From mboxrd@z Thu Jan 1 00:00:00 1970 From: andrew-sh.cheng Subject: Re: [PATCH 3/3] devfreq: add mediatek cci devfreq Date: Tue, 12 Feb 2019 17:05:40 +0800 Message-ID: <1549962340.7155.2.camel@mtksdaap41> References: <1548743704-16821-1-git-send-email-andrew-sh.cheng@mediatek.com> <1548743704-16821-4-git-send-email-andrew-sh.cheng@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Nicolas Boichat Cc: Mark Rutland , devicetree@vger.kernel.org, srv_heupstream@mediatek.com, linux-pm@vger.kernel.org, Viresh Kumar , "Rafael J. Wysocki" , lkml , Chanwoo Choi , Kyungmin Park , Rob Herring , "moderated list:ARM/Mediatek SoC support" , MyungJoo Ham , Matthias Brugger , Fan Chen , linux-arm Mailing List List-Id: devicetree@vger.kernel.org On Fri, 2019-02-01 at 10:43 +0700, Nicolas Boichat wrote: > On Tue, Jan 29, 2019 at 1:36 PM Andrew-sh Cheng > wrote: > > > > From: "Andrew-sh.Cheng" > > > > For big/little cpu cluster architecture, > > not only CPU frequency, but CCI frequency will also affect performance. > > > > Little cores and cci share the same buck in Mediatek mt8183 IC, > > so we add a CCI devfreq which will get notification when buck voltage > > is changed, then CCI devfreq can set cci frequency as high as possible. > > > > Signed-off-by: Andrew-sh.Cheng > > --- > > drivers/devfreq/Kconfig | 9 ++ > > drivers/devfreq/Makefile | 1 + > > drivers/devfreq/mt8183-cci-devfreq.c | 224 +++++++++++++++++++++++++++++++++++ > > 3 files changed, 234 insertions(+) > > create mode 100644 drivers/devfreq/mt8183-cci-devfreq.c > > > > diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig > > index 6a172d3..0b14aab 100644 > > --- a/drivers/devfreq/Kconfig > > +++ b/drivers/devfreq/Kconfig > > @@ -113,6 +113,15 @@ config ARM_RK3399_DMC_DEVFREQ > > It sets the frequency for the memory controller and reads the usage counts > > from hardware. > > > > +config ARM_MT8183_CCI_DEVFREQ > > + tristate "MT8183 CCI DEVFREQ Driver" > > + depends on ARM_MEDIATEK_CPUFREQ > > + help > > + This adds devfreq for cci clock > > It might be nice to spell out that CCI stands for "Cache Coherent Interconnect". I will modify in next patch. > > > + which is shared the same regulator with cpu cluster. > > + It can track buck voltage and update a proper cci frequency. > > + Use notification to get regulator status. > > + > > source "drivers/devfreq/event/Kconfig" > > > > endif # PM_DEVFREQ > > diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile > > index 32b8d4d..25afe8c 100644 > > --- a/drivers/devfreq/Makefile > > +++ b/drivers/devfreq/Makefile > > @@ -11,6 +11,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += governor_passive.o > > obj-$(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-$(CONFIG_ARM_MT8183_CCI_DEVFREQ) += mt8183-cci-devfreq.o > > > > # DEVFREQ Event Drivers > > obj-$(CONFIG_PM_DEVFREQ_EVENT) += event/ > > diff --git a/drivers/devfreq/mt8183-cci-devfreq.c b/drivers/devfreq/mt8183-cci-devfreq.c > > new file mode 100644 > > index 0000000..4837892 > > --- /dev/null > > +++ b/drivers/devfreq/mt8183-cci-devfreq.c > > @@ -0,0 +1,224 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +// > > +// Copyright (c) 2018 MediaTek Inc. > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > + > > +#include "governor.h" > > + > > +struct cci_devfreq_data { > > + struct devfreq *devfreq; > > + struct regulator *proc_reg; > > + struct clk *cci_clk; > > + unsigned long buck_volt; > > + int volt_increasing; > > + struct notifier_block nb; > > +}; > > + > > +static int mtk_cci_governor_get_target(struct devfreq *devfreq, > > + unsigned long *freq) > > +{ > > + struct cci_devfreq_data *cci_devdata; > > + int i, opp_count; > > No tab here: single space between int and i. I will modify in next patch. > > > + struct dev_pm_opp *opp; > > + unsigned long opp_rate, opp_voltage; > > + > > + cci_devdata = dev_get_drvdata(devfreq->dev.parent); > > + > > + /* find available frequency */ > > + opp_count = dev_pm_opp_get_opp_count(devfreq->dev.parent); > > + for (i = 0, opp_rate = ULONG_MAX; i < opp_count; i++, opp_rate--) { > > + opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, > > + &opp_rate); > > This is quite inefficient as each call to dev_pm_opp_find_freq_floor > may go through the whole OPP table (so your loop is O(n**2), but this > can be done in O(n) by simply walking through the list). > > I'd just copy what dev_pm_opp_find_freq_ceil does > (https://elixir.bootlin.com/linux/v4.19/source/drivers/opp/core.c#L425). > Or maybe we need a new function in the opp core. I will add an API for opp framework for this in next patch > > > + opp_voltage = dev_pm_opp_get_voltage(opp); > > + dev_pm_opp_put(opp); > > + > > + if (opp_voltage <= cci_devdata->buck_volt) > > + break; > > + } > > + *freq = opp_rate; > > + > > + return 0; > > +} > > + > > +static int mtk_cci_governor_event_handler(struct devfreq *devfreq, > > + unsigned int event, void *data) > > +{ > > + return 0; > > +} > > + > > +static struct devfreq_governor mtk_cci_devfreq_governor = { > > + .name = "voltage_monitor", > > + .get_target_freq = mtk_cci_governor_get_target, > > + .event_handler = mtk_cci_governor_event_handler, > > +}; > > + > > +static int mtk_cci_devfreq_target(struct device *dev, unsigned long *freq, > > + u32 flags) > > +{ > > + struct cci_devfreq_data *cci_devdata; > > + > > + cci_devdata = dev_get_drvdata(dev); > > + > > + clk_set_rate(cci_devdata->cci_clk, *freq); > > + > > + return 0; > > +} > > + > > +static struct devfreq_dev_profile cci_devfreq_profile = { > > + .polling_ms = 0, > > + .target = mtk_cci_devfreq_target, > > +}; > > + > > +static int cci_devfreq_regulator_notifier(struct notifier_block *nb, > > + unsigned long val, void *data) > > +{ > > + struct cci_devfreq_data *cci_devdata = > > + container_of(nb, struct cci_devfreq_data, nb); > > + > > + /* deal with reduce frequency */ > > + if (val & REGULATOR_EVENT_PRE_VOLTAGE_CHANGE) { > > + struct pre_voltage_change_data *pvc_data = data; > > + > > + if (pvc_data->old_uV > pvc_data->min_uV) { > > + cci_devdata->volt_increasing = 0; > > + cci_devdata->buck_volt = > > + (unsigned long)(pvc_data->min_uV); > > + mutex_lock(&cci_devdata->devfreq->lock); > > + update_devfreq(cci_devdata->devfreq); > > + mutex_unlock(&cci_devdata->devfreq->lock); > > + } else { > > + cci_devdata->volt_increasing = 1; > > + } > > + } > > + /* deal with abort reduce frequency */ > > + if ((val & REGULATOR_EVENT_ABORT_VOLTAGE_CHANGE) || > > + /* deal with increase frequency */ > > + ((val & REGULATOR_EVENT_VOLTAGE_CHANGE) && > > + cci_devdata->volt_increasing == 1)) { > > + cci_devdata->buck_volt = (unsigned long)data; > > + mutex_lock(&cci_devdata->devfreq->lock); > > + update_devfreq(cci_devdata->devfreq); > > + mutex_unlock(&cci_devdata->devfreq->lock); > > + } > > + > > + return 0; > > +} > > + > > +static int mtk_cci_devfreq_probe(struct platform_device *pdev) > > +{ > > + struct device *cci_dev = &pdev->dev; > > + struct cci_devfreq_data *cci_devdata; > > + struct notifier_block *nb; > > + int ret; > > + > > + dev_pm_opp_of_add_table(&pdev->dev); > > + > > + cci_devdata = devm_kzalloc(cci_dev, sizeof(*cci_devdata), GFP_KERNEL); > > + if (!cci_devdata) > > + return -ENOMEM; > > + nb = &cci_devdata->nb; > > + cci_devdata->cci_clk = ERR_PTR(-ENODEV); > > This one is useless as you set cci_clk again just below. > > > + cci_devdata->proc_reg = ERR_PTR(-ENODEV); > > For this one, I'd just create 2 goto targets below, instead of those > ifs in the error path. I will modify and change to 2 goto in next patch. > > > + > > + cci_devdata->cci_clk = clk_get(cci_dev, "cci_clock"); > > + ret = PTR_ERR_OR_ZERO(cci_devdata->cci_clk); > > + if (ret) { > > + if (ret == -EPROBE_DEFER) > > + pr_err("cci clock not ready, retry\n"); > > + else > > + pr_err("no clock for cci: %d\n", ret); > > + > > + goto out_free_resources; > > + } > > + > > + cci_devdata->proc_reg = regulator_get_optional(cci_dev, "proc"); > > + ret = PTR_ERR_OR_ZERO(cci_devdata->proc_reg); > > + if (ret) { > > + if (ret == -EPROBE_DEFER) > > + pr_err("cci regulator not ready, retry\n"); > > + else > > + pr_err("no regulator for cci: %d\n", ret); > > + > > + goto out_free_resources; > > + } > > + > > + platform_set_drvdata(pdev, cci_devdata); > > + > > + /* create cci_devfreq and add to cci device. > > + * governor is voltage_monitor. > > + * governor will get platform_device data to make decision. > > + */ > > + cci_devdata->devfreq = devm_devfreq_add_device(cci_dev, > > + &cci_devfreq_profile, > > + "voltage_monitor", > > + NULL); > > + > > + nb->notifier_call = cci_devfreq_regulator_notifier; > > + regulator_register_notifier(cci_devdata->proc_reg, > > + nb); > > + > > + return 0; > > + > > +out_free_resources: > > + if (!IS_ERR(cci_devdata->cci_clk)) > > + clk_put(cci_devdata->cci_clk); > > + if (!IS_ERR(cci_devdata->proc_reg)) > > + regulator_put(cci_devdata->proc_reg); > > + > > + return ret; > > +} > > + > > +static const struct of_device_id mediatek_cci_devfreq_of_match[] = { > > + { .compatible = "mediatek,mt8183-cci" }, > > + { }, > > +}; > > +MODULE_DEVICE_TABLE(of, mediatek_cci_devfreq_of_match); > > + > > +static struct platform_driver cci_devfreq_driver = { > > + .probe = mtk_cci_devfreq_probe, > > + .driver = { > > + .name = "mediatek-cci-devfreq", > > + .of_match_table = mediatek_cci_devfreq_of_match, > > + }, > > +}; > > + > > +static int __init mtk_cci_devfreq_init(void) > > +{ > > + int ret = 0; > > + > > + ret = devfreq_add_governor(&mtk_cci_devfreq_governor); > > + if (ret) { > > + pr_err("%s: failed to add governor: %d\n", __func__, ret); > > + return ret; > > + } > > + > > + ret = platform_driver_register(&cci_devfreq_driver); > > + if (ret) > > + devfreq_remove_governor(&mtk_cci_devfreq_governor); > > + > > + return ret; > > +} > > +module_init(mtk_cci_devfreq_init) > > + > > +static void __exit mtk_cci_devfreq_exit(void) > > +{ > > + int ret = 0; > > + > > + platform_driver_unregister(&cci_devfreq_driver); > > + > > + ret = devfreq_remove_governor(&mtk_cci_devfreq_governor); > > + if (ret) > > + pr_err("%s: failed to remove governor: %d\n", __func__, ret); > > +} > > +module_exit(mtk_cci_devfreq_exit) > > + > > +MODULE_LICENSE("GPL v2"); > > +MODULE_DESCRIPTION("Mediatek CCI devfreq driver"); > > +MODULE_AUTHOR("andrew-sh.cheng"); > > + > > -- > > 1.8.1.1.dirty > > > > > > _______________________________________________ > > Linux-mediatek mailing list > > Linux-mediatek@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-mediatek > > _______________________________________________ > Linux-mediatek mailing list > Linux-mediatek@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-mediatek