linux-kernel - Re: [PATCH v2] serial: 8250_pcilib: Replace deprecated PCI functions

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Message-ID: <aPPreT00iiTDzJwG@ashevche-desk.local>
Date: Sat, 18 Oct 2025 22:33:13 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Florian Eckert <fe@....tdt.de>
Cc: gregkh@...uxfoundation.org, jirislaby@...nel.org,
	kumaravel.thiagarajan@...rochip.com, pnewman@...necttech.com,
	angelogioacchino.delregno@...labora.com, peterz@...radead.org,
	yujiaoliang@...o.com, arnd@...nel.org, cang1@...e.co.uk,
	macro@...am.me.uk, schnelle@...ux.ibm.com,
	Eckert.Florian@...glemail.com, linux-kernel@...r.kernel.org,
	linux-serial@...r.kernel.org
Subject: Re: [PATCH v2] serial: 8250_pcilib: Replace deprecated PCI functions

On Tue, Sep 30, 2025 at 09:27:43AM +0200, Florian Eckert wrote:
> When the '8250_exar' module is loaded into the kernel, a kernel trace
> with 'WARN_ON(legacy_iomap_table[bar])' is dumped to the console,
> because the old pci table mapping is still used in '8250_pcilib'.
> 
> The old function have been deprecated in commit e354bb84a4c1 ("PCI:
> Deprecate pcim_iomap_table(), pcim_iomap_regions_request_all()").
> 
> The remapping already takes or must take place in the driver that calls
> the function 'serial8250_pci_setup_port()'. The remapping should only be
> called once via 'pcim_iomap()'. Therefore the remapping moved to the
> caller of 'serial8250_pci_setup_port()'.
> 
> To replace the outdated/legacy iomap_table processing in '8250_pcilib' the
> function signature of 'serial8250_pci_setup_port()' has been extended with
> an already iomapped address value. So this can be used directly without
> io mapping again.

...

> +	if (pci_resource_flags(priv->dev, bar) & IORESOURCE_MEM) {

Dunno if this is included already in Linux Next, but here is room for
improvement.

The problem with the above code is it (wrongly?) checks for bit and not
for the resource type. OTOH I don't remember if 64-bit version requires
the IORESOURCE_MEM to be set along with that.


> +		iomem = pcim_iomap(priv->dev, bar, 0);
> +		if (!iomem)
> +			return -ENOMEM;
> +	}


-- 
With Best Regards,
Andy Shevchenko