a handler so that
243  * they can refer to a context, and the new context ID we pass to the
244  * ELSP so that the GPU can inform us of the context status via
245  * interrupts.
246  *
247  * Return: 20-bits globally unique context ID.
248  */
249 u32 intel_execlists_ctx_id(struct drm_i915_gem_object *ctx_obj)
250 {
251 	u32 lrca = i915_gem_obj_ggtt_offset(ctx_obj);
252 
253 	/* LRCA is required to be 4K aligned so the more significant 20 bits
254 	 * are globally unique */
255 	return lrca >> 12;
256 }
257 
258 static uint64_t execlists_ctx_descriptor(struct intel_engine_cs *ring,
259 					 struct drm_i915_gem_object *ctx_obj)
260 {
261 	struct drm_device *dev = ring->dev;
262 	uint64_t desc;
263 	uint64_t lrca = i915_gem_obj_ggtt_offset(ctx_obj);
264 
265 	WARN_ON(lrca & 0xFFFFFFFF00000FFFULL);
266 
267 	desc = GEN8_CTX_VALID;
268 	desc |= LEGACY_CONTEXT << GEN8_CTX_MODE_SHIFT;
269 	desc |= GEN8_CTX_L3LLC_COHERENT;
270 	desc |= GEN8_CTX_PRIVILEGE;
271 	desc |= lrca;
272 	desc |= (u64)intel_execlists_ctx_id(ctx_obj) << GEN8_CTX_ID_SHIFT;
273 
274 	/* TODO: WaDisableLiteRestore when we start using semaphore
275 	 * signalling between Command Streamers */
276 	/* desc |= GEN8_CTX_FORCE_RESTORE; */
277 
278 	/* WaEnableForceRestoreInCtxtDescForVCS:skl */
279 	if (IS_GEN9(dev) &&
280 	    INTEL_REVID(dev) <= SKL_REVID_B0 &&
281 	    (ring->id == BCS || ring->id == VCS ||
282 	    ring->id == VECS || ring->id == VCS2))
283 		desc |= GEN8_CTX_FORCE_RESTORE;
284 
285 	return desc;
286 }
287 
288 static void execlists_elsp_write(struct intel_engine_cs *ring,
289 				 struct drm_i915_gem_object *ctx_obj0,
290 				 struct drm_i915_gem_object *ctx_obj1)
291 {
292 	struct drm_device *dev = ring->dev;
293 	struct drm_i915_private *dev_priv = dev->dev_private;
294 	uint64_t temp = 0;
295 	uint32_t desc[4];
296 
297 	/* XXX: You must always write both descriptors in the order below. */
298 	if (ctx_obj1)
299 		temp = execlists_ctx_descriptor(ring, ctx_obj1);
300 	else
301 		temp = 0;
302 	desc[1] = (u32)(temp >> 32);
303 	desc[0] = (u32)temp;
304 
305 	temp = execlists_ctx_descriptor(ring, ctx_obj0);
306 	desc[3] = (u32)(temp >> 32);
307 	desc[2] = (u32)temp;
308 
309 	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
310 	I915_WRITE(RING_ELSP(ring), desc[1]);
311 	I915_WRITE(RING_ELSP(ring), desc[0]);
312 	I915_WRITE(RING_ELSP(ring), desc[3]);
313 
314 	/* The context is automatically loaded after the following */
315 	I915_WRITE(RING_ELSP(ring), desc[2]);
316 
317 	/* ELSP is a wo register, so use another nearby reg for posting instead */
318 	POSTING_READ(RING_EXECLIST_STATUS(ring));
319 	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
320 }
321 
322 static int execlists_update_context(struct drm_i915_gem_object *ctx_obj,
323 				    struct drm_i915_gem_object *ring_obj,
324 				    u32 tail)
325 {
326 	struct vm_page *page;
327 	uint32_t *reg_state;
328 
329 	page = i915_gem_object_get_page(ctx_obj, 1);
330 	reg_state = kmap_atomic(page);
331 
332 	reg_state[CTX_RING_TAIL+1] = tail;
333 	reg_state[CTX_RING_BUFFER_START+1] = i915_gem_obj_ggtt_offset(ring_obj);
334 
335 	kunmap_atomic(reg_state);
336 
337 	return 0;
338 }
339 
340 static void execlists_submit_contexts(struct intel_engine_cs *ring,
341 				      struct intel_context *to0, u32 tail0,
342 				      struct intel_context *to1, u32 tail1)
343 {
344 	struct drm_i915_gem_object *ctx_obj0 = to0->engine[ring->id].state;
345 	struct intel_ringbuffer *ringbuf0 = to0->engine[ring->id].ringbuf;
346 	struct drm_i915_gem_object *ctx_obj1 = NULL;
347 	struct intel_ringbuffer *ringbuf1 = NULL;
348 
349 	BUG_ON(!ctx_obj0);
350 	WARN_ON(!i915_gem_obj_is_pinned(ctx_obj0));
351 	WARN_ON(!i915_gem_obj_is_pinned(ringbuf0->obj));
352 
353 	execlists_update_context(ctx_obj0, ringbuf0->obj, tail0);
354 
355 	if (to1) {
356 		ringbuf1 = to1->engine[ring->id].ringbuf;
357 		ctx_obj1 = to1->engine[ring->id].state;
358 		BUG_ON(!ctx_obj1);
359 		WARN_ON(!i915_gem_obj_is_pinned(ctx_obj1));
360 		WARN_ON(!i915_gem_obj_is_pinned(ringbuf1->obj));
361 
362 		execlists_update_context(ctx_obj1, ringbuf1->obj, tail1);
363 	}
364 
365 	execlists_elsp_write(ring, ctx_obj0, ctx_obj1);
366 }
367 
368 static void execlists_context_unqueue(struct intel_engine_cs *ring)
369 {
370 	struct drm_i915_gem_request *req0 = NULL, *req1 = NULL;
371 	struct drm_i915_gem_request *cursor = NULL, *tmp = NULL;
372 
373 	assert_spin_locked(&ring->execlist_lock);
374 
375 	if (list_empty(&ring->execlist_queue))
376 		return;
377 
378 	/* Try to read in pairs */
379 	list_for_each_entry_safe(cursor, tmp, &ring->execlist_queue,
380 				 execlist_link) {
381 		if (!req0) {
382 			req0 = cursor;
383 		} else if (req0->ctx == cursor->ctx) {
384 			/* Same ctx: ignore first request, as second request
385 			 * will update tail past first request's workload */
386 			cursor->elsp_submitted = req0->elsp_submitted;
387 			list_del(&req0->execlist_link);
388 			list_add_tail(&req0->execlist_link,
389 				&ring->execlist_retired_req_list);
390 			req0 = cursor;
391 		} else {
392 			req1 = cursor;
393 			break;
394 		}
395 	}
396 
397 	if (IS_GEN8(ring->dev) || IS_GEN9(ring->dev)) {
398 		/*
399 		 * WaIdleLiteRestore: make sure we never cause a lite
400 		 * restore with HEAD==TAIL
401 		 */
402 		if (req0 && req0->elsp_submitted) {
403 			/*
404 			 * Apply the wa NOOPS to prevent ring:HEAD == req:TAIL
405 			 * as we resubmit the request. See gen8_emit_request()
406 			 * for where we prepare the padding after the end of the
407 			 * request.
408 			 */
409 			struct intel_ringbuffer *ringbuf;
410 
411 			ringbuf = req0->ctx->engine[ring->id].ringbuf;
412 			req0->tail += 8;
413 			req0->tail &= ringbuf->size - 1;
414 		}
415 	}
416 
417 	WARN_ON(req1 && req1->elsp_submitted);
418 
419 	execlists_submit_contexts(ring, req0->ctx, req0->tail,
420 				  req1 ? req1->ctx : NULL,
421 				  req1 ? req1->tail : 0);
422 
423 	req0->elsp_submitted++;
424 	if (req1)
425 		req1->elsp_submitted++;
426 }
427 
428 static bool execlists_check_remove_request(struct intel_engine_cs *ring,
429 					   u32 request_id)
430 {
431 	struct drm_i915_gem_request *head_req;
432 
433 	assert_spin_locked(&ring->execlist_lock);
434 
435 	head_req = list_first_entry_or_null(&ring->execlist_queue,
436 					    struct drm_i915_gem_request,
437 					    execlist_link);
438 
439 	if (head_req != NULL) {
440 		struct drm_i915_gem_object *ctx_obj =
441 				head_req->ctx->engine[ring->id].state;
442 		if (intel_execlists_ctx_id(ctx_obj) == request_id) {
443 			WARN(head_req->elsp_submitted == 0,
444 			     "Never submitted head request\n");
445 
446 			if (--head_req->elsp_submitted <= 0) {
447 				list_del(&head_req->execlist_link);
448 				list_add_tail(&head_req->execlist_link,
449 					&ring->execlist_retired_req_list);
450 				return true;
451 			}
452 		}
453 	}
454 
455 	return false;
456 }
457 
458 /**
459  * intel_lrc_irq_handler() - handle Context Switch interrupts
460  * @ring: Engine Command Streamer to handle.
461  *
462  * Check the unread Context Status Buffers and manage the submission of new
463  * contexts to the ELSP accordingly.
464  */
465 void intel_lrc_irq_handler(struct intel_engine_cs *ring)
466 {
467 	struct drm_i915_private *dev_priv = ring->dev->dev_private;
468 	u32 status_pointer;
469 	u8 read_pointer;
470 	u8 write_pointer;
471 	u32 status;
472 	u32 status_id;
473 	u32 submit_contexts = 0;
474 
475 	status_pointer = I915_READ(RING_CONTEXT_STATUS_PTR(ring));
476 
477 	read_pointer = ring->next_context_status_buffer;
478 	write_pointer = status_pointer & 0x07;
479 	if (read_pointer > write_pointer)
480 		write_pointer += 6;
481 
482 	lockmgr(&ring->execlist_lock, LK_EXCLUSIVE);
483 
484 	while (read_pointer < write_pointer) {
485 		read_pointer++;
486 		status = I915_READ(RING_CONTEXT_STATUS_BUF(ring) +
487 				(read_pointer % 6) * 8);
488 		status_id = I915_READ(RING_CONTEXT_STATUS_BUF(ring) +
489 				(read_pointer % 6) * 8 + 4);
490 
491 		if (status & GEN8_CTX_STATUS_PREEMPTED) {
492 			if (status & GEN8_CTX_STATUS_LITE_RESTORE) {
493 				if (execlists_check_remove_request(ring, status_id))
494 					WARN(1, "Lite Restored request removed from queue\n");
495 			} else
496 				WARN(1, "Preemption without Lite Restore\n");
497 		}
498 
499 		 if ((status & GEN8_CTX_STATUS_ACTIVE_IDLE) ||
500 		     (status & GEN8_CTX_STATUS_ELEMENT_SWITCH)) {
501 			if (execlists_check_remove_request(ring, status_id))
502 				submit_contexts++;
503 		}
504 	}
505 
506 	if (submit_contexts != 0)
507 		execlists_context_unqueue(ring);
508 
509 	lockmgr(&ring->execlist_lock, LK_RELEASE);
510 
511 	WARN(submit_contexts > 2, "More than two context complete events?\n");
512 	ring->next_context_status_buffer = write_pointer % 6;
513 
514 	I915_WRITE(RING_CONTEXT_STATUS_PTR(ring),
515 		   ((u32)ring->next_context_status_buffer & 0x07) << 8);
516 }
517 
518 static int execlists_context_queue(struct intel_engine_cs *ring,
519 				   struct intel_context *to,
520 				   u32 tail,
521 				   struct drm_i915_gem_request *request)
522 {
523 	struct drm_i915_gem_request *cursor;
524 	struct drm_i915_private *dev_priv = ring->dev->dev_private;
525 	int num_elements = 0;
526 
527 	if (to != ring->default_context)
528 		intel_lr_context_pin(ring, to);
529 
530 	if (!request) {
531 		/*
532 		 * If there isn't a request associated with this submission,
533 		 * create one as a temporary holder.
534 		 */
535 		request = kzalloc(sizeof(*request), GFP_KERNEL);
536 		if (request == NULL)
537 			return -ENOMEM;
538 		request->ring = ring;
539 		request->ctx = to;
540 		kref_init(&request->ref);
541 		request->uniq = dev_priv->request_uniq++;
542 		i915_gem_context_reference(request->ctx);
543 	} else {
544 		i915_gem_request_reference(request);
545 		WARN_ON(to != request->ctx);
546 	}
547 	request->tail = tail;
548 
549 	intel_runtime_pm_get(dev_priv);
550 
551 	lockmgr(&ring->execlist_lock, LK_EXCLUSIVE);
552 
553 	list_for_each_entry(cursor, &ring->execlist_queue, execlist_link)
554 		if (++num_elements > 2)
555 			break;
556 
557 	if (num_elements > 2) {
558 		struct drm_i915_gem_request *tail_req;
559 
560 		tail_req = list_last_entry(&ring->execlist_queue,
561 					   struct drm_i915_gem_request,
562 					   execlist_link);
563 
564 		if (to == tail_req->ctx) {
565 			WARN(tail_req->elsp_submitted != 0,
566 				"More than 2 already-submitted reqs queued\n");
567 			list_del(&tail_req->execlist_link);
568 			list_add_tail(&tail_req->execlist_link,
569 				&ring->execlist_retired_req_list);
570 		}
571 	}
572 
573 	list_add_tail(&request->execlist_link, &ring->execlist_queue);
574 	if (num_elements == 0)
575 		execlists_context_unqueue(ring);
576 
577 	lockmgr(&ring->execlist_lock, LK_RELEASE);
578 
579 	return 0;
580 }
581 
582 static int logical_ring_invalidate_all_caches(struct intel_ringbuffer *ringbuf,
583 					      struct intel_context *ctx)
584 {
585 	struct intel_engine_cs *ring = ringbuf->ring;
586 	uint32_t flush_domains;
587 	int ret;
588 
589 	flush_domains = 0;
590 	if (ring->gpu_caches_dirty)
591 		flush_domains = I915_GEM_GPU_DOMAINS;
592 
593 	ret = ring->emit_flush(ringbuf, ctx,
594 			       I915_GEM_GPU_DOMAINS, flush_domains);
595 	if (ret)
596 		return ret;
597 
598 	ring->gpu_caches_dirty = false;
599 	return 0;
600 }
601 
602 static int execlists_move_to_gpu(struct intel_ringbuffer *ringbuf,
603 				 struct intel_context *ctx,
604 				 struct list_head *vmas)
605 {
606 	struct intel_engine_cs *ring = ringbuf->ring;
607 	struct i915_vma *vma;
608 	uint32_t flush_domains = 0;
609 	bool flush_chipset = false;
610 	int ret;
611 
612 	list_for_each_entry(vma, vmas, exec_list) {
613 		struct drm_i915_gem_object *obj = vma->obj;
614 
615 		ret = i915_gem_object_sync(obj, ring);
616 		if (ret)
617 			return ret;
618 
619 		if (obj->base.write_domain & I915_GEM_DOMAIN_CPU)
620 			flush_chipset |= i915_gem_clflush_object(obj, false);
621 
622 		flush_domains |= obj->base.write_domain;
623 	}
624 
625 	if (flush_domains & I915_GEM_DOMAIN_GTT)
626 		wmb();
627 
628 	/* Unconditionally invalidate gpu caches and ensure that we do flush
629 	 * any residual writes from the previous batch.
630 	 */
631 	return logical_ring_invalidate_all_caches(ringbuf, ctx);
632 }
633 
634 /**
635  * execlists_submission() - submit a batchbuffer for execution, Execlists style
636  * @dev: DRM device.
637  * @file: DRM file.
638  * @ring: Engine Command Streamer to submit to.
639  * @ctx: Context to employ for this submission.
640  * @args: execbuffer call arguments.
641  * @vmas: list of vmas.
642  * @batch_obj: the batchbuffer to submit.
643  * @exec_start: batchbuffer start virtual address pointer.
644  * @dispatch_flags: translated execbuffer call flags.
645  *
646  * This is the evil twin version of i915_gem_ringbuffer_submission. It abstracts
647  * away the submission details of the execbuffer ioctl call.
648  *
649  * Return: non-zero if the submission fails.
650  */
651 int intel_execlists_submission(struct drm_device *dev, struct drm_file *file,
652 			       struct intel_engine_cs *ring,
653 			       struct intel_context *ctx,
654 			       struct drm_i915_gem_execbuffer2 *args,
655 			       struct list_head *vmas,
656 			       struct drm_i915_gem_object *batch_obj,
657 			       u64 exec_start, u32 dispatch_flags)
658 {
659 	struct drm_i915_private *dev_priv = dev->dev_private;
660 	struct intel_ringbuffer *ringbuf = ctx->engine[ring->id].ringbuf;
661 	int instp_mode;
662 	u32 instp_mask;
663 	int ret;
664 
665 	instp_mode = args->flags & I915_EXEC_CONSTANTS_MASK;
666 	instp_mask = I915_EXEC_CONSTANTS_MASK;
667 	switch (instp_mode) {
668 	case I915_EXEC_CONSTANTS_REL_GENERAL:
669 	case I915_EXEC_CONSTANTS_ABSOLUTE:
670 	case I915_EXEC_CONSTANTS_REL_SURFACE:
671 		if (instp_mode != 0 && ring != &dev_priv->ring[RCS]) {
672 			DRM_DEBUG("non-0 rel constants mode on non-RCS\n");
673 			return -EINVAL;
674 		}
675 
676 		if (instp_mode != dev_priv->relative_constants_mode) {
677 			if (instp_mode == I915_EXEC_CONSTANTS_REL_SURFACE) {
678 				DRM_DEBUG("rel surface constants mode invalid on gen5+\n");
679 				return -EINVAL;
680 			}
681 
682 			/* The HW changed the meaning on this bit on gen6 */
683 			instp_mask &= ~I915_EXEC_CONSTANTS_REL_SURFACE;
684 		}
685 		break;
686 	default:
687 		DRM_DEBUG("execbuf with unknown constants: %d\n", instp_mode);
688 		return -EINVAL;
689 	}
690 
691 	if (args->num_cliprects != 0) {
692 		DRM_DEBUG("clip rectangles are only valid on pre-gen5\n");
693 		return -EINVAL;
694 	} else {
695 		if (args->DR4 == 0xffffffff) {
696 			DRM_DEBUG("UXA submitting garbage DR4, fixing up\n");
697 			args->DR4 = 0;
698 		}
699 
700 		if (args->DR1 || args->DR4 || args->cliprects_ptr) {
701 			DRM_DEBUG("0 cliprects but dirt in cliprects fields\n");
702 			return -EINVAL;
703 		}
704 	}
705 
706 	if (args->flags & I915_EXEC_GEN7_SOL_RESET) {
707 		DRM_DEBUG("sol reset is gen7 only\n");
708 		return -EINVAL;
709 	}
710 
711 	ret = execlists_move_to_gpu(ringbuf, ctx, vmas);
712 	if (ret)
713 		return ret;
714 
715 	if (ring == &dev_priv->ring[RCS] &&
716 	    instp_mode != dev_priv->relative_constants_mode) {
717 		ret = intel_logical_ring_begin(ringbuf, ctx, 4);
718 		if (ret)
719 			return ret;
720 
721 		intel_logical_ring_emit(ringbuf, MI_NOOP);
722 		intel_logical_ring_emit(ringbuf, MI_LOAD_REGISTER_IMM(1));
723 		intel_logical_ring_emit(ringbuf, INSTPM);
724 		intel_logical_ring_emit(ringbuf, instp_mask << 16 | instp_mode);
725 		intel_logical_ring_advance(ringbuf);
726 
727 		dev_priv->relative_constants_mode = instp_mode;
728 	}
729 
730 	ret = ring->emit_bb_start(ringbuf, ctx, exec_start, dispatch_flags);
731 	if (ret)
732 		return ret;
733 
734 	trace_i915_gem_ring_dispatch(intel_ring_get_request(ring), dispatch_flags);
735 
736 	i915_gem_execbuffer_move_to_active(vmas, ring);
737 	i915_gem_execbuffer_retire_commands(dev, file, ring, batch_obj);
738 
739 	return 0;
740 }
741 
742 void intel_execlists_retire_requests(struct intel_engine_cs *ring)
743 {
744 	struct drm_i915_gem_request *req, *tmp;
745 	struct drm_i915_private *dev_priv = ring->dev->dev_private;
746 	struct list_head retired_list;
747 
748 	WARN_ON(!mutex_is_locked(&ring->dev->struct_mutex));
749 	if (list_empty(&ring->execlist_retired_req_list))
750 		return;
751 
752 	INIT_LIST_HEAD(&retired_list);
753 	lockmgr(&ring->execlist_lock, LK_EXCLUSIVE);
754 	list_replace_init(&ring->execlist_retired_req_list, &retired_list);
755 	lockmgr(&ring->execlist_lock, LK_RELEASE);
756 
757 	list_for_each_entry_safe(req, tmp, &retired_list, execlist_link) {
758 		struct intel_context *ctx = req->ctx;
759 		struct drm_i915_gem_object *ctx_obj =
760 				ctx->engine[ring->id].state;
761 
762 		if (ctx_obj && (ctx != ring->default_context))
763 			intel_lr_context_unpin(ring, ctx);
764 		intel_runtime_pm_put(dev_priv);
765 		list_del(&req->execlist_link);
766 		i915_gem_request_unreference(req);
767 	}
768 }
769 
770 void intel_logical_ring_stop(struct intel_engine_cs *ring)
771 {
772 	struct drm_i915_private *dev_priv = ring->dev->dev_private;
773 	int ret;
774 
775 	if (!intel_ring_initialized(ring))
776 		return;
777 
778 	ret = intel_ring_idle(ring);
779 	if (ret && !i915_reset_in_progress(&to_i915(ring->dev)->gpu_error))
780 		DRM_ERROR("failed to quiesce %s whilst cleaning up: %d\n",
781 			  ring->name, ret);
782 
783 	/* TODO: Is this correct with Execlists enabled? */
784 	I915_WRITE_MODE(ring, _MASKED_BIT_ENABLE(STOP_RING));
785 	if (wait_for_atomic((I915_READ_MODE(ring) & MODE_IDLE) != 0, 1000)) {
786 		DRM_ERROR("%s :timed out trying to stop ring\n", ring->name);
787 		return;
788 	}
789 	I915_WRITE_MODE(ring, _MASKED_BIT_DISABLE(STOP_RING));
790 }
791 
792 int logical_ring_flush_all_caches(struct intel_ringbuffer *ringbuf,
793 				  struct intel_context *ctx)
794 {
795 	struct intel_engine_cs *ring = ringbuf->ring;
796 	int ret;
797 
798 	if (!ring->gpu_caches_dirty)
799 		return 0;
800 
801 	ret = ring->emit_flush(ringbuf, ctx, 0, I915_GEM_GPU_DOMAINS);
802 	if (ret)
803 		return ret;
804 
805 	ring->gpu_caches_dirty = false;
806 	return 0;
807 }
808 
809 /*
810  * intel_logical_ring_advance_and_submit() - advance the tail and submit the workload
811  * @ringbuf: Logical Ringbuffer to advance.
812  *
813  * The tail is updated in our logical ringbuffer struct, not in the actual context. What
814  * really happens during submission is that the context and current tail will be placed
815  * on a queue waiting for the ELSP to be ready to accept a new context submission. At that
816  * point, the tail *inside* the context is updated and the ELSP written to.
817  */
818 static void
819 intel_logical_ring_advance_and_submit(struct intel_ringbuffer *ringbuf,
820 				      struct intel_context *ctx,
821 				      struct drm_i915_gem_request *request)
822 {
823 	struct intel_engine_cs *ring = ringbuf->ring;
824 
825 	intel_logical_ring_advance(ringbuf);
826 
827 	if (intel_ring_stopped(ring))
828 		return;
829 
830 	execlists_context_queue(ring, ctx, ringbuf->tail, request);
831 }
832 
833 static int intel_lr_context_pin(struct intel_engine_cs *ring,
834 		struct intel_context *ctx)
835 {
836 	struct drm_i915_gem_object *ctx_obj = ctx->engine[ring->id].state;
837 	struct intel_ringbuffer *ringbuf = ctx->engine[ring->id].ringbuf;
838 	int ret = 0;
839 
840 	WARN_ON(!mutex_is_locked(&ring->dev->struct_mutex));
841 	if (ctx->engine[ring->id].pin_count++ == 0) {
842 		ret = i915_gem_obj_ggtt_pin(ctx_obj,
843 				GEN8_LR_CONTEXT_ALIGN, 0);
844 		if (ret)
845 			goto reset_pin_count;
846 
847 		ret = intel_pin_and_map_ringbuffer_obj(ring->dev, ringbuf);
848 		if (ret)
849 			goto unpin_ctx_obj;
850 	}
851 
852 	return ret;
853 
854 unpin_ctx_obj:
855 	i915_gem_object_ggtt_unpin(ctx_obj);
856 reset_pin_count:
857 	ctx->engine[ring->id].pin_count = 0;
858 
859 	return ret;
860 }
861 
862 void intel_lr_context_unpin(struct intel_engine_cs *ring,
863 		struct intel_context *ctx)
864 {
865 	struct drm_i915_gem_object *ctx_obj = ctx->engine[ring->id].state;
866 	struct intel_ringbuffer *ringbuf = ctx->engine[ring->id].ringbuf;
867 
868 	if (ctx_obj) {
869 		WARN_ON(!mutex_is_locked(&ring->dev->struct_mutex));
870 		if (--ctx->engine[ring->id].pin_count == 0) {
871 			intel_unpin_ringbuffer_obj(ringbuf);
872 			i915_gem_object_ggtt_unpin(ctx_obj);
873 		}
874 	}
875 }
876 
877 static int logical_ring_alloc_request(struct intel_engine_cs *ring,
878 				      struct intel_context *ctx)
879 {
880 	struct drm_i915_gem_request *request;
881 	struct drm_i915_private *dev_private = ring->dev->dev_private;
882 	int ret;
883 
884 	if (ring->outstanding_lazy_request)
885 		return 0;
886 
887 	request = kzalloc(sizeof(*request), GFP_KERNEL);
888 	if (request == NULL)
889 		return -ENOMEM;
890 
891 	if (ctx != ring->default_context) {
892 		ret = intel_lr_context_pin(ring, ctx);
893 		if (ret) {
894 			kfree(request);
895 			return ret;
896 		}
897 	}
898 
899 	kref_init(&request->ref);
900 	request->ring = ring;
901 	request->uniq = dev_private->request_uniq++;
902 
903 	ret = i915_gem_get_seqno(ring->dev, &request->seqno);
904 	if (ret) {
905 		intel_lr_context_unpin(ring, ctx);
906 		kfree(request);
907 		return ret;
908 	}
909 
910 	request->ctx = ctx;
911 	i915_gem_context_reference(request->ctx);
912 	request->ringbuf = ctx->engine[ring->id].ringbuf;
913 
914 	ring->outstanding_lazy_request = request;
915 	return 0;
916 }
917 
918 static int logical_ring_wait_request(struct intel_ringbuffer *ringbuf,
919 				     int bytes)
920 {
921 	struct intel_engine_cs *ring = ringbuf->ring;
922 	struct drm_i915_gem_request *request;
923 	int ret;
924 
925 	if (intel_ring_space(ringbuf) >= bytes)
926 		return 0;
927 
928 	list_for_each_entry(request, &ring->request_list, list) {
929 		/*
930 		 * The request queue is per-engine, so can contain requests
931 		 * from multiple ringbuffers. Here, we must ignore any that
932 		 * aren't from the ringbuffer we're considering.
933 		 */
934 		struct intel_context *ctx = request->ctx;
935 		if (ctx->engine[ring->id].ringbuf != ringbuf)
936 			continue;
937 
938 		/* Would completion of this request free enough space? */
939 		if (__intel_ring_space(request->tail, ringbuf->tail,
940 				       ringbuf->size) >= bytes) {
941 			break;
942 		}
943 	}
944 
945 	if (&request->list == &ring->request_list)
946 		return -ENOSPC;
947 
948 	ret = i915_wait_request(request);
949 	if (ret)
950 		return ret;
951 
952 	i915_gem_retire_requests_ring(ring);
953 
954 	return intel_ring_space(ringbuf) >= bytes ? 0 : -ENOSPC;
955 }
956 
957 static int logical_ring_wait_for_space(struct intel_ringbuffer *ringbuf,
958 				       struct intel_context *ctx,
959 				       int bytes)
960 {
961 	struct intel_engine_cs *ring = ringbuf->ring;
962 	struct drm_device *dev = ring->dev;
963 	struct drm_i915_private *dev_priv = dev->dev_private;
964 	unsigned long end;
965 	int ret;
966 
967 	ret = logical_ring_wait_request(ringbuf, bytes);
968 	if (ret != -ENOSPC)
969 		return ret;
970 
971 	/* Force the context submission in case we have been skipping it */
972 	intel_logical_ring_advance_and_submit(ringbuf, ctx, NULL);
973 
974 	/* With GEM the hangcheck timer should kick us out of the loop,
975 	 * leaving it early runs the risk of corrupting GEM state (due
976 	 * to running on almost untested codepaths). But on resume
977 	 * timers don't work yet, so prevent a complete hang in that
978 	 * case by choosing an insanely large timeout. */
979 	end = jiffies + 60 * HZ;
980 
981 	ret = 0;
982 	do {
983 		if (intel_ring_space(ringbuf) >= bytes)
984 			break;
985 
986 		msleep(1);
987 
988 		if (dev_priv->mm.interruptible && signal_pending(curthread->td_lwp)) {
989 			ret = -ERESTARTSYS;
990 			break;
991 		}
992 
993 		ret = i915_gem_check_wedge(&dev_priv->gpu_error,
994 					   dev_priv->mm.interruptible);
995 		if (ret)
996 			break;
997 
998 		if (time_after(jiffies, end)) {
999 			ret = -EBUSY;
1000 			break;
1001 		}
1002 	} while (1);
1003 
1004 	return ret;
1005 }
1006 
1007 static int logical_ring_wrap_buffer(struct intel_ringbuffer *ringbuf,
1008 				    struct intel_context *ctx)
1009 {
1010 	uint32_t __iomem *virt;
1011 	int rem = ringbuf->size - ringbuf->tail;
1012 
1013 	if (ringbuf->space < rem) {
1014 		int ret = logical_ring_wait_for_space(ringbuf, ctx, rem);
1015 
1016 		if (ret)
1017 			return ret;
1018 	}
1019 
1020 	virt = (unsigned int *)((char *)ringbuf->virtual_start + ringbuf->tail);
1021 	rem /= 4;
1022 	while (rem--)
1023 		iowrite32(MI_NOOP, virt++);
1024 
1025 	ringbuf->tail = 0;
1026 	intel_ring_update_space(ringbuf);
1027 
1028 	return 0;
1029 }
1030 
1031 static int logical_ring_prepare(struct intel_ringbuffer *ringbuf,
1032 				struct intel_context *ctx, int bytes)
1033 {
1034 	int ret;
1035 
1036 	if (unlikely(ringbuf->tail + bytes > ringbuf->effective_size)) {
1037 		ret = logical_ring_wrap_buffer(ringbuf, ctx);
1038 		if (unlikely(ret))
1039 			return ret;
1040 	}
1041 
1042 	if (unlikely(ringbuf->space < bytes)) {
1043 		ret = logical_ring_wait_for_space(ringbuf, ctx, bytes);
1044 		if (unlikely(ret))
1045 			return ret;
1046 	}
1047 
1048 	return 0;
1049 }
1050 
1051 /**
1052  * intel_logical_ring_begin() - prepare the logical ringbuffer to accept some commands
1053  *
1054  * @ringbuf: Logical ringbuffer.
1055  * @num_dwords: number of DWORDs that we plan to write to the ringbuffer.
1056  *
1057  * The ringbuffer might not be ready to accept the commands right away (maybe it needs to
1058  * be wrapped, or wait a bit for the tail to be updated). This function takes care of that
1059  * and also preallocates a request (every workload submission is still mediated through
1060  * requests, same as it did with legacy ringbuffer submission).
1061  *
1062  * Return: non-zero if the ringbuffer is not ready to be written to.
1063  */
1064 int intel_logical_ring_begin(struct intel_ringbuffer *ringbuf,
1065 			     struct intel_context *ctx, int num_dwords)
1066 {
1067 	struct intel_engine_cs *ring = ringbuf->ring;
1068 	struct drm_device *dev = ring->dev;
1069 	struct drm_i915_private *dev_priv = dev->dev_private;
1070 	int ret;
1071 
1072 	ret = i915_gem_check_wedge(&dev_priv->gpu_error,
1073 				   dev_priv->mm.interruptible);
1074 	if (ret)
1075 		return ret;
1076 
1077 	ret = logical_ring_prepare(ringbuf, ctx, num_dwords * sizeof(uint32_t));
1078 	if (ret)
1079 		return ret;
1080 
1081 	/* Preallocate the olr before touching the ring */
1082 	ret = logical_ring_alloc_request(ring, ctx);
1083 	if (ret)
1084 		return ret;
1085 
1086 	ringbuf->space -= num_dwords * sizeof(uint32_t);
1087 	return 0;
1088 }
1089 
1090 static int intel_logical_ring_workarounds_emit(struct intel_engine_cs *ring,
1091 					       struct intel_context *ctx)
1092 {
1093 	int ret, i;
1094 	struct intel_ringbuffer *ringbuf = ctx->engine[ring->id].ringbuf;
1095 	struct drm_device *dev = ring->dev;
1096 	struct drm_i915_private *dev_priv = dev->dev_private;
1097 	struct i915_workarounds *w = &dev_priv->workarounds;
1098 
1099 	if (WARN_ON_ONCE(w->count == 0))
1100 		return 0;
1101 
1102 	ring->gpu_caches_dirty = true;
1103 	ret = logical_ring_flush_all_caches(ringbuf, ctx);
1104 	if (ret)
1105 		return ret;
1106 
1107 	ret = intel_logical_ring_begin(ringbuf, ctx, w->count * 2 + 2);
1108 	if (ret)
1109 		return ret;
1110 
1111 	intel_logical_ring_emit(ringbuf, MI_LOAD_REGISTER_IMM(w->count));
1112 	for (i = 0; i < w->count; i++) {
1113 		intel_logical_ring_emit(ringbuf, w->reg[i].addr);
1114 		intel_logical_ring_emit(ringbuf, w->reg[i].value);
1115 	}
1116 	intel_logical_ring_emit(ringbuf, MI_NOOP);
1117 
1118 	intel_logical_ring_advance(ringbuf);
1119 
1120 	ring->gpu_caches_dirty = true;
1121 	ret = logical_ring_flush_all_caches(ringbuf, ctx);
1122 	if (ret)
1123 		return ret;
1124 
1125 	return 0;
1126 }
1127 
1128 static int gen8_init_common_ring(struct intel_engine_cs *ring)
1129 {
1130 	struct drm_device *dev = ring->dev;
1131 	struct drm_i915_private *dev_priv = dev->dev_private;
1132 
1133 	I915_WRITE_IMR(ring, ~(ring->irq_enable_mask | ring->irq_keep_mask));
1134 	I915_WRITE(RING_HWSTAM(ring->mmio_base), 0xffffffff);
1135 
1136 	if (ring->status_page.obj) {
1137 		I915_WRITE(RING_HWS_PGA(ring->mmio_base),
1138 			   (u32)ring->status_page.gfx_addr);
1139 		POSTING_READ(RING_HWS_PGA(ring->mmio_base));
1140 	}
1141 
1142 	I915_WRITE(RING_MODE_GEN7(ring),
1143 		   _MASKED_BIT_DISABLE(GFX_REPLAY_MODE) |
1144 		   _MASKED_BIT_ENABLE(GFX_RUN_LIST_ENABLE));
1145 	POSTING_READ(RING_MODE_GEN7(ring));
1146 	ring->next_context_status_buffer = 0;
1147 	DRM_DEBUG_DRIVER("Execlists enabled for %s\n", ring->name);
1148 
1149 	memset(&ring->hangcheck, 0, sizeof(ring->hangcheck));
1150 
1151 	return 0;
1152 }
1153 
1154 static int gen8_init_render_ring(struct intel_engine_cs *ring)
1155 {
1156 	struct drm_device *dev = ring->dev;
1157 	struct drm_i915_private *dev_priv = dev->dev_private;
1158 	int ret;
1159 
1160 	ret = gen8_init_common_ring(ring);
1161 	if (ret)
1162 		return ret;
1163 
1164 	/* We need to disable the AsyncFlip performance optimisations in order
1165 	 * to use MI_WAIT_FOR_EVENT within the CS. It should already be
1166 	 * programmed to '1' on all products.
1167 	 *
1168 	 * WaDisableAsyncFlipPerfMode:snb,ivb,hsw,vlv,bdw,chv
1169 	 */
1170 	I915_WRITE(MI_MODE, _MASKED_BIT_ENABLE(ASYNC_FLIP_PERF_DISABLE));
1171 
1172 	I915_WRITE(INSTPM, _MASKED_BIT_ENABLE(INSTPM_FORCE_ORDERING));
1173 
1174 	return init_workarounds_ring(ring);
1175 }
1176 
1177 static int gen9_init_render_ring(struct intel_engine_cs *ring)
1178 {
1179 	int ret;
1180 
1181 	ret = gen8_init_common_ring(ring);
1182 	if (ret)
1183 		return ret;
1184 
1185 	return init_workarounds_ring(ring);
1186 }
1187 
1188 static int gen8_emit_bb_start(struct intel_ringbuffer *ringbuf,
1189 			      struct intel_context *ctx,
1190 			      u64 offset, unsigned dispatch_flags)
1191 {
1192 	bool ppgtt = !(dispatch_flags & I915_DISPATCH_SECURE);
1193 	int ret;
1194 
1195 	ret = intel_logical_ring_begin(ringbuf, ctx, 4);
1196 	if (ret)
1197 		return ret;
1198 
1199 	/* FIXME(BDW): Address space and security selectors. */
1200 	intel_logical_ring_emit(ringbuf, MI_BATCH_BUFFER_START_GEN8 | (ppgtt<<8));
1201 	intel_logical_ring_emit(ringbuf, lower_32_bits(offset));
1202 	intel_logical_ring_emit(ringbuf, upper_32_bits(offset));
1203 	intel_logical_ring_emit(ringbuf, MI_NOOP);
1204 	intel_logical_ring_advance(ringbuf);
1205 
1206 	return 0;
1207 }
1208 
1209 static bool gen8_logical_ring_get_irq(struct intel_engine_cs *ring)
1210 {
1211 	struct drm_device *dev = ring->dev;
1212 	struct drm_i915_private *dev_priv = dev->dev_private;
1213 
1214 	if (WARN_ON(!intel_irqs_enabled(dev_priv)))
1215 		return false;
1216 
1217 	lockmgr(&dev_priv->irq_lock, LK_EXCLUSIVE);
1218 	if (ring->irq_refcount++ == 0) {
1219 		I915_WRITE_IMR(ring, ~(ring->irq_enable_mask | ring->irq_keep_mask));
1220 		POSTING_READ(RING_IMR(ring->mmio_base));
1221 	}
1222 	lockmgr(&dev_priv->irq_lock, LK_RELEASE);
1223 
1224 	return true;
1225 }
1226 
1227 static void gen8_logical_ring_put_irq(struct intel_engine_cs *ring)
1228 {
1229 	struct drm_device *dev = ring->dev;
1230 	struct drm_i915_private *dev_priv = dev->dev_private;
1231 
1232 	lockmgr(&dev_priv->irq_lock, LK_EXCLUSIVE);
1233 	if (--ring->irq_refcount == 0) {
1234 		I915_WRITE_IMR(ring, ~ring->irq_keep_mask);
1235 		POSTING_READ(RING_IMR(ring->mmio_base));
1236 	}
1237 	lockmgr(&dev_priv->irq_lock, LK_RELEASE);
1238 }
1239 
1240 static int gen8_emit_flush(struct intel_ringbuffer *ringbuf,
1241 			   struct intel_context *ctx,
1242 			   u32 invalidate_domains,
1243 			   u32 unused)
1244 {
1245 	struct intel_engine_cs *ring = ringbuf->ring;
1246 	struct drm_device *dev = ring->dev;
1247 	struct drm_i915_private *dev_priv = dev->dev_private;
1248 	uint32_t cmd;
1249 	int ret;
1250 
1251 	ret = intel_logical_ring_begin(ringbuf, ctx, 4);
1252 	if (ret)
1253 		return ret;
1254 
1255 	cmd = MI_FLUSH_DW + 1;
1256 
1257 	/* We always require a command barrier so that subsequent
1258 	 * commands, such as breadcrumb interrupts, are strictly ordered
1259 	 * wrt the contents of the write cache being flushed to memory
1260 	 * (and thus being coherent from the CPU).
1261 	 */
1262 	cmd |= MI_FLUSH_DW_STORE_INDEX | MI_FLUSH_DW_OP_STOREDW;
1263 
1264 	if (invalidate_domains & I915_GEM_GPU_DOMAINS) {
1265 		cmd |= MI_INVALIDATE_TLB;
1266 		if (ring == &dev_priv->ring[VCS])
1267 			cmd |= MI_INVALIDATE_BSD;
1268 	}
1269 
1270 	intel_logical_ring_emit(ringbuf, cmd);
1271 	intel_logical_ring_emit(ringbuf,
1272 				I915_GEM_HWS_SCRATCH_ADDR |
1273 				MI_FLUSH_DW_USE_GTT);
1274 	intel_logical_ring_emit(ringbuf, 0); /* upper addr */
1275 	intel_logical_ring_emit(ringbuf, 0); /* value */
1276 	intel_logical_ring_advance(ringbuf);
1277 
1278 	return 0;
1279 }
1280 
1281 static int gen8_emit_flush_render(struct intel_ringbuffer *ringbuf,
1282 				  struct intel_context *ctx,
1283 				  u32 invalidate_domains,
1284 				  u32 flush_domains)
1285 {
1286 	struct intel_engine_cs *ring = ringbuf->ring;
1287 	u32 scratch_addr = ring->scratch.gtt_offset + 2 * CACHELINE_BYTES;
1288 	u32 flags = 0;
1289 	int ret;
1290 
1291 	flags |= PIPE_CONTROL_CS_STALL;
1292 
1293 	if (flush_domains) {
1294 		flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH;
1295 		flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH;
1296 	}
1297 
1298 	if (invalidate_domains) {
1299 		flags |= PIPE_CONTROL_TLB_INVALIDATE;
1300 		flags |= PIPE_CONTROL_INSTRUCTION_CACHE_INVALIDATE;
1301 		flags |= PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE;
1302 		flags |= PIPE_CONTROL_VF_CACHE_INVALIDATE;
1303 		flags |= PIPE_CONTROL_CONST_CACHE_INVALIDATE;
1304 		flags |= PIPE_CONTROL_STATE_CACHE_INVALIDATE;
1305 		flags |= PIPE_CONTROL_QW_WRITE;
1306 		flags |= PIPE_CONTROL_GLOBAL_GTT_IVB;
1307 	}
1308 
1309 	ret = intel_logical_ring_begin(ringbuf, ctx, 6);
1310 	if (ret)
1311 		return ret;
1312 
1313 	intel_logical_ring_emit(ringbuf, GFX_OP_PIPE_CONTROL(6));
1314 	intel_logical_ring_emit(ringbuf, flags);
1315 	intel_logical_ring_emit(ringbuf, scratch_addr);
1316 	intel_logical_ring_emit(ringbuf, 0);
1317 	intel_logical_ring_emit(ringbuf, 0);
1318 	intel_logical_ring_emit(ringbuf, 0);
1319 	intel_logical_ring_advance(ringbuf);
1320 
1321 	return 0;
1322 }
1323 
1324 static u32 gen8_get_seqno(struct intel_engine_cs *ring, bool lazy_coherency)
1325 {
1326 	return intel_read_status_page(ring, I915_GEM_HWS_INDEX);
1327 }
1328 
1329 static void gen8_set_seqno(struct intel_engine_cs *ring, u32 seqno)
1330 {
1331 	intel_write_status_page(ring, I915_GEM_HWS_INDEX, seqno);
1332 }
1333 
1334 static int gen8_emit_request(struct intel_ringbuffer *ringbuf,
1335 			     struct drm_i915_gem_request *request)
1336 {
1337 	struct intel_engine_cs *ring = ringbuf->ring;
1338 	u32 cmd;
1339 	int ret;
1340 
1341 	/*
1342 	 * Reserve space for 2 NOOPs at the end of each request to be
1343 	 * used as a workaround for not being allowed to do lite
1344 	 * restore with HEAD==TAIL (WaIdleLiteRestore).
1345 	 */
1346 	ret = intel_logical_ring_begin(ringbuf, request->ctx, 8);
1347 	if (ret)
1348 		return ret;
1349 
1350 	cmd = MI_STORE_DWORD_IMM_GEN4;
1351 	cmd |= MI_GLOBAL_GTT;
1352 
1353 	intel_logical_ring_emit(ringbuf, cmd);
1354 	intel_logical_ring_emit(ringbuf,
1355 				(ring->status_page.gfx_addr +
1356 				(I915_GEM_HWS_INDEX << MI_STORE_DWORD_INDEX_SHIFT)));
1357 	intel_logical_ring_emit(ringbuf, 0);
1358 	intel_logical_ring_emit(ringbuf,
1359 		i915_gem_request_get_seqno(ring->outstanding_lazy_request));
1360 	intel_logical_ring_emit(ringbuf, MI_USER_INTERRUPT);
1361 	intel_logical_ring_emit(ringbuf, MI_NOOP);
1362 	intel_logical_ring_advance_and_submit(ringbuf, request->ctx, request);
1363 
1364 	/*
1365 	 * Here we add two extra NOOPs as padding to avoid
1366 	 * lite restore of a context with HEAD==TAIL.
1367 	 */
1368 	intel_logical_ring_emit(ringbuf, MI_NOOP);
1369 	intel_logical_ring_emit(ringbuf, MI_NOOP);
1370 	intel_logical_ring_advance(ringbuf);
1371 
1372 	return 0;
1373 }
1374 
1375 static int intel_lr_context_render_state_init(struct intel_engine_cs *ring,
1376 					      struct intel_context *ctx)
1377 {
1378 	struct intel_ringbuffer *ringbuf = ctx->engine[ring->id].ringbuf;
1379 	struct render_state so;
1380 	struct drm_i915_file_private *file_priv = ctx->file_priv;
1381 	struct drm_file *file = file_priv ? file_priv->file : NULL;
1382 	int ret;
1383 
1384 	ret = i915_gem_render_state_prepare(ring, &so);
1385 	if (ret)
1386 		return ret;
1387 
1388 	if (so.rodata == NULL)
1389 		return 0;
1390 
1391 	ret = ring->emit_bb_start(ringbuf,
1392 			ctx,
1393 			so.ggtt_offset,
1394 			I915_DISPATCH_SECURE);
1395 	if (ret)
1396 		goto out;
1397 
1398 	i915_vma_move_to_active(i915_gem_obj_to_ggtt(so.obj), ring);
1399 
1400 	ret = __i915_add_request(ring, file, so.obj);
1401 	/* intel_logical_ring_add_request moves object to inactive if it
1402 	 * fails */
1403 out:
1404 	i915_gem_render_state_fini(&so);
1405 	return ret;
1406 }
1407 
1408 static int gen8_init_rcs_context(struct intel_engine_cs *ring,
1409 		       struct intel_context *ctx)
1410 {
1411 	int ret;
1412 
1413 	ret = intel_logical_ring_workarounds_emit(ring, ctx);
1414 	if (ret)
1415 		return ret;
1416 
1417 	return intel_lr_context_render_state_init(ring, ctx);
1418 }
1419 
1420 /**
1421  * intel_logical_ring_cleanup() - deallocate the Engine Command Streamer
1422  *
1423  * @ring: Engine Command Streamer.
1424  *
1425  */
1426 void intel_logical_ring_cleanup(struct intel_engine_cs *ring)
1427 {
1428 	struct drm_i915_private *dev_priv;
1429 
1430 	if (!intel_ring_initialized(ring))
1431 		return;
1432 
1433 	dev_priv = ring->dev->dev_private;
1434 
1435 	intel_logical_ring_stop(ring);
1436 	WARN_ON((I915_READ_MODE(ring) & MODE_IDLE) == 0);
1437 	i915_gem_request_assign(&ring->outstanding_lazy_request, NULL);
1438 
1439 	if (ring->cleanup)
1440 		ring->cleanup(ring);
1441 
1442 	i915_cmd_parser_fini_ring(ring);
1443 
1444 	if (ring->status_page.obj) {
1445 		kunmap(ring->status_page.obj->pages[0]);
1446 		ring->status_page.obj = NULL;
1447 	}
1448 }
1449 
1450 static int logical_ring_init(struct drm_device *dev, struct intel_engine_cs *ring)
1451 {
1452 	int ret;
1453 
1454 	/* Intentionally left blank. */
1455 	ring->buffer = NULL;
1456 
1457 	ring->dev = dev;
1458 	INIT_LIST_HEAD(&ring->active_list);
1459 	INIT_LIST_HEAD(&ring->request_list);
1460 	init_waitqueue_head(&ring->irq_queue);
1461 
1462 	INIT_LIST_HEAD(&ring->execlist_queue);
1463 	INIT_LIST_HEAD(&ring->execlist_retired_req_list);
1464 	lockinit(&ring->execlist_lock, "i915el", 0, LK_CANRECURSE);
1465 
1466 	ret = i915_cmd_parser_init_ring(ring);
1467 	if (ret)
1468 		return ret;
1469 
1470 	ret = intel_lr_context_deferred_create(ring->default_context, ring);
1471 
1472 	return ret;
1473 }
1474 
1475 static int logical_render_ring_init(struct drm_device *dev)
1476 {
1477 	struct drm_i915_private *dev_priv = dev->dev_private;
1478 	struct intel_engine_cs *ring = &dev_priv->ring[RCS];
1479 	int ret;
1480 
1481 	ring->name = "render ring";
1482 	ring->id = RCS;
1483 	ring->mmio_base = RENDER_RING_BASE;
1484 	ring->irq_enable_mask =
1485 		GT_RENDER_USER_INTERRUPT << GEN8_RCS_IRQ_SHIFT;
1486 	ring->irq_keep_mask =
1487 		GT_CONTEXT_SWITCH_INTERRUPT << GEN8_RCS_IRQ_SHIFT;
1488 	if (HAS_L3_DPF(dev))
1489 		ring->irq_keep_mask |= GT_RENDER_L3_PARITY_ERROR_INTERRUPT;
1490 
1491 	if (INTEL_INFO(dev)->gen >= 9)
1492 		ring->init_hw = gen9_init_render_ring;
1493 	else
1494 		ring->init_hw = gen8_init_render_ring;
1495 	ring->init_context = gen8_init_rcs_context;
1496 	ring->cleanup = intel_fini_pipe_control;
1497 	ring->get_seqno = gen8_get_seqno;
1498 	ring->set_seqno = gen8_set_seqno;
1499 	ring->emit_request = gen8_emit_request;
1500 	ring->emit_flush = gen8_emit_flush_render;
1501 	ring->irq_get = gen8_logical_ring_get_irq;
1502 	ring->irq_put = gen8_logical_ring_put_irq;
1503 	ring->emit_bb_start = gen8_emit_bb_start;
1504 
1505 	ring->dev = dev;
1506 	ret = logical_ring_init(dev, ring);
1507 	if (ret)
1508 		return ret;
1509 
1510 	return intel_init_pipe_control(ring);
1511 }
1512 
1513 static int logical_bsd_ring_init(struct drm_device *dev)
1514 {
1515 	struct drm_i915_private *dev_priv = dev->dev_private;
1516 	struct intel_engine_cs *ring = &dev_priv->ring[VCS];
1517 
1518 	ring->name = "bsd ring";
1519 	ring->id = VCS;
1520 	ring->mmio_base = GEN6_BSD_RING_BASE;
1521 	ring->irq_enable_mask =
1522 		GT_RENDER_USER_INTERRUPT << GEN8_VCS1_IRQ_SHIFT;
1523 	ring->irq_keep_mask =
1524 		GT_CONTEXT_SWITCH_INTERRUPT << GEN8_VCS1_IRQ_SHIFT;
1525 
1526 	ring->init_hw = gen8_init_common_ring;
1527 	ring->get_seqno = gen8_get_seqno;
1528 	ring->set_seqno = gen8_set_seqno;
1529 	ring->emit_request = gen8_emit_request;
1530 	ring->emit_flush = gen8_emit_flush;
1531 	ring->irq_get = gen8_logical_ring_get_irq;
1532 	ring->irq_put = gen8_logical_ring_put_irq;
1533 	ring->emit_bb_start = gen8_emit_bb_start;
1534 
1535 	return logical_ring_init(dev, ring);
1536 }
1537 
1538 static int logical_bsd2_ring_init(struct drm_device *dev)
1539 {
1540 	struct drm_i915_private *dev_priv = dev->dev_private;
1541 	struct intel_engine_cs *ring = &dev_priv->ring[VCS2];
1542 
1543 	ring->name = "bds2 ring";
1544 	ring->id = VCS2;
1545 	ring->mmio_base = GEN8_BSD2_RING_BASE;
1546 	ring->irq_enable_mask =
1547 		GT_RENDER_USER_INTERRUPT << GEN8_VCS2_IRQ_SHIFT;
1548 	ring->irq_keep_mask =
1549 		GT_CONTEXT_SWITCH_INTERRUPT << GEN8_VCS2_IRQ_SHIFT;
1550 
1551 	ring->init_hw = gen8_init_common_ring;
1552 	ring->get_seqno = gen8_get_seqno;
1553 	ring->set_seqno = gen8_set_seqno;
1554 	ring->emit_request = gen8_emit_request;
1555 	ring->emit_flush = gen8_emit_flush;
1556 	ring->irq_get = gen8_logical_ring_get_irq;
1557 	ring->irq_put = gen8_logical_ring_put_irq;
1558 	ring->emit_bb_start = gen8_emit_bb_start;
1559 
1560 	return logical_ring_init(dev, ring);
1561 }
1562 
1563 static int logical_blt_ring_init(struct drm_device *dev)
1564 {
1565 	struct drm_i915_private *dev_priv = dev->dev_private;
1566 	struct intel_engine_cs *ring = &dev_priv->ring[BCS];
1567 
1568 	ring->name = "blitter ring";
1569 	ring->id = BCS;
1570 	ring->mmio_base = BLT_RING_BASE;
1571 	ring->irq_enable_mask =
1572 		GT_RENDER_USER_INTERRUPT << GEN8_BCS_IRQ_SHIFT;
1573 	ring->irq_keep_mask =
1574 		GT_CONTEXT_SWITCH_INTERRUPT << GEN8_BCS_IRQ_SHIFT;
1575 
1576 	ring->init_hw = gen8_init_common_ring;
1577 	ring->get_seqno = gen8_get_seqno;
1578 	ring->set_seqno = gen8_set_seqno;
1579 	ring->emit_request = gen8_emit_request;
1580 	ring->emit_flush = gen8_emit_flush;
1581 	ring->irq_get = gen8_logical_ring_get_irq;
1582 	ring->irq_put = gen8_logical_ring_put_irq;
1583 	ring->emit_bb_start = gen8_emit_bb_start;
1584 
1585 	return logical_ring_init(dev, ring);
1586 }
1587 
1588 static int logical_vebox_ring_init(struct drm_device *dev)
1589 {
1590 	struct drm_i915_private *dev_priv = dev->dev_private;
1591 	struct intel_engine_cs *ring = &dev_priv->ring[VECS];
1592 
1593 	ring->name = "video enhancement ring";
1594 	ring->id = VECS;
1595 	ring->mmio_base = VEBOX_RING_BASE;
1596 	ring->irq_enable_mask =
1597 		GT_RENDER_USER_INTERRUPT << GEN8_VECS_IRQ_SHIFT;
1598 	ring->irq_keep_mask =
1599 		GT_CONTEXT_SWITCH_INTERRUPT << GEN8_VECS_IRQ_SHIFT;
1600 
1601 	ring->init_hw = gen8_init_common_ring;
1602 	ring->get_seqno = gen8_get_seqno;
1603 	ring->set_seqno = gen8_set_seqno;
1604 	ring->emit_request = gen8_emit_request;
1605 	ring->emit_flush = gen8_emit_flush;
1606 	ring->irq_get = gen8_logical_ring_get_irq;
1607 	ring->irq_put = gen8_logical_ring_put_irq;
1608 	ring->emit_bb_start = gen8_emit_bb_start;
1609 
1610 	return logical_ring_init(dev, ring);
1611 }
1612 
1613 /**
1614  * intel_logical_rings_init() - allocate, populate and init the Engine Command Streamers
1615  * @dev: DRM device.
1616  *
1617  * This function inits the engines for an Execlists submission style (the equivalent in the
1618  * legacy ringbuffer submission world would be i915_gem_init_rings). It does it only for
1619  * those engines that are present in the hardware.
1620  *
1621  * Return: non-zero if the initialization failed.
1622  */
1623 int intel_logical_rings_init(struct drm_device *dev)
1624 {
1625 	struct drm_i915_private *dev_priv = dev->dev_private;
1626 	int ret;
1627 
1628 	ret = logical_render_ring_init(dev);
1629 	if (ret)
1630 		return ret;
1631 
1632 	if (HAS_BSD(dev)) {
1633 		ret = logical_bsd_ring_init(dev);
1634 		if (ret)
1635 			goto cleanup_render_ring;
1636 	}
1637 
1638 	if (HAS_BLT(dev)) {
1639 		ret = logical_blt_ring_init(dev);
1640 		if (ret)
1641 			goto cleanup_bsd_ring;
1642 	}
1643 
1644 	if (HAS_VEBOX(dev)) {
1645 		ret = logical_vebox_ring_init(dev);
1646 		if (ret)
1647 			goto cleanup_blt_ring;
1648 	}
1649 
1650 	if (HAS_BSD2(dev)) {
1651 		ret = logical_bsd2_ring_init(dev);
1652 		if (ret)
1653 			goto cleanup_vebox_ring;
1654 	}
1655 
1656 	ret = i915_gem_set_seqno(dev, ((u32)~0 - 0x1000));
1657 	if (ret)
1658 		goto cleanup_bsd2_ring;
1659 
1660 	return 0;
1661 
1662 cleanup_bsd2_ring:
1663 	intel_logical_ring_cleanup(&dev_priv->ring[VCS2]);
1664 cleanup_vebox_ring:
1665 	intel_logical_ring_cleanup(&dev_priv->ring[VECS]);
1666 cleanup_blt_ring:
1667 	intel_logical_ring_cleanup(&dev_priv->ring[BCS]);
1668 cleanup_bsd_ring:
1669 	intel_logical_ring_cleanup(&dev_priv->ring[VCS]);
1670 cleanup_render_ring:
1671 	intel_logical_ring_cleanup(&dev_priv->ring[RCS]);
1672 
1673 	return ret;
1674 }
1675 
1676 static u32
1677 make_rpcs(struct drm_device *dev)
1678 {
1679 	u32 rpcs = 0;
1680 
1681 	/*
1682 	 * No explicit RPCS request is needed to ensure full
1683 	 * slice/subslice/EU enablement prior to Gen9.
1684 	*/
1685 	if (INTEL_INFO(dev)->gen < 9)
1686 		return 0;
1687 
1688 	/*
1689 	 * Starting in Gen9, render power gating can leave
1690 	 * slice/subslice/EU in a partially enabled state. We
1691 	 * must make an explicit request through RPCS for full
1692 	 * enablement.
1693 	*/
1694 	if (INTEL_INFO(dev)->has_slice_pg) {
1695 		rpcs |= GEN8_RPCS_S_CNT_ENABLE;
1696 		rpcs |= INTEL_INFO(dev)->slice_total <<
1697 			GEN8_RPCS_S_CNT_SHIFT;
1698 		rpcs |= GEN8_RPCS_ENABLE;
1699 	}
1700 
1701 	if (INTEL_INFO(dev)->has_subslice_pg) {
1702 		rpcs |= GEN8_RPCS_SS_CNT_ENABLE;
1703 		rpcs |= INTEL_INFO(dev)->subslice_per_slice <<
1704 			GEN8_RPCS_SS_CNT_SHIFT;
1705 		rpcs |= GEN8_RPCS_ENABLE;
1706 	}
1707 
1708 	if (INTEL_INFO(dev)->has_eu_pg) {
1709 		rpcs |= INTEL_INFO(dev)->eu_per_subslice <<
1710 			GEN8_RPCS_EU_MIN_SHIFT;
1711 		rpcs |= INTEL_INFO(dev)->eu_per_subslice <<
1712 			GEN8_RPCS_EU_MAX_SHIFT;
1713 		rpcs |= GEN8_RPCS_ENABLE;
1714 	}
1715 
1716 	return rpcs;
1717 }
1718 
1719 static int
1720 populate_lr_context(struct intel_context *ctx, struct drm_i915_gem_object *ctx_obj,
1721 		    struct intel_engine_cs *ring, struct intel_ringbuffer *ringbuf)
1722 {
1723 	struct drm_device *dev = ring->dev;
1724 	struct drm_i915_private *dev_priv = dev->dev_private;
1725 	struct i915_hw_ppgtt *ppgtt = ctx->ppgtt;
1726 	struct vm_page *page;
1727 	uint32_t *reg_state;
1728 	int ret;
1729 
1730 	if (!ppgtt)
1731 		ppgtt = dev_priv->mm.aliasing_ppgtt;
1732 
1733 	ret = i915_gem_object_set_to_cpu_domain(ctx_obj, true);
1734 	if (ret) {
1735 		DRM_DEBUG_DRIVER("Could not set to CPU domain\n");
1736 		return ret;
1737 	}
1738 
1739 	ret = i915_gem_object_get_pages(ctx_obj);
1740 	if (ret) {
1741 		DRM_DEBUG_DRIVER("Could not get object pages\n");
1742 		return ret;
1743 	}
1744 
1745 	i915_gem_object_pin_pages(ctx_obj);
1746 
1747 	/* The second page of the context object contains some fields which must
1748 	 * be set up prior to the first execution. */
1749 	page = i915_gem_object_get_page(ctx_obj, 1);
1750 	reg_state = kmap_atomic(page);
1751 
1752 	/* A context is actually a big batch buffer with several MI_LOAD_REGISTER_IMM
1753 	 * commands followed by (reg, value) pairs. The values we are setting here are
1754 	 * only for the first context restore: on a subsequent save, the GPU will
1755 	 * recreate this batchbuffer with new values (including all the missing
1756 	 * MI_LOAD_REGISTER_IMM commands that we are not initializing here). */
1757 	if (ring->id == RCS)
1758 		reg_state[CTX_LRI_HEADER_0] = MI_LOAD_REGISTER_IMM(14);
1759 	else
1760 		reg_state[CTX_LRI_HEADER_0] = MI_LOAD_REGISTER_IMM(11);
1761 	reg_state[CTX_LRI_HEADER_0] |= MI_LRI_FORCE_POSTED;
1762 	reg_state[CTX_CONTEXT_CONTROL] = RING_CONTEXT_CONTROL(ring);
1763 	reg_state[CTX_CONTEXT_CONTROL+1] =
1764 		_MASKED_BIT_ENABLE(CTX_CTRL_INHIBIT_SYN_CTX_SWITCH |
1765 				CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT);
1766 	reg_state[CTX_RING_HEAD] = RING_HEAD(ring->mmio_base);
1767 	reg_state[CTX_RING_HEAD+1] = 0;
1768 	reg_state[CTX_RING_TAIL] = RING_TAIL(ring->mmio_base);
1769 	reg_state[CTX_RING_TAIL+1] = 0;
1770 	reg_state[CTX_RING_BUFFER_START] = RING_START(ring->mmio_base);
1771 	/* Ring buffer start address is not known until the buffer is pinned.
1772 	 * It is written to the context image in execlists_update_context()
1773 	 */
1774 	reg_state[CTX_RING_BUFFER_CONTROL] = RING_CTL(ring->mmio_base);
1775 	reg_state[CTX_RING_BUFFER_CONTROL+1] =
1776 			((ringbuf->size - PAGE_SIZE) & RING_NR_PAGES) | RING_VALID;
1777 	reg_state[CTX_BB_HEAD_U] = ring->mmio_base + 0x168;
1778 	reg_state[CTX_BB_HEAD_U+1] = 0;
1779 	reg_state[CTX_BB_HEAD_L] = ring->mmio_base + 0x140;
1780 	reg_state[CTX_BB_HEAD_L+1] = 0;
1781 	reg_state[CTX_BB_STATE] = ring->mmio_base + 0x110;
1782 	reg_state[CTX_BB_STATE+1] = (1<<5);
1783 	reg_state[CTX_SECOND_BB_HEAD_U] = ring->mmio_base + 0x11c;
1784 	reg_state[CTX_SECOND_BB_HEAD_U+1] = 0;
1785 	reg_state[CTX_SECOND_BB_HEAD_L] = ring->mmio_base + 0x114;
1786 	reg_state[CTX_SECOND_BB_HEAD_L+1] = 0;
1787 	reg_state[CTX_SECOND_BB_STATE] = ring->mmio_base + 0x118;
1788 	reg_state[CTX_SECOND_BB_STATE+1] = 0;
1789 	if (ring->id == RCS) {
1790 		/* TODO: according to BSpec, the register state context
1791 		 * for CHV does not have these. OTOH, these registers do
1792 		 * exist in CHV. I'm waiting for a clarification */
1793 		reg_state[CTX_BB_PER_CTX_PTR] = ring->mmio_base + 0x1c0;
1794 		reg_state[CTX_BB_PER_CTX_PTR+1] = 0;
1795 		reg_state[CTX_RCS_INDIRECT_CTX] = ring->mmio_base + 0x1c4;
1796 		reg_state[CTX_RCS_INDIRECT_CTX+1] = 0;
1797 		reg_state[CTX_RCS_INDIRECT_CTX_OFFSET] = ring->mmio_base + 0x1c8;
1798 		reg_state[CTX_RCS_INDIRECT_CTX_OFFSET+1] = 0;
1799 	}
1800 	reg_state[CTX_LRI_HEADER_1] = MI_LOAD_REGISTER_IMM(9);
1801 	reg_state[CTX_LRI_HEADER_1] |= MI_LRI_FORCE_POSTED;
1802 	reg_state[CTX_CTX_TIMESTAMP] = ring->mmio_base + 0x3a8;
1803 	reg_state[CTX_CTX_TIMESTAMP+1] = 0;
1804 	reg_state[CTX_PDP3_UDW] = GEN8_RING_PDP_UDW(ring, 3);
1805 	reg_state[CTX_PDP3_LDW] = GEN8_RING_PDP_LDW(ring, 3);
1806 	reg_state[CTX_PDP2_UDW] = GEN8_RING_PDP_UDW(ring, 2);
1807 	reg_state[CTX_PDP2_LDW] = GEN8_RING_PDP_LDW(ring, 2);
1808 	reg_state[CTX_PDP1_UDW] = GEN8_RING_PDP_UDW(ring, 1);
1809 	reg_state[CTX_PDP1_LDW] = GEN8_RING_PDP_LDW(ring, 1);
1810 	reg_state[CTX_PDP0_UDW] = GEN8_RING_PDP_UDW(ring, 0);
1811 	reg_state[CTX_PDP0_LDW] = GEN8_RING_PDP_LDW(ring, 0);
1812 	reg_state[CTX_PDP3_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[3]->daddr);
1813 	reg_state[CTX_PDP3_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[3]->daddr);
1814 	reg_state[CTX_PDP2_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[2]->daddr);
1815 	reg_state[CTX_PDP2_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[2]->daddr);
1816 	reg_state[CTX_PDP1_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[1]->daddr);
1817 	reg_state[CTX_PDP1_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[1]->daddr);
1818 	reg_state[CTX_PDP0_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[0]->daddr);
1819 	reg_state[CTX_PDP0_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[0]->daddr);
1820 	if (ring->id == RCS) {
1821 		reg_state[CTX_LRI_HEADER_2] = MI_LOAD_REGISTER_IMM(1);
1822 		reg_state[CTX_R_PWR_CLK_STATE] = GEN8_R_PWR_CLK_STATE;
1823 		reg_state[CTX_R_PWR_CLK_STATE+1] = make_rpcs(dev);
1824 	}
1825 
1826 	kunmap_atomic(reg_state);
1827 
1828 	ctx_obj->dirty = 1;
1829 	set_page_dirty(page);
1830 	i915_gem_object_unpin_pages(ctx_obj);
1831 
1832 	return 0;
1833 }
1834 
1835 /**
1836  * intel_lr_context_free() - free the LRC specific bits of a context
1837  * @ctx: the LR context to free.
1838  *
1839  * The real context freeing is done in i915_gem_context_free: this only
1840  * takes care of the bits that are LRC related: the per-engine backing
1841  * objects and the logical ringbuffer.
1842  */
1843 void intel_lr_context_free(struct intel_context *ctx)
1844 {
1845 	int i;
1846 
1847 	for (i = 0; i < I915_NUM_RINGS; i++) {
1848 		struct drm_i915_gem_object *ctx_obj = ctx->engine[i].state;
1849 
1850 		if (ctx_obj) {
1851 			struct intel_ringbuffer *ringbuf =
1852 					ctx->engine[i].ringbuf;
1853 			struct intel_engine_cs *ring = ringbuf->ring;
1854 
1855 			if (ctx == ring->default_context) {
1856 				intel_unpin_ringbuffer_obj(ringbuf);
1857 				i915_gem_object_ggtt_unpin(ctx_obj);
1858 			}
1859 			WARN_ON(ctx->engine[ring->id].pin_count);
1860 			intel_destroy_ringbuffer_obj(ringbuf);
1861 			kfree(ringbuf);
1862 			drm_gem_object_unreference(&ctx_obj->base);
1863 		}
1864 	}
1865 }
1866 
1867 static uint32_t get_lr_context_size(struct intel_engine_cs *ring)
1868 {
1869 	int ret = 0;
1870 
1871 	WARN_ON(INTEL_INFO(ring->dev)->gen < 8);
1872 
1873 	switch (ring->id) {
1874 	case RCS:
1875 		if (INTEL_INFO(ring->dev)->gen >= 9)
1876 			ret = GEN9_LR_CONTEXT_RENDER_SIZE;
1877 		else
1878 			ret = GEN8_LR_CONTEXT_RENDER_SIZE;
1879 		break;
1880 	case VCS:
1881 	case BCS:
1882 	case VECS:
1883 	case VCS2:
1884 		ret = GEN8_LR_CONTEXT_OTHER_SIZE;
1885 		break;
1886 	}
1887 
1888 	return ret;
1889 }
1890 
1891 static void lrc_setup_hardware_status_page(struct intel_engine_cs *ring,
1892 		struct drm_i915_gem_object *default_ctx_obj)
1893 {
1894 	struct drm_i915_private *dev_priv = ring->dev->dev_private;
1895 
1896 	/* The status page is offset 0 from the default context object
1897 	 * in LRC mode. */
1898 	ring->status_page.gfx_addr = i915_gem_obj_ggtt_offset(default_ctx_obj);
1899 	ring->status_page.page_addr =
1900 			kmap(default_ctx_obj->pages[0]);
1901 	ring->status_page.obj = default_ctx_obj;
1902 
1903 	I915_WRITE(RING_HWS_PGA(ring->mmio_base),
1904 			(u32)ring->status_page.gfx_addr);
1905 	POSTING_READ(RING_HWS_PGA(ring->mmio_base));
1906 }
1907 
1908 /**
1909  * intel_lr_context_deferred_create() - create the LRC specific bits of a context
1910  * @ctx: LR context to create.
1911  * @ring: engine to be used with the context.
1912  *
1913  * This function can be called more than once, with different engines, if we plan
1914  * to use the context with them. The context backing objects and the ringbuffers
1915  * (specially the ringbuffer backing objects) suck a lot of memory up, and that's why
1916  * the creation is a deferred call: it's better to make sure first that we need to use
1917  * a given ring with the context.
1918  *
1919  * Return: non-zero on error.
1920  */
1921 int intel_lr_context_deferred_create(struct intel_context *ctx,
1922 				     struct intel_engine_cs *ring)
1923 {
1924 	const bool is_global_default_ctx = (ctx == ring->default_context);
1925 	struct drm_device *dev = ring->dev;
1926 	struct drm_i915_gem_object *ctx_obj;
1927 	uint32_t context_size;
1928 	struct intel_ringbuffer *ringbuf;
1929 	int ret;
1930 
1931 	WARN_ON(ctx->legacy_hw_ctx.rcs_state != NULL);
1932 	WARN_ON(ctx->engine[ring->id].state);
1933 
1934 	context_size = round_up(get_lr_context_size(ring), 4096);
1935 
1936 	ctx_obj = i915_gem_alloc_context_obj(dev, context_size);
1937 	if (IS_ERR(ctx_obj)) {
1938 		ret = PTR_ERR(ctx_obj);
1939 		DRM_DEBUG_DRIVER("Alloc LRC backing obj failed: %d\n", ret);
1940 		return ret;
1941 	}
1942 
1943 	if (is_global_default_ctx) {
1944 		ret = i915_gem_obj_ggtt_pin(ctx_obj, GEN8_LR_CONTEXT_ALIGN, 0);
1945 		if (ret) {
1946 			DRM_DEBUG_DRIVER("Pin LRC backing obj failed: %d\n",
1947 					ret);
1948 			drm_gem_object_unreference(&ctx_obj->base);
1949 			return ret;
1950 		}
1951 	}
1952 
1953 	ringbuf = kzalloc(sizeof(*ringbuf), GFP_KERNEL);
1954 	if (!ringbuf) {
1955 		DRM_DEBUG_DRIVER("Failed to allocate ringbuffer %s\n",
1956 				ring->name);
1957 		ret = -ENOMEM;
1958 		goto error_unpin_ctx;
1959 	}
1960 
1961 	ringbuf->ring = ring;
1962 
1963 	ringbuf->size = 32 * PAGE_SIZE;
1964 	ringbuf->effective_size = ringbuf->size;
1965 	ringbuf->head = 0;
1966 	ringbuf->tail = 0;
1967 	ringbuf->last_retired_head = -1;
1968 	intel_ring_update_space(ringbuf);
1969 
1970 	if (ringbuf->obj == NULL) {
1971 		ret = intel_alloc_ringbuffer_obj(dev, ringbuf);
1972 		if (ret) {
1973 			DRM_DEBUG_DRIVER(
1974 				"Failed to allocate ringbuffer obj %s: %d\n",
1975 				ring->name, ret);
1976 			goto error_free_rbuf;
1977 		}
1978 
1979 		if (is_global_default_ctx) {
1980 			ret = intel_pin_and_map_ringbuffer_obj(dev, ringbuf);
1981 			if (ret) {
1982 				DRM_ERROR(
1983 					"Failed to pin and map ringbuffer %s: %d\n",
1984 					ring->name, ret);
1985 				goto error_destroy_rbuf;
1986 			}
1987 		}
1988 
1989 	}
1990 
1991 	ret = populate_lr_context(ctx, ctx_obj, ring, ringbuf);
1992 	if (ret) {
1993 		DRM_DEBUG_DRIVER("Failed to populate LRC: %d\n", ret);
1994 		goto error;
1995 	}
1996 
1997 	ctx->engine[ring->id].ringbuf = ringbuf;
1998 	ctx->engine[ring->id].state = ctx_obj;
1999 
2000 	if (ctx == ring->default_context)
2001 		lrc_setup_hardware_status_page(ring, ctx_obj);
2002 	else if (ring->id == RCS && !ctx->rcs_initialized) {
2003 		if (ring->init_context) {
2004 			ret = ring->init_context(ring, ctx);
2005 			if (ret) {
2006 				DRM_ERROR("ring init context: %d\n", ret);
2007 				ctx->engine[ring->id].ringbuf = NULL;
2008 				ctx->engine[ring->id].state = NULL;
2009 				goto error;
2010 			}
2011 		}
2012 
2013 		ctx->rcs_initialized = true;
2014 	}
2015 
2016 	return 0;
2017 
2018 error:
2019 	if (is_global_default_ctx)
2020 		intel_unpin_ringbuffer_obj(ringbuf);
2021 error_destroy_rbuf:
2022 	intel_destroy_ringbuffer_obj(ringbuf);
2023 error_free_rbuf:
2024 	kfree(ringbuf);
2025 error_unpin_ctx:
2026 	if (is_global_default_ctx)
2027 		i915_gem_object_ggtt_unpin(ctx_obj);
2028 	drm_gem_object_unreference(&ctx_obj->base);
2029 	return ret;
2030 }
2031 
2032 void intel_lr_context_reset(struct drm_device *dev,
2033 			struct intel_context *ctx)
2034 {
2035 	struct drm_i915_private *dev_priv = dev->dev_private;
2036 	struct intel_engine_cs *ring;
2037 	int i;
2038 
2039 	for_each_ring(ring, dev_priv, i) {
2040 		struct drm_i915_gem_object *ctx_obj =
2041 				ctx->engine[ring->id].state;
2042 		struct intel_ringbuffer *ringbuf =
2043 				ctx->engine[ring->id].ringbuf;
2044 		uint32_t *reg_state;
2045 		struct vm_page *page;
2046 
2047 		if (!ctx_obj)
2048 			continue;
2049 
2050 		if (i915_gem_object_get_pages(ctx_obj)) {
2051 			WARN(1, "Failed get_pages for context obj\n");
2052 			continue;
2053 		}
2054 		page = i915_gem_object_get_page(ctx_obj, 1);
2055 		reg_state = kmap_atomic(page);
2056 
2057 		reg_state[CTX_RING_HEAD+1] = 0;
2058 		reg_state[CTX_RING_TAIL+1] = 0;
2059 
2060 		kunmap_atomic(reg_state);
2061 
2062 		ringbuf->head = 0;
2063 		ringbuf->tail = 0;
2064 	}
2065 }
2066