From mboxrd@z Thu Jan 1 00:00:00 1970 From: r.sricharan@ti.com (Sricharan R) Date: Tue, 13 Aug 2013 15:26:10 +0530 Subject: [PATCH 1/3] misc: Add crossbar driver In-Reply-To: <20130813081003.GU7656@atomide.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> Message-ID: <520A02BA.4090805@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Tony, On Tuesday 13 August 2013 01:40 PM, 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. > > Regards, > > Tony > Initially irqchip was discussed, but we also have a DMA crossbar to map the dma-requests. Since both irq/dma crossbars should be handled, pinctrl was suggested as the appropriate place to handle this. Regards, Sricharan