Re: [RFC/RFT PATCH 05/18] ARM: PCI: dove: Convert PCI scan API to pci_scan_root_bus_bridge()

From: Arnd Bergmann <arnd@arndb.de>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Pratyush Anand <pratyush.anand@gmail.com>,
	Gabriele Paoloni <gabriele.paoloni@huawei.com>,
	linux-pci <linux-pci@vger.kernel.org>,
	Shawn Lin <shawn.lin@rock-chips.com>,
	Will Deacon <will.deacon@arm.com>,
	Michal Simek <michal.simek@xilinx.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	Tanmay Inamdar <tinamdar@apm.com>,
	Matthew Minter <matt@masarand.com>, Rob Herring <robh@kernel.org>,
	Joao Pinto <Joao.Pinto@synopsys.com>,
	Wenrui Li <wenrui.li@rock-chips.com>,
	Russell King <linux@armlinux.org.uk>,
	Murali Karicheri <m-karicheri2@ti.com>,
	Jason Cooper <jason@lakedaemon.net>,
	Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>,
	Simon Horman <horms@verge.net.au>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Mingkai Hu <mingkai.hu@freescale.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
	Jingoo Han <jingoohan1@gmail.com>,
	Stanimir Varbanov <svarbanov@mm-sol.com>,
	Minghuan Lian <minghuan.Lian@freescale.com>,
	Zhou Wang <wangzhou1@hisilicon.com>,
	Roy Zang <tie-fei.zang@freescale.com>
Subject: Re: [RFC/RFT PATCH 05/18] ARM: PCI: dove: Convert PCI scan API to pci_scan_root_bus_bridge()
Date: Fri, 28 Apr 2017 14:52:14 +0200	[thread overview]
Message-ID: <CAK8P3a26HBoN=ZcNwB30AGheEy3AU1GrTWGXQ9pmQHe8sH+vTw@mail.gmail.com> (raw)
In-Reply-To: <CAK8P3a1bnnq-9iuse43bCNX_9TirZPOtmH_vFsvJ9VOAsoUBzQ@mail.gmail.com>

On Fri, Apr 28, 2017 at 2:38 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Wed, Apr 26, 2017 at 1:17 PM, Lorenzo Pieralisi
> <lorenzo.pieralisi@arm.com> wrote:
>> The introduction of pci_scan_root_bus_bridge() provides a PCI core
>> API to scan a PCI root bus backed by an already initialized
>> struct pci_host_bridge object, which simplifies the bus scan
>> interface and makes the PCI scan root bus interface easier to
>> generalize as members are added to the struct pci_host_bridge().
>>
>> Convert ARM dove platform code to pci_scan_root_bus_bridge() to improve
>> the PCI root bus scanning interface.
>>
>> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
>
> Is this patch required for one of the later steps in the series?
>
> As non-DT dove uses the traditional pci_common_init() helper rather
> than registering its own driver, I wonder if there is anything to gain here.

Thinking about it some more, if we make the change to allocate from
pcibios_init_hw(), we can also initialize most of the fields there and
do the cleanup in common code when the scan callback fails, which
in turn makes the changes in arch/arm/mach*/pci.c drivers very simple.

        Arnd

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