From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH 2/4] ARM: OMAP2/3: intc: Add DT support for TI interrupt controller Date: Fri, 09 Dec 2011 09:22:12 -0600 Message-ID: <4EE227A4.2030209@gmail.com> References: <1323291049-24964-1-git-send-email-b-cousson@ti.com> <1323291049-24964-3-git-send-email-b-cousson@ti.com> <4EDFD88B.8060008@gmail.com> <4EE0D0E6.3060202@ti.com> <4EE20B38.8050006@gmail.com> <4EE2209E.2040209@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4EE2209E.2040209@ti.com> Sender: linux-omap-owner@vger.kernel.org To: "Cousson, Benoit" Cc: tony@atomide.com, devicetree-discuss@lists.ozlabs.org, grant.likely@secretlab.ca, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org On 12/09/2011 08:52 AM, Cousson, Benoit wrote: > On 12/9/2011 2:20 PM, Rob Herring wrote: >> On 12/08/2011 08:59 AM, Cousson, Benoit wrote: >>> On 12/7/2011 10:20 PM, Rob Herring wrote: >>>> On 12/07/2011 02:50 PM, Benoit Cousson wrote: >>> >>> [...] >>> >>>>> +#ifdef CONFIG_OF >>>>> +int __init intc_of_init(struct device_node *node, struct device_node >>>>> *parent) >>>>> +{ >>>>> + struct resource res; >>>>> + u32 nr_irqs; >>>>> + >>>>> + if (WARN_ON(!node)) >>>>> + return -ENODEV; >>>>> + >>>>> + if (of_address_to_resource(node, 0,&res)) { >>>>> + WARN(1, "unable to get intc registers\n"); >>>>> + return -EINVAL; >>>>> + } >>>>> + >>>>> + if (of_property_read_u32(node, "ti,intc-size",&nr_irqs)) { >>>>> + WARN(1, "unable to get intc-size\n"); >>>>> + return -EINVAL; >>>> >>>> There is no default value that makes sense? >>> >>> So far we have 96 or 128, so I can put 96 as a default and just keep the >>> warning without returning an error. >>> >>>>> + } >>>>> + >>>>> + omap_init_irq(res.start, nr_irqs); >>>>> + irq_domain_add_simple(node, 0); >>>> >>>> Have you read the NO_IRQ thread... >>> >>> Yeah, I tried, but that's a long email thread with some unclear >>> conclusion... >>> The point is that the few users of that API today are using 0 as a base >>> as well, so I thought it was still valid. >>> >>>> Is 0 ever a valid interrupt for a driver? If so, you must not use 0 for >>>> the base. I would pick 16 to skip over legacy ISA irqs. >>> >>> I do not have any 0 interrupts right now, my concern is that I still >>> have some legacy non-DT drivers that expect the previous hwirq = irq >>> mapping. >> >> I guess it depends how easily you can shift all the irq defines. You >> allow specifying the base so that you can set it to 0 for non-DT and -1 >> (dynamic allocation) for DT. > > The issue, is that the IRQs are not defined anymore but hard coded in > the hwmod database. And the idea is that this is reflecting exactly the > hwirq from the spec, so I do not want to add any artificial offset for > the domain in the original data. > >>>> irqdomains should always be enabled regardless of CONFIG_OF. So either >>>> you can leave it as is if OF is always enabled for OMAP, or you should >>>> move domain setup into omap_init_irq. >>> >>> OK, but it looks like I cannot really modify the current INTC to DT >>> without having fully adapted the OMAP drivers to use >>> irq_of_parse_and_map. Or did I miss something? >>> >> >> No, the drivers should not need to be modified as long as they get the >> irq's from platform device resources. You just want to make sure the >> INTC has no knowledge of it's irq base so it can change. > > OK, the driver will not have to change but the IRQ value will not be the > same in the case of DT since it will use the irq_create_of_mapping. > > Currently, the driver IRQ resource is 7 for example for the twl, this is > the hwirq (= irq). If I use a domain with a base of 16, the resource > will still be 7 except if the resource is created from OF, then it will > be 23. > > The only way I have today to maintain the legacy drivers to work without > hacking the OMAP resource code is to keep the base_irq at 0. > For non-DT case, that is fine. It should not be hard to support 0 for legacy and !0 for DT. > Since I do not have any hwirq at 0 so far, is it a big deal to keep the > base_irq at 0 for the moment? > It will be easier to transition to DT that way without breaking the > existing drivers. As long as it is trivial to change later. I'm afraid that if it is not changed, then we won't know if it is trivial. Rob