From patchwork Thu Nov 27 16:51:33 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Abhilash Kesavan X-Patchwork-Id: 5397991 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id D2A519F2F5 for ; Thu, 27 Nov 2014 16:53:51 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id EBC092010E for ; Thu, 27 Nov 2014 16:53:50 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D1C162010B for ; Thu, 27 Nov 2014 16:53:45 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Xu2IX-0006i5-CS; Thu, 27 Nov 2014 16:52:05 +0000 Received: from mail-qa0-f46.google.com ([209.85.216.46]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Xu2IS-0006Xo-CL for linux-arm-kernel@lists.infradead.org; Thu, 27 Nov 2014 16:52:01 +0000 Received: by mail-qa0-f46.google.com with SMTP id u7so3500338qaz.33 for ; Thu, 27 Nov 2014 08:51:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=t5cq14M0UiLB1fMDFuZvUT/aCIA4XpkKWrZVib5SoKM=; b=tO9aMZdb+ZWgwvdRzbysQ2m+RrtFr/hsqyknpx6+0HKhh6sSA5irp+9VXq3CdTNL7T UNWfJh8AeWi8bt+uD3II1BGi91ou/jPStPsrAuz5kNLXwMlzohBUtTWFbcHbxqAWH3pk 1Q5dVZO6xVxzqlRj4Thoq8vBKMJvcATqFUbChIiZwYDY/RRynmC8sncfw45WQUSTM7HL iYjCzMtlKIKrH398+fRu2zg/RZKPvR1TygjE0TIgIiyOtyB53ZBUQurtBpcMMQNgMOQx lyFTNakbgDBcGo/cIEZxdS7KAIfdIJYG44DmiMUdYmysjdbiUJqtZD3AHFhXDZYyek7m BOIw== MIME-Version: 1.0 X-Received: by 10.140.23.35 with SMTP id 32mr29845240qgo.73.1417107093685; Thu, 27 Nov 2014 08:51:33 -0800 (PST) Received: by 10.229.214.67 with HTTP; Thu, 27 Nov 2014 08:51:33 -0800 (PST) In-Reply-To: References: <1414796382-5447-1-git-send-email-khilman@kernel.org> <000e01cffb39$5ef0a2d0$1cd1e870$@kernel.org> <7hegtaq26c.fsf@deeprootsystems.com> <044101d00852$3f421420$bdc63c60$@kernel.org> <7hvbm2ixmo.fsf@deeprootsystems.com> <7hmw7dg81l.fsf@deeprootsystems.com> Date: Thu, 27 Nov 2014 22:21:33 +0530 Message-ID: Subject: Re: [PATCH] ARM: exynos_defconfig: disable CONFIG_EXYNOS5420_MCPM; not stable From: Abhilash Kesavan To: Nicolas Pitre X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141127_085200_571246_D152CC4D X-CRM114-Status: GOOD ( 24.13 ) X-Spam-Score: -0.8 (/) Cc: Krzysztof Kozlowski , "linux-samsung-soc@vger.kernel.org" , Bartlomiej Zolnierkiewicz , Kevin Hilman , Sachin Kamat , Doug Anderson , Kukjin Kim , "linux-arm-kernel@lists.infradead.org" , Olof Johansson , Kukjin Kim , Javier Martinez Canillas , "linaro-kernel@lists.linaro.org" X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_LOW, T_DKIM_INVALID, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Hi Kevin, On Thu, Nov 27, 2014 at 12:11 AM, Nicolas Pitre wrote: > On Wed, 26 Nov 2014, Kevin Hilman wrote: > >> Abhilash Kesavan writes: >> >> > Hi Kevin, >> > >> > On Wed, Nov 26, 2014 at 6:30 AM, Kevin Hilman wrote: >> >> [...] >> >> >> >> More specifically, with only the loopback call to turn off CCI commented >> >> out, the imprecise aborts go away. >> > >> > I can't see how enabling snoops for the boot cluster is causing these >> > aborts. Perhaps as Krzysztof commented it has something to do with the >> > secure firmware/tz software on these boards ? Other than there does >> > not appear to be any difference between the working/non-working >> > setups. >> >> Perhaps the secure firmware is preventing the CCI to be enabled by the >> kernel, and that is causing the imprecise abort? > > That is well possible. > > Now...... if the bootloader/firmware does not let Linux deal with both > the CCI and caches then MCPM simply has no more purpose for this board. > The whole point of MCPM is actually to handle the CCI properly and the > most efficient way despite all the possible races and opportunities for > memory corruptions. And yes, this is a complex task. > > So there is actually two choices: the firmware let Linux take care of it > via the MCPM layer (easy), or the firmware has to implement it all > _properly_ (hard) behind an interface such as PSCI, at which point MCPM > should be configured out. > > If the firmware does not let Linux interact with the CCI _and_ does not > implement full MCPM-like services then the platform is broken and only a > firmware upgrade could fix that. It might still be possible to boot all > CPUs through other means, but power management would then be severely > limited. How about restricting the mcpm initialization to only known working boards like chromebooks and smdk. This would be better than disabling the config altogether from exynos_defconfig. The non-working boards would then default to platsmp. Assuming that the firmware handles all CCI/cache activities then platsmp may work for secondary core boot-up ? Can you please apply the below diff and test the non-working boards with CONFIG_EXYNOS5420_MCPM enabled. On a different note, I did not see any mainline support for Odroid Xu3, are you testing this board with a non-mainline kernel ? Regards, Abhilash > > > > Nicolas diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c index b0d3c2e..34d77bb 100644 --- a/arch/arm/mach-exynos/mcpm-exynos.c +++ b/arch/arm/mach-exynos/mcpm-exynos.c @@ -316,8 +316,9 @@ static void __init exynos_cache_off(void) } static const struct of_device_id exynos_dt_mcpm_match[] = { - { .compatible = "samsung,exynos5420" }, - { .compatible = "samsung,exynos5800" }, + { .compatible = "samsung,smdk5420" }, + { .compatible = "google,pi" }, + { .compatible = "google,pit" }, {}, };