From mboxrd@z Thu Jan 1 00:00:00 1970 From: Santosh Shilimkar Subject: Re: [PATCH 1/3] misc: Add crossbar driver Date: Tue, 13 Aug 2013 09:28:04 -0400 Message-ID: <520A3464.10406@ti.com> References: <51E83A4F.5080904@ti.com> <51ED2385.60108@ti.com> <51ED5C66.1010407@ti.com> <51EFFBE1.4090505@ti.com> <51F0031B.1050307@ti.com> <51F00530.9090703@ti.com> <51F02069.3050207@ti.com> <51F0223E.4050008@ti.com> <51F0240F.3050507@ti.com> <20130813081003.GU7656@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130813081003.GU7656@atomide.com> Sender: linux-kernel-owner@vger.kernel.org To: Tony Lindgren Cc: Nishanth Menon , Sricharan R , Linus Walleij , "linux-kernel@vger.kernel.org" , "devicetree-discuss@lists.ozlabs.org" , "linux-doc@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Linux-OMAP , Russell King - ARM Linux , Rajendra Nayak , Felipe Balbi , Thomas Gleixner , Grant Likely List-Id: devicetree@vger.kernel.org On Tuesday 13 August 2013 04:10 AM, Tony Lindgren wrote: > * Santosh Shilimkar [130724 12:06]: >> On Wednesday 24 July 2013 02:51 PM, Nishanth Menon wrote: >>> On 07/24/2013 01:43 PM, Sricharan R wrote: >>>> On Wednesday 24 July 2013 10:17 PM, Nishanth Menon wrote: >>>>> On 07/24/2013 11:38 AM, Santosh Shilimkar wrote: >>>>>> On Wednesday 24 July 2013 12:08 PM, Nishanth Menon wrote: >>>>>>> That said, maybe a intermediate pinctrl approach might be more pragmatic and less theoretically flexible. >>>>>>> an option might be to "statically allocate" default number of interrupts to a domain - example: >>>>>>> * GIC IRQ 72->78 allotted to UARTs >>>>>>> * pinctrl mapping provided for those but only 6 can be used (rest are marked status="disabled" as default) at any given time (choice of pinctrl option determines GIC interrupt line to use) >>>>>>> * All modules will have a pinctrl definition to have a mapping - to avoid bootloader overriding default cross bar setting in ways un-expected by kernel. >>>>>>> >>>>>>> Does that sound fair trade off? >>>>>> This sounds better. That way we can get all the devices in the DT at least. >>>>> >>>>> Fair enough - if Linus and Tony are still ok with this approach to the problem, seeing a patch series with the effect would be beneficial. >>>>> >>>> Ok, i will use this idea of certain number interrupts to groups. >>>> Yes on DRA7XX, we have about 160 gic lines and 320 irq crossbar device inputs contending for it. >>>> 1:2 and fully arbitrary. But will we be really exhausting them ? >>>> >>> Depends on how we allocate :). The default arbitary allocation can be made more logical in your series ofcourse :). >>> >> I would just most logical peripherals rather than providing every single >> IP connected to cross bar. Otherwise we will end up wth hwmod like >> scenario where now started removing the unused stuff because of >> maintenance and loc issues ;-) > > Sorry for the delay on this, I think the best way to set this up > is as a separate drivers/irqchip controller. Then just map the > configured interrupts for the board with interrupt-map and > interrupt-map-mask binding. No need to stuff all the SoC specific > maps to the .dts, just the ones used for the board. > Interrupt mask/unmask, really ? Thats like abusing those irqchip hooks completely. Your point is to just setup events which we need and thats what I also suggested. But the use of irqchip hooks is certainly not the right idea since they are for masking/unmasking interrupts in running system and not for joining the interrupt line which needs to happen once during probe. Regards, Santosh