asoc: msm_common: add mutex lock for vote against sleep cnt

add mutex for vote_against_sleep_cnt to avoid race conditions
while updating the cnt value at the time of SSR. Add check
while decrementing the cnt.

Change-Id: Ic8e40fa6b4a68c05fb70369ecb764943d5f582fa
Signed-off-by: Prasad Kumpatla <[email protected]>

asoc/msm_common.c

@@ -48,6 +48,8 @@ struct snd_card_pdata {
 #define SAMPLING_RATE_176P4KHZ  176400
 #define SAMPLING_RATE_352P8KHZ  352800
 
+struct mutex vote_against_sleep_lock;
+
 static struct attribute device_state_attr = {
 	.name = "state",
 	.mode = 0660,
@@ -173,8 +175,13 @@ int snd_card_notify_user(snd_card_status_t card_status)
 {
 	snd_card_pdata->card_status = card_status;
 	sysfs_notify(&snd_card_pdata->snd_card_kobj, NULL, "card_state");
-	if (card_status == 0)
+	if (card_status == 0) {
+		mutex_lock(&vote_against_sleep_lock);
 		vote_against_sleep_cnt = 0;
+		pr_debug("%s: SSR/PDR triggered reset vote_against_sleep_cnt = %d\n",
+					__func__, vote_against_sleep_cnt);
+		mutex_unlock(&vote_against_sleep_lock);
+	}
 	return 0;
 }
 
@@ -809,6 +816,8 @@ exit:
 		devm_kfree(&pdev->dev, core_val_array);
 	}
 
+	mutex_init(&vote_against_sleep_lock);
+
 	return 0;
 };
 
@@ -819,6 +828,7 @@ void msm_common_snd_deinit(struct msm_common_pdata *common_pdata)
 	if (!common_pdata)
 		return;
 
+	mutex_destroy(&vote_against_sleep_lock);
 	msm_audio_remove_qos_request();
 
 	mutex_destroy(&common_pdata->aud_dev_lock);
@@ -1098,6 +1108,7 @@ static int msm_vote_against_sleep_ctl_put(struct snd_kcontrol *kcontrol,
 {
 	int ret = 0;
 
+	mutex_lock(&vote_against_sleep_lock);
 	vote_against_sleep_enable = ucontrol->value.integer.value[0];
 	pr_debug("%s: vote against sleep enable: %d sleep cnt: %d", __func__,
 			vote_against_sleep_enable, vote_against_sleep_cnt);
@@ -1107,7 +1118,8 @@ static int msm_vote_against_sleep_ctl_put(struct snd_kcontrol *kcontrol,
 		if (vote_against_sleep_cnt ==  1) {
 			ret = audio_prm_set_vote_against_sleep(1);
 			if (ret < 0) {
-				--vote_against_sleep_cnt;
+				if (vote_against_sleep_cnt > 0)
+					--vote_against_sleep_cnt;
 				pr_err("%s: failed to vote against sleep ret: %d\n", __func__, ret);
 			}
 		}
@@ -1119,6 +1131,7 @@ static int msm_vote_against_sleep_ctl_put(struct snd_kcontrol *kcontrol,
 	}
 
 	pr_debug("%s: vote against sleep vote ret: %d\n", __func__, ret);
+	mutex_unlock(&vote_against_sleep_lock);
 	return ret;
 }