drm/nouveau/disp/dp: no need for lt_state except during manual link training

This struct doesn't hold link configuration data anymore, so we can
limit its use to internal DP training (anx9805 handles training for
external DP).
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c

@@ -196,9 +196,8 @@ nvkm_dp_train_cr(struct lt_state *lt)
 }
 
 static int
-nvkm_dp_train_links(struct lt_state *lt)
+nvkm_dp_train_links(struct nvkm_dp *dp)
 {
-	struct nvkm_dp *dp = lt->dp;
 	struct nvkm_ior *ior = dp->outp.ior;
 	struct nvkm_disp *disp = dp->outp.disp;
 	struct nvkm_subdev *subdev = &disp->engine.subdev;
@@ -211,6 +210,9 @@ nvkm_dp_train_links(struct lt_state *lt)
 		.crtc = -1,
 		.execute = 1,
 	};
+	struct lt_state lt = {
+		.dp = dp,
+	};
 	u32 lnkcmp;
 	u8 sink[2];
 	int ret;
@@ -220,11 +222,11 @@ nvkm_dp_train_links(struct lt_state *lt)
 
 	/* Intersect misc. capabilities of the OR and sink. */
 	if (disp->engine.subdev.device->chipset < 0xd0)
-		dp->dpcd[2] &= ~DPCD_RC02_TPS3_SUPPORTED;
-	lt->pc2 = dp->dpcd[2] & DPCD_RC02_TPS3_SUPPORTED;
+		dp->dpcd[DPCD_RC02] &= ~DPCD_RC02_TPS3_SUPPORTED;
+	lt.pc2 = dp->dpcd[DPCD_RC02] & DPCD_RC02_TPS3_SUPPORTED;
 
 	/* Set desired link configuration on the source. */
-	if ((lnkcmp = lt->dp->info.lnkcmp)) {
+	if ((lnkcmp = lt.dp->info.lnkcmp)) {
 		if (dp->version < 0x30) {
 			while ((ior->dp.bw * 2700) < nvbios_rd16(bios, lnkcmp))
 				lnkcmp += 4;
@@ -253,13 +255,22 @@ nvkm_dp_train_links(struct lt_state *lt)
 	if (ior->dp.ef)
 		sink[1] |= DPCD_LC01_ENHANCED_FRAME_EN;
 
-	return nvkm_wraux(dp->aux, DPCD_LC00_LINK_BW_SET, sink, 2);
+	ret = nvkm_wraux(dp->aux, DPCD_LC00_LINK_BW_SET, sink, 2);
+	if (ret)
+		return ret;
+
+	/* Attempt to train the link in this configuration. */
+	memset(lt.stat, 0x00, sizeof(lt.stat));
+	ret = nvkm_dp_train_cr(&lt);
+	if (ret == 0)
+		ret = nvkm_dp_train_eq(&lt);
+	nvkm_dp_train_pattern(&lt, 0);
+	return ret;
 }
 
 static void
-nvkm_dp_train_fini(struct lt_state *lt)
+nvkm_dp_train_fini(struct nvkm_dp *dp)
 {
-	struct nvkm_dp *dp = lt->dp;
 	struct nvkm_subdev *subdev = &dp->outp.disp->engine.subdev;
 	struct nvbios_init init = {
 		.subdev = subdev,
@@ -275,9 +286,8 @@ nvkm_dp_train_fini(struct lt_state *lt)
 }
 
 static void
-nvkm_dp_train_init(struct lt_state *lt)
+nvkm_dp_train_init(struct nvkm_dp *dp)
 {
-	struct nvkm_dp *dp = lt->dp;
 	struct nvkm_subdev *subdev = &dp->outp.disp->engine.subdev;
 	struct nvbios_init init = {
 		.subdev = subdev,
@@ -326,9 +336,6 @@ nvkm_dp_train(struct nvkm_dp *dp)
 	const u8 outp_nr = dp->outp.info.dpconf.link_nr;
 	const u8 outp_bw = dp->outp.info.dpconf.link_bw;
 	const struct dp_rates *cfg;
-	struct lt_state lt = {
-		.dp = dp,
-	};
 	u8  pwr;
 	int ret;
 
@@ -345,8 +352,8 @@ nvkm_dp_train(struct nvkm_dp *dp)
 	}
 
 	/* Link training. */
-	nvkm_dp_train_init(&lt);
-	for (ret = -EINVAL, cfg = nvkm_dp_rates; cfg->rate; cfg++) {
+	nvkm_dp_train_init(dp);
+	for (ret = -EINVAL, cfg = nvkm_dp_rates; ret < 0 && cfg->rate; cfg++) {
 		/* Skip configurations not supported by both OR and sink. */
 		if (cfg[1].rate &&
 		    (cfg->nr > outp_nr || cfg->bw > outp_bw ||
@@ -358,23 +365,9 @@ nvkm_dp_train(struct nvkm_dp *dp)
 		ior->dp.nr = cfg->nr;
 
 		/* Program selected link configuration. */
-		ret = nvkm_dp_train_links(&lt);
-		if (ret == 0) {
-			/* Attempt to train the link in this configuration. */
-			memset(lt.stat, 0x00, sizeof(lt.stat));
-			if (!nvkm_dp_train_cr(&lt) &&
-			    !nvkm_dp_train_eq(&lt))
-				break;
-		} else
-		if (ret) {
-			/* nvkm_dp_train_links() handled training, or
-			 * we failed to communicate with the sink.
-			 */
-			break;
-		}
+		ret = nvkm_dp_train_links(dp);
 	}
-	nvkm_dp_train_pattern(&lt, 0);
-	nvkm_dp_train_fini(&lt);
+	nvkm_dp_train_fini(dp);
 	if (ret < 0)
 		OUTP_ERR(&dp->outp, "training failed");