[PATCH v5 1/5] mailbox: zynqmp: fix counts of child nodes

[Tanmay Shah <tanmay.shah@amd.com>]

If child mailbox node status is disabled it causes
crash in interrupt handler. Fix this by assigning
only available child node during driver probe.

Fixes: 4981b82ba2ff ("mailbox: ZynqMP IPI mailbox controller")
Signed-off-by: Tanmay Shah <tanmay.shah@amd.com>
---

Changes in v5:
  - mailbox node count should not be 0 for driver to probe

 drivers/mailbox/zynqmp-ipi-mailbox.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/mailbox/zynqmp-ipi-mailbox.c b/drivers/mailbox/zynqmp-ipi-mailbox.c
index a4c8d23c76e2..ae47fbac38d2 100644
--- a/drivers/mailbox/zynqmp-ipi-mailbox.c
+++ b/drivers/mailbox/zynqmp-ipi-mailbox.c
@@ -634,7 +634,12 @@ static int zynqmp_ipi_probe(struct platform_device *pdev)
 	struct zynqmp_ipi_mbox *mbox;
 	int num_mboxes, ret = -EINVAL;
 
-	num_mboxes = of_get_child_count(np);
+	num_mboxes = of_get_available_child_count(np);
+	if (num_mboxes == 0) {
+		dev_err(dev, "mailbox nodes not available\n");
+		return -EINVAL;
+	}
+
 	pdata = devm_kzalloc(dev, struct_size(pdata, ipi_mboxes, num_mboxes),
 			     GFP_KERNEL);
 	if (!pdata)
-- 
2.25.1