RE: [PATCH 2/2] net: ethernet: Add driver for Sunplus SP7021

[Wells Lu 呂芳騰]

Thanks a lot for your review.

> From: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> Sent: Wednesday, November 3, 2021 8:10 PM
> To: Wells Lu <wellslutw@xxxxxxxxx>; davem@xxxxxxxxxxxxx;
> kuba@xxxxxxxxxx; robh+dt@xxxxxxxxxx; netdev@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Cc: Wells Lu 呂芳騰 <wells.lu@xxxxxxxxxxx>
> Subject: Re: [PATCH 2/2] net: ethernet: Add driver for Sunplus SP7021
> 
> On Wed, 2021-11-03 at 19:02 +0800, Wells Lu wrote:
> [...]
> > diff --git a/drivers/net/ethernet/sunplus/l2sw_driver.c
> > b/drivers/net/ethernet/sunplus/l2sw_driver.c
> > new file mode 100644
> > index 0000000..3dfd0dd
> > --- /dev/null
> > +++ b/drivers/net/ethernet/sunplus/l2sw_driver.c
> > @@ -0,0 +1,779 @@
> [...]
> > +static int l2sw_probe(struct platform_device *pdev) {
> > +	struct l2sw_common *comm;
> > +	struct resource *r_mem;
> > +	struct net_device *net_dev, *net_dev2;
> > +	struct l2sw_mac *mac, *mac2;
> > +	u32 mode;
> > +	int ret = 0;
> > +	int rc;
> > +
> > +	if (platform_get_drvdata(pdev))
> > +		return -ENODEV;
> > +
> > +	// Allocate memory for l2sw 'common' area.
> > +	comm = kmalloc(sizeof(*comm), GFP_KERNEL);
> 
> I'd use devm_kzalloc() here for initialization and to simplify the cleanup
> path.

I'll replace kmalloc() with devm_kzalloc() and remove the kfree(...) in
cleanup path (platform remove) in PATCH v2.

> > +	if (!comm)
> > +		return -ENOMEM;
> > +	pr_debug(" comm = %p\n", comm);
> 
> What is this useful for?

'pr_debug(" comm = %p\n", comm);' is for early-stage debug.
I'll remove the line in PATCH v2.

> > +	memset(comm, '\0', sizeof(struct l2sw_common));
> 
> Not needed with kzalloc, See above.

Yes, I'll remove the line 'memset(...);' as devm_kzalloc() will be used in PATCH v2.

> [...]
> > +	// Get memory resoruce 0 from dts.
> > +	r_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	if (r_mem) {
> > +		pr_debug(" res->name = \"%s\", r_mem->start = %pa\n",
> r_mem->name, &r_mem->start);
> > +		if (l2sw_reg_base_set(devm_ioremap(&pdev->dev, r_mem->start,
> > +						   (r_mem->end - r_mem->start + 1))) != 0) {
> > +			pr_err(" ioremap failed!\n");
> > +			ret = -ENOMEM;
> > +			goto out_free_comm;
> > +		}
> > +	} else {
> > +		pr_err(" No MEM resource 0 found!\n");
> > +		ret = -ENXIO;
> > +		goto out_free_comm;
> > +	}
> > +
> > +	// Get memory resoruce 1 from dts.
> > +	r_mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> > +	if (r_mem) {
> > +		pr_debug(" res->name = \"%s\", r_mem->start = %pa\n",
> r_mem->name, &r_mem->start);
> > +		if (moon5_reg_base_set(devm_ioremap(&pdev->dev,
> r_mem->start,
> > +						    (r_mem->end - r_mem->start + 1))) != 0) {
> > +			pr_err(" ioremap failed!\n");
> > +			ret = -ENOMEM;
> > +			goto out_free_comm;
> > +		}
> > +	} else {
> > +		pr_err(" No MEM resource 1 found!\n");
> > +		ret = -ENXIO;
> > +		goto out_free_comm;
> > +	}
> 
> Using devm_ioremap_resource() would simplify both a lot.

Yes, I'll replace devm_ioremap() with devm_ioremap_resource() in PATCH v2.

> [...]
> > +	comm->rstc = devm_reset_control_get(&pdev->dev, NULL);
> 
> Please use devm_reset_control_get_exclusive().

Yes, I'll replace devm_reset_control_get() with devm_reset_control_get_exclusive() in PATCH v2.

> > +	if (IS_ERR(comm->rstc)) {
> > +		dev_err(&pdev->dev, "Failed to retrieve reset controller!\n");
> > +		ret = PTR_ERR(comm->rstc);
> > +		goto out_free_comm;
> > +	}
> > +
> > +	// Enable clock.
> > +	clk_prepare_enable(comm->clk);
> > +	udelay(1);
> > +
> > +	ret = reset_control_assert(comm->rstc);
> 
> No need to assign to ret if you ignore it anyway.

Ok, I'll remove 'ret =' in PATCH v2

> > +	udelay(1);
> > +	ret = reset_control_deassert(comm->rstc);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "Failed to deassert reset line (err = %d)!\n",
> ret);
> > +		ret = -ENODEV;
> > +		goto out_free_comm;
> > +	}
> > +	udelay(1);
> 
> regards
> Philipp

Best regards,
Wells