From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Likely Subject: Re: [PATCH v6 4/5] MIPS: Octeon: Setup irq_domains for interrupts. Date: Thu, 08 Mar 2012 22:57:04 -0700 Message-ID: <20120309055704.465823E0901@localhost> References: <1330563422-14078-1-git-send-email-ddaney.cavm@gmail.com> <1330563422-14078-5-git-send-email-ddaney.cavm@gmail.com> <4F50D7C2.7080204@gmail.com> <4F510B8E.3070201@cavium.com> <20120302190744.571E03E1C63@localhost> <4F511FB0.5070901@cavium.com> <4F527285.1020500@gmail.com> <4F52F90C.5060306@gmail.com> Return-path: In-Reply-To: <4F52F90C.5060306@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: David Daney , Rob Herring Cc: David Daney , David Daney , "linux-mips@linux-mips.org" , "ralf@linux-mips.org" , "devicetree-discuss@lists.ozlabs.org" , Rob Herring , "linux-kernel@vger.kernel.org" List-Id: devicetree@vger.kernel.org On Sat, 03 Mar 2012 21:09:32 -0800, David Daney wrote: > On 03/03/2012 11:35 AM, Rob Herring wrote: > > On 03/02/2012 01:29 PM, David Daney wrote: > >> On 03/02/2012 11:07 AM, Grant Likely wrote: > >>> +static void __init octeon_irq_set_ciu_mapping(unsigned int irq, > >>> + unsigned int line, > >>> + unsigned int bit, > >>> + struct irq_domain *domain, > >>> struct irq_chip *chip, > >>> irq_flow_handler_t handler) > >>> { > >>> + struct irq_data *irqd; > >>> union octeon_ciu_chip_data cd; > >>> > >>> irq_set_chip_and_handler(irq, chip, handler); > >>> - > >>> cd.l = 0; > >>> cd.s.line = line; > >>> cd.s.bit = bit; > >>> > >>> irq_set_chip_data(irq, cd.p); > >>> octeon_irq_ciu_to_irq[line][bit] = irq; > >>> + > >>> + irqd = irq_get_irq_data(irq); > >>> + irqd->hwirq = line<< 6 | bit; > >>> + irqd->domain = domain; > >>>>> I think the domain code will set these. > >>>> It is my understanding that the domain code only does this for: > >>>> > >>>> o irq_domain_add_legacy() > >>>> > >>>> o irq_create_direct_mapping() > >>>> > >>>> o irq_create_mapping() > >>>> > >>>> We use none of those. So I do it here. > >>>> > >>>> If there is a better way, I am open to suggestions. > >>> irq_create_mapping is called by irq_create_of_mapping() which is > >>> in turn called by irq_of_parse_and-map(). irq_domain always > >>> manages the hwirq and domain values. Driver code cannot manipulate > >>> them manually. > >>> > >> I really must be missing something. > >> > >> Given: > >> > >> 1) I must have a mapping between hwirq and irq that I control so that > >> non-OF code using the OCTEON_IRQ_* constants continues to work. > > Those defines are what you need to work to get rid of. > > We are not starting from a blank slate here. There is a lot of in-tree > code using these symbols. We cannot make them disappear with wishful > thinking. > > The first step is a switch to irq_domains using the existing mappings. > > After we do that, I have patches to transition some drivers to use the > OF mapping via irq_domains. After those are merged, we can work toward > getting rid of OCTEON_IRQ_*. But I think it must be the last step in > the process, not the first. > > > >> 2) irq_create_mapping() will allocate a random irq value if none is > >> already assigned to the hwirq. > >> > >> Therefore: To avoid having random irq values assigned, I must manually > >> assign them. > >> > > So you should be using legacy domain if you need to maintain fixed hwirq > > to linux irq numbers. "linear" is a bit confusing as it doesn't mean > > linear 1:1 irq number assignment, but linear search. > > My reading of Grant's code in linux-next directly contradicts this > statement. There is no code in irqdomain.c, that I can see, that allows > me to have an arbitrary mapping of irq <--> hwirq values. There are 4 kinds of mappings available; legacy, linear, radix and nomap. Ignore nomap and radix; you don't want them. legacy maps a contiguous range of hwirq numbers to a contiguous range of linux irq numbers. To preserve the exising #define mappings but still add DT support, this is the one that you want. The downside is that it requires all the irq_descs to be allocated ahead of time (which probably isn't a problem for you). The linear map has a linear reverse map lookup table that allows arbitrary irq <--> hwirq mappings. This mapping is preferred, but it doesn't work if you need to preserve #defined irq mappings. g.