From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8FA823264DD; Tue, 28 Apr 2026 20:17:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777407436; cv=none; b=Obl2f7o/yOwWxdGvjAj8Hx2qTEthP6Fzd8vD/LXipWqzD+YrauYloe+aTwtYYjs3P1v81O8CMSw7qyCRcMTX7TzdcBGMuGfzKYlKbveb7R5bq5ApHiS6IWB7hIfyaXAGIQ/koCiYMGxtBEapLCGGyobI7W7g9gAPoP+J5flBeUA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777407436; c=relaxed/simple; bh=P2pDG/wbyXu8rvvGPP+RiEpj+f5STXBcLJcHsAu83UY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Lp7YAQcGE056/1T3dScBlnorRxYCIigDFkoq5wP09qa78BrP6HY1ZYN1E6k7WoxbMCjjNiGASH1T/1OCB4CAIBSiRS7PHReNkX6gNyFBJp3beOjdgZMqja8AnZ7WC/P/AOCOxlZVPduvDiKcjfeLLLqiI5FNy5IGPYnLwiTxwPU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=mwefKaPm; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="mwefKaPm" 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 9B8401C01; Tue, 28 Apr 2026 13:17:08 -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 2DA1F3F763; Tue, 28 Apr 2026 13:17:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1777407434; bh=P2pDG/wbyXu8rvvGPP+RiEpj+f5STXBcLJcHsAu83UY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mwefKaPmm0jyQSIKhiKALsZAnUBD5homuXnTZ/E9KJK9X2uI+QGVOROS/kc7ndgUY byJn61FFion6HCwp0l5D6sE/lnrOo+yvE4lierNqg5tBQffFaurJAzZDVvDgpkfCRF sqsf8B072etWsleBq+rnQDxnw661yx2Nv8ujsJTE= 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 13/15] firmware: arm_scmi: Use bound iterators to minimize discovered rates Date: Tue, 28 Apr 2026 21:15:20 +0100 Message-ID: <20260428201522.903875-14-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> Precedence: bulk X-Mailing-List: linux-clk@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Clock rates are guaranteed to be returned in ascending order for SCMI clock protocol versions greater than 1.0: in such a case, use bounded iterators to minimize the number of message exchanges needed to discover min and max rate. Signed-off-by: Cristian Marussi --- v1 --> v2 - fixed final ret value in scmi_clock_describe_get --- drivers/firmware/arm_scmi/clock.c | 90 +++++++++++++++++++++++++++---- 1 file changed, 81 insertions(+), 9 deletions(-) diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c index 8ce889dfc87b..15a963b1edb9 100644 --- a/drivers/firmware/arm_scmi/clock.c +++ b/drivers/firmware/arm_scmi/clock.c @@ -160,6 +160,7 @@ struct scmi_clock_rate_notify_payld { struct scmi_clock_desc { u32 id; bool rate_discrete; + unsigned int tot_rates; unsigned int num_rates; u64 *rates; #define RATE_MIN 0 @@ -483,15 +484,16 @@ iter_clk_describe_update_state(struct scmi_iterator_state *st, } if (!st->max_resources) { - int num_rates = st->num_returned + st->num_remaining; + unsigned int tot_rates = st->num_returned + st->num_remaining; - p->clkd->rates = devm_kcalloc(p->dev, num_rates, + p->clkd->rates = devm_kcalloc(p->dev, tot_rates, sizeof(*p->clkd->rates), GFP_KERNEL); if (!p->clkd->rates) return -ENOMEM; /* max_resources is used by the iterators to control bounds */ - st->max_resources = st->num_returned + st->num_remaining; + p->clkd->tot_rates = tot_rates; + st->max_resources = tot_rates; } return 0; @@ -514,8 +516,8 @@ iter_clk_describe_process_response(const struct scmi_protocol_handle *ph, } static int -scmi_clock_describe_rates_get(const struct scmi_protocol_handle *ph, u32 clk_id, - struct clock_info *cinfo) +scmi_clock_describe_rates_get_full(const struct scmi_protocol_handle *ph, + struct scmi_clock_desc *clkd) { int ret; void *iter; @@ -524,7 +526,6 @@ scmi_clock_describe_rates_get(const struct scmi_protocol_handle *ph, u32 clk_id, .update_state = iter_clk_describe_update_state, .process_response = iter_clk_describe_process_response, }; - struct scmi_clock_desc *clkd = &cinfo->clkds[clk_id]; struct scmi_clk_ipriv cpriv = { .clkd = clkd, .dev = ph->dev, @@ -544,17 +545,88 @@ scmi_clock_describe_rates_get(const struct scmi_protocol_handle *ph, u32 clk_id, if (!clkd->num_rates) return 0; + if (clkd->rate_discrete) + sort(clkd->rates, clkd->num_rates, + sizeof(clkd->rates[0]), rate_cmp_func, NULL); + + return 0; +} + +static int +scmi_clock_describe_rates_get_lazy(const struct scmi_protocol_handle *ph, + struct scmi_clock_desc *clkd) +{ + struct scmi_iterator_ops ops = { + .prepare_message = iter_clk_describe_prepare_message, + .update_state = iter_clk_describe_update_state, + .process_response = iter_clk_describe_process_response, + }; + struct scmi_clk_ipriv cpriv = { + .clkd = clkd, + .dev = ph->dev, + }; + unsigned int first, last; + void *iter; + int ret; + + iter = ph->hops->iter_response_init(ph, &ops, 0, CLOCK_DESCRIBE_RATES, + sizeof(struct scmi_msg_clock_describe_rates), + &cpriv); + if (IS_ERR(iter)) + return PTR_ERR(iter); + + /* Try to grab a triplet, so that in case is NON-discrete we are done */ + first = 0; + last = 2; + ret = ph->hops->iter_response_run_bound(iter, &first, &last); + if (ret) + goto out; + + /* If discrete grab the last value, which should be the max */ + if (clkd->rate_discrete && clkd->tot_rates > 3) { + first = clkd->tot_rates - 1; + last = clkd->tot_rates - 1; + ret = ph->hops->iter_response_run_bound(iter, &first, &last); + } + +out: + ph->hops->iter_response_cleanup(iter); + + return ret; +} + +static int +scmi_clock_describe_rates_get(const struct scmi_protocol_handle *ph, + u32 clk_id, struct clock_info *cinfo) +{ + struct scmi_clock_desc *clkd = &cinfo->clkds[clk_id]; + int ret; + + /* + * Since only after SCMI Clock v1.0 the returned rates are guaranteed to + * be discovered in ascending order, lazy enumeration cannot be use for + * SCMI Clock v1.0 protocol. + */ + if (PROTOCOL_REV_MAJOR(ph->version) > 0x1) + ret = scmi_clock_describe_rates_get_lazy(ph, clkd); + else + ret = scmi_clock_describe_rates_get_full(ph, clkd); + + if (ret) + return ret; + + clkd->info.min_rate = clkd->rates[RATE_MIN]; if (!clkd->rate_discrete) { clkd->info.max_rate = clkd->rates[RATE_MAX]; dev_dbg(ph->dev, "Min %llu Max %llu Step %llu Hz\n", clkd->rates[RATE_MIN], clkd->rates[RATE_MAX], clkd->rates[RATE_STEP]); } else { - sort(clkd->rates, clkd->num_rates, - sizeof(clkd->rates[0]), rate_cmp_func, NULL); clkd->info.max_rate = clkd->rates[clkd->num_rates - 1]; + dev_dbg(ph->dev, "Clock:%s DISCRETE:%d -> Min %llu Max %llu\n", + clkd->info.name, clkd->rate_discrete, + clkd->info.min_rate, clkd->info.max_rate); } - clkd->info.min_rate = clkd->rates[RATE_MIN]; return 0; } -- 2.53.0