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 43433C10DC2 for ; Thu, 30 Nov 2023 16:26:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=jOc5lgKcjBxkUkN1hUeGvpzo4wkzvyiOPeh81UCG2DE=; b=rVOtUAbM/3tpGj CpE7Z12BPgUx/6L2YYfCAD7Ep/+XLh/xYRRSJx7FhYkRj/JCjKjDGPr7SCIBcOeJuL7dJjFjpppJw R56Ru+TYUaxrkpRdX7t+V1NfB6CqQRqzHKQ9G0vsEsmp4KjX9rBGVdZhD7g7ihVb9SGQzoJEqVIt+ hb+K5l7mLDuzyAk7ag7wUGYd3fa670HB0uD4BPJp+Lw5i5Qe4wRPbG4SZ+8Erou6eE2FdcOGYFNOH 6aI5SMetLa8kiYA8UxcBLIHEuj/igH39Ls0i9sGfb/CRuU15gIEUP9hgFqNZtGnmCgI15mpPvBMZb G76uRJJ5lBjdr8wXNonw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1r8jrO-00BLAs-11; Thu, 30 Nov 2023 16:25:54 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1r8jrL-00BL8n-1T for linux-arm-kernel@lists.infradead.org; Thu, 30 Nov 2023 16:25:52 +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 EACC81042; Thu, 30 Nov 2023 08:26:35 -0800 (PST) Received: from pluto (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 11E1B3F6C4; Thu, 30 Nov 2023 08:25:46 -0800 (PST) Date: Thu, 30 Nov 2023 16:25:44 +0000 From: Cristian Marussi To: Sudeep Holla Cc: Sibi Sankar , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, quic_mdtipton@quicinc.com, linux-arm-kernel@lists.infradead.org, quic_asartor@quicinc.com, quic_lingutla@quicinc.com Subject: Re: [PATCH 2/3] firmware: arm_scmi: Fix freq/power truncation in the perf protocol Message-ID: References: <20231129065748.19871-1-quic_sibis@quicinc.com> <20231129065748.19871-3-quic_sibis@quicinc.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231130_082551_548525_B62A25B0 X-CRM114-Status: GOOD ( 24.06 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Nov 30, 2023 at 01:56:56PM +0000, Sudeep Holla wrote: > On Thu, Nov 30, 2023 at 12:49:42PM +0000, Cristian Marussi wrote: > > On Thu, Nov 30, 2023 at 12:05:06PM +0000, Sudeep Holla wrote: > > > On Wed, Nov 29, 2023 at 12:27:47PM +0530, Sibi Sankar wrote: > > > > Fix frequency and power truncation seen in the performance protocol by > > > > casting it with the correct type. > > > > > > > > > > While I always remembered to handle this when reviewing the spec, seem to > > > have forgotten when it came to handling in the implementation :(. Thanks > > > for spotting this. > > > > > > However I don't like the ugly type casting. I think we can do better. Also > > > looking at the code around the recently added level index mode, I think we > > > can simplify things like below patch. > > > > > > Cristian, > > > What do you think ? > > > > > > > Hi > > > > the cleanup seems nice in general to compact the mult_factor multipliers > > in one place, and regarding addressing the problem of truncation without > > the need of the explicit casting, should not be enough to change to > > additionally also change mult_factor to be an u64 ? > > > > I started exactly with that, but when I completed the patch, there was no > explicit need for it, so dropped it again. I can bump mult_factor to be > u64 but do you see any other place that would need it apart from having > single statement that does multiplication and assignment ? I am exploiting > the conditional based on level_indexing_mode here but I agree it may help > in backporting if I make mult_factor u64. > Ah right freq *= dom->multi_fact; does the trick..but cannot this by itself (under unplausibl conds) overflow and does not fit into a u32 mult_factor ? dom_info->mult_factor = (dom_info->sustained_freq_khz * 1000UL) / dom_info->sustained_perf_level; Thanks, Cristian _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel