MLK-14241-2 ARM: imx: pm-rpmsg: add mutex protect for pm_send_message

Heatbeat workqueue and suspend/resume may call pm_send_message at the same
time as pf1550-regulator-rpmsg driver, so add mutex to avoid the potential
pm_qpos_* reentry issue.

Signed-off-by: Robin Gong <yibin.gong@nxp.com>

diff --git a/arch/arm/mach-imx/pm-rpmsg.c b/arch/arm/mach-imx/pm-rpmsg.c
index e6f02d9..4cd9262 100644 (file)
--- a/arch/arm/mach-imx/pm-rpmsg.c
+++ b/arch/arm/mach-imx/pm-rpmsg.c
@@ -54,6 +54,7 @@ struct pm_rpmsg_info {
        struct pm_qos_request pm_qos_req;
        struct notifier_block restart_handler;
        struct completion cmd_complete;
+       struct mutex lock;
 };
 
 static struct pm_rpmsg_info pm_rpmsg;
@@ -75,6 +76,8 @@ static int pm_send_message(struct pm_rpmsg_data *msg,
                        "rpmsg channel not ready, m4 image ready?\n");
                return -EINVAL;
        }
+
+       mutex_lock(&info->lock);
        pm_qos_add_request(&info->pm_qos_req,
                        PM_QOS_CPU_DMA_LATENCY, 0);
 
@@ -83,11 +86,9 @@ static int pm_send_message(struct pm_rpmsg_data *msg,
        err = rpmsg_send(info->rpdev->ept, (void *)msg,
                            sizeof(struct pm_rpmsg_data));
 
-       pm_qos_remove_request(&info->pm_qos_req);
-
        if (err) {
                dev_err(&info->rpdev->dev, "rpmsg_send failed: %d\n", err);
-               return err;
+               goto err_out;
        }
 
        if (ack) {
@@ -95,18 +96,24 @@ static int pm_send_message(struct pm_rpmsg_data *msg,
                                        msecs_to_jiffies(RPMSG_TIMEOUT));
                if (!err) {
                        dev_err(&info->rpdev->dev, "rpmsg_send timeout!\n");
-                       return -ETIMEDOUT;
+                       err = -ETIMEDOUT;
+                       goto err_out;
                }
 
                if (info->msg->data != 0) {
                        dev_err(&info->rpdev->dev, "rpmsg not ack %d!\n",
                                info->msg->data);
-                       return -EINVAL;
+                       err = -EINVAL;
+                       goto err_out;
                }
 
                err = 0;
        }
 
+err_out:
+       pm_qos_remove_request(&info->pm_qos_req);
+       mutex_unlock(&info->lock);
+
        return err;
 }
 
@@ -188,12 +195,13 @@ static int pm_rpmsg_probe(struct rpmsg_device *rpdev)
                        rpdev->src, rpdev->dst);
 
        init_completion(&pm_rpmsg.cmd_complete);
+       mutex_init(&pm_rpmsg.lock);
 
        INIT_DELAYED_WORK(&heart_beat_work,
                pm_heart_beat_work_handler);
 
        schedule_delayed_work(&heart_beat_work,
-               msecs_to_jiffies(10000));
+                       msecs_to_jiffies(10000));
 
        pm_vlls_notify_m4(false);