From patchwork Mon Aug 1 09:54:15 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 9254149 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 400F96077C for ; Mon, 1 Aug 2016 09:55:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2EF0428407 for ; Mon, 1 Aug 2016 09:55:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 232582848E; Mon, 1 Aug 2016 09:55:18 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id A0A4628407 for ; Mon, 1 Aug 2016 09:55:17 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bU9wD-0006Z1-OS; Mon, 01 Aug 2016 09:55:09 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bU9w4-0005xE-1h; Mon, 01 Aug 2016 09:55:06 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8594A41D; Mon, 1 Aug 2016 02:56:04 -0700 (PDT) Received: from approximate.cambridge.arm.com (approximate.cambridge.arm.com [10.1.207.16]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 42D373F213; Mon, 1 Aug 2016 02:54:39 -0700 (PDT) From: Marc Zyngier To: Thomas Gleixner , Daniel Lezcano , arm@kernel.org Subject: [PATCH v2 1/2] clocksource/arm_arch_timer: Force per-CPU interrupt to be level-triggered Date: Mon, 1 Aug 2016 10:54:15 +0100 Message-Id: <1470045256-9032-2-git-send-email-marc.zyngier@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1470045256-9032-1-git-send-email-marc.zyngier@arm.com> References: <1470045256-9032-1-git-send-email-marc.zyngier@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160801_025500_327072_7579B3C0 X-CRM114-Status: GOOD ( 13.95 ) X-BeenThere: linux-amlogic@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Lunn , Liu Gang , Mark Rutland , Masahiro Yamada , Florian Fainelli , Kevin Hilman , Hou Zhiqiang , Michal Simek , Jon Hunter , Kukjin Kim , bcm-kernel-feedback-list@broadcom.com, linux-arm-kernel@lists.infradead.org, Sebastian Hesselbarth , Jason Cooper , Ray Jui , Tirumalesh Chalamarla , linux-samsung-soc@vger.kernel.org, Yuan Yao , Wenbin Song , Jan Glauber , Gregory Clement , linux-amlogic@lists.infradead.org, Mingkai Hu , soren.brinkmann@xilinx.com, Rajesh Bhagat , Scott Branden , Duc Dang , linux-kernel@vger.kernel.org, Carlo Caione , Dinh Nguyen MIME-Version: 1.0 Sender: "linux-amlogic" Errors-To: linux-amlogic-bounces+patchwork-linux-amlogic=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP The ARM architected timer produces level-triggered interrupts (this is mandated by the architecture). Unfortunately, a number of device-trees get this wrong, and expose an edge-triggered interrupt. Until now, this wasn't too much an issue, as the programming of the trigger would fail (the corresponding PPI cannot be reconfigured), and the kernel would be happy with this. But we're about to change this, and trust DT a lot if the driver doesn't provide its own trigger information. In that context, the timer breaks badly. While we do need to fix the DTs, there is also some userspace out there (kvmtool) that generates the same kind of broken DT on the fly, and that will completely break with newer kernels. As a safety measure, and to keep buggy software alive as well as buying us some time to fix DTs all over the place, let's check what trigger configuration has been given us by the firmware. If this is not a level configuration, then we know that the DT/ACPI configuration is bust, and we pick some defaults which won't be worse than the existing setup. Signed-off-by: Marc Zyngier --- drivers/clocksource/arm_arch_timer.c | 26 +++++++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 28bce3f..5770054 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -8,6 +8,9 @@ * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ + +#define pr_fmt(fmt) "arm_arch_timer: " fmt + #include #include #include @@ -370,16 +373,33 @@ static bool arch_timer_has_nonsecure_ppi(void) arch_timer_ppi[PHYS_NONSECURE_PPI]); } +static u32 check_ppi_trigger(int irq) +{ + u32 flags = irq_get_trigger_type(irq); + + if (flags != IRQF_TRIGGER_HIGH && flags != IRQF_TRIGGER_LOW) { + pr_warn("WARNING: Invalid trigger for IRQ%d, assuming level low\n", irq); + pr_warn("WARNING: Please fix your firmware\n"); + flags = IRQF_TRIGGER_LOW; + } + + return flags; +} + static int arch_timer_starting_cpu(unsigned int cpu) { struct clock_event_device *clk = this_cpu_ptr(arch_timer_evt); + u32 flags; __arch_timer_setup(ARCH_CP15_TIMER, clk); - enable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], 0); + flags = check_ppi_trigger(arch_timer_ppi[arch_timer_uses_ppi]); + enable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], flags); - if (arch_timer_has_nonsecure_ppi()) - enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], 0); + if (arch_timer_has_nonsecure_ppi()) { + flags = check_ppi_trigger(arch_timer_ppi[PHYS_NONSECURE_PPI]); + enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], flags); + } arch_counter_set_user_access(); if (evtstrm_enable)