From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from down.free-electrons.com ([37.187.137.238]:60361 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751670AbbJLHPr (ORCPT ); Mon, 12 Oct 2015 03:15:47 -0400 Date: Mon, 12 Oct 2015 09:15:44 +0200 From: Thomas Petazzoni To: Bjorn Helgaas Cc: Minghuan Lian , linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Zang Roy-R61911 , Hu Mingkai-B21284 , Yoder Stuart-B08248 , Li Yang , Arnd Bergmann , Bjorn Helgaas , Jingoo Han , Zhou Wang , Jason Cooper , Tanmay Inamdar Subject: Re: [PATCH v2] PCI: layerscape: Add PCIe support for LS1043a and LS2080a Message-ID: <20151012091544.7dbbe330@free-electrons.com> In-Reply-To: <20151011191027.GA29221@localhost> References: <1442481219-28299-1-git-send-email-Minghuan.Lian@freescale.com> <20151007175725.GC27633@localhost> <20151011191027.GA29221@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-pci-owner@vger.kernel.org List-ID: Bjorn, On Sun, 11 Oct 2015 14:10:27 -0500, Bjorn Helgaas wrote: > > driver/of/irq.c void of_msi_configure(struct device *dev, struct > > device_node *np) will bind "msi-parent" to each device if there is > > "msi-parent" handler. The PCIe driver do not need to do anything. If > > we do not check "msi-parent" here, we will have no chance to check it. > > The common code of 'of' and 'pci' bus driver will not complain, > > because the msi controller may be found by other way. > > Hmm. In mvebu_pcie_msi_enable() and xgene_pcie_msi_enable(), we > also look for "msi-parent". If that fails, mvebu continues silently > and xgene complains (but only if CONFIG_PCI_MSI=y). I don't really have the context of the discussion here. But the reason why the mvebu pcie driver silently continues if msi-parent is missing is because we initially introduced the PCIe mvebu Device Tree binding without MSI support. When we later added MSI support thanks to the msi-parent property, we wanted to preserve backward compatibility with old DTs that didn't had the msi-parent property. Such DTs would continue to work, albeit without the MSI functionality obviously. Other drivers that had the MSI functionality from day 1 may want to make such a property mandatory rather than optional. Best regards, Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com From mboxrd@z Thu Jan 1 00:00:00 1970 From: thomas.petazzoni@free-electrons.com (Thomas Petazzoni) Date: Mon, 12 Oct 2015 09:15:44 +0200 Subject: [PATCH v2] PCI: layerscape: Add PCIe support for LS1043a and LS2080a In-Reply-To: <20151011191027.GA29221@localhost> References: <1442481219-28299-1-git-send-email-Minghuan.Lian@freescale.com> <20151007175725.GC27633@localhost> <20151011191027.GA29221@localhost> Message-ID: <20151012091544.7dbbe330@free-electrons.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Bjorn, On Sun, 11 Oct 2015 14:10:27 -0500, Bjorn Helgaas wrote: > > driver/of/irq.c void of_msi_configure(struct device *dev, struct > > device_node *np) will bind "msi-parent" to each device if there is > > "msi-parent" handler. The PCIe driver do not need to do anything. If > > we do not check "msi-parent" here, we will have no chance to check it. > > The common code of 'of' and 'pci' bus driver will not complain, > > because the msi controller may be found by other way. > > Hmm. In mvebu_pcie_msi_enable() and xgene_pcie_msi_enable(), we > also look for "msi-parent". If that fails, mvebu continues silently > and xgene complains (but only if CONFIG_PCI_MSI=y). I don't really have the context of the discussion here. But the reason why the mvebu pcie driver silently continues if msi-parent is missing is because we initially introduced the PCIe mvebu Device Tree binding without MSI support. When we later added MSI support thanks to the msi-parent property, we wanted to preserve backward compatibility with old DTs that didn't had the msi-parent property. Such DTs would continue to work, albeit without the MSI functionality obviously. Other drivers that had the MSI functionality from day 1 may want to make such a property mandatory rather than optional. Best regards, Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com