Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758849AbaDBRYO (ORCPT ); Wed, 2 Apr 2014 13:24:14 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:53336 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758761AbaDBRYL (ORCPT ); Wed, 2 Apr 2014 13:24:11 -0400 Message-ID: <533C4795.9080209@ti.com> Date: Wed, 2 Apr 2014 13:23:33 -0400 From: Murali Karicheri User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:16.0) Gecko/20121010 Thunderbird/16.0.1 MIME-Version: 1.0 To: Andrew Murray CC: Thierry Reding , Arnd Bergmann , "linux-arm-kernel@lists.infradead.org" , Richard Zhu , "linux-samsung-soc@vger.kernel.org" , "linux-pci@vger.kernel.org" , Jingoo Han , LKML , "Shilimkar, Santosh" , Mohit Kumar , Bjorn Helgaas , Kukjin Kim , Shawn Guo Subject: Re: [RESEND: RFC PATCH 3/3] pcie: keystone: add pcie driver based on designware core driver References: <1395707726-20437-1-git-send-email-m-karicheri2@ti.com> <1395707726-20437-4-git-send-email-m-karicheri2@ti.com> <235376049.yyfljDtinu@wuerfel> <20140325103525.GA14789@ulmo> <533C300E.7070109@ti.com> In-Reply-To: Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/2/2014 12:47 PM, Andrew Murray wrote: > On 2 April 2014 16:43, Murali Karicheri wrote: > >> Keystone pcie driver is developed based on other dw based pcie drivers >> >> such as pci-exynos that uses subsys_initcall(). I am new to this list, >> >> probably Jingoo (copied) has some history on why we can't use module. >> For now I will keep it as is and can be re-visited in the next revisions. >> Also I will experiment with PCIE port driver as well. >> >> >> BTW, PCIE driver currently uses Legacy or MSI IRQ. Keystone PCI has >> a platform IRQ. Is DT based irq configuration is the appropriate way >> to add this capability? > As far as I am aware - the PCI standards define a particular way for > devices to describe which interrupt will be used for things like > hotplug, AER and PME. These interrupts are always PCI interrupts (i.e. > MSI/MSI-X/legacy). Thus the port services code in the kernel uses > standard configuration space accesses to determine the interrupt to > use. Also note that it's not just the host bridge that can provide > these services but any PCIE device, I guess in this sense a host > bridge is treated like any other device. > > If my understanding is correct I don't believe the current port > services code allows exceptions to this, i.e. to say this host bridge > actually uses a platform IRQ for AER rather than an MSI. Though this > may be quite useful as I suspect many host bridges provide interrupts > for things like PME through platform IRQs rather that PCI interrupts. > > Does the Keystone have platform IRQs for things like AER? Is that > because the IP makes these events available through platform IRQs in > addition to the standard PCI means? > > Andrew Murray Andrew, Yes. Keystone PCIe hw is based on designware hw version v3.65 that implements Error interrupt as a platform IRQ only (not in addition) and unfortunately standard PCI means are not supported. The latter versions do support standard PCI means. Murali -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/