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 F208AFD4F1A for ; Tue, 10 Mar 2026 18:41:00 +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=OaoQ4PXvtW2e4SpKr55wZLfKPd /xPFX198g04OGpJEQmE19dqXMJ9Mowjcu8qomWUZknjS0cIu+lDShlk+v4fBhES2U9OToK8l1t/M4 Dgr7C2l2gGy6BHIqL3gu34RPACuFQo17KMnBBTHKaq9De39cy8P6ovU6DiZo9Bx3hEjHFbvQi9+W6 pgxK9q1KOtnySX3Ii2NO/pEm5VXeEYRoRUdpup5ILmfrfV1GcF2gqFNk3Q6ZHWpDhalzTvaSBhzoO FBA4qNaAgQEXK1OeLA2j3uuCuqa61IBcY3v7J8Qig6CS8vmPAAmNj7YIgvCoiN3RGTw6Nsb9dXdSZ i2cUVkSw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w020k-0000000A6E4-0rth; Tue, 10 Mar 2026 18:40:54 +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 1w020h-0000000A6Bd-1Jnq for linux-arm-kernel@lists.infradead.org; Tue, 10 Mar 2026 18:40:53 +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 976191596; Tue, 10 Mar 2026 11:40:43 -0700 (PDT) Received: from pluto.guest.local (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BCAD83F7BD; Tue, 10 Mar 2026 11:40:46 -0700 (PDT) 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, dan.carpenter@linaro.org, geert+renesas@glider.be, kuninori.morimoto.gx@renesas.com, marek.vasut+renesas@gmail.com, Cristian Marussi Subject: [PATCH v2 02/13] firmware: arm_scmi: Add clock determine_rate operation Date: Tue, 10 Mar 2026 18:40:19 +0000 Message-ID: <20260310184030.3669330-3-cristian.marussi@arm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260310184030.3669330-1-cristian.marussi@arm.com> References: <20260310184030.3669330-1-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-20260310_114051_447171_8FA1020A X-CRM114-Status: GOOD ( 17.64 ) 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