Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751159AbbF3LvR (ORCPT ); Tue, 30 Jun 2015 07:51:17 -0400 Received: from mail-pd0-f173.google.com ([209.85.192.173]:35031 "EHLO mail-pd0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753153AbbF3LvK (ORCPT ); Tue, 30 Jun 2015 07:51:10 -0400 Message-ID: <559282A0.8090601@linaro.org> Date: Tue, 30 Jun 2015 19:50:56 +0800 From: Hanjun Guo User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Marc Zyngier , Lorenzo Pieralisi CC: Jason Cooper , Will Deacon , Catalin Marinas , "Rafael J. Wysocki" , Thomas Gleixner , Jiang Liu , Arnd Bergmann , Tomasz Nowicki , "grant.likely@linaro.org" , Olof Johansson , Wei Huang , "linux-arm-kernel@lists.infradead.org" , "linux-acpi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linaro-acpi@lists.linaro.org" Subject: Re: [PATCH v2 6/9] irqchip / gic: Add stacked irqdomain support for ACPI based GICv2 init References: <1434703572-26221-1-git-send-email-hanjun.guo@linaro.org> <1434703572-26221-7-git-send-email-hanjun.guo@linaro.org> <20150622172014.GB26129@red-moon> <5589772A.8070708@linaro.org> <20150623173845.GC31466@red-moon> <558E1DEE.3090900@linaro.org> <55910440.8070702@arm.com> In-Reply-To: <55910440.8070702@arm.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2782 Lines: 72 Hi Marc, On 06/29/2015 04:39 PM, Marc Zyngier wrote: > On 27/06/15 04:52, Hanjun Guo wrote: >> On 06/24/2015 01:38 AM, Lorenzo Pieralisi wrote: >>> On Tue, Jun 23, 2015 at 04:11:38PM +0100, Hanjun Guo wrote: [...] >>> >>>>>> for (i = 0; i < nr_irqs; i++) >>>>>> gic_irq_domain_map(domain, virq + i, hwirq + i); >>>>>> @@ -945,11 +952,11 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start, >>>>>> gic_irqs = 1020; >>>>>> gic->gic_irqs = gic_irqs; >>>>>> >>>>>> - if (node) { /* DT case */ >>>>>> + if (node || !acpi_disabled) { /* DT or ACPI case */ >>>>>> gic->domain = irq_domain_add_linear(node, gic_irqs, >>>>>> &gic_irq_domain_hierarchy_ops, >>>>>> gic); >>> >>> I think this is a bit more worrying, I mean passing a NULL node pointer to >>> the irqdomain layer which basically means you are booting out of ACPI >> >> I'm little confused here, would you mind explaining more for your >> worrying? To me, node pointer is optional and it's ok for ACPI >> case. >> >>> (for you, if that's true for the irq_domain_add_linear implementation >>> that's another story), the node pointer should be optional but you >>> need feedback from IRQ layer maintainers here. >> >> Sure. > > Frankly, I'd really like to see ACPI using the "node" parameter for > something useful. This would save having to cache pointers all over the > place, will make find_irq_host() work as expected... etc. > > See the comment at the top of linux/irqdomain.h : > > "... This code could thus be used on other architectures by replacing > those two by some sort of arch-specific void * "token" used to identify > interrupt controllers." To init GIC in ACPI, we can only use the table entry pointer as the token, but the ACPI static tables are early mem/io remapped memory at boot stage, and it will be not available after boot, also we need muti types of MADT enties to init GIC (GICC and GICD for GICv2, GICC or GICR and GICD for GICv3), not as DT, just one single node to include all the information needed to init the GIC. We use ACPI handle for devices as node for DT when the namespace is available, but that's pretty late in the boot stage which GIC, SMP and timers were already initialized, so ACPI handle can not use as the token too. I see multi places just pass NULL as the pointer directly for irq_domain_add_linear() which works fine, and for ACPI, we tested this patch and also it works. > > Maybe it is time to bite the bullet. Hope comment above explains :) Thanks Hanjun -- 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/