From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Hunter Subject: Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document Date: Fri, 18 Mar 2016 12:42:41 +0000 Message-ID: <56EBF7C1.6030100@nvidia.com> References: <1458224359-32665-1-git-send-email-jonathanh@nvidia.com> <1458224359-32665-15-git-send-email-jonathanh@nvidia.com> <56EBD4E5.1060002@nvidia.com> <56EBDEFA.30102@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Geert Uytterhoeven Cc: Thomas Gleixner , Jason Cooper , Marc Zyngier , =?UTF-8?Q?Beno=c3=aet_Cousson?= , Tony Lindgren , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Stephen Warren , Thierry Reding , Kevin Hilman , Grygorii Strashko , Lars-Peter Clausen , Linus Walleij , linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-tegra@vger.kernel.org On 18/03/16 12:05, Geert Uytterhoeven wrote: > Hi Jon, > > On Fri, Mar 18, 2016 at 11:56 AM, Jon Hunter wrote: >> On 18/03/16 10:52, Geert Uytterhoeven wrote: >>> On Fri, Mar 18, 2016 at 11:13 AM, Jon Hunter wrote: >>>> On 18/03/16 09:13, Geert Uytterhoeven wrote: >>>>> On Thu, Mar 17, 2016 at 3:19 PM, Jon Hunter wrote: >>>>>> Commit afbbd2338176 ("irqchip/gic: Document optional Clock and Power >>>>>> Domain properties") documented optional clock and power-dmoain properties >>>>>> for the ARM GIC. Currently, there are no users of these and for the >>>>>> Tegra210 Audio GIC (based upon the GIC-400) there are two clocks, a >>>>>> functional clock and interface clock, that need to be enabled. >>>>> >>>>> The reason that there are no users for this is twofold: >>>>> 1. The GIC driver doesn't have Runtime PM support yet, >>>>> 2. There was no clean way to prevent the GIC's clock from being disabled. >>>>> Due to this, adding the clocks to the DTSes would mean that they will be >>>>> disabled during boot up as unused clocks, leading to a system lock-up. >>>>> >>>>> I had hoped your series would fix part 1. I gave it a try on r8a7791/koelsch, >>>>> but unfortunately it seems the platform driver only supports non-root >>>>> controllers, while the r8a7791 GIC is the primary one... >>>> >>>> Can you try making the following change ... >>> >>> Thanks! I gave it a try, but no difference. >> >> I assume you added the appropriate compatible flag? Any more details you > > Doh... bad assumption... Silly me. > >> can share about why it is not working? Is it not registered early enough? > > With > > + { .compatible = "arm,gic-400", }, > > the kernel no longer crashes due to accessing the GIC registers while the > GIC module clock is disabled. > > However, the system doesn't boot completely, and time outs on SPI transfers > make me believe interrupts are not working. > Both with and without "the following change". Yes, I recall now why I did not support primary controllers and it is because you need to call set_smp_cross_call() (for SMP) and set_handle_irq(). Both of which are located in the __init section and need to be called early during boot. So to make this work for primary controllers, more work would need to be done. Jon