From patchwork Wed Apr 6 15:39:07 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 607078 Return-Path: X-Original-To: incoming-imx@patchwork.ozlabs.org Delivered-To: patchwork-incoming-imx@bilbo.ozlabs.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3qg9232jGWz9sD2 for ; Thu, 7 Apr 2016 01:41:47 +1000 (AEST) 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 1anpYi-0004Qk-54; Wed, 06 Apr 2016 15:39:56 +0000 Received: from linutronix.de ([2001:470:1f0b:db:abcd:42:0:1] helo=Galois.linutronix.de) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1anpYe-0004KK-7q for linux-arm-kernel@lists.infradead.org; Wed, 06 Apr 2016 15:39:53 +0000 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1anpYG-00009D-RW; Wed, 06 Apr 2016 17:39:28 +0200 From: Sebastian Andrzej Siewior To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] ARM: imx: always use TWD on IMX6Q Date: Wed, 6 Apr 2016 17:39:07 +0200 Message-Id: <1459957147-10133-1-git-send-email-bigeasy@linutronix.de> X-Mailer: git-send-email 2.8.0.rc3 X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1, SHORTCIRCUIT=-0.0001 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160406_083952_466679_BE5FC8B1 X-CRM114-Status: GOOD ( 13.37 ) X-Spam-Score: -5.2 (-----) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-5.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [2001:470:1f0b:db:abcd:42:0:1 listed in] [list.dnswl.org] -1.0 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sebastian Andrzej Siewior , Shawn Guo , Sascha Hauer MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+incoming-imx=patchwork.ozlabs.org@lists.infradead.org List-Id: linux-imx-kernel.lists.patchwork.ozlabs.org There is no reason to limit the TWD to be used on SMP kernels only if the hardware has it available. On Wandboard i.MX6SOLO, running PREEMPT-RT and cyclictest I see as max immediately after start in idle: UP : ~90us SMP: ~50us UP + TWD: ~20us. Based on this numbers I prefer the TWD over the slightly slower MXC timer. Signed-off-by: Sebastian Andrzej Siewior --- arch/arm/mach-imx/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig index 8ceda2844c4f..08bcf8fb76f2 100644 --- a/arch/arm/mach-imx/Kconfig +++ b/arch/arm/mach-imx/Kconfig @@ -524,7 +524,7 @@ config SOC_IMX6Q bool "i.MX6 Quad/DualLite support" select ARM_ERRATA_764369 if SMP select HAVE_ARM_SCU if SMP - select HAVE_ARM_TWD if SMP + select HAVE_ARM_TWD select PCI_DOMAINS if PCI select PINCTRL_IMX6Q select SOC_IMX6