From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com ([217.140.101.70]:33859 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161307AbcA1RZN (ORCPT ); Thu, 28 Jan 2016 12:25:13 -0500 Date: Thu, 28 Jan 2016 17:27:01 +0000 From: Lorenzo Pieralisi To: Phil Edworthy , Pratyush Anand , Jingoo Han , Gabriele Paoloni Cc: "linux-pci@vger.kernel.org" , Zhou Wang , Bjorn Helgaas , Sinan Kaya Subject: Re: [RFC] ARM/ARM64 PCI_PROBE_ONLY platforms Message-ID: <20160128172701.GA28468@red-moon> References: <20160120160427.GD13437@red-moon> <569FB210.9090605@codeaurora.org> <20160120181003.GF13437@red-moon> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-pci-owner@vger.kernel.org List-ID: [+ Pratyush, Jingoo, Gabriele] any comment on this for the designware driver ? Thanks, Lorenzo On Fri, Jan 22, 2016 at 04:28:39PM +0000, Phil Edworthy wrote: > Hi Lorenzo, > > On 20 January 2016 18:10, Lorenzo Pieralisi wrote: > > On Wed, Jan 20, 2016 at 11:13:04AM -0500, Sinan Kaya wrote: > > > On 1/20/2016 11:04 AM, Lorenzo Pieralisi wrote: > > > > Hi, > > > > > > > > I noticed that: > > > > > > > > 79953dd22c1d ("PCI: rcar: Remove dependency on ARM-specific struct > > hw_pci") > > > > cbce7900598c ("PCI: designware: Make driver arch-agnostic") > > > > > > > > added code in the respective host controller drivers to size bridges > > > > and assign resources only if the PCI_PROBE_ONLY flag is clear, which makes > > > > me wonder if there exists PCI_PROBE_ONLY set-ups for the respective > > > > host controllers: > > > > > > > > Resources claiming and assignment should be managed in arch code, > > not in host controllers specific code, and that's the reason I > > complained in this RFC about the scattering of PCI_PROBE_ONLY flag > > checks in host drivers, it is becoming unmanageable (if useful > > at all on designware and rcar, I would like to know if there are > > PCI_PROBE_ONLY set-ups probing those host drivers). > > I am pretty sure there are no rcar set-ups that use PCI_PROBE_ONLY, > so I am happy for that code to go. > > Thanks > Phil > > > Does it make the point clearer ? > > > > > > https://patchwork.ozlabs.org/patch/545671/ > > > > > > > > so unless you really have *existing* set-ups that require it, please > > > > remove the respective checks from the host controller drivers, this is > > > > becoming a serious issue, because either: > > > > > > > > - we claim resources if and only if PCI_PROBE_ONLY is set > > > > > > > > Either like this (to be done for every host controllers and ARM > > > > bios32): > > > > > > > > https://patchwork.ozlabs.org/patch/545670/ > > > > > > > > or in core ARM/ARM64 code - eg pcibios_fixup_bus() - (to avoid adding a > > > > resource claiming call in ALL PCI host controllers) > > > > > > > > - or we *always* carry out resource claiming regardless of PCI_PROBE_ONLY > > > > (but on ARM we can't really do that since PCI FW set-up on most of the > > > > platforms is not present) > > > > > > > > On PCI_PROBE_ONLY systems resources claiming is mandatory if we want > > > > to get rid of arches workarounds: > > > > > > I'm hoping to see x86 like behavior on ARM64 without any gotchas as > > > there is nothing special about CPU type when it comes to PCI. > > > > As I said, we must enforce it with ACPI, for DT platforms I am all > > ears to decide how we can implement it sanely (I think the only way > > to do it is by claiming the PCI resources on PCI_PROBE_ONLY systems, > > that's not ideal but it simplifies things a lot). > > > > Thanks, > > Lorenzo > > > > > > > > > > > > > https://patchwork.ozlabs.org/patch/545671/ > > > > > > > > Comments very appreciated. > > > > > > > > Thanks, > > > > Lorenzo > > > > -- > > > > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > > > > the body of a message to majordomo@vger.kernel.org > > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > > > > > > > > > > -- > > > Sinan Kaya > > > Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc. > > > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux > > Foundation Collaborative Project > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >