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[PATCH v2 06/10] soc: aspeed: lpc-snoop: Rearrange channel paths

Andrew Jeffery posted 10 patches 3 months, 3 weeks ago
[PATCH v2 06/10] soc: aspeed: lpc-snoop: Rearrange channel paths
Posted by Andrew Jeffery 3 months, 3 weeks ago 
Order assignments such that tests for conditions not involving resource
acquisition are ordered before those testing acquired resources, and
order managed resource acquisition before unmanaged where possible. This
way we minimise the amount of manual cleanup required.

In the process, improve readability of the code by introducing a channel
pointer that takes the place of the repeated object lookups.

Acked-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
---
 drivers/soc/aspeed/aspeed-lpc-snoop.c | 51 ++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 22 deletions(-)

diff --git a/drivers/soc/aspeed/aspeed-lpc-snoop.c b/drivers/soc/aspeed/aspeed-lpc-snoop.c
index e9d17239163a8ae5145bd3652fcec572b70bd11c..9992212c789d4224edcc0ee1a3bb9c73f9fc661b 100644
--- a/drivers/soc/aspeed/aspeed-lpc-snoop.c
+++ b/drivers/soc/aspeed/aspeed-lpc-snoop.c
@@ -194,28 +194,30 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 {
 	const struct aspeed_lpc_snoop_model_data *model_data;
 	u32 hicr5_en, snpwadr_mask, snpwadr_shift, hicrb_en;
+	struct aspeed_lpc_snoop_channel *channel;
 	int rc = 0;
 
-	if (WARN_ON(lpc_snoop->chan[index].enabled))
+	channel = &lpc_snoop->chan[index];
+
+	if (WARN_ON(channel->enabled))
 		return -EBUSY;
 
-	init_waitqueue_head(&lpc_snoop->chan[index].wq);
-	/* Create FIFO datastructure */
-	rc = kfifo_alloc(&lpc_snoop->chan[index].fifo,
-			 SNOOP_FIFO_SIZE, GFP_KERNEL);
+	init_waitqueue_head(&channel->wq);
+
+	channel->miscdev.minor = MISC_DYNAMIC_MINOR;
+	channel->miscdev.fops = &snoop_fops;
+	channel->miscdev.parent = dev;
+
+	channel->miscdev.name =
+		devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, index);
+	if (!channel->miscdev.name)
+		return -ENOMEM;
+
+	rc = kfifo_alloc(&channel->fifo, SNOOP_FIFO_SIZE, GFP_KERNEL);
 	if (rc)
 		return rc;
 
-	lpc_snoop->chan[index].miscdev.minor = MISC_DYNAMIC_MINOR;
-	lpc_snoop->chan[index].miscdev.name =
-		devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, index);
-	if (!lpc_snoop->chan[index].miscdev.name) {
-		rc = -ENOMEM;
-		goto err_free_fifo;
-	}
-	lpc_snoop->chan[index].miscdev.fops = &snoop_fops;
-	lpc_snoop->chan[index].miscdev.parent = dev;
-	rc = misc_register(&lpc_snoop->chan[index].miscdev);
+	rc = misc_register(&channel->miscdev);
 	if (rc)
 		goto err_free_fifo;
 
@@ -238,6 +240,7 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 		goto err_misc_deregister;
 	}
 
+	/* Enable LPC snoop channel at requested port */
 	regmap_update_bits(lpc_snoop->regmap, HICR5, hicr5_en, hicr5_en);
 	regmap_update_bits(lpc_snoop->regmap, SNPWADR, snpwadr_mask,
 			   lpc_port << snpwadr_shift);
@@ -246,14 +249,14 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 	if (model_data && model_data->has_hicrb_ensnp)
 		regmap_update_bits(lpc_snoop->regmap, HICRB, hicrb_en, hicrb_en);
 
-	lpc_snoop->chan[index].enabled = true;
+	channel->enabled = true;
 
 	return 0;
 
 err_misc_deregister:
-	misc_deregister(&lpc_snoop->chan[index].miscdev);
+	misc_deregister(&channel->miscdev);
 err_free_fifo:
-	kfifo_free(&lpc_snoop->chan[index].fifo);
+	kfifo_free(&channel->fifo);
 	return rc;
 }
 
@@ -261,7 +264,11 @@ __attribute__((nonnull))
 static void aspeed_lpc_disable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 				     enum aspeed_lpc_snoop_index index)
 {
-	if (!lpc_snoop->chan[index].enabled)
+	struct aspeed_lpc_snoop_channel *channel;
+
+	channel = &lpc_snoop->chan[index];
+
+	if (!channel->enabled)
 		return;
 
 	/* Disable interrupts along with the device */
@@ -280,10 +287,10 @@ static void aspeed_lpc_disable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 		return;
 	}
 
-	lpc_snoop->chan[index].enabled = false;
+	channel->enabled = false;
 	/* Consider improving safety wrt concurrent reader(s) */
-	misc_deregister(&lpc_snoop->chan[index].miscdev);
-	kfifo_free(&lpc_snoop->chan[index].fifo);
+	misc_deregister(&channel->miscdev);
+	kfifo_free(&channel->fifo);
 }
 
 static int aspeed_lpc_snoop_probe(struct platform_device *pdev)

-- 
2.39.5
Re: [PATCH v2 06/10] soc: aspeed: lpc-snoop: Rearrange channel paths
Posted by Jean Delvare 3 months, 1 week ago 
On Mon, 16 Jun 2025 22:43:43 +0930, Andrew Jeffery wrote:
> Order assignments such that tests for conditions not involving resource
> acquisition are ordered before those testing acquired resources, and
> order managed resource acquisition before unmanaged where possible. This
> way we minimise the amount of manual cleanup required.
> 
> In the process, improve readability of the code by introducing a channel
> pointer that takes the place of the repeated object lookups.
> 
> Acked-by: Jean Delvare <jdelvare@suse.de>
> Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
> ---
>  drivers/soc/aspeed/aspeed-lpc-snoop.c | 51 ++++++++++++++++++++---------------
>  1 file changed, 29 insertions(+), 22 deletions(-)
> (...)
> @@ -238,6 +240,7 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
>  		goto err_misc_deregister;
>  	}
>  
> +	/* Enable LPC snoop channel at requested port */
>  	regmap_update_bits(lpc_snoop->regmap, HICR5, hicr5_en, hicr5_en);
>  	regmap_update_bits(lpc_snoop->regmap, SNPWADR, snpwadr_mask,
>  			   lpc_port << snpwadr_shift);

This duplicates a comment which is already present in the driver a few
lines before.

This duplicated comment gets cleaned up later in patch 10/10 (soc:
aspeed: lpc-snoop: Lift channel config to const structs).

-- 
Jean Delvare
SUSE L3 Support
Re: [PATCH v2 06/10] soc: aspeed: lpc-snoop: Rearrange channel paths
Posted by Andrew Jeffery 3 months ago 
Hi Jean,

On Fri, 2025-07-04 at 17:34 +0200, Jean Delvare wrote:
> On Mon, 16 Jun 2025 22:43:43 +0930, Andrew Jeffery wrote:
> > Order assignments such that tests for conditions not involving resource
> > acquisition are ordered before those testing acquired resources, and
> > order managed resource acquisition before unmanaged where possible. This
> > way we minimise the amount of manual cleanup required.
> > 
> > In the process, improve readability of the code by introducing a channel
> > pointer that takes the place of the repeated object lookups.
> > 
> > Acked-by: Jean Delvare <jdelvare@suse.de>
> > Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
> > ---
> >  drivers/soc/aspeed/aspeed-lpc-snoop.c | 51 ++++++++++++++++++++---------------
> >  1 file changed, 29 insertions(+), 22 deletions(-)
> > (...)
> > @@ -238,6 +240,7 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
> >                 goto err_misc_deregister;
> >         }
> >  
> > +       /* Enable LPC snoop channel at requested port */
> >         regmap_update_bits(lpc_snoop->regmap, HICR5, hicr5_en, hicr5_en);
> >         regmap_update_bits(lpc_snoop->regmap, SNPWADR, snpwadr_mask,
> >                            lpc_port << snpwadr_shift);
> 
> This duplicates a comment which is already present in the driver a few
> lines before.
> 
> This duplicated comment gets cleaned up later in patch 10/10 (soc:
> aspeed: lpc-snoop: Lift channel config to const structs).
> 

Thanks, I've dropped the duplicate in the process of applying the
patches.

Andrew

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