slimbus: qcom-ngd-ctrl: Avoid sending power requests without QMI

[ Upstream commit 39014ce ]

Attempting to send a power request during PM operations, when the QMI
handle isn't initialized results in a NULL pointer dereference. So check
if the QMI handle has been initialized before attempting to post the
power requests.

Fixes: 917809e ("slimbus: ngd: Add qcom SLIMBus NGD driver")
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20201127102451.17114-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/slimbus/qcom-ngd-ctrl.c

@@ -1205,6 +1205,9 @@ static int qcom_slim_ngd_runtime_resume(struct device *dev)
 	struct qcom_slim_ngd_ctrl *ctrl = dev_get_drvdata(dev);
 	int ret = 0;
 
+	if (!ctrl->qmi.handle)
+		return 0;
+
 	if (ctrl->state >= QCOM_SLIM_NGD_CTRL_ASLEEP)
 		ret = qcom_slim_ngd_power_up(ctrl);
 	if (ret) {
@@ -1503,6 +1506,9 @@ static int __maybe_unused qcom_slim_ngd_runtime_suspend(struct device *dev)
 	struct qcom_slim_ngd_ctrl *ctrl = dev_get_drvdata(dev);
 	int ret = 0;
 
+	if (!ctrl->qmi.handle)
+		return 0;
+
 	ret = qcom_slim_qmi_power_request(ctrl, false);
 	if (ret && ret != -EBUSY)
 		dev_info(ctrl->dev, "slim resource not idle:%d\n", ret);