From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2CA5BCA0EE0 for ; Wed, 13 Aug 2025 11:39:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=5U7qY17YQD06QSaz8hj3toKPlBJNvlaASJImOFX/yqw=; b=NcJN7t2+ld8NLgk883razJCHAT ddmqzPMYxtbNx1MG1CXyELw/RKEzj98XJdTqQUP8E+lophjfGXvOTMUDehwyHlo9np0si+lDK1jtA y3qqUSJoMOKhUuqhPNLCljMiaoMT/7ned2DcfCwADkwgrPOf+YeT7IFYxxY4tBVhS80UJAynirt8b dT8D0DqsnvmEflq0MnOE8PMYwgtUJQonGLqMvWAPrGvchK4QnvB1yVY84qtnHwx3iDan5DXggqUQE 2as4WPx7BwnNmn5wG0B0/z+ViqXIve5saf6ehY95sLRSbTy+FplotUjJ36ucr2aid79NyWbyayxQT gGFyuVcQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1um9p3-0000000DXHv-3Bih; Wed, 13 Aug 2025 11:39:13 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1um998-0000000DRS5-2NM3 for linux-arm-kernel@lists.infradead.org; Wed, 13 Aug 2025 10:55:55 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9F78512FC; Wed, 13 Aug 2025 03:55:45 -0700 (PDT) Received: from bogus (e133711.arm.com [10.1.196.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BE9C03F63F; Wed, 13 Aug 2025 03:55:51 -0700 (PDT) Date: Wed, 13 Aug 2025 11:55:48 +0100 From: Sudeep Holla To: Marc Zyngier Cc: linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sudeep Holla , Lorenzo Pieralisi , Hanjun Guo , "Rafael J. Wysocki" , Daniel Lezcano , Thomas Gleixner , Alexandru Elisei , Mark Rutland Subject: Re: [PATCH 0/4] clocksource: Add standalone MMIO ARM arch timer driver Message-ID: <20250813-macho-snobbish-alpaca-ff07fa@sudeepholla> References: <20250807160243.1970533-1-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250807160243.1970533-1-maz@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250813_035554_653794_03945627 X-CRM114-Status: GOOD ( 18.33 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org +Alexandru On Thu, Aug 07, 2025 at 05:02:39PM +0100, Marc Zyngier wrote: > For the past 10 years, both Mark and I have been lamenting about the > sorry state of the badly named "arch_timer" driver, and about the way > the MMIO part is intricately weaved into the system-register part. > > The time has finally come to have a stab at it. > > This small series simply creates a new timer driver for the MMIO arch > timer, and only that. It is an actual driver, and not some kludge that > has to run super early (that's what the per-CPU timers are for). This > allows, in turn, a pretty large cleanup of the per-CPU driver, though > there is more to come -- one thing at a time. > > As an added bonus, we get a clocksource, which the original code > didn't provide. Just in case it might be useful. The end-result is far > more readable, and about 100 lines smaller. > (Tested it on Juno R2 and FVP in both DT and ACPI boot) Tested-by: Sudeep Holla Reviewed-by: Sudeep Holla Alexandru found it useful(avoids some unexpected hang IIUC) in his setup based on bootwrapper which doesn't initialise MMIO timers. -- Regards, Sudeep