linux-kernel - [PATCH v2 07/12] rpmsg: qcom_smd: Use qcom_smem_is

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Message-Id: <20230531-rpm-rproc-v2-7-56a4a00c8260@gerhold.net>
Date:   Thu, 08 Jun 2023 09:10:27 +0200
From:   Stephan Gerhold <stephan@...hold.net>
To:     Bjorn Andersson <andersson@...nel.org>
Cc:     Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-remoteproc@...r.kernel.org,
        Stephan Gerhold <stephan@...hold.net>
Subject: [PATCH v2 07/12] rpmsg: qcom_smd: Use qcom_smem_is_available()

Rather than looking up a dummy item from SMEM, use the new
qcom_smem_is_available() function to make the code more clear
(and reduce the overhead slightly).

Add the same check to qcom_smd_register_edge() as well to ensure that
it only succeeds if SMEM is already available - if a driver calls the
function and SMEM is not available yet then the initial state will be
read incorrectly and the RPMSG devices might never become available.

Signed-off-by: Stephan Gerhold <stephan@...hold.net>
---
 drivers/rpmsg/qcom_smd.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/rpmsg/qcom_smd.c b/drivers/rpmsg/qcom_smd.c
index 7b9c298aa491..43f601c84b4f 100644
--- a/drivers/rpmsg/qcom_smd.c
+++ b/drivers/rpmsg/qcom_smd.c
@@ -1479,6 +1479,9 @@ struct qcom_smd_edge *qcom_smd_register_edge(struct device *parent,
 	struct qcom_smd_edge *edge;
 	int ret;
 
+	if (!qcom_smem_is_available())
+		return ERR_PTR(-EPROBE_DEFER);
+
 	edge = kzalloc(sizeof(*edge), GFP_KERNEL);
 	if (!edge)
 		return ERR_PTR(-ENOMEM);
@@ -1553,12 +1556,9 @@ EXPORT_SYMBOL(qcom_smd_unregister_edge);
 static int qcom_smd_probe(struct platform_device *pdev)
 {
 	struct device_node *node;
-	void *p;
 
-	/* Wait for smem */
-	p = qcom_smem_get(QCOM_SMEM_HOST_ANY, smem_items[0].alloc_tbl_id, NULL);
-	if (PTR_ERR(p) == -EPROBE_DEFER)
-		return PTR_ERR(p);
+	if (!qcom_smem_is_available())
+		return -EPROBE_DEFER;
 
 	for_each_available_child_of_node(pdev->dev.of_node, node)
 		qcom_smd_register_edge(&pdev->dev, node);

-- 
2.40.1