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 C56D8FF885A for ; Tue, 28 Apr 2026 20:16:59 +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:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=B3kVqp2D30ZiifaCkY7PynVemZLjHxNADA2gX5jVbtM=; b=NM2ZaP+GV33H7reZqutg2yOKU8 lPggBjia8N/Kep57MwrG0TBGlvmkgVB58R69AZBkVheCDuRuad0nJGB0WbgsLk4W5NJJUvIwuIU0B 1CkAvKTV0eb5VJxhBE5jZ51wr4Sf6hq8ZAl+UWZ6Bk5IVo2IFzIdVMeQJ+N9bSkURPRyYFA2DeEXJ 8lN4BzHz0GXMq4iLulDiOQvImKKLtjBvUrrhxFAUpeFVA/yVLTjJHAlXA6rutabl2DJRCW9ZEMRPh jmDXlAzDq0ZhDpStsjwsiHVObYmHHfYrMxMJP/hLguuzsakWKvUNhPlQncYnocjyJG4oiQgydAYwR eA+Yn39Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wHorT-00000002OzL-0URH; Tue, 28 Apr 2026 20:16:51 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wHorP-00000002Ot2-2ujO for linux-arm-kernel@bombadil.infradead.org; Tue, 28 Apr 2026 20:16:47 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=B3kVqp2D30ZiifaCkY7PynVemZLjHxNADA2gX5jVbtM=; b=i87wXp8pY9N+HCJnZ5LX46CLl+ SXsod8zWzASVRuqJAV2LpA+9U+DGAmmXgK7g4pmTE8zY7RrBXaDid2f8dXKfbHmFgvCS8gx3P5bVq IOCqfazD52Eil7Dx2gsnxpzh5naRFmMNxJiildifis5c4TLp+xFmw3xTvztmffe1CojmTh/lIHGL6 C1hGFx1zsr63fBPwQtg/yKhYK0WxjdK1tyizZ7/6StqHQyc54jJBv/QuoDevw5KhTqPicCBO80GxM g31YHoxcA74Kd+wXk2/QUNMm6Dd9swzRf356OUq63X0Kv6k7XQYL4xbnNz9XVfAFJjGW7BLghm7N3 5LF/h8Pw==; Received: from foss.arm.com ([217.140.110.172]) by casper.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wHorI-00000004Olk-46SJ for linux-arm-kernel@lists.infradead.org; Tue, 28 Apr 2026 20:16:46 +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 4BBC13295; Tue, 28 Apr 2026 13:16:31 -0700 (PDT) Received: from pluto.fritz.box (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 043A73F763; Tue, 28 Apr 2026 13:16:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1777407396; bh=FouQA+bv5j1EdgH3z1eqPEIT8/R9xB/bagn+V+J4Zec=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MFx+FfVS7ekISqM2rC0y9p6YaqHj+egphpXU1nI6RUH1Fy1d+2YVVCcd7mki2DfWg Q7AizXEqaBzeIjEhKDYugYignd54bKJCO9um69zP9UWvpFfw8pyiuO0GWBQSbNdlAP WtlVihIU7iFjXmcLmDZNPrE7Vd/0EnVPdUli5Mwg= From: Cristian Marussi To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, arm-scmi@vger.kernel.org, linux-clk@vger.kernel.org, linux-renesas-soc@vger.kernel.org Cc: sudeep.holla@arm.com, philip.radford@arm.com, james.quinlan@broadcom.com, f.fainelli@gmail.com, vincent.guittot@linaro.org, etienne.carriere@foss.st.com, peng.fan@oss.nxp.com, michal.simek@amd.com, geert+renesas@glider.be, kuninori.morimoto.gx@renesas.com, marek.vasut+renesas@gmail.com, Cristian Marussi Subject: [PATCH v3 02/15] firmware: arm_scmi: Add clock determine_rate operation Date: Tue, 28 Apr 2026 21:15:09 +0100 Message-ID: <20260428201522.903875-3-cristian.marussi@arm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260428201522.903875-1-cristian.marussi@arm.com> References: <20260428201522.903875-1-cristian.marussi@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260428_211641_245985_2B9AA283 X-CRM114-Status: GOOD ( 19.45 ) 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 Add a clock operation to help determining the effective rate, closest to the required one, that a specific clock can support. Calculation is currently performed kernel side and the logic is taken directly from the SCMI Clock driver: embedding the determinate rate logic in the protocol layer enables simplifications in the SCMI Clock protocol interface and will more easily accommodate further evolutions where such determine_rate logic into is optionally delegated to the platform SCMI server. Signed-off-by: Cristian Marussi --- v1 --> v2 - use the fixed rounding algo using div64_ul Spoiler alert next SCMI spec will most probably include a new CLOCK_DETERMINE_RATE command to delegate to the platform such calculations, so this clock proto_ops will be needed anyway sooner or later --- drivers/firmware/arm_scmi/clock.c | 42 +++++++++++++++++++++++++++++++ include/linux/scmi_protocol.h | 6 +++++ 2 files changed, 48 insertions(+) diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c index ab36871650a1..54b55517b759 100644 --- a/drivers/firmware/arm_scmi/clock.c +++ b/drivers/firmware/arm_scmi/clock.c @@ -5,6 +5,7 @@ * Copyright (C) 2018-2022 ARM Ltd. */ +#include #include #include #include @@ -624,6 +625,46 @@ static int scmi_clock_rate_set(const struct scmi_protocol_handle *ph, return ret; } +static int scmi_clock_determine_rate(const struct scmi_protocol_handle *ph, + u32 clk_id, unsigned long *rate) +{ + u64 fmin, fmax, ftmp; + struct scmi_clock_info *clk; + struct clock_info *ci = ph->get_priv(ph); + + if (!rate) + return -EINVAL; + + clk = scmi_clock_domain_lookup(ci, clk_id); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + /* + * If we can't figure out what rate it will be, so just return the + * rate back to the caller. + */ + if (clk->rate_discrete) + return 0; + + fmin = clk->range.min_rate; + fmax = clk->range.max_rate; + if (*rate <= fmin) { + *rate = fmin; + return 0; + } else if (*rate >= fmax) { + *rate = fmax; + return 0; + } + + ftmp = *rate - fmin; + ftmp += clk->range.step_size - 1; /* to round up */ + ftmp = div64_ul(ftmp, clk->range.step_size); + + *rate = ftmp * clk->range.step_size + fmin; + + return 0; +} + static int scmi_clock_config_set(const struct scmi_protocol_handle *ph, u32 clk_id, enum clk_state state, @@ -936,6 +977,7 @@ static const struct scmi_clk_proto_ops clk_proto_ops = { .info_get = scmi_clock_info_get, .rate_get = scmi_clock_rate_get, .rate_set = scmi_clock_rate_set, + .determine_rate = scmi_clock_determine_rate, .enable = scmi_clock_enable, .disable = scmi_clock_disable, .state_get = scmi_clock_state_get, diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h index aafaac1496b0..28579c145045 100644 --- a/include/linux/scmi_protocol.h +++ b/include/linux/scmi_protocol.h @@ -91,6 +91,10 @@ enum scmi_clock_oem_config { * @info_get: get the information of the specified clock * @rate_get: request the current clock rate of a clock * @rate_set: set the clock rate of a clock + * @determine_rate: determine the effective rate that can be supported by a + * clock calculating the closest allowed rate. + * Note that @rate is an input/output parameter used both to + * describe the requested rate and report the closest match * @enable: enables the specified clock * @disable: disables the specified clock * @state_get: get the status of the specified clock @@ -108,6 +112,8 @@ struct scmi_clk_proto_ops { u64 *rate); int (*rate_set)(const struct scmi_protocol_handle *ph, u32 clk_id, u64 rate); + int (*determine_rate)(const struct scmi_protocol_handle *ph, u32 clk_id, + unsigned long *rate); int (*enable)(const struct scmi_protocol_handle *ph, u32 clk_id, bool atomic); int (*disable)(const struct scmi_protocol_handle *ph, u32 clk_id, -- 2.53.0