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[188.155.174.239]) by smtp.gmail.com with ESMTPSA id ky5-20020a170907778500b006d1b2dd8d4csm5197701ejc.99.2022.03.07.13.51.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 07 Mar 2022 13:51:29 -0800 (PST) Message-ID: <8ee350be-b3a6-ce39-03bf-95d51fb8ff1b@canonical.com> Date: Mon, 7 Mar 2022 22:51:28 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH 2/3] devfreq: mediatek: add mt8183 cci devfreq driver Content-Language: en-US To: Tim Chang , MyungJoo Ham , Kyungmin Park , Chanwoo Choi , Rob Herring , Matthias Brugger , Liam Girdwood , Mark Brown Cc: linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, fan.chen@mediatek.com, louis.yu@mediatek.com, roger.lu@mediatek.com, Allen-yy.Lin@mediatek.com, Project_Global_Chrome_Upstream_Group@mediatek.com, hsinyi@google.com, Jia-Wei Chang References: <20220307122513.11822-1-jia-wei.chang@mediatek.com> <20220307122513.11822-3-jia-wei.chang@mediatek.com> From: Krzysztof Kozlowski In-Reply-To: <20220307122513.11822-3-jia-wei.chang@mediatek.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/03/2022 13:25, Tim Chang wrote: > This adds a devfreq driver for the Cache Coherent Interconnect (CCI) of > the Mediatek MT8183. > > On mt8183 the cci is supplied by the same regulator as the little cores. > The driver is notified when the regulator voltage changes (driven by > cpufreq) and adjusts the cci frequency to the maximum possible value. > > Add need_voltage_tracking variable to platforma data. if true, it > indicates soc is required to realize the voltage tracking between > voltage of sram and voltage of cci by software approach. otherwise, the > voltage tracking is realized by hardware appraoch. > > Add the notifier to cci so that it could react after svs driver changes > opp table of cci. > > Signed-off-by: Jia-Wei Chang > --- > drivers/devfreq/Kconfig | 11 +- > drivers/devfreq/Makefile | 2 +- > drivers/devfreq/mtk-cci-devfreq.c | 471 ++++++++++++++++++++++++++++++ > 3 files changed, 482 insertions(+), 2 deletions(-) > create mode 100644 drivers/devfreq/mtk-cci-devfreq.c > > diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig > index 1ec36ae93f31..a6be3c6b5691 100644 > --- a/drivers/devfreq/Kconfig > +++ b/drivers/devfreq/Kconfig > @@ -110,7 +110,7 @@ config ARM_IMX8M_DDRC_DEVFREQ > > config ARM_MT8183_CCI_DEVFREQ > tristate "MT8183 CCI DEVFREQ Driver" > - depends on ARM_MEDIATEK_CPUFREQ > + depends on OF && ARM_MEDIATEK_CPUFREQ Why do you need that dependency? Isn't your arch already OF-only? > help > This adds a devfreq driver for Cache Coherent Interconnect > of Mediatek MT8183, which is shared the same regulator > @@ -130,6 +130,15 @@ config ARM_TEGRA_DEVFREQ > It reads ACTMON counters of memory controllers and adjusts the > operating frequencies and voltages with OPP support. > > +config ARM_MEDIATEK_CCI_DEVFREQ > + tristate "MEDIATEK CCI DEVFREQ Driver" > + depends on OF && ARM_MEDIATEK_CPUFREQ > + help > + This adds a devfreq driver for Mediatek Cache Coherent Interconnect > + 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. > + > config ARM_RK3399_DMC_DEVFREQ > tristate "ARM RK3399 DMC DEVFREQ Driver" > depends on (ARCH_ROCKCHIP && HAVE_ARM_SMCCC) || \ > diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile > index 991ef7740759..0493516a16f2 100644 > --- a/drivers/devfreq/Makefile > +++ b/drivers/devfreq/Makefile > @@ -11,7 +11,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += governor_passive.o > obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ) += exynos-bus.o > obj-$(CONFIG_ARM_IMX_BUS_DEVFREQ) += imx-bus.o > obj-$(CONFIG_ARM_IMX8M_DDRC_DEVFREQ) += imx8m-ddrc.o > -obj-$(CONFIG_ARM_MT8183_CCI_DEVFREQ) += mt8183-cci-devfreq.o > +obj-$(CONFIG_ARM_MEDIATEK_CCI_DEVFREQ) += mtk-cci-devfreq.o How is this related? You say in commit subject and description that you add a devfreq driver. But here you remove some other file... > obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ) += rk3399_dmc.o > obj-$(CONFIG_ARM_TEGRA_DEVFREQ) += tegra30-devfreq.o > > diff --git a/drivers/devfreq/mtk-cci-devfreq.c b/drivers/devfreq/mtk-cci-devfreq.c > new file mode 100644 > index 000000000000..986f34689f5c > --- /dev/null > +++ b/drivers/devfreq/mtk-cci-devfreq.c > @@ -0,0 +1,471 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (C) 2022 MediaTek Inc. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +struct mtk_ccifreq_platform_data; Move struct mtk_ccifreq_platform_data definition here. No need for forward declaration. > + > +struct mtk_ccifreq_drv { > + struct device *cci_dev; > + struct devfreq *devfreq; > + struct regulator *proc_reg; > + struct regulator *sram_reg; > + struct clk *cci_clk; > + struct clk *inter_clk; > + int inter_voltage; > + int old_voltage; > + unsigned long old_freq; > + struct mutex lock; /* avoid notify and policy race condition */ > + struct notifier_block opp_nb; > + const struct mtk_ccifreq_platform_data *soc_data; > +}; > + > +struct mtk_ccifreq_platform_data { > + int min_volt_shift; > + int max_volt_shift; > + int proc_max_volt; > + int sram_min_volt; > + int sram_max_volt; > + bool need_voltage_tracking; > +}; > + > +static int mtk_ccifreq_voltage_tracking(struct mtk_ccifreq_drv *drv, int new_voltage) > +{ > + const struct mtk_ccifreq_platform_data *soc_data = drv->soc_data; > + struct regulator *proc_reg = drv->proc_reg; > + struct regulator *sram_reg = drv->sram_reg; > + int old_voltage, old_vsram, new_vsram, vsram, voltage, ret; > + > + old_voltage = regulator_get_voltage(proc_reg); > + if (old_voltage < 0) { > + pr_err("%s: invalid vproc value: %d\n", __func__, old_voltage); > + return old_voltage; > + } > + > + old_vsram = regulator_get_voltage(sram_reg); > + if (old_vsram < 0) { > + pr_err("%s: invalid vsram value: %d\n", __func__, old_vsram); > + return old_vsram; > + } > + > + new_vsram = clamp(new_voltage + soc_data->min_volt_shift, > + soc_data->sram_min_volt, soc_data->sram_max_volt); > + > + do { > + if (old_voltage <= new_voltage) { > + vsram = clamp(old_voltage + soc_data->max_volt_shift, > + soc_data->sram_min_volt, new_vsram); > + ret = regulator_set_voltage(sram_reg, vsram, > + soc_data->sram_max_volt); > + if (ret) > + return ret; > + > + if (vsram == soc_data->sram_max_volt || > + new_vsram == soc_data->sram_min_volt) > + voltage = new_voltage; > + else > + voltage = vsram - soc_data->min_volt_shift; > + > + ret = regulator_set_voltage(proc_reg, voltage, > + soc_data->proc_max_volt); > + if (ret) { > + regulator_set_voltage(sram_reg, old_vsram, > + soc_data->sram_max_volt); > + return ret; > + } > + } else if (old_voltage > new_voltage) { > + voltage = max(new_voltage, > + old_vsram - soc_data->max_volt_shift); > + ret = regulator_set_voltage(proc_reg, voltage, > + soc_data->proc_max_volt); > + if (ret) > + return ret; > + > + if (voltage == new_voltage) > + vsram = new_vsram; > + else > + vsram = max(new_vsram, > + voltage + soc_data->min_volt_shift); > + > + ret = regulator_set_voltage(sram_reg, vsram, > + soc_data->sram_max_volt); > + if (ret) { > + regulator_set_voltage(proc_reg, old_voltage, > + soc_data->proc_max_volt); > + return ret; > + } > + } > + > + old_voltage = voltage; > + old_vsram = vsram; > + } while (voltage != new_voltage || vsram != new_vsram); > + > + return 0; > +} > + > +static int mtk_ccifreq_set_voltage(struct mtk_ccifreq_drv *drv, int voltage) > +{ > + int ret; > + > + if (drv->soc_data->need_voltage_tracking) > + ret = mtk_ccifreq_voltage_tracking(drv, voltage); > + else > + ret = regulator_set_voltage(drv->proc_reg, voltage, > + drv->soc_data->proc_max_volt); > + > + if (!ret) > + drv->old_voltage = voltage; > + > + return ret; > +} > + > +static int mtk_ccifreq_target(struct device *dev, unsigned long *freq, > + u32 flags) > +{ > + struct mtk_ccifreq_drv *drv = dev_get_drvdata(dev); > + struct clk *cci_pll = clk_get_parent(drv->cci_clk); > + struct dev_pm_opp *opp; > + unsigned long opp_rate; > + int voltage, old_voltage, inter_voltage, target_voltage, ret; > + > + if (!drv) > + return -EINVAL; > + > + if (drv->old_freq == *freq) > + return 0; > + > + inter_voltage = drv->inter_voltage; > + > + opp_rate = *freq; > + opp = devfreq_recommended_opp(dev, &opp_rate, 1); > + if (IS_ERR(opp)) { > + pr_err("cci: failed to find opp for freq: %ld\n", opp_rate); dev_err() everywhere. > + return PTR_ERR(opp); > + } > + voltage = dev_pm_opp_get_voltage(opp); > + dev_pm_opp_put(opp); > + > + old_voltage = drv->old_voltage; > + if (old_voltage == 0) > + old_voltage = regulator_get_voltage(drv->proc_reg); > + if (old_voltage < 0) { > + pr_err("cci: invalid vproc value: %d\n", old_voltage); > + return old_voltage; > + } > + > + mutex_lock(&drv->lock); > + > + /* scale up: set voltage first then freq. */ > + target_voltage = max(inter_voltage, voltage); > + if (old_voltage <= target_voltage) { > + ret = mtk_ccifreq_set_voltage(drv, target_voltage); > + if (ret) { > + pr_err("cci: failed to scale up voltage\n"); > + mtk_ccifreq_set_voltage(drv, old_voltage); > + mutex_unlock(&drv->lock); > + return ret; > + } > + } > + > + /* switch the cci clock to intermediate clock source. */ > + ret = clk_set_parent(drv->cci_clk, drv->inter_clk); > + if (ret) { > + pr_err("cci: failed to re-parent cci clock\n"); > + mtk_ccifreq_set_voltage(drv, old_voltage); > + WARN_ON(1); Debug code... please clean up your driver. > + mutex_unlock(&drv->lock); > + return ret; > + } > + > + /* set the original clock to target rate. */ > + ret = clk_set_rate(cci_pll, *freq); > + if (ret) { > + pr_err("cci: failed to set cci pll rate: %d\n", ret); > + clk_set_parent(drv->cci_clk, cci_pll); > + mtk_ccifreq_set_voltage(drv, old_voltage); > + mutex_unlock(&drv->lock); > + return ret; > + } > + > + /* switch the cci clock back to the original clock source. */ > + ret = clk_set_parent(drv->cci_clk, cci_pll); > + if (ret) { > + pr_err("cci: failed to re-parent cci clock\n"); > + mtk_ccifreq_set_voltage(drv, inter_voltage); > + WARN_ON(1); > + mutex_unlock(&drv->lock); Use goto to error handling pattern. > + return ret; > + } > + > + /* > + * If the new voltage is lower than the intermediate voltage or the > + * original voltage, scale down to the new voltage. > + */ > + if (voltage < inter_voltage || voltage < old_voltage) { > + ret = mtk_ccifreq_set_voltage(drv, voltage); > + if (ret) { > + pr_err("cci: failed to scale down voltage\n"); > + WARN_ON(1); > + mutex_unlock(&drv->lock); > + return ret; > + } > + } > + > + drv->old_freq = *freq; > + mutex_unlock(&drv->lock); > + > + return 0; > +} > + > +static int mtk_ccifreq_opp_notifier(struct notifier_block *nb, > + unsigned long event, void *data) > +{ > + struct dev_pm_opp *opp = data; > + struct mtk_ccifreq_drv *drv; > + unsigned long freq, volt; > + > + drv = container_of(nb, struct mtk_ccifreq_drv, opp_nb); > + > + if (event == OPP_EVENT_ADJUST_VOLTAGE) { > + freq = dev_pm_opp_get_freq(opp); > + > + mutex_lock(&drv->lock); > + /* current opp item is changed */ > + if (freq == drv->old_freq) { > + volt = dev_pm_opp_get_voltage(opp); > + mtk_ccifreq_set_voltage(drv, volt); > + } > + mutex_unlock(&drv->lock); > + } > + > + return 0; > +} > + > +static struct devfreq_dev_profile mtk_ccifreq_profile = { > + .target = mtk_ccifreq_target, > +}; > + > +static int mtk_ccifreq_probe(struct platform_device *pdev) > +{ > + struct device *cci_dev = &pdev->dev; > + struct mtk_ccifreq_drv *drv; > + struct devfreq_passive_data *passive_data; > + struct dev_pm_opp *opp; > + unsigned long rate, opp_volt; > + int ret; > + > + drv = devm_kzalloc(cci_dev, sizeof(*drv), GFP_KERNEL); > + if (!drv) > + return -ENOMEM; > + > + drv->cci_dev = cci_dev; > + drv->soc_data = (const struct mtk_ccifreq_platform_data *) > + of_device_get_match_data(&pdev->dev); > + mutex_init(&drv->lock); > + platform_set_drvdata(pdev, drv); > + > + drv->cci_clk = devm_clk_get(cci_dev, "cci"); > + if (IS_ERR(drv->cci_clk)) { > + ret = PTR_ERR(drv->cci_clk); > + return dev_err_probe(cci_dev, ret, > + "cci: failed to get cci clk: %d\n", > + ret); > + } > + > + drv->inter_clk = devm_clk_get(cci_dev, "intermediate"); > + if (IS_ERR(drv->inter_clk)) { > + ret = PTR_ERR(drv->inter_clk); > + return dev_err_probe(cci_dev, ret, > + "cci: failed to get intermediate clk: %d\n", > + ret); > + } > + > + if (drv->soc_data->need_voltage_tracking) { > + drv->sram_reg = regulator_get_optional(cci_dev, "sram"); > + if (IS_ERR_OR_NULL(drv->sram_reg)) { NULL pointer cannot be returned. Best regards, Krzysztof