Re: [PATCH v4] PCI: Unify ECAM constants in native PCI Express drivers

From: "Krzysztof Wilczyński" <kw@linux.com>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: Heiko Stuebner <heiko@sntech.de>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Shawn Lin <shawn.lin@rock-chips.com>,
	Paul Mackerras <paulus@samba.org>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Jonathan Chocron <jonnyc@amazon.com>,
	Toan Le <toan@os.amperecomputing.com>,
	Will Deacon <will@kernel.org>, Rob Herring <robh@kernel.org>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Michal Simek <michal.simek@xilinx.com>,
	linux-rockchip@lists.infradead.org,
	bcm-kernel-feedback-list@broadcom.com,
	Jonathan Derrick <jonathan.derrick@intel.com>,
	linux-pci@vger.kernel.org, Ray Jui <rjui@broadcom.com>,
	linux-rpi-kernel@lists.infradead.org,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	linux-arm-kernel@lists.infradead.org,
	Scott Branden <sbranden@broadcom.com>,
	Zhou Wang <wangzhou1@hisilicon.com>,
	Robert Richter <rrichter@marvell.com>,
	linuxppc-dev@lists.ozlabs.org,
	Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Subject: Re: [PATCH v4] PCI: Unify ECAM constants in native PCI Express drivers
Date: Sun, 15 Nov 2020 06:50:57 +0100	[thread overview]
Message-ID: <X7DBwZ5cJrbQspM+@rocinante> (raw)
In-Reply-To: <429099a8-5186-40c3-f5c0-f219b3e79f01@gmail.com>

On 20-10-04 19:53:06, Florian Fainelli wrote:

Hi Florian,

Sorry for taking a long time to get back to you.

[...]
> This appears to be correct, so:
> 
> Acked-by: Florian Fainelli <f.fainelli@gmail.com>

Thank you!

> however, I would have defined a couple of additional helper macros and do:
> 
> 	idx = PCIE_ECAM_BUS(bus->number) | PCIE_ECAM_DEV(devfn) |
> PCIE_ECAM_FUN(devfn);
> 
> for clarity.
> 
[...]
> For instance, adding these two:
> 
> #define PCIE_ECAM_DEV(x)		(((x) & 0x1f) << PCIE_ECAM_DEV_SHIFT)
> #define PCIE_ECAM_FUN(x)		(((x) & 0x7) << PCIE_ECAM_FUN_SHIFT)
> 
> may be clearer for use in drivers like pcie-brcmstb.c that used to treat the
> device function in terms of device and function (though it was called slot
> there).

Regarding the suggestion above - it has been like that initially, albeit
Bjorn suggested that there is no need to reply on the macros that use
PCI_SLOT() and PCI_FUNC() macros, see:

https://lore.kernel.org/linux-pci/20200922232715.GA2238688@bjorn-Precision-5520/

I would be happy to put the macros back if there is a value in having
the extra macros added - perhaps for clarify, as you suggest.

Krzysztof

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