Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754089AbaKXOUN (ORCPT ); Mon, 24 Nov 2014 09:20:13 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:46702 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753835AbaKXOUL (ORCPT ); Mon, 24 Nov 2014 09:20:11 -0500 Message-ID: <54733E7C.60005@huawei.com> Date: Mon, 24 Nov 2014 22:19:40 +0800 From: "Yun Wu (Abel)" User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:11.0) Gecko/20120327 Thunderbird/11.0.1 MIME-Version: 1.0 To: Jiang Liu CC: Thomas Gleixner , LKML , Bjorn Helgaas , Grant Likely , Marc Zyngier , Yingjoe Chen , Yijing Wang Subject: Re: [patch 01/16] irqdomain: Introduce new interfaces to support hierarchy irqdomains References: <20141112133941.647950773@linutronix.de> <20141112134119.881823615@linutronix.de> <547325A9.3000109@huawei.com> <54733A4E.8020304@huawei.com> <54733C7D.2010405@linux.intel.com> In-Reply-To: <54733C7D.2010405@linux.intel.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.24.136] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020204.54733E86.01FB,ss=1,re=0.001,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 7e1ae2310568d419ea66557ddbfd4639 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014/11/24 22:11, Jiang Liu wrote: > On 2014/11/24 22:01, Yun Wu (Abel) wrote: >> On 2014/11/24 21:13, Thomas Gleixner wrote: >> >>> On Mon, 24 Nov 2014, Yun Wu (Abel) wrote: >>>> Hi Thomas, Jiang, >>>> On 2014/11/12 21:42, Thomas Gleixner wrote: >>>> >>>>> From: Jiang Liu >>>>> >>>> [...] >>>>> /* Number of irqs reserved for a legacy isa controller */ >>>>> #define NUM_ISA_INTERRUPTS 16 >>>>> @@ -64,6 +66,16 @@ struct irq_domain_ops { >>>>> int (*xlate)(struct irq_domain *d, struct device_node *node, >>>>> const u32 *intspec, unsigned int intsize, >>>>> unsigned long *out_hwirq, unsigned int *out_type); >>>>> + >>>>> +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY >>>>> + /* extended V2 interfaces to support hierarchy irq_domains */ >>>>> + int (*alloc)(struct irq_domain *d, unsigned int virq, >>>>> + unsigned int nr_irqs, void *arg); >>>>> + void (*free)(struct irq_domain *d, unsigned int virq, >>>>> + unsigned int nr_irqs); >>>>> + void (*activate)(struct irq_domain *d, struct irq_data *irq_data); >>>>> + void (*deactivate)(struct irq_domain *d, struct irq_data *irq_data); >>>> >>>> What's the usage of the parameter domain reference in activate/deactivate? >>>> I think the purpose of the two callbacks is to activate/deactivate the >>>> irq_data->hwirq in irq_data->domain. If so, the first parameter @domain is >>>> required to be equal to irq_data->domain (which makes @domain useless). >>>> Besides, the main responsibility of interrupt domains is to manage mappings >>>> between hardware and linux interrupt numbers, so would it be better if move >>>> the two callbacks into struct irq_chip? >>> >>> No. It's not a function of the irq_chip to activate/deactivate a >>> hierarchy. As I explained you before: >>> >>> The existing irqdomain code maps between hardware and virtual >>> interrupts and thereby activates the interrupt in hardware. >>> >>> In the hierarchical case we do not touch the hardware in the >>> allocation step, so we need to activate the allocated interrupt in the >>> hardware before we can use it. And that's clearly a domain interface >>> not a irq chip issue. >>> >> >> Makes sense, now the interrupt domain seems to be the best place. >> And when the @domain parameter can be really useful? I haven't see >> anyone using it so far. > We will use it for IOAPIC on x86, as below: > void mp_irqdomain_deactivate(struct irq_domain *domain, > struct irq_data *irq_data) > { > ioapic_mask_entry(mp_irqdomain_ioapic_idx(domain), > (int)irq_data->hwirq); > } > >>From an object oriented point of view, we pass the object as the > first parameter. It's true that we could retrieve domain from > irq_data->domain instead of explicitly passing it in, but that > will cause irqdomain interfaces depends on irq_data, not sounds > a good situation:) Hi Gerry, Is there any possibility that domain doesn't equal to irq_data->domain? I'm a little confused.. Thanks, Abel -- 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/