1 files changed, 26 insertions, 4 deletions

diff --git a/drivers/soc/aspeed/aspeed-lpc-snoop.c b/drivers/soc/aspeed/aspeed-lpc-snoop.c
index 9ab5ba9cf1d6..fc3a2c41cc10 100644
--- a/drivers/soc/aspeed/aspeed-lpc-snoop.c
+++ b/drivers/soc/aspeed/aspeed-lpc-snoop.c
@@ -58,6 +58,7 @@ struct aspeed_lpc_snoop_model_data {
 };
 
 struct aspeed_lpc_snoop_channel {
+	bool enabled;
 	struct kfifo		fifo;
 	wait_queue_head_t	wq;
 	struct miscdevice	miscdev;
@@ -166,7 +167,7 @@ static int aspeed_lpc_snoop_config_irq(struct aspeed_lpc_snoop *lpc_snoop,
 	int rc;
 
 	lpc_snoop->irq = platform_get_irq(pdev, 0);
-	if (!lpc_snoop->irq)
+	if (lpc_snoop->irq < 0)
 		return -ENODEV;
 
 	rc = devm_request_irq(dev, lpc_snoop->irq,
@@ -190,6 +191,9 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 	const struct aspeed_lpc_snoop_model_data *model_data =
 		of_device_get_match_data(dev);
 
+	if (WARN_ON(lpc_snoop->chan[channel].enabled))
+		return -EBUSY;
+
 	init_waitqueue_head(&lpc_snoop->chan[channel].wq);
 	/* Create FIFO datastructure */
 	rc = kfifo_alloc(&lpc_snoop->chan[channel].fifo,
@@ -200,11 +204,15 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 	lpc_snoop->chan[channel].miscdev.minor = MISC_DYNAMIC_MINOR;
 	lpc_snoop->chan[channel].miscdev.name =
 		devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, channel);
+	if (!lpc_snoop->chan[channel].miscdev.name) {
+		rc = -ENOMEM;
+		goto err_free_fifo;
+	}
 	lpc_snoop->chan[channel].miscdev.fops = &snoop_fops;
 	lpc_snoop->chan[channel].miscdev.parent = dev;
 	rc = misc_register(&lpc_snoop->chan[channel].miscdev);
 	if (rc)
-		return rc;
+		goto err_free_fifo;
 
 	/* Enable LPC snoop channel at requested port */
 	switch (channel) {
@@ -221,7 +229,8 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 		hicrb_en = HICRB_ENSNP1D;
 		break;
 	default:
-		return -EINVAL;
+		rc = -EINVAL;
+		goto err_misc_deregister;
 	}
 
 	regmap_update_bits(lpc_snoop->regmap, HICR5, hicr5_en, hicr5_en);
@@ -231,12 +240,23 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 		regmap_update_bits(lpc_snoop->regmap, HICRB,
 				hicrb_en, hicrb_en);
 
+	lpc_snoop->chan[channel].enabled = true;
+
+	return 0;
+
+err_misc_deregister:
+	misc_deregister(&lpc_snoop->chan[channel].miscdev);
+err_free_fifo:
+	kfifo_free(&lpc_snoop->chan[channel].fifo);
 	return rc;
 }
 
 static void aspeed_lpc_disable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 				     int channel)
 {
+	if (!lpc_snoop->chan[channel].enabled)
+		return;
+
 	switch (channel) {
 	case 0:
 		regmap_update_bits(lpc_snoop->regmap, HICR5,
@@ -252,8 +272,10 @@ static void aspeed_lpc_disable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 		return;
 	}
 
-	kfifo_free(&lpc_snoop->chan[channel].fifo);
+	lpc_snoop->chan[channel].enabled = false;
+	/* Consider improving safety wrt concurrent reader(s) */
 	misc_deregister(&lpc_snoop->chan[channel].miscdev);
+	kfifo_free(&lpc_snoop->chan[channel].fifo);
 }
 
 static int aspeed_lpc_snoop_probe(struct platform_device *pdev)