interconnect: qcom: rpm: fix registration race

The current interconnect provider registration interface is inherently
racy as nodes are not added until the after adding the provider. This
can specifically cause racing DT lookups to fail.

Switch to using the new API where the provider is not registered until
after it has been fully initialised.

Fixes: 62feb14e ("interconnect: qcom: Consolidate interconnect RPM support")
Fixes: 30c8fa3e ("interconnect: qcom: Add MSM8916 interconnect provider driver")
Cc: stable@vger.kernel.org	# 5.7
Reviewed-by: NKonrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: NJun Nie <jun.nie@linaro.org>
Signed-off-by: NJohan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20230306075651.2449-9-johan+linaro@kernel.orgSigned-off-by: NGeorgi Djakov <djakov@kernel.org>

drivers/interconnect/qcom/icc-rpm.c

@@ -503,7 +503,6 @@ int qnoc_probe(struct platform_device *pdev)
 	}
 
 	provider = &qp->provider;
-	INIT_LIST_HEAD(&provider->nodes);
 	provider->dev = dev;
 	provider->set = qcom_icc_set;
 	provider->pre_aggregate = qcom_icc_pre_bw_aggregate;
@@ -511,12 +510,7 @@ int qnoc_probe(struct platform_device *pdev)
 	provider->xlate_extended = qcom_icc_xlate_extended;
 	provider->data = data;
 
-	ret = icc_provider_add(provider);
-	if (ret) {
-		dev_err(dev, "error adding interconnect provider: %d\n", ret);
-		clk_bulk_disable_unprepare(qp->num_clks, qp->bus_clks);
-		return ret;
-	}
+	icc_provider_init(provider);
 
 	for (i = 0; i < num_nodes; i++) {
 		size_t j;
@@ -524,7 +518,7 @@ int qnoc_probe(struct platform_device *pdev)
 		node = icc_node_create(qnodes[i]->id);
 		if (IS_ERR(node)) {
 			ret = PTR_ERR(node);
-			goto err;
+			goto err_remove_nodes;
 		}
 
 		node->name = qnodes[i]->name;
@@ -538,20 +532,26 @@ int qnoc_probe(struct platform_device *pdev)
 	}
 	data->num_nodes = num_nodes;
 
+	ret = icc_provider_register(provider);
+	if (ret)
+		goto err_remove_nodes;
+
 	platform_set_drvdata(pdev, qp);
 
 	/* Populate child NoC devices if any */
 	if (of_get_child_count(dev->of_node) > 0) {
 		ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
 		if (ret)
-			goto err;
+			goto err_deregister_provider;
 	}
 
 	return 0;
-err:
+
+err_deregister_provider:
+	icc_provider_deregister(provider);
+err_remove_nodes:
 	icc_nodes_remove(provider);
 	clk_bulk_disable_unprepare(qp->num_clks, qp->bus_clks);
-	icc_provider_del(provider);
 
 	return ret;
 }
@@ -561,9 +561,9 @@ int qnoc_remove(struct platform_device *pdev)
 {
 	struct qcom_icc_provider *qp = platform_get_drvdata(pdev);
 
+	icc_provider_deregister(&qp->provider);
 	icc_nodes_remove(&qp->provider);
 	clk_bulk_disable_unprepare(qp->num_clks, qp->bus_clks);
-	icc_provider_del(&qp->provider);
 
 	return 0;
 }