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 X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 976F8ECDFD0 for ; Fri, 14 Sep 2018 12:53:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E2EA20881 for ; Fri, 14 Sep 2018 12:53:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="fTHZZPgy"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="Sa4nt4V1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E2EA20881 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728362AbeINSH6 (ORCPT ); Fri, 14 Sep 2018 14:07:58 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:57690 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728100AbeINSH6 (ORCPT ); Fri, 14 Sep 2018 14:07:58 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id D6F43608C9; Fri, 14 Sep 2018 12:53:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1536929615; bh=PbJ9Qwh6/14CfAMHLYNV1jf8m7MxovqM3biHARCR+L8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=fTHZZPgywnIlVpaVCnKueqdOpZQCM95sPXRcdJ5OPAWS63mBhECiTTvt6ChcQtHsg Pmta2HEdIOeADNWUm0Nxc9T7v2Pk9p0sch6LXRol53q48O+zmk3za0K2MXZOEGztuE diYxNgLns/hfzGc4amAP8SrsysfFZPs2X5qVzLe8= Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id 3C8EF6081C; Fri, 14 Sep 2018 12:53:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1536929614; bh=PbJ9Qwh6/14CfAMHLYNV1jf8m7MxovqM3biHARCR+L8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Sa4nt4V15UTG9yFCnlfYF20Wu8TdUu746iZQVEPGvksLrjJPq3B7hogD+TqMBztj5 MTnXTthAJyueT684QntXUmHfy+P0TaI0339I+My3h3rkPuZZ0WxoysIjrbhNxkAsAo qNePWMHe/aq0g2nM7oSiYkhkewF8UJzWYYdf3ARM= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Fri, 14 Sep 2018 18:23:34 +0530 From: Sibi Sankar To: Saravana Kannan Cc: MyungJoo Ham , Kyungmin Park , Chanwoo Choi , Rob Herring , Mark Rutland , georgi.djakov@linaro.org, vincent.guittot@linaro.org, daidavid1@codeaurora.org, bjorn.andersson@linaro.org, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kernel-owner@vger.kernel.org, rnayak@codeaurora.org Subject: Re: [PATCH v3 2/2] PM / devfreq: Add devfreq driver for interconnect bandwidth voting In-Reply-To: <1533171465-25508-2-git-send-email-skannan@codeaurora.org> References: <1533171465-25508-2-git-send-email-skannan@codeaurora.org> Message-ID: <66c67d0b0e551aba11a83ce6a840ad29@codeaurora.org> X-Sender: sibis@codeaurora.org User-Agent: Roundcube Webmail/1.2.5 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Saravana, On 2018-08-02 06:27, Saravana Kannan wrote: > This driver registers itself as a devfreq device that allows devfreq > governors to make bandwidth votes for an interconnect path. This allows > applying various policies for different interconnect paths using > devfreq > governors. > > Example uses: > * Use the devfreq performance governor to set the CPU to DDR > interconnect > path for maximum performance. > * Use the devfreq performance governor to set the GPU to DDR > interconnect > path for maximum performance. > * Use the CPU frequency to device frequency mapping governor to scale > the > DDR frequency based on the needs of the CPUs' current frequency. > > Signed-off-by: Saravana Kannan > --- > Documentation/devicetree/bindings/devfreq/icbw.txt | 21 ++++ > drivers/devfreq/Kconfig | 13 +++ > drivers/devfreq/Makefile | 1 + > drivers/devfreq/devfreq_icbw.c | 116 > +++++++++++++++++++++ > 4 files changed, 151 insertions(+) > create mode 100644 Documentation/devicetree/bindings/devfreq/icbw.txt > create mode 100644 drivers/devfreq/devfreq_icbw.c > > diff --git a/Documentation/devicetree/bindings/devfreq/icbw.txt > b/Documentation/devicetree/bindings/devfreq/icbw.txt > new file mode 100644 > index 0000000..36cf045 > --- /dev/null > +++ b/Documentation/devicetree/bindings/devfreq/icbw.txt > @@ -0,0 +1,21 @@ > +Interconnect bandwidth device > + > +icbw is a device that represents an interconnect path that connects > two > +devices. This device is typically used to vote for BW requirements > between > +two devices. Eg: CPU to DDR, GPU to DDR, etc > + > +Required properties: > +- compatible: Must be "devfreq-icbw" > +- interconnects: Pairs of phandles and interconnect provider specifier > + to denote the edge source and destination ports of > + the interconnect path. See also: > + Documentation/devicetree/bindings/interconnect/interconnect.txt > +- interconnect-names: Must have one entry with the name "path". > + > +Example: > + > + qcom,cpubw { > + compatible = "devfreq-icbw"; > + interconnects = <&snoc MASTER_APSS_1 &bimc SLAVE_EBI_CH0>; > + interconnect-names = "path"; > + }; > diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig > index 3d9ae68..590370e 100644 > --- a/drivers/devfreq/Kconfig > +++ b/drivers/devfreq/Kconfig > @@ -121,6 +121,19 @@ config ARM_RK3399_DMC_DEVFREQ > It sets the frequency for the memory controller and reads > the usage counts > from hardware. > > +config DEVFREQ_ICBW > + bool "DEVFREQ device for making bandwidth votes on interconnect > paths" > + select DEVFREQ_GOV_PERFORMANCE > + select DEVFREQ_GOV_POWERSAVE > + select DEVFREQ_GOV_USERSPACE > + default n > + help > + Different devfreq governors use this devfreq device to make > + bandwidth votes for interconnect paths between different devices > + (Eg: CPU to DDR, GPU to DDR, etc). This driver provides a generic > + interface so that the devfreq governors can be shared across SoCs > + and architectures. > + > source "drivers/devfreq/event/Kconfig" > > endif # PM_DEVFREQ > diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile > index e9dc3e9..b302c5cf 100644 > --- a/drivers/devfreq/Makefile > +++ b/drivers/devfreq/Makefile > @@ -12,6 +12,7 @@ obj-$(CONFIG_DEVFREQ_GOV_CPUFREQ_MAP) += > governor_cpufreq_map.o > obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ) += exynos-bus.o > obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ) += rk3399_dmc.o > obj-$(CONFIG_ARM_TEGRA_DEVFREQ) += tegra-devfreq.o > +obj-$(CONFIG_DEVFREQ_ICBW) += devfreq_icbw.o > > # DEVFREQ Event Drivers > obj-$(CONFIG_PM_DEVFREQ_EVENT) += event/ > diff --git a/drivers/devfreq/devfreq_icbw.c > b/drivers/devfreq/devfreq_icbw.c > new file mode 100644 > index 0000000..231fb21 > --- /dev/null > +++ b/drivers/devfreq/devfreq_icbw.c > @@ -0,0 +1,116 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (c) 2013-2014, 2018, The Linux Foundation. All rights > reserved. > + */ > + > +#define pr_fmt(fmt) "icbw: " fmt > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +struct dev_data { > + struct icc_path *path; > + u32 cur_ab; > + u32 cur_pb; > + unsigned long gov_ab; > + struct devfreq *df; > + struct devfreq_dev_profile dp; > +}; > + > +static int icbw_target(struct device *dev, unsigned long *freq, u32 > flags) > +{ > + struct dev_data *d = dev_get_drvdata(dev); > + int ret; > + u32 new_pb = *freq, new_ab = d->gov_ab; > + > + if (d->cur_pb == new_pb && d->cur_ab == new_ab) > + return 0; > + > + dev_dbg(dev, "BW KBps: AB: %u PB: %u\n", new_ab, new_pb); > + > + ret = icc_set(d->path, new_ab, new_pb); > + if (ret) { > + dev_err(dev, "bandwidth request failed (%d)\n", ret); > + } else { > + d->cur_pb = new_pb; > + d->cur_ab = new_ab; > + } > + > + return ret; > +} > + > +static int icbw_get_dev_status(struct device *dev, > + struct devfreq_dev_status *stat) > +{ > + struct dev_data *d = dev_get_drvdata(dev); > + > + stat->private_data = &d->gov_ab; > + return 0; > +} > + > +static int devfreq_icbw_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct dev_data *d; > + struct devfreq_dev_profile *p; > + > + d = devm_kzalloc(dev, sizeof(*d), GFP_KERNEL); > + if (!d) > + return -ENOMEM; > + dev_set_drvdata(dev, d); > + > + p = &d->dp; > + p->polling_ms = 50; > + p->target = icbw_target; > + p->get_dev_status = icbw_get_dev_status; > + > + d->path = of_icc_get(dev, "path"); > + if (IS_ERR(d->path)) { > + dev_err(dev, "Unable to register interconnect path\n"); > + return -ENODEV; > + } The probe fails if the provider is not registered yet. Worked around it using -EPROBE_DEFER but this should probably come from of_icc_get itself. > + > + d->df = devfreq_add_device(dev, p, "performance", NULL); > + if (IS_ERR(d->df)) { > + icc_put(d->path); > + return PTR_ERR(d->df); > + } devfreq_add_device will fail with -EINVAL for set_table_freq, find_available_min_freq and find_available_max_freq. If you end up working your way around it, I still ended up getting multiple errors like "Couldn't update frequency transition information" after probing. > + > + return 0; > +} > + > +static int devfreq_icbw_remove(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct dev_data *d = dev_get_drvdata(dev); > + > + devfreq_remove_device(d->df); > + icc_put(d->path); > + return 0; > +} > + > +static const struct of_device_id icbw_match_table[] = { > + { .compatible = "devfreq-icbw" }, > + {} > +}; > + > +static struct platform_driver icbw_driver = { > + .probe = devfreq_icbw_probe, > + .remove = devfreq_icbw_remove, > + .driver = { > + .name = "devfreq-icbw", > + .of_match_table = icbw_match_table, > + }, > +}; > + > +module_platform_driver(icbw_driver); > +MODULE_DESCRIPTION("Interconnect bandwidth voting driver"); > +MODULE_LICENSE("GPL v2"); -- -- Sibi Sankar -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.