remoteproc: qcom: wcnss: Fix race with iris probe

The remoteproc driver is split between the responsibilities of getting
the SoC-internal ARM core up and running and the external RF (aka
"Iris") part configured.

In order to satisfy the regulator framework's need of a struct device *
to look up supplies this was implemented as two different drivers, using
of_platform_populate() in the remoteproc part to probe the iris part.

Unfortunately it's possible that the iris part probe defers on yet not
available regulators and an attempt to start the remoteproc will have to
be rejected, until this has been resolved. But there's no useful
mechanism of knowing when this would be.

Instead replace the of_platform_populate() and the iris probe with a
function that rolls its own struct device, with the relevant of_node
associated that is enough to acquire regulators and clocks specified in
the DT node and that may propagate the EPROBE_DEFER back to the wcnss
device's probe.

Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reported-by: Anibal Limon <anibal.limon@linaro.org>
Reported-by: Loic Poulain <loic.poulain@linaro.org>
Tested-by: Anibal Limon <anibal.limon@linaro.org>
Link: https://lore.kernel.org/r/20210312002251.3273013-1-bjorn.andersson@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

1 files changed, 75 insertions, 45 deletions

diff --git a/drivers/remoteproc/qcom_wcnss_iris.c b/drivers/remoteproc/qcom_wcnss_iris.c
index 169acd305ae3..09720ddddc85 100644
--- a/drivers/remoteproc/qcom_wcnss_iris.c
+++ b/drivers/remoteproc/qcom_wcnss_iris.c
@@ -17,7 +17,7 @@
 #include "qcom_wcnss.h"
 
 struct qcom_iris {
-	struct device *dev;
+	struct device dev;
 
 	struct clk *xo_clk;
 
@@ -75,7 +75,7 @@ int qcom_iris_enable(struct qcom_iris *iris)
 
 	ret = clk_prepare_enable(iris->xo_clk);
 	if (ret) {
-		dev_err(iris->dev, "failed to enable xo clk\n");
+		dev_err(&iris->dev, "failed to enable xo clk\n");
 		goto disable_regulators;
 	}
 
@@ -93,43 +93,90 @@ void qcom_iris_disable(struct qcom_iris *iris)
 	regulator_bulk_disable(iris->num_vregs, iris->vregs);
 }
 
-static int qcom_iris_probe(struct platform_device *pdev)
+static const struct of_device_id iris_of_match[] = {
+	{ .compatible = "qcom,wcn3620", .data = &wcn3620_data },
+	{ .compatible = "qcom,wcn3660", .data = &wcn3660_data },
+	{ .compatible = "qcom,wcn3660b", .data = &wcn3680_data },
+	{ .compatible = "qcom,wcn3680", .data = &wcn3680_data },
+	{}
+};
+
+static void qcom_iris_release(struct device *dev)
+{
+	struct qcom_iris *iris = container_of(dev, struct qcom_iris, dev);
+
+	of_node_put(iris->dev.of_node);
+	kfree(iris);
+}
+
+struct qcom_iris *qcom_iris_probe(struct device *parent, bool *use_48mhz_xo)
 {
+	const struct of_device_id *match;
 	const struct iris_data *data;
-	struct qcom_wcnss *wcnss;
+	struct device_node *of_node;
 	struct qcom_iris *iris;
 	int ret;
 	int i;
 
-	iris = devm_kzalloc(&pdev->dev, sizeof(struct qcom_iris), GFP_KERNEL);
-	if (!iris)
-		return -ENOMEM;
+	of_node = of_get_child_by_name(parent->of_node, "iris");
+	if (!of_node) {
+		dev_err(parent, "No child node \"iris\" found\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	iris = kzalloc(sizeof(*iris), GFP_KERNEL);
+	if (!iris) {
+		of_node_put(of_node);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	device_initialize(&iris->dev);
+	iris->dev.parent = parent;
+	iris->dev.release = qcom_iris_release;
+	iris->dev.of_node = of_node;
+
+	dev_set_name(&iris->dev, "%s.iris", dev_name(parent));
+
+	ret = device_add(&iris->dev);
+	if (ret) {
+		put_device(&iris->dev);
+		return ERR_PTR(ret);
+	}
+
+	match = of_match_device(iris_of_match, &iris->dev);
+	if (!match) {
+		dev_err(&iris->dev, "no matching compatible for iris\n");
+		ret = -EINVAL;
+		goto err_device_del;
+	}
 
-	data = of_device_get_match_data(&pdev->dev);
-	wcnss = dev_get_drvdata(pdev->dev.parent);
+	data = match->data;
 
-	iris->xo_clk = devm_clk_get(&pdev->dev, "xo");
+	iris->xo_clk = devm_clk_get(&iris->dev, "xo");
 	if (IS_ERR(iris->xo_clk)) {
-		if (PTR_ERR(iris->xo_clk) != -EPROBE_DEFER)
-			dev_err(&pdev->dev, "failed to acquire xo clk\n");
-		return PTR_ERR(iris->xo_clk);
+		ret = PTR_ERR(iris->xo_clk);
+		if (ret != -EPROBE_DEFER)
+			dev_err(&iris->dev, "failed to acquire xo clk\n");
+		goto err_device_del;
 	}
 
 	iris->num_vregs = data->num_vregs;
-	iris->vregs = devm_kcalloc(&pdev->dev,
+	iris->vregs = devm_kcalloc(&iris->dev,
 				   iris->num_vregs,
 				   sizeof(struct regulator_bulk_data),
 				   GFP_KERNEL);
-	if (!iris->vregs)
-		return -ENOMEM;
+	if (!iris->vregs) {
+		ret = -ENOMEM;
+		goto err_device_del;
+	}
 
 	for (i = 0; i < iris->num_vregs; i++)
 		iris->vregs[i].supply = data->vregs[i].name;
 
-	ret = devm_regulator_bulk_get(&pdev->dev, iris->num_vregs, iris->vregs);
+	ret = devm_regulator_bulk_get(&iris->dev, iris->num_vregs, iris->vregs);
 	if (ret) {
-		dev_err(&pdev->dev, "failed to get regulators\n");
-		return ret;
+		dev_err(&iris->dev, "failed to get regulators\n");
+		goto err_device_del;
 	}
 
 	for (i = 0; i < iris->num_vregs; i++) {
@@ -143,34 +190,17 @@ static int qcom_iris_probe(struct platform_device *pdev)
 					   data->vregs[i].load_uA);
 	}
 
-	qcom_wcnss_assign_iris(wcnss, iris, data->use_48mhz_xo);
-
-	return 0;
-}
+	*use_48mhz_xo = data->use_48mhz_xo;
 
-static int qcom_iris_remove(struct platform_device *pdev)
-{
-	struct qcom_wcnss *wcnss = dev_get_drvdata(pdev->dev.parent);
+	return iris;
 
-	qcom_wcnss_assign_iris(wcnss, NULL, false);
+err_device_del:
+	device_del(&iris->dev);
 
-	return 0;
+	return ERR_PTR(ret);
 }
 
-static const struct of_device_id iris_of_match[] = {
-	{ .compatible = "qcom,wcn3620", .data = &wcn3620_data },
-	{ .compatible = "qcom,wcn3660", .data = &wcn3660_data },
-	{ .compatible = "qcom,wcn3660b", .data = &wcn3680_data },
-	{ .compatible = "qcom,wcn3680", .data = &wcn3680_data },
-	{}
-};
-MODULE_DEVICE_TABLE(of, iris_of_match);
-
-struct platform_driver qcom_iris_driver = {
-	.probe = qcom_iris_probe,
-	.remove = qcom_iris_remove,
-	.driver = {
-		.name = "qcom-iris",
-		.of_match_table = iris_of_match,
-	},
-};
+void qcom_iris_remove(struct qcom_iris *iris)
+{
+	device_del(&iris->dev);
+}