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

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Message-ID: <aPX15a2Zv9b_wM3u@smile.fi.intel.com>
Date: Mon, 20 Oct 2025 11:42:13 +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 Mon, Oct 20, 2025 at 08:47:16AM +0200, Florian Eckert wrote:
> On 2025-10-18 21:33, Andy Shevchenko wrote:
> > On Tue, Sep 30, 2025 at 09:27:43AM +0200, Florian Eckert wrote:

...

> > > +	if (pci_resource_flags(priv->dev, bar) & IORESOURCE_MEM) {
> > 
> > Dunno if this is included already in Linux Next, but here is room for
> > improvement.
> 
> I followed the code in the 'serial8250_pci_setup_port()' [1] function.
> The same pattern is used there [2].

I see. So if we want to amend that, it should be done separately.

> > 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.
> 
> Do you mean the function 'platform_get_resource()' [3]? This is a platform
> device function?

I mean that the IORESOURCE_MEM and IORESOURCE_MEM_64 are separate bit flags in
struct resource::flags. Checking on one might not imply the other be set,
however brief look at the sources shows that _MEM_64 is supposed to be set on
top of _MEM.

> [1] https://elixir.bootlin.com/linux/v6.18-rc1/source/drivers/tty/serial/8250/8250_pcilib.c#L24
> [2] https://elixir.bootlin.com/linux/v6.18-rc1/source/drivers/tty/serial/8250/8250_pcilib.c#L30
> [3]
> https://elixir.bootlin.com/linux/v6.17.3/source/drivers/base/platform.c#L55

-- 
With Best Regards,
Andy Shevchenko