From: Saravana Kannan <[email protected]> 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 powersave governor to set the GPU to DDR interconnect path for minimum performance. * Use the Passive governor to scale the DDR frequency based on the needs of the CPUs' current frequency Signed-off-by: Saravana Kannan <[email protected]> [Sibi: cleanup and added passive governor support] Signed-off-by: Sibi Sankar <[email protected]> --- drivers/devfreq/Kconfig | 15 ++++ drivers/devfreq/Makefile | 1 + drivers/devfreq/devfreq_icbw.c | 132 +++++++++++++++++++++++++++++++++ 3 files changed, 148 insertions(+) create mode 100644 drivers/devfreq/devfreq_icbw.c diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig index 9a45f464a56b..0df5b65f157a 100644 --- a/drivers/devfreq/Kconfig +++ b/drivers/devfreq/Kconfig @@ -117,6 +117,21 @@ config ARM_RK3399_DMC_DEVFREQ It sets the frequency for the memory controller and reads the usage counts from hardware. +config DEVFREQ_ICBW + tristate "Driver for making bandwidth votes on interconnect paths" + select DEVFREQ_GOV_PASSIVE + select DEVFREQ_GOV_PERFORMANCE + select DEVFREQ_GOV_POWERSAVE + select DEVFREQ_GOV_USERSPACE + depends on INTERCONNECT + 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 32b8d4d3f12c..66591b0e5259 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-$(CONFIG_DEVFREQ_ICBW) += devfreq_icbw.o # DEVFREQ Event Drivers obj-$(CONFIG_PM_DEVFREQ_EVENT) += event/ diff --git a/drivers/devfreq/devfreq_icbw.c b/drivers/devfreq/devfreq_icbw.c new file mode 100644 index 000000000000..c552cf4218c8 --- /dev/null +++ b/drivers/devfreq/devfreq_icbw.c @@ -0,0 +1,132 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2018, The Linux Foundation. All rights reserved. + */ + +#include <linux/devfreq.h> +#include <linux/interconnect.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> + +struct icbw_data { + struct devfreq *df; + struct icc_path *path; + u32 cur_ab; + u32 cur_pb; +}; + +static int icbw_target(struct device *dev, unsigned long *freq, u32 flags) +{ + struct dev_pm_opp *opp; + struct icbw_data *data = dev_get_drvdata(dev); + u32 new_pb, new_ab; + int ret; + + opp = devfreq_recommended_opp(dev, freq, flags); + if (IS_ERR(opp)) + return PTR_ERR(opp); + + /* Get avg and peak bandwidth */ + new_ab = dev_pm_opp_get_avg_bw(opp); + new_pb = dev_pm_opp_get_peak_bw(opp); + dev_pm_opp_put(opp); + + if (data->cur_pb == new_pb && data->cur_ab == new_ab) + return 0; + + dev_dbg(dev, "BW icc: AB: %u PB: %u\n", new_ab, new_pb); + + ret = icc_set_bw(data->path, new_ab, new_pb); + if (ret) { + dev_err(dev, "bandwidth request failed (%d)\n", ret); + } else { + data->cur_pb = new_pb; + data->cur_ab = new_ab; + } + + return ret; +} + +static int devfreq_icbw_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct devfreq_dev_profile *profile; + struct devfreq_passive_data *passive_data; + struct icbw_data *data; + int ret; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + dev_set_drvdata(dev, data); + + passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL); + if (!passive_data) + return -ENOMEM; + + passive_data->cpufreq_type = true; + + profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL); + if (!profile) + return -ENOMEM; + + profile->target = icbw_target; + + data->path = of_icc_get(dev, NULL); + if (IS_ERR(data->path)) { + dev_err(dev, "Unable to register interconnect path\n"); + return PTR_ERR(data->path); + } + + ret = dev_pm_opp_of_add_table(dev); + if (ret) { + dev_err(dev, "Couldn't find OPP table\n"); + goto err_icc; + } + + data->df = devfreq_add_device(dev, profile, + DEVFREQ_GOV_PASSIVE, passive_data); + if (IS_ERR(data->df)) { + ret = PTR_ERR(data->df); + goto err_opp_table; + } + + return 0; + +err_opp_table: + dev_pm_opp_of_remove_table(dev); +err_icc: + icc_put(data->path); + return ret; +} + +static int devfreq_icbw_remove(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct icbw_data *data = dev_get_drvdata(dev); + + devfreq_remove_device(data->df); + icc_put(data->path); + return 0; +} + +static const struct of_device_id icbw_match_table[] = { + { .compatible = "devfreq-icbw" }, + {} +}; +MODULE_DEVICE_TABLE(of, icbw_match_table); + +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"); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
