Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755795Ab2K1RoT (ORCPT ); Wed, 28 Nov 2012 12:44:19 -0500 Received: from mail-ie0-f174.google.com ([209.85.223.174]:39412 "EHLO mail-ie0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755720Ab2K1RoN (ORCPT ); Wed, 28 Nov 2012 12:44:13 -0500 MIME-Version: 1.0 X-Originating-IP: [173.13.129.225] In-Reply-To: References: <1354045994-8977-1-git-send-email-dianders@chromium.org> <50B53E37.40303@samsung.com> <18d701cdcd28$74198d70$5c4ca850$%kim@samsung.com> <20121128060553.GA18166@quad.lixom.net> Date: Wed, 28 Nov 2012 09:44:12 -0800 Message-ID: Subject: Re: [PATCH] ARM: EXYNOS: Avoid early use of of_machine_is_compatible() From: Olof Johansson To: Doug Anderson Cc: Kukjin Kim , Arnd Bergmann , linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, Russell King , linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6518 Lines: 167 On Wed, Nov 28, 2012 at 8:16 AM, Doug Anderson wrote: > Olof / Kukjin, > > On Tue, Nov 27, 2012 at 10:05 PM, Olof Johansson wrote: >> On Wed, Nov 28, 2012 at 02:23:09PM +0900, Kukjin Kim wrote: >>> Olof Johansson wrote: >>> > >>> > On Tue, Nov 27, 2012 at 2:27 PM, Kukjin Kim wrote: >>> > > On 11/28/12 07:11, Olof Johansson wrote: >>> > >> >>> > >> On Tue, Nov 27, 2012 at 11:53 AM, Doug Anderson >>> > >> wrote: >>> > >>> >>> > >>> The recent commit "ARM: EXYNOS: add support for EXYNOS5440 SoC" broke >>> > >>> support for exynos5250 because of_machine_is_compatible() was used too >>> > >>> early in the boot process. It also probably meant that the exynos5440 >>> > >>> failed to use the proper iotable. Switch to use >>> > >>> of_flat_dt_is_compatible() in both of these cases. >>> > >>> >>> > >>> The failure I was seeing in exynos5250 because of this was: >>> > >>> Division by zero in kernel. >>> > >>> [<80015ed4>] (unwind_backtrace+0x0/0xec) from [<8045c7a4>] >>> > >>> (dump_stack+0x20/0x24) >>> > >>> [<8045c7a4>] (dump_stack+0x20/0x24) from [<80012990>] >>> > >>> (__div0+0x20/0x28) >>> > >>> [<80012990>] (__div0+0x20/0x28) from [<8021ab04>] >>> (Ldiv0_64+0x8/0x18) >>> > >>> [<8021ab04>] (Ldiv0_64+0x8/0x18) from [<80068560>] >>> > >>> (__clocksource_updatefreq_scale+0x54/0x134) >>> > >>> [<80068560>] (__clocksource_updatefreq_scale+0x54/0x134) from >>> > >>> [<8006865c>] (__clocksource_register_scale+0x1c/0x54) >>> > >>> [<8006865c>] (__clocksource_register_scale+0x1c/0x54) from >>> > >>> [<80612a18>] (exynos_timer_init+0x100/0x1e8) >>> > >>> [<80612a18>] (exynos_timer_init+0x100/0x1e8) from [<8060d184>] >>> > >>> (time_init+0x28/0x38) >>> > >>> [<8060d184>] (time_init+0x28/0x38) from [<8060a754>] >>> > >>> (start_kernel+0x1e0/0x3c8) >>> > >>> [<8060a754>] (start_kernel+0x1e0/0x3c8) from [<40008078>] >>> > (0x40008078) >>> > >>> >>> > >>> Signed-off-by: Doug Anderson >>> > >> >>> > >> >>> > >> Thanks Doug. >>> > >> >>> > >> Kukjin, I'll apply this directly on top of the previous branch in >>> > >> arm-soc, if that's OK with you. >>> > >> >>> > > Sure, go ahead with my ack if you want, >>> > > >>> > > Acked-by: Kukjin Kim >>> > > >>> > > Note, actually there was a fix which uses soc_is_exynos5440() in my >>> > local >>> > > :-) I'm not sure which one is better at this moment, but I'm OK on this. >>> > >>> > Ok, applied. Thanks all. >>> > >>> Olof, just note, happens build error with exynos4_defconfig because of >>> non-DT. >> >> Ick, thanks for catching that. > > Sorry for this! I will try to be more diligent about trying > exynos4_defconfig before submitting future patches to these files. > >>> >>> Following can resolve it or we should create null function for >>> of_get_flat_dt_root() and of_flat_dt_is_compatible()... >>> >>> 8<--------------------------------------- >>> From: Kukjin Kim >>> Subject: ARM: EXYNOS: fix a build error with non-DT for exynos4 >>> >>> This fixes following in case of non-DT: >>> arch/arm/mach-exynos/common.c: In function 'exynos_init_io': >>> arch/arm/mach-exynos/common.c:339: error: implicit declaration of function >>> 'of_get_flat_dt_root' >>> arch/arm/mach-exynos/common.c:342: error: implicit declaration of function >>> 'of_flat_dt_is_compatible' >>> make[1]: *** [arch/arm/mach-exynos/common.o] Error 1 >>> >>> Signed-off-by: Kukjin Kim >>> --- >>> diff --git a/arch/arm/mach-exynos/common.c b/arch/arm/mach-exynos/common.c >>> index b919f5f..2110091 100644 >>> --- a/arch/arm/mach-exynos/common.c >>> +++ b/arch/arm/mach-exynos/common.c >>> @@ -336,12 +336,14 @@ void __init exynos_init_late(void) >>> >>> void __init exynos_init_io(struct map_desc *mach_desc, int size) >>> { >>> +#ifdef CONFIG_OF >>> unsigned long root = of_get_flat_dt_root(); >>> >>> /* initialize the io descriptors we need for initialization */ >>> if (of_flat_dt_is_compatible(root, "samsung,exynos5440")) >>> iotable_init(exynos5440_iodesc, >>> ARRAY_SIZE(exynos5440_iodesc)); >>> else >>> +#endif >>> iotable_init(exynos_iodesc, ARRAY_SIZE(exynos_iodesc)); >> >> I really don't like splitting an if/else with an ifdef like this, it's fragile >> code and can be hard to follow. > > Agree. > >> There's also a second build error with exynos_defconfig in the >> exynos5-dt.c board file due to a missing include. Teaches me to just apply >> patches without trying to build. :( > > In the tree I was testing against (the arm-soc/for-next branch at > 659b19ca3a77e2ac32fe84d95242653c75dd07c7) I see the include file in > the exynos5-dt.c file already. In my tree it was added by "2eae613b: > ARM: EXYNOS: Add MFC device tree support". > > Your patch applies cleanly on mine but I end up with: > > #include > #include > #include > #include > #include > #include Sigh, this is because people add includes out of alphabetical order. We'll just have to fix it up later, if we don't add of_fdt.h in the exynos5440 branch, the code will not be bisectable. >> I'll squash this into Doug's original patch, if that's OK? > > No objection to squashing a fix and your CL is better than what I > have, but see below for an issue. > > >> diff --git a/arch/arm/mach-exynos/common.c b/arch/arm/mach-exynos/common.c >> index 796e0c9..77e7c5b 100644 >> --- a/arch/arm/mach-exynos/common.c >> +++ b/arch/arm/mach-exynos/common.c >> @@ -122,6 +122,7 @@ static struct map_desc exynos_iodesc[] __initdata = { >> }, >> }; >> >> +#ifdef CONFIG_ARCH_EXYNOS5 > > Are you sure you want this #ifdef? If so it should match the ifdef > used below. With your patch applied I can get a compile error with: > > make exynos_defconfig > echo '# CONFIG_ARCH_EXYNOS5 is not set' >> .config > > In other words your code will fail if someone wants a FDT-enabled exynos4 build. Yep, the above needs to be: #if defined(CONFIG_OF) && defined(CONFIG_ARCH_EXYNOS5) I've pushed out the branch with the patch applied (with the above changed). -Olof -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/