Merge tag 'aspeed-6.16-fixes-0' of https://git.kernel.org/pub/scm/linux/kernel/git/bmc/linux into arm/fixes

ASPEED SoC driver fixes for 6.16

Address concerns in the ASPEED LPC snoop driver identified in the first two
patches of the cleanup series at [1].

[1]: https://lore.kernel.org/all/20250616-aspeed-lpc-snoop-fixes-v2-0-3cdd59c934d3@codeconstruct.com.au/

* tag 'aspeed-6.16-fixes-0' of https://git.kernel.org/pub/scm/linux/kernel/git/bmc/linux:
  soc: aspeed: lpc-snoop: Don't disable channels that aren't enabled
  soc: aspeed: lpc-snoop: Cleanup resources in stack-order

Signed-off-by: Arnd Bergmann <[email protected]>

Author: arndb

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;
@@ -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,
@@ -236,6 +240,8 @@ 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:
@@ -248,6 +254,9 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 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,
@@ -263,8 +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)