drm/msm/dpu: avoid tracking reservations in RM

RM was equipped with reservation tracking structure RSVP
to cache HW reservation of displays for certain clients
where atomic_checks (atomic commit with TEST_ONLY) for all
the displays are called before their respective atomic_commits.
Since DPU doesn't support the sequence anymore, clean up
the support from RM. Replace rsvp with the corresponding
encoder id to tag the HW blocks reserved. It prepares DPU
to get rid of RM altogether and track reservations using
private states.

changes in v2:
	- none

Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>

2 files changed, 43 insertions, 245 deletions

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
index bdb117709674..36a929bc1d18 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
@@ -21,8 +21,8 @@
 #include "dpu_encoder.h"
 #include "dpu_trace.h"
 
-#define RESERVED_BY_OTHER(h, r) \
-	((h)->rsvp && ((h)->rsvp->enc_id != (r)->enc_id))
+#define RESERVED_BY_OTHER(h, r)  \
+		((h)->enc_id && (h)->enc_id != r)
 
 /**
  * struct dpu_rm_requirements - Reservation requirements parameter bundle
@@ -34,85 +34,23 @@ struct dpu_rm_requirements {
 	struct dpu_encoder_hw_resources hw_res;
 };
 
-/**
- * struct dpu_rm_rsvp - Use Case Reservation tagging structure
- *	Used to tag HW blocks as reserved by a CRTC->Encoder->Connector chain
- *	By using as a tag, rather than lists of pointers to HW blocks used
- *	we can avoid some list management since we don't know how many blocks
- *	of each type a given use case may require.
- * @list:	List head for list of all reservations
- * @seq:	Global RSVP sequence number for debugging, especially for
- *		differentiating differenct allocations for same encoder.
- * @enc_id:	Reservations are tracked by Encoder DRM object ID.
- *		CRTCs may be connected to multiple Encoders.
- *		An encoder or connector id identifies the display path.
- */
-struct dpu_rm_rsvp {
-	struct list_head list;
-	uint32_t seq;
-	uint32_t enc_id;
-};
 
 /**
  * struct dpu_rm_hw_blk - hardware block tracking list member
  * @list:	List head for list of all hardware blocks tracking items
- * @rsvp:	Pointer to use case reservation if reserved by a client
- * @rsvp_nxt:	Temporary pointer used during reservation to the incoming
- *		request. Will be swapped into rsvp if proposal is accepted
  * @type:	Type of hardware block this structure tracks
  * @id:		Hardware ID number, within it's own space, ie. LM_X
- * @catalog:	Pointer to the hardware catalog entry for this block
+ * @enc_id:	Encoder id to which this blk is binded
  * @hw:		Pointer to the hardware register access object for this block
  */
 struct dpu_rm_hw_blk {
 	struct list_head list;
-	struct dpu_rm_rsvp *rsvp;
-	struct dpu_rm_rsvp *rsvp_nxt;
 	enum dpu_hw_blk_type type;
 	uint32_t id;
+	uint32_t enc_id;
 	struct dpu_hw_blk *hw;
 };
 
-/**
- * dpu_rm_dbg_rsvp_stage - enum of steps in making reservation for event logging
- */
-enum dpu_rm_dbg_rsvp_stage {
-	DPU_RM_STAGE_BEGIN,
-	DPU_RM_STAGE_AFTER_CLEAR,
-	DPU_RM_STAGE_AFTER_RSVPNEXT,
-	DPU_RM_STAGE_FINAL
-};
-
-static void _dpu_rm_print_rsvps(
-		struct dpu_rm *rm,
-		enum dpu_rm_dbg_rsvp_stage stage)
-{
-	struct dpu_rm_rsvp *rsvp;
-	struct dpu_rm_hw_blk *blk;
-	enum dpu_hw_blk_type type;
-
-	DPU_DEBUG("%d\n", stage);
-
-	list_for_each_entry(rsvp, &rm->rsvps, list) {
-		DRM_DEBUG_KMS("%d rsvp[s%ue%u]\n", stage, rsvp->seq,
-			      rsvp->enc_id);
-	}
-
-	for (type = 0; type < DPU_HW_BLK_MAX; type++) {
-		list_for_each_entry(blk, &rm->hw_blks[type], list) {
-			if (!blk->rsvp && !blk->rsvp_nxt)
-				continue;
-
-			DRM_DEBUG_KMS("%d rsvp[s%ue%u->s%ue%u] %d %d\n", stage,
-				(blk->rsvp) ? blk->rsvp->seq : 0,
-				(blk->rsvp) ? blk->rsvp->enc_id : 0,
-				(blk->rsvp_nxt) ? blk->rsvp_nxt->seq : 0,
-				(blk->rsvp_nxt) ? blk->rsvp_nxt->enc_id : 0,
-				blk->type, blk->id);
-		}
-	}
-}
-
 struct dpu_hw_mdp *dpu_rm_get_mdp(struct dpu_rm *rm)
 {
 	return rm->hw_mdp;
@@ -148,15 +86,13 @@ static bool _dpu_rm_get_hw_locked(struct dpu_rm *rm, struct dpu_rm_hw_iter *i)
 	i->blk = list_prepare_entry(i->blk, blk_list, list);
 
 	list_for_each_entry_continue(i->blk, blk_list, list) {
-		struct dpu_rm_rsvp *rsvp = i->blk->rsvp;
-
 		if (i->blk->type != i->type) {
 			DPU_ERROR("found incorrect block type %d on %d list\n",
 					i->blk->type, i->type);
 			return false;
 		}
 
-		if ((i->enc_id == 0) || (rsvp && rsvp->enc_id == i->enc_id)) {
+		if (i->enc_id == i->blk->enc_id) {
 			i->hw = i->blk->hw;
 			DPU_DEBUG("found type %d id %d for enc %d\n",
 					i->type, i->blk->id, i->enc_id);
@@ -208,22 +144,9 @@ static void _dpu_rm_hw_destroy(enum dpu_hw_blk_type type, void *hw)
 
 int dpu_rm_destroy(struct dpu_rm *rm)
 {
-
-	struct dpu_rm_rsvp *rsvp_cur, *rsvp_nxt;
 	struct dpu_rm_hw_blk *hw_cur, *hw_nxt;
 	enum dpu_hw_blk_type type;
 
-	if (!rm) {
-		DPU_ERROR("invalid rm\n");
-		return -EINVAL;
-	}
-
-	list_for_each_entry_safe(rsvp_cur, rsvp_nxt, &rm->rsvps, list) {
-		list_del(&rsvp_cur->list);
-		kfree(rsvp_cur);
-	}
-
-
 	for (type = 0; type < DPU_HW_BLK_MAX; type++) {
 		list_for_each_entry_safe(hw_cur, hw_nxt, &rm->hw_blks[type],
 				list) {
@@ -293,6 +216,7 @@ static int _dpu_rm_hw_blk_create(
 	blk->type = type;
 	blk->id = id;
 	blk->hw = hw;
+	blk->enc_id = 0;
 	list_add_tail(&blk->list, &rm->hw_blks[type]);
 
 	return 0;
@@ -316,7 +240,6 @@ int dpu_rm_init(struct dpu_rm *rm,
 
 	mutex_init(&rm->rm_lock);
 
-	INIT_LIST_HEAD(&rm->rsvps);
 	for (type = 0; type < DPU_HW_BLK_MAX; type++)
 		INIT_LIST_HEAD(&rm->hw_blks[type]);
 
@@ -410,7 +333,7 @@ static bool _dpu_rm_needs_split_display(const struct msm_display_topology *top)
  *	proposed use case requirements, incl. hardwired dependent blocks like
  *	pingpong
  * @rm: dpu resource manager handle
- * @rsvp: reservation currently being created
+ * @enc_id: encoder id requesting for allocation
  * @reqs: proposed use case requirements
  * @lm: proposed layer mixer, function checks if lm, and all other hardwired
  *      blocks connected to the lm (pp) is available and appropriate
@@ -422,7 +345,7 @@ static bool _dpu_rm_needs_split_display(const struct msm_display_topology *top)
  */
 static bool _dpu_rm_check_lm_and_get_connected_blks(
 		struct dpu_rm *rm,
-		struct dpu_rm_rsvp *rsvp,
+		uint32_t enc_id,
 		struct dpu_rm_requirements *reqs,
 		struct dpu_rm_hw_blk *lm,
 		struct dpu_rm_hw_blk **pp,
@@ -449,7 +372,7 @@ static bool _dpu_rm_check_lm_and_get_connected_blks(
 	}
 
 	/* Already reserved? */
-	if (RESERVED_BY_OTHER(lm, rsvp)) {
+	if (RESERVED_BY_OTHER(lm, enc_id)) {
 		DPU_DEBUG("lm %d already reserved\n", lm_cfg->id);
 		return false;
 	}
@@ -467,7 +390,7 @@ static bool _dpu_rm_check_lm_and_get_connected_blks(
 		return false;
 	}
 
-	if (RESERVED_BY_OTHER(*pp, rsvp)) {
+	if (RESERVED_BY_OTHER(*pp, enc_id)) {
 		DPU_DEBUG("lm %d pp %d already reserved\n", lm->id,
 				(*pp)->id);
 		return false;
@@ -476,10 +399,8 @@ static bool _dpu_rm_check_lm_and_get_connected_blks(
 	return true;
 }
 
-static int _dpu_rm_reserve_lms(
-		struct dpu_rm *rm,
-		struct dpu_rm_rsvp *rsvp,
-		struct dpu_rm_requirements *reqs)
+static int _dpu_rm_reserve_lms(struct dpu_rm *rm, uint32_t enc_id,
+			       struct dpu_rm_requirements *reqs)
 
 {
 	struct dpu_rm_hw_blk *lm[MAX_BLOCKS];
@@ -504,7 +425,7 @@ static int _dpu_rm_reserve_lms(
 		lm[lm_count] = iter_i.blk;
 
 		if (!_dpu_rm_check_lm_and_get_connected_blks(
-				rm, rsvp, reqs, lm[lm_count],
+				rm, enc_id, reqs, lm[lm_count],
 				&pp[lm_count], NULL))
 			continue;
 
@@ -519,7 +440,7 @@ static int _dpu_rm_reserve_lms(
 				continue;
 
 			if (!_dpu_rm_check_lm_and_get_connected_blks(
-					rm, rsvp, reqs, iter_j.blk,
+					rm, enc_id, reqs, iter_j.blk,
 					&pp[lm_count], iter_i.blk))
 				continue;
 
@@ -537,10 +458,10 @@ static int _dpu_rm_reserve_lms(
 		if (!lm[i])
 			break;
 
-		lm[i]->rsvp_nxt = rsvp;
-		pp[i]->rsvp_nxt = rsvp;
+		lm[i]->enc_id = enc_id;
+		pp[i]->enc_id = enc_id;
 
-		trace_dpu_rm_reserve_lms(lm[i]->id, lm[i]->type, rsvp->enc_id,
+		trace_dpu_rm_reserve_lms(lm[i]->id, lm[i]->type, enc_id,
 					 pp[i]->id);
 	}
 
@@ -549,7 +470,7 @@ static int _dpu_rm_reserve_lms(
 
 static int _dpu_rm_reserve_ctls(
 		struct dpu_rm *rm,
-		struct dpu_rm_rsvp *rsvp,
+		uint32_t enc_id,
 		const struct msm_display_topology *top)
 {
 	struct dpu_rm_hw_blk *ctls[MAX_BLOCKS];
@@ -570,7 +491,7 @@ static int _dpu_rm_reserve_ctls(
 		unsigned long features = ctl->caps->features;
 		bool has_split_display;
 
-		if (RESERVED_BY_OTHER(iter.blk, rsvp))
+		if (RESERVED_BY_OTHER(iter.blk, enc_id))
 			continue;
 
 		has_split_display = BIT(DPU_CTL_SPLIT_DISPLAY) & features;
@@ -591,9 +512,9 @@ static int _dpu_rm_reserve_ctls(
 		return -ENAVAIL;
 
 	for (i = 0; i < ARRAY_SIZE(ctls) && i < num_ctls; i++) {
-		ctls[i]->rsvp_nxt = rsvp;
+		ctls[i]->enc_id = enc_id;
 		trace_dpu_rm_reserve_ctls(ctls[i]->id, ctls[i]->type,
-					  rsvp->enc_id);
+					  enc_id);
 	}
 
 	return 0;
@@ -601,7 +522,7 @@ static int _dpu_rm_reserve_ctls(
 
 static int _dpu_rm_reserve_intf(
 		struct dpu_rm *rm,
-		struct dpu_rm_rsvp *rsvp,
+		uint32_t enc_id,
 		uint32_t id,
 		enum dpu_hw_blk_type type)
 {
@@ -614,14 +535,14 @@ static int _dpu_rm_reserve_intf(
 		if (iter.blk->id != id)
 			continue;
 
-		if (RESERVED_BY_OTHER(iter.blk, rsvp)) {
+		if (RESERVED_BY_OTHER(iter.blk, enc_id)) {
 			DPU_ERROR("type %d id %d already reserved\n", type, id);
 			return -ENAVAIL;
 		}
 
-		iter.blk->rsvp_nxt = rsvp;
+		iter.blk->enc_id = enc_id;
 		trace_dpu_rm_reserve_intf(iter.blk->id, iter.blk->type,
-					  rsvp->enc_id);
+					  enc_id);
 		break;
 	}
 
@@ -636,7 +557,7 @@ static int _dpu_rm_reserve_intf(
 
 static int _dpu_rm_reserve_intf_related_hw(
 		struct dpu_rm *rm,
-		struct dpu_rm_rsvp *rsvp,
+		uint32_t enc_id,
 		struct dpu_encoder_hw_resources *hw_res)
 {
 	int i, ret = 0;
@@ -646,7 +567,7 @@ static int _dpu_rm_reserve_intf_related_hw(
 		if (hw_res->intfs[i] == INTF_MODE_NONE)
 			continue;
 		id = i + INTF_0;
-		ret = _dpu_rm_reserve_intf(rm, rsvp, id,
+		ret = _dpu_rm_reserve_intf(rm, enc_id, id,
 				DPU_HW_BLK_INTF);
 		if (ret)
 			return ret;
@@ -655,33 +576,27 @@ static int _dpu_rm_reserve_intf_related_hw(
 	return ret;
 }
 
-static int _dpu_rm_make_next_rsvp(
+static int _dpu_rm_make_reservation(
 		struct dpu_rm *rm,
 		struct drm_encoder *enc,
 		struct drm_crtc_state *crtc_state,
-		struct dpu_rm_rsvp *rsvp,
 		struct dpu_rm_requirements *reqs)
 {
 	int ret;
 
-	/* Create reservation info, tag reserved blocks with it as we go */
-	rsvp->seq = ++rm->rsvp_next_seq;
-	rsvp->enc_id = enc->base.id;
-	list_add_tail(&rsvp->list, &rm->rsvps);
-
-	ret = _dpu_rm_reserve_lms(rm, rsvp, reqs);
+	ret = _dpu_rm_reserve_lms(rm, enc->base.id, reqs);
 	if (ret) {
 		DPU_ERROR("unable to find appropriate mixers\n");
 		return ret;
 	}
 
-	ret = _dpu_rm_reserve_ctls(rm, rsvp, &reqs->topology);
+	ret = _dpu_rm_reserve_ctls(rm, enc->base.id, &reqs->topology);
 	if (ret) {
 		DPU_ERROR("unable to find appropriate CTL\n");
 		return ret;
 	}
 
-	ret = _dpu_rm_reserve_intf_related_hw(rm, rsvp, &reqs->hw_res);
+	ret = _dpu_rm_reserve_intf_related_hw(rm, enc->base.id, &reqs->hw_res);
 	if (ret)
 		return ret;
 
@@ -706,108 +621,31 @@ static int _dpu_rm_populate_requirements(
 	return 0;
 }
 
-static struct dpu_rm_rsvp *_dpu_rm_get_rsvp(
-		struct dpu_rm *rm,
-		struct drm_encoder *enc)
+static void _dpu_rm_release_reservation(struct dpu_rm *rm, uint32_t enc_id)
 {
-	struct dpu_rm_rsvp *i;
-
-	if (!rm || !enc) {
-		DPU_ERROR("invalid params\n");
-		return NULL;
-	}
-
-	if (list_empty(&rm->rsvps))
-		return NULL;
-
-	list_for_each_entry(i, &rm->rsvps, list)
-		if (i->enc_id == enc->base.id)
-			return i;
-
-	return NULL;
-}
-
-/**
- * _dpu_rm_release_rsvp - release resources and release a reservation
- * @rm:	KMS handle
- * @rsvp:	RSVP pointer to release and release resources for
- */
-static void _dpu_rm_release_rsvp(struct dpu_rm *rm, struct dpu_rm_rsvp *rsvp)
-{
-	struct dpu_rm_rsvp *rsvp_c, *rsvp_n;
 	struct dpu_rm_hw_blk *blk;
 	enum dpu_hw_blk_type type;
 
-	if (!rsvp)
-		return;
-
-	DPU_DEBUG("rel rsvp %d enc %d\n", rsvp->seq, rsvp->enc_id);
-
-	list_for_each_entry_safe(rsvp_c, rsvp_n, &rm->rsvps, list) {
-		if (rsvp == rsvp_c) {
-			list_del(&rsvp_c->list);
-			break;
-		}
-	}
-
 	for (type = 0; type < DPU_HW_BLK_MAX; type++) {
 		list_for_each_entry(blk, &rm->hw_blks[type], list) {
-			if (blk->rsvp == rsvp) {
-				blk->rsvp = NULL;
-				DPU_DEBUG("rel rsvp %d enc %d %d %d\n",
-						rsvp->seq, rsvp->enc_id,
-						blk->type, blk->id);
-			}
-			if (blk->rsvp_nxt == rsvp) {
-				blk->rsvp_nxt = NULL;
-				DPU_DEBUG("rel rsvp_nxt %d enc %d %d %d\n",
-						rsvp->seq, rsvp->enc_id,
-						blk->type, blk->id);
+			if (blk->enc_id == enc_id) {
+				blk->enc_id = 0;
+				DPU_DEBUG("rel enc %d %d %d\n", enc_id,
+					  blk->type, blk->id);
 			}
 		}
 	}
-
-	kfree(rsvp);
 }
 
 void dpu_rm_release(struct dpu_rm *rm, struct drm_encoder *enc)
 {
-	struct dpu_rm_rsvp *rsvp;
-
-	if (!rm || !enc) {
-		DPU_ERROR("invalid params\n");
-		return;
-	}
-
 	mutex_lock(&rm->rm_lock);
 
-	rsvp = _dpu_rm_get_rsvp(rm, enc);
-	if (!rsvp) {
-		DPU_ERROR("failed to find rsvp for enc %d\n", enc->base.id);
-		goto end;
-	}
+	_dpu_rm_release_reservation(rm, enc->base.id);
 
-	_dpu_rm_release_rsvp(rm, rsvp);
-end:
 	mutex_unlock(&rm->rm_lock);
 }
 
-static void _dpu_rm_commit_rsvp(struct dpu_rm *rm, struct dpu_rm_rsvp *rsvp)
-{
-	struct dpu_rm_hw_blk *blk;
-	enum dpu_hw_blk_type type;
-
-	/* Swap next rsvp to be the active */
-	for (type = 0; type < DPU_HW_BLK_MAX; type++) {
-		list_for_each_entry(blk, &rm->hw_blks[type], list) {
-			if (blk->rsvp_nxt) {
-				blk->rsvp = blk->rsvp_nxt;
-				blk->rsvp_nxt = NULL;
-			}
-		}
-	}
-}
-
 int dpu_rm_reserve(
 		struct dpu_rm *rm,
 		struct drm_encoder *enc,
@@ -815,7 +653,6 @@ int dpu_rm_reserve(
 		struct msm_display_topology topology,
 		bool test_only)
 {
-	struct dpu_rm_rsvp *rsvp_cur, *rsvp_nxt;
 	struct dpu_rm_requirements reqs;
 	int ret;
 
@@ -828,8 +665,6 @@ int dpu_rm_reserve(
 
 	mutex_lock(&rm->rm_lock);
 
-	_dpu_rm_print_rsvps(rm, DPU_RM_STAGE_BEGIN);
-
 	ret = _dpu_rm_populate_requirements(rm, enc, crtc_state, &reqs,
 					    topology);
 	if (ret) {
@@ -837,50 +672,17 @@ int dpu_rm_reserve(
 		goto end;
 	}
 
-	/*
-	 * We only support one active reservation per-hw-block. But to implement
-	 * transactional semantics for test-only, and for allowing failure while
-	 * modifying your existing reservation, over the course of this
-	 * function we can have two reservations:
-	 * Current: Existing reservation
-	 * Next: Proposed reservation. The proposed reservation may fail, or may
-	 *       be discarded if in test-only mode.
-	 * If reservation is successful, and we're not in test-only, then we
-	 * replace the current with the next.
-	 */
-	rsvp_nxt = kzalloc(sizeof(*rsvp_nxt), GFP_KERNEL);
-	if (!rsvp_nxt) {
-		ret = -ENOMEM;
-		goto end;
-	}
-
-	rsvp_cur = _dpu_rm_get_rsvp(rm, enc);
-
-	/* Check the proposed reservation, store it in hw's "next" field */
-	ret = _dpu_rm_make_next_rsvp(rm, enc, crtc_state, rsvp_nxt, &reqs);
-
-	_dpu_rm_print_rsvps(rm, DPU_RM_STAGE_AFTER_RSVPNEXT);
-
+	ret = _dpu_rm_make_reservation(rm, enc, crtc_state, &reqs);
 	if (ret) {
 		DPU_ERROR("failed to reserve hw resources: %d\n", ret);
-		_dpu_rm_release_rsvp(rm, rsvp_nxt);
+		_dpu_rm_release_reservation(rm, enc->base.id);
 	} else if (test_only) {
-		/*
-		 * Normally, if test_only, test the reservation and then undo
-		 * However, if the user requests LOCK, then keep the reservation
-		 * made during the atomic_check phase.
-		 */
-		DPU_DEBUG("test_only: discard test rsvp[s%de%d]\n",
-				rsvp_nxt->seq, rsvp_nxt->enc_id);
-		_dpu_rm_release_rsvp(rm, rsvp_nxt);
-	} else {
-		_dpu_rm_release_rsvp(rm, rsvp_cur);
-
-		_dpu_rm_commit_rsvp(rm, rsvp_nxt);
+		 /* test_only: test the reservation and then undo */
+		DPU_DEBUG("test_only: discard test [enc: %d]\n",
+				enc->base.id);
+		_dpu_rm_release_reservation(rm, enc->base.id);
 	}
 
-	_dpu_rm_print_rsvps(rm, DPU_RM_STAGE_FINAL);
-
 end:
 	mutex_unlock(&rm->rm_lock);
 
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h
index b8273bd23801..0dd3c2131ca1 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h
@@ -23,21 +23,17 @@
 /**
  * struct dpu_rm - DPU dynamic hardware resource manager
  * @dev: device handle for event logging purposes
- * @rsvps: list of hardware reservations by each crtc->encoder->connector
  * @hw_blks: array of lists of hardware resources present in the system, one
  *	list per type of hardware block
  * @hw_mdp: hardware object for mdp_top
  * @lm_max_width: cached layer mixer maximum width
- * @rsvp_next_seq: sequence number for next reservation for debugging purposes
  * @rm_lock: resource manager mutex
  */
 struct dpu_rm {
 	struct drm_device *dev;
-	struct list_head rsvps;
 	struct list_head hw_blks[DPU_HW_BLK_MAX];
 	struct dpu_hw_mdp *hw_mdp;
 	uint32_t lm_max_width;
-	uint32_t rsvp_next_seq;
 	struct mutex rm_lock;
 };