From patchwork Tue Aug 20 15:45:11 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leonard Crestez X-Patchwork-Id: 11104123 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E9C911395 for ; Tue, 20 Aug 2019 15:45:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C7A4B22DA9 for ; Tue, 20 Aug 2019 15:45:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730387AbfHTPp3 (ORCPT ); Tue, 20 Aug 2019 11:45:29 -0400 Received: from inva021.nxp.com ([92.121.34.21]:39176 "EHLO inva021.nxp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726879AbfHTPp3 (ORCPT ); Tue, 20 Aug 2019 11:45:29 -0400 Received: from inva021.nxp.com (localhost [127.0.0.1]) by inva021.eu-rdc02.nxp.com (Postfix) with ESMTP id 3FBE12002A9; Tue, 20 Aug 2019 17:45:27 +0200 (CEST) Received: from inva024.eu-rdc02.nxp.com (inva024.eu-rdc02.nxp.com [134.27.226.22]) by inva021.eu-rdc02.nxp.com (Postfix) with ESMTP id 229812001B7; Tue, 20 Aug 2019 17:45:27 +0200 (CEST) Received: from fsr-ub1864-112.ea.freescale.net (fsr-ub1864-112.ea.freescale.net [10.171.82.98]) by inva024.eu-rdc02.nxp.com (Postfix) with ESMTP id 1D2A420604; Tue, 20 Aug 2019 17:45:26 +0200 (CEST) From: Leonard Crestez To: Stephen Boyd , Shawn Guo , MyungJoo Ham , Chanwoo Choi , Rob Herring Cc: Kyungmin Park , Mark Rutland , Michael Turquette , =?utf-8?b?QXJ0dXIgxZp3aWdvxYQ=?= , Saravana Kannan , Krzysztof Kozlowski , Alexandre Bailon , Georgi Djakov , Dong Aisheng , Abel Vesa , Jacky Bai , Anson Huang , Fabio Estevam , Viresh Kumar , devicetree@vger.kernel.org, linux-pm@vger.kernel.org, linux-clk@vger.kernel.org, linux-imx@nxp.com, kernel@pengutronix.de, linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 6/7] PM / devfreq: imx-ddrc: Measure bandwidth with perf Date: Tue, 20 Aug 2019 18:45:11 +0300 Message-Id: <7ecf82d17b1afaf095c582055b1c5882045833cb.1566315740.git.leonard.crestez@nxp.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: In-Reply-To: References: X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org The imx8m ddrc has a performance monitoring block attached which can be used to measure bandwidth usage and automatically adjust frequency. There is already a perf driver for that block so instead of implementing a devfreq events driver use the in-kernel perf API to implement get_dev_status directly. Signed-off-by: Leonard Crestez --- drivers/devfreq/imx-ddrc.c | 146 ++++++++++++++++++++++++++++++++++++- 1 file changed, 143 insertions(+), 3 deletions(-) diff --git a/drivers/devfreq/imx-ddrc.c b/drivers/devfreq/imx-ddrc.c index 253138f608e7..f9a11a1825ea 100644 --- a/drivers/devfreq/imx-ddrc.c +++ b/drivers/devfreq/imx-ddrc.c @@ -11,10 +11,13 @@ #include #include #include #include +#include +#include + #define IMX_SIP_DDR_DVFS 0xc2000004 /* Values starting from 0 switch to specific frequency */ #define IMX_SIP_DDR_FREQ_SET_HIGH 0x00 @@ -80,10 +83,22 @@ struct imx_ddrc { struct clk *dram_alt; struct clk *dram_apb; int freq_count; struct imx_ddrc_freq freq_table[IMX_DDRC_MAX_FREQ_COUNT]; + + /* For measuring load with perf events: */ + struct platform_device *pmu_pdev; + struct pmu *pmu; + + struct perf_event_attr rd_event_attr; + struct perf_event_attr wr_event_attr; + struct perf_event *rd_event; + struct perf_event *wr_event; + + u64 last_rd_val, last_rd_ena, last_rd_run; + u64 last_wr_val, last_wr_ena, last_wr_run; }; static struct imx_ddrc_freq *imx_ddrc_find_freq(struct imx_ddrc *priv, unsigned long rate) { @@ -228,19 +243,127 @@ static int imx_ddrc_get_cur_freq(struct device *dev, unsigned long *freq) return 0; } static int imx_ddrc_get_dev_status(struct device *dev, - struct devfreq_dev_status *stat) + struct devfreq_dev_status *stat) { struct imx_ddrc *priv = dev_get_drvdata(dev); - stat->busy_time = 0; - stat->total_time = 0; stat->current_frequency = clk_get_rate(priv->dram_core); + if (priv->rd_event && priv->wr_event) { + u64 rd_delta, rd_val, rd_ena, rd_run; + u64 wr_delta, wr_val, wr_ena, wr_run; + + rd_val = perf_event_read_value(priv->rd_event, + &rd_ena, &rd_run); + wr_val = perf_event_read_value(priv->wr_event, + &wr_ena, &wr_run); + + rd_delta = (rd_val - priv->last_rd_val) * + (rd_ena - priv->last_rd_ena) / + (rd_run - priv->last_rd_run); + priv->last_rd_val = rd_val; + priv->last_rd_ena = rd_ena; + priv->last_rd_run = rd_run; + wr_delta = (wr_val - priv->last_wr_val) * + (wr_ena - priv->last_wr_ena) / + (wr_run - priv->last_wr_run); + priv->last_wr_val = wr_val; + priv->last_wr_ena = wr_ena; + priv->last_wr_run = wr_run; + + /* magic numbers, possibly wrong */ + stat->busy_time = 4 * (rd_delta + wr_delta); + stat->total_time = stat->current_frequency; + } else { + stat->busy_time = 0; + stat->total_time = 0; + } + + return 0; +} + +static int imx_ddrc_perf_disable(struct imx_ddrc *priv) +{ + /* release and set to NULL */ + if (!IS_ERR_OR_NULL(priv->rd_event)) + perf_event_release_kernel(priv->rd_event); + if (!IS_ERR_OR_NULL(priv->wr_event)) + perf_event_release_kernel(priv->wr_event); + priv->rd_event = NULL; + priv->wr_event = NULL; + + return 0; +} + +static int imx_ddrc_perf_enable(struct imx_ddrc *priv) +{ + int ret; + + priv->rd_event_attr.size = sizeof(priv->rd_event_attr); + priv->rd_event_attr.type = priv->pmu->type; + priv->rd_event_attr.config = 0x2a; + + priv->rd_event = perf_event_create_kernel_counter( + &priv->rd_event_attr, 0, NULL, NULL, NULL); + if (IS_ERR(priv->rd_event)) { + ret = PTR_ERR(priv->rd_event); + goto err; + } + + priv->wr_event_attr.size = sizeof(priv->wr_event_attr); + priv->wr_event_attr.type = priv->pmu->type; + priv->wr_event_attr.config = 0x2b; + + priv->wr_event = perf_event_create_kernel_counter( + &priv->wr_event_attr, 0, NULL, NULL, NULL); + if (IS_ERR(priv->wr_event)) { + ret = PTR_ERR(priv->wr_event); + goto err; + } + return 0; + +err: + imx_ddrc_perf_disable(priv); + return ret; +} + +static int imx_ddrc_init_events(struct device *dev, + struct device_node *events_node) +{ + struct imx_ddrc *priv = dev_get_drvdata(dev); + struct device_driver *driver; + + /* + * We need pmu->type for perf_event_attr but there is no API for + * mapping device_node to pmu. Fetch private data for imx-ddr-pmu and + * cast that to a struct pmu instead. + */ + priv->pmu_pdev = of_find_device_by_node(events_node); + if (!priv->pmu_pdev) + return -EPROBE_DEFER; + driver = priv->pmu_pdev->dev.driver; + if (!driver) + return -EPROBE_DEFER; + if (strcmp(driver->name, "imx-ddr-pmu")) { + dev_warn(dev, "devfreq-events node %pOF has unexpected driver %s\n", + events_node, driver->name); + return -ENODEV; + } + + priv->pmu = platform_get_drvdata(priv->pmu_pdev); + if (!priv->pmu) { + dev_err(dev, "devfreq-events device missing private data\n"); + return -EINVAL; + } + + dev_dbg(dev, "events from pmu %s\n", priv->pmu->name); + + return imx_ddrc_perf_enable(priv); } static int imx_ddrc_init_freq_info(struct device *dev) { struct imx_ddrc *priv = dev_get_drvdata(dev); @@ -288,10 +411,15 @@ static int imx_ddrc_init_freq_info(struct device *dev) return 0; } static void imx_ddrc_exit(struct device *dev) { + struct imx_ddrc *priv = dev_get_drvdata(dev); + + imx_ddrc_perf_disable(priv); + platform_device_put(priv->pmu_pdev); + dev_pm_opp_of_remove_table(dev); } static int imx_ddrc_probe(struct platform_device *pdev) { @@ -337,10 +465,20 @@ static int imx_ddrc_probe(struct platform_device *pdev) priv->profile.get_dev_status = imx_ddrc_get_dev_status; priv->profile.exit = imx_ddrc_exit; priv->profile.get_cur_freq = imx_ddrc_get_cur_freq; priv->profile.initial_freq = clk_get_rate(priv->dram_core); + /* Handle devfreq-events */ + events_node = of_parse_phandle(dev->of_node, "devfreq-events", 0); + if (events_node) { + ret = imx_ddrc_init_events(dev, events_node); + of_node_put(events_node); + if (ret) + goto err; + gov = DEVFREQ_GOV_SIMPLE_ONDEMAND; + } + priv->devfreq = devm_devfreq_add_device(dev, &priv->profile, gov, NULL); if (IS_ERR(priv->devfreq)) { ret = PTR_ERR(priv->devfreq); dev_err(dev, "failed to add devfreq device: %d\n", ret); @@ -348,10 +486,12 @@ static int imx_ddrc_probe(struct platform_device *pdev) } return 0; err: + imx_ddrc_perf_disable(priv); + platform_device_put(priv->pmu_pdev); dev_pm_opp_of_remove_table(dev); return ret; } static const struct of_device_id imx_ddrc_of_match[] = {