Hi Chen-Yu, On Fri, 2022-05-13 at 11:54 +0800, Chen-Yu Tsai wrote: > On Fri, May 13, 2022 at 11:31 AM Johnson Wang < > johnson.wang@xxxxxxxxxxxx> wrote: > > > > We introduce a devfreq driver for the MediaTek Cache Coherent > > Interconnect > > (CCI) used by some MediaTek SoCs. > > > > In this driver, we use the passive devfreq driver to get target > > frequencies > > and adjust voltages accordingly. In MT8183 and MT8186, the MediaTek > > CCI > > is supplied by the same regulators with the little core CPUs. > > > > Signed-off-by: Jia-Wei Chang <jia-wei.chang@xxxxxxxxxxxx> > > Signed-off-by: Johnson Wang <johnson.wang@xxxxxxxxxxxx> > > Acked-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx> > > --- > > This patch depends on "devfreq-testing"[1]. > > [1] > > https://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/log/?h=devfreq-testing__;!!CTRNKA9wMg0ARbw!zzOSoso9udvDV3h6kYlmizFtbn3ACA5aS2jCAjKyvtu4z0fobv1mD5uF9YbPSme8l_NnR05unTxkZfDdzohu8asWZQ$ > > > > --- > > drivers/devfreq/Kconfig | 10 + > > drivers/devfreq/Makefile | 1 + > > drivers/devfreq/mtk-cci-devfreq.c | 474 > > ++++++++++++++++++++++++++++++ > > 3 files changed, 485 insertions(+) > > create mode 100644 drivers/devfreq/mtk-cci-devfreq.c > > > > diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig > > index 87eb2b837e68..9754d8b31621 100644 > > --- a/drivers/devfreq/Kconfig > > +++ b/drivers/devfreq/Kconfig > > @@ -120,6 +120,16 @@ 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 ARM_MEDIATEK_CPUFREQ || COMPILE_TEST > > + select DEVFREQ_GOV_PASSIVE > > + help > > + This adds a devfreq driver for MediaTek Cache Coherent > > Interconnect > > + which is shared the same regulators with the cpu cluster. > > It can track > > + buck voltages and update a proper CCI frequency. Use the > > notification > > + to get the 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 0b6be92a25d9..bf40d04928d0 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-$(CONFIG_ARM_IMX_BUS_DEVFREQ) += imx-bus.o > > obj-$(CONFIG_ARM_IMX8M_DDRC_DEVFREQ) += imx8m-ddrc.o > > +obj-$(CONFIG_ARM_MEDIATEK_CCI_DEVFREQ) += mtk-cci-devfreq.o > > obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ) += rk3399_dmc.o > > obj-$(CONFIG_ARM_SUN8I_A33_MBUS_DEVFREQ) += sun8i-a33-mbus.o > > obj-$(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..aa8c37eb4a06 > > --- /dev/null > > +++ b/drivers/devfreq/mtk-cci-devfreq.c > > @@ -0,0 +1,474 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > +/* > > + * Copyright (C) 2022 MediaTek Inc. > > + */ > > + > > +#include <linux/clk.h> > > +#include <linux/devfreq.h> > > +#include <linux/minmax.h> > > +#include <linux/module.h> > > +#include <linux/of.h> > > +#include <linux/of_device.h> > > +#include <linux/platform_device.h> > > +#include <linux/pm_opp.h> > > +#include <linux/regulator/consumer.h> > > + > > +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; > > +}; > > + > > +struct mtk_ccifreq_drv { > > + struct device *dev; > > + struct devfreq *devfreq; > > + struct regulator *proc_reg; > > + struct regulator *sram_reg; > > + struct clk *cci_clk; > > + struct clk *inter_clk; > > + int inter_voltage; > > + int pre_voltage; > > + unsigned long pre_freq; > > + /* Avoid race condition for regulators between notify and > > policy */ > > + struct mutex reg_lock; > > + struct notifier_block opp_nb; > > + const struct mtk_ccifreq_platform_data *soc_data; > > + int vtrack_max; > > +}; > > + > > +static int mtk_ccifreq_set_voltage(struct mtk_ccifreq_drv *drv, > > int new_voltage) > > +{ > > + const struct mtk_ccifreq_platform_data *soc_data = drv- > > >soc_data; > > + struct device *dev = drv->dev; > > + int pre_voltage, pre_vsram, new_vsram, vsram, voltage, ret; > > + int retry_max = drv->vtrack_max; > > + > > + if (!drv->sram_reg) { > > + ret = regulator_set_voltage(drv->proc_reg, > > new_voltage, > > + drv->soc_data- > > >proc_max_volt); > > + goto out_set_voltage; > > + } > > + > > + pre_voltage = regulator_get_voltage(drv->proc_reg); > > + if (pre_voltage < 0) { > > + dev_err(dev, "invalid vproc value: %d\n", > > pre_voltage); > > + return pre_voltage; > > + } > > + > > + pre_vsram = regulator_get_voltage(drv->sram_reg); > > + if (pre_vsram < 0) { > > + dev_err(dev, "invalid vsram value: %d\n", > > pre_vsram); > > + return pre_vsram; > > + } > > + > > + new_vsram = clamp(new_voltage + soc_data->min_volt_shift, > > + soc_data->sram_min_volt, soc_data- > > >sram_max_volt); > > + > > + do { > > + if (pre_voltage <= new_voltage) { > > + vsram = clamp(pre_voltage + soc_data- > > >max_volt_shift, > > + soc_data->sram_min_volt, > > new_vsram); > > + ret = regulator_set_voltage(drv->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(drv->proc_reg, > > voltage, > > + soc_data- > > >proc_max_volt); > > + if (ret) { > > + regulator_set_voltage(drv- > > >sram_reg, pre_vsram, > > + soc_data- > > >sram_max_volt); > > + return ret; > > + } > > + } else if (pre_voltage > new_voltage) { > > + voltage = max(new_voltage, > > + pre_vsram - soc_data- > > >max_volt_shift); > > + ret = regulator_set_voltage(drv->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(drv->sram_reg, > > vsram, > > + soc_data- > > >sram_max_volt); > > + if (ret) { > > + regulator_set_voltage(drv- > > >proc_reg, pre_voltage, > > + soc_data- > > >proc_max_volt); > > + return ret; > > + } > > + } > > + > > + pre_voltage = voltage; > > + pre_vsram = vsram; > > + > > + if (--retry_max < 0) { > > + dev_err(dev, > > + "over loop count, failed to set > > voltage\n"); > > + return -EINVAL; > > + } > > + } while (voltage != new_voltage || vsram != new_vsram); > > + > > +out_set_voltage: > > + if (!ret) > > + drv->pre_voltage = new_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, pre_voltage, inter_voltage, target_voltage, > > ret; > > + > > + if (!drv) > > + return -EINVAL; > > + > > + if (drv->pre_freq == *freq) > > + return 0; > > + > > + inter_voltage = drv->inter_voltage; > > + > > + opp_rate = *freq; > > + opp = devfreq_recommended_opp(dev, &opp_rate, 1); > > + if (IS_ERR(opp)) { > > + dev_err(dev, "failed to find opp for freq: %ld\n", > > opp_rate); > > + return PTR_ERR(opp); > > + } > > + > > + mutex_lock(&drv->reg_lock); > > + > > + voltage = dev_pm_opp_get_voltage(opp); > > + dev_pm_opp_put(opp); > > + > > + if (unlikely(drv->pre_voltage <= 0)) > > + pre_voltage = regulator_get_voltage(drv->proc_reg); > > + else > > + pre_voltage = drv->pre_voltage; > > Could you explain why the previous voltage setting is cached like > this? > > The CCI is sharing the regulator supply with one of the CPU clusters, > and cpufreq could also change the voltage, so it's better to always > retrieve the current setting directly from the regulator core. And > those values might be cached iun the core, so it's unlikely to incur > a significant cost. Thanks for your suggestion. I will modify it as mtk_ccifreq_set_voltage() does. In that way I will try to remove pre_voltage member because it's no longer needed. > > + > > + if (pre_voltage < 0) { > > + dev_err(dev, "invalid vproc value: %d\n", > > pre_voltage); > > + return pre_voltage; > > + } > > + > > + /* scale up: set voltage first then freq. */ > > + target_voltage = max(inter_voltage, voltage); > > + if (pre_voltage <= target_voltage) { > > + ret = mtk_ccifreq_set_voltage(drv, target_voltage); > > + if (ret) { > > + dev_err(dev, "failed to scale up > > voltage\n"); > > + goto out_restore_voltage; > > + } > > + } > > + > > + /* switch the cci clock to intermediate clock source. */ > > + ret = clk_set_parent(drv->cci_clk, drv->inter_clk); > > + if (ret) { > > + dev_err(dev, "failed to re-parent cci clock\n"); > > + goto out_restore_voltage; > > + } > > + > > + /* set the original clock to target rate. */ > > + ret = clk_set_rate(cci_pll, *freq); > > + if (ret) { > > + dev_err(dev, "failed to set cci pll rate: %d\n", > > ret); > > + clk_set_parent(drv->cci_clk, cci_pll); > > + goto out_restore_voltage; > > + } > > + > > + /* switch the cci clock back to the original clock source. > > */ > > + ret = clk_set_parent(drv->cci_clk, cci_pll); > > + if (ret) { > > + dev_err(dev, "failed to re-parent cci clock\n"); > > + mtk_ccifreq_set_voltage(drv, inter_voltage); > > + goto out_unlock; > > + } > > + > > + /* > > + * 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 < pre_voltage) { > > + ret = mtk_ccifreq_set_voltage(drv, voltage); > > + if (ret) { > > + dev_err(dev, "failed to scale down > > voltage\n"); > > + goto out_unlock; > > + } > > + } > > + > > + drv->pre_freq = *freq; > > + mutex_unlock(&drv->reg_lock); > > + > > + return 0; > > + > > +out_restore_voltage: > > + mtk_ccifreq_set_voltage(drv, pre_voltage); > > + > > +out_unlock: > > + mutex_unlock(&drv->reg_lock); > > + return ret; > > +} > > + > > +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->reg_lock); > > + /* current opp item is changed */ > > + if (freq == drv->pre_freq) { > > + volt = dev_pm_opp_get_voltage(opp); > > + mtk_ccifreq_set_voltage(drv, volt); > > + } > > + mutex_unlock(&drv->reg_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 *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(dev, sizeof(*drv), GFP_KERNEL); > > + if (!drv) > > + return -ENOMEM; > > + > > + drv->dev = dev; > > + drv->soc_data = (const struct mtk_ccifreq_platform_data *) > > + of_device_get_match_data(&pdev- > > >dev); > > + mutex_init(&drv->reg_lock); > > + platform_set_drvdata(pdev, drv); > > + > > + drv->cci_clk = devm_clk_get(dev, "cci"); > > + if (IS_ERR(drv->cci_clk)) { > > + ret = PTR_ERR(drv->cci_clk); > > + return dev_err_probe(dev, ret, > > + "failed to get cci clk: %d\n", > > ret); > > + } > > + > > + drv->inter_clk = devm_clk_get(dev, "intermediate"); > > + if (IS_ERR(drv->inter_clk)) { > > + ret = PTR_ERR(drv->inter_clk); > > + dev_err_probe(dev, ret, > > + "failed to get intermediate clk: > > %d\n", ret); > > + goto out_free_resources; > > + } > > + > > + drv->proc_reg = devm_regulator_get_optional(dev, "proc"); > > + if (IS_ERR(drv->proc_reg)) { > > + ret = PTR_ERR(drv->proc_reg); > > + dev_err_probe(dev, ret, > > + "failed to get proc regulator: %d\n", > > ret); > > + goto out_free_resources; > > + } > > + > > + ret = regulator_enable(drv->proc_reg); > > + if (ret) { > > + dev_err(dev, "failed to enable proc regulator\n"); > > + goto out_free_resources; > > + } > > + > > + drv->sram_reg = regulator_get_optional(dev, "sram"); > > devm_ for this as well? > I will modify it in the next version. > > + if (IS_ERR(drv->sram_reg)) > > + drv->sram_reg = NULL; > > + else { > > + ret = regulator_enable(drv->sram_reg); > > + if (ret) { > > + dev_err(dev, "failed to enable sram > > regulator\n"); > > + goto out_free_resources; > > + } > > + } > > + > > + /* > > + * We assume min voltage is 0 and tracking target voltage > > using > > + * min_volt_shift for each iteration. > > + * The retry_max is 3 times of expeted iteration count. > > expected? > Maybe "the maximum" will be more appropriate? > > + */ > > + drv->vtrack_max = 3 * DIV_ROUND_UP(max(drv->soc_data- > > >sram_max_volt, > > + drv->soc_data- > > >proc_max_volt), > > + drv->soc_data- > > >min_volt_shift); > > + > > + ret = clk_prepare_enable(drv->cci_clk); > > + if (ret) > > + goto out_free_resources; > > + > > + ret = clk_prepare_enable(drv->inter_clk); > > You don't need to enable the intermediate clock here. You shouldn't > need > to at all, as the CCF core will do it when the CCI clock is > reparented > over to it. I will remove it and all of clk_disable_unprepare(drv->inter_clk) in this file. > > > + if (ret) > > + goto out_disable_cci_clk; > > + > > + ret = dev_pm_opp_of_add_table(dev); > > + if (ret) { > > + dev_err(dev, "failed to add opp table: %d\n", ret); > > + goto out_disable_inter_clk; > > + } > > + > > + rate = clk_get_rate(drv->inter_clk); > > + opp = dev_pm_opp_find_freq_ceil(dev, &rate); > > + if (IS_ERR(opp)) { > > + ret = PTR_ERR(opp); > > + dev_err(dev, "failed to get intermediate opp: > > %d\n", ret); > > + goto out_remove_opp_table; > > + } > > + drv->inter_voltage = dev_pm_opp_get_voltage(opp); > > + dev_pm_opp_put(opp); > > + > > + rate = U32_MAX; > > + opp = dev_pm_opp_find_freq_floor(drv->dev, &rate); > > + if (IS_ERR(opp)) { > > + dev_err(dev, "failed to get opp\n"); > > + ret = PTR_ERR(opp); > > + goto out_remove_opp_table; > > + } > > + > > + opp_volt = dev_pm_opp_get_voltage(opp); > > + dev_pm_opp_put(opp); > > + ret = mtk_ccifreq_set_voltage(drv, opp_volt); > > + if (ret) { > > + dev_err(dev, "failed to scale to highest voltage > > %lu in proc_reg\n", > > + opp_volt); > > + goto out_remove_opp_table; > > + } > > + > > + passive_data = devm_kzalloc(dev, sizeof(struct > > devfreq_passive_data), > > + GFP_KERNEL); > > + if (!passive_data) { > > + ret = -ENOMEM; > > + goto out_remove_opp_table; > > + } > > + > > + passive_data->parent_type = CPUFREQ_PARENT_DEV; > > + drv->devfreq = devm_devfreq_add_device(dev, > > &mtk_ccifreq_profile, > > + DEVFREQ_GOV_PASSIVE, > > + passive_data); > > + if (IS_ERR(drv->devfreq)) { > > + ret = -EPROBE_DEFER; > > + dev_err(dev, "failed to add devfreq device: %ld\n", > > + PTR_ERR(drv->devfreq)); > > + goto out_remove_opp_table; > > + } > > + > > + drv->opp_nb.notifier_call = mtk_ccifreq_opp_notifier; > > + ret = dev_pm_opp_register_notifier(dev, &drv->opp_nb); > > + if (ret) { > > + dev_err(dev, "failed to register opp notifier: > > %d\n", ret); > > + goto out_remove_devfreq_device; > > + } > > + return 0; > > + > > +out_remove_devfreq_device: > > + devm_devfreq_remove_device(dev, drv->devfreq); > > + > > +out_remove_opp_table: > > + dev_pm_opp_of_remove_table(dev); > > + > > +out_disable_inter_clk: > > + clk_disable_unprepare(drv->inter_clk); > > + > > +out_disable_cci_clk: > > + clk_disable_unprepare(drv->cci_clk); > > + > > +out_free_resources: > > + if (regulator_is_enabled(drv->proc_reg)) > > + regulator_disable(drv->proc_reg); > > + if (drv->sram_reg && regulator_is_enabled(drv->sram_reg)) > > + regulator_disable(drv->sram_reg); > > + > > + if (!IS_ERR(drv->proc_reg)) > > + regulator_put(drv->proc_reg); > > + if (!IS_ERR(drv->sram_reg)) > > + regulator_put(drv->sram_reg); > > + if (!IS_ERR(drv->cci_clk)) > > + clk_put(drv->cci_clk); > > + if (!IS_ERR(drv->inter_clk)) > > + clk_put(drv->inter_clk); > > You don't need to "put" the resources you got using devm_ variants. > If you really want to, you need to use devm_(clk|regulator)_put. > I think I will remove these lines in the next version. > > + > > + return ret; > > +} > > + > > +static int mtk_ccifreq_remove(struct platform_device *pdev) > > +{ > > + struct device *dev = &pdev->dev; > > + struct mtk_ccifreq_drv *drv; > > + > > + drv = platform_get_drvdata(pdev); > > + > > + dev_pm_opp_unregister_notifier(dev, &drv->opp_nb); > > + dev_pm_opp_of_remove_table(dev); > > + clk_disable_unprepare(drv->inter_clk); > > + clk_disable_unprepare(drv->cci_clk); > > + regulator_disable(drv->proc_reg); > > + if (drv->sram_reg) > > + regulator_disable(drv->sram_reg); > > + > > + return 0; > > +} > > + > > +static const struct mtk_ccifreq_platform_data mt8183_platform_data > > = { > > + .min_volt_shift = 100000, > > + .max_volt_shift = 200000, > > + .proc_max_volt = 1150000, > > + .sram_min_volt = 0, > > + .sram_max_volt = 1150000, > > AFAICT there's no sram supply for MT8183, so set max to zero as well? > And you can just drop the two lines instead of explicitly setting > them to zero. > Sure, I will drop these two line. > > +}; > > + > > +static const struct mtk_ccifreq_platform_data mt8186_platform_data > > = { > > + .min_volt_shift = 100000, > > + .max_volt_shift = 250000, > > + .proc_max_volt = 1118750, > > + .sram_min_volt = 850000, > > + .sram_max_volt = 1118750, > > A side note about this: the min/max voltage values should also be set > on the regulator nodes in the device tree. The range then gets > enforced > by the regulator core. > Thanks for your reminder. We will notice this when we are sending dts patches. BRs, Johnson Wang > > Regards > ChenYu > > > +}; > > + > > +static const struct of_device_id mtk_ccifreq_machines[] = { > > + { .compatible = "mediatek,mt8183-cci", .data = > > &mt8183_platform_data }, > > + { .compatible = "mediatek,mt8186-cci", .data = > > &mt8186_platform_data }, > > + { }, > > +}; > > +MODULE_DEVICE_TABLE(of, mtk_ccifreq_machines); > > + > > +static struct platform_driver mtk_ccifreq_platdrv = { > > + .probe = mtk_ccifreq_probe, > > + .remove = mtk_ccifreq_remove, > > + .driver = { > > + .name = "mtk-ccifreq", > > + .of_match_table = mtk_ccifreq_machines, > > + }, > > +}; > > +module_platform_driver(mtk_ccifreq_platdrv); > > + > > +MODULE_DESCRIPTION("MediaTek CCI devfreq driver"); > > +MODULE_AUTHOR("Jia-Wei Chang <jia-wei.chang@xxxxxxxxxxxx>"); > > +MODULE_LICENSE("GPL v2"); > > -- > > 2.18.0 > > > > > > _______________________________________________ > > Linux-mediatek mailing list > > Linux-mediatek@xxxxxxxxxxxxxxxxxxx > > http://lists.infradead.org/mailman/listinfo/linux-mediatek
