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.

Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20230531-rpm-rproc-v3-8-a07dcdefd918@gerhold.net
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

diff --git a/drivers/rpmsg/qcom_smd.c b/drivers/rpmsg/qcom_smd.c
index 7b9c298aa4912901ded89e9cb85730e728594194..43f601c84b4fcbf969d17e2d2fd829bc920ced99 100644 (file)
--- 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);