From 496747e7d907b01bd2507d61bdd6874b987c9629 Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Thu, 25 Jul 2019 18:18:31 +0300 Subject: soc/tegra: regulators: Add regulators coupler for Tegra20 Add regulators coupler for Tegra20 SoCs that performs voltage balancing of a coupled regulators and thus provides voltage scaling functionality. There are 3 coupled regulators on all Tegra20 SoCs: CORE, RTC and CPU. The CORE and RTC voltages shall be in range of 170mV from each other and they both shall be higher than the CPU voltage by at least 120mV. This sounds like it could be handle by a generic voltage balancer, but the CORE voltage scaling isn't implemented in any of the upstream drivers yet. It will take quite some time and effort to hook up voltage scaling for all of the drivers, hence we will use a custom coupler that will manage the CPU voltage scaling for the starter. Signed-off-by: Dmitry Osipenko Acked-By: Peter De Schrijver Signed-off-by: Thierry Reding --- drivers/soc/tegra/Kconfig | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/soc/tegra/Kconfig') diff --git a/drivers/soc/tegra/Kconfig b/drivers/soc/tegra/Kconfig index c8ef05d6b8c7..437466aa57e1 100644 --- a/drivers/soc/tegra/Kconfig +++ b/drivers/soc/tegra/Kconfig @@ -15,6 +15,7 @@ config ARCH_TEGRA_2x_SOC select PL310_ERRATA_769419 if CACHE_L2X0 select SOC_TEGRA_FLOWCTRL select SOC_TEGRA_PMC + select SOC_TEGRA20_VOLTAGE_COUPLER select TEGRA_TIMER help Support for NVIDIA Tegra AP20 and T20 processors, based on the @@ -135,3 +136,7 @@ config SOC_TEGRA_POWERGATE_BPMP def_bool y depends on PM_GENERIC_DOMAINS depends on TEGRA_BPMP + +config SOC_TEGRA20_VOLTAGE_COUPLER + bool "Voltage scaling support for Tegra20 SoCs" + depends on ARCH_TEGRA_2x_SOC || COMPILE_TEST -- cgit v1.2.3 From 783807436f363e5b1ad4d43ba7debbedfcadbb99 Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Thu, 25 Jul 2019 18:18:32 +0300 Subject: soc/tegra: regulators: Add regulators coupler for Tegra30 Add regulators coupler for Tegra30 SoCs that performs voltage balancing of a coupled regulators and thus provides voltage scaling functionality. There are 2 coupled regulators on all Tegra30 SoCs: CORE and CPU. The coupled regulator voltages shall be in a range of 300mV from each other and CORE voltage shall be higher than the CPU by N mV, where N depends on the CPU voltage. Signed-off-by: Dmitry Osipenko Acked-By: Peter De Schrijver Signed-off-by: Thierry Reding --- drivers/soc/tegra/Kconfig | 5 + drivers/soc/tegra/Makefile | 1 + drivers/soc/tegra/regulators-tegra30.c | 317 +++++++++++++++++++++++++++++++++ 3 files changed, 323 insertions(+) create mode 100644 drivers/soc/tegra/regulators-tegra30.c (limited to 'drivers/soc/tegra/Kconfig') diff --git a/drivers/soc/tegra/Kconfig b/drivers/soc/tegra/Kconfig index 437466aa57e1..84bd615c4a92 100644 --- a/drivers/soc/tegra/Kconfig +++ b/drivers/soc/tegra/Kconfig @@ -29,6 +29,7 @@ config ARCH_TEGRA_3x_SOC select PL310_ERRATA_769419 if CACHE_L2X0 select SOC_TEGRA_FLOWCTRL select SOC_TEGRA_PMC + select SOC_TEGRA30_VOLTAGE_COUPLER select TEGRA_TIMER help Support for NVIDIA Tegra T30 processor family, based on the @@ -140,3 +141,7 @@ config SOC_TEGRA_POWERGATE_BPMP config SOC_TEGRA20_VOLTAGE_COUPLER bool "Voltage scaling support for Tegra20 SoCs" depends on ARCH_TEGRA_2x_SOC || COMPILE_TEST + +config SOC_TEGRA30_VOLTAGE_COUPLER + bool "Voltage scaling support for Tegra30 SoCs" + depends on ARCH_TEGRA_3x_SOC || COMPILE_TEST diff --git a/drivers/soc/tegra/Makefile b/drivers/soc/tegra/Makefile index 9f0bdd53bef8..9c809c1814bd 100644 --- a/drivers/soc/tegra/Makefile +++ b/drivers/soc/tegra/Makefile @@ -6,3 +6,4 @@ obj-$(CONFIG_SOC_TEGRA_FLOWCTRL) += flowctrl.o obj-$(CONFIG_SOC_TEGRA_PMC) += pmc.o obj-$(CONFIG_SOC_TEGRA_POWERGATE_BPMP) += powergate-bpmp.o obj-$(CONFIG_SOC_TEGRA20_VOLTAGE_COUPLER) += regulators-tegra20.o +obj-$(CONFIG_SOC_TEGRA30_VOLTAGE_COUPLER) += regulators-tegra30.o diff --git a/drivers/soc/tegra/regulators-tegra30.c b/drivers/soc/tegra/regulators-tegra30.c new file mode 100644 index 000000000000..8e623ff18e70 --- /dev/null +++ b/drivers/soc/tegra/regulators-tegra30.c @@ -0,0 +1,317 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Voltage regulators coupler for NVIDIA Tegra30 + * Copyright (C) 2019 GRATE-DRIVER project + * + * Voltage constraints borrowed from downstream kernel sources + * Copyright (C) 2010-2011 NVIDIA Corporation + */ + +#define pr_fmt(fmt) "tegra voltage-coupler: " fmt + +#include +#include +#include +#include +#include +#include + +#include + +struct tegra_regulator_coupler { + struct regulator_coupler coupler; + struct regulator_dev *core_rdev; + struct regulator_dev *cpu_rdev; + int core_min_uV; +}; + +static inline struct tegra_regulator_coupler * +to_tegra_coupler(struct regulator_coupler *coupler) +{ + return container_of(coupler, struct tegra_regulator_coupler, coupler); +} + +static int tegra30_core_limit(struct tegra_regulator_coupler *tegra, + struct regulator_dev *core_rdev) +{ + int core_min_uV = 0; + int core_max_uV; + int core_cur_uV; + int err; + + if (tegra->core_min_uV > 0) + return tegra->core_min_uV; + + core_cur_uV = regulator_get_voltage_rdev(core_rdev); + if (core_cur_uV < 0) + return core_cur_uV; + + core_max_uV = max(core_cur_uV, 1200000); + + err = regulator_check_voltage(core_rdev, &core_min_uV, &core_max_uV); + if (err) + return err; + + /* + * Limit minimum CORE voltage to a value left from bootloader or, + * if it's unreasonably low value, to the most common 1.2v or to + * whatever maximum value defined via board's device-tree. + */ + tegra->core_min_uV = core_max_uV; + + pr_info("core minimum voltage limited to %duV\n", tegra->core_min_uV); + + return tegra->core_min_uV; +} + +static int tegra30_core_cpu_limit(int cpu_uV) +{ + if (cpu_uV < 800000) + return 950000; + + if (cpu_uV < 900000) + return 1000000; + + if (cpu_uV < 1000000) + return 1100000; + + if (cpu_uV < 1100000) + return 1200000; + + if (cpu_uV < 1250000) { + switch (tegra_sku_info.cpu_speedo_id) { + case 0 ... 1: + case 4: + case 7 ... 8: + return 1200000; + + default: + return 1300000; + } + } + + return -EINVAL; +} + +static int tegra30_voltage_update(struct tegra_regulator_coupler *tegra, + struct regulator_dev *cpu_rdev, + struct regulator_dev *core_rdev) +{ + int core_min_uV, core_max_uV = INT_MAX; + int cpu_min_uV, cpu_max_uV = INT_MAX; + int cpu_min_uV_consumers = 0; + int core_min_limited_uV; + int core_target_uV; + int cpu_target_uV; + int core_max_step; + int cpu_max_step; + int max_spread; + int core_uV; + int cpu_uV; + int err; + + /* + * CPU voltage should not got lower than 300mV from the CORE. + * CPU voltage should stay below the CORE by 100mV+, depending + * by the CORE voltage. This applies to all Tegra30 SoC's. + */ + max_spread = cpu_rdev->constraints->max_spread[0]; + cpu_max_step = cpu_rdev->constraints->max_uV_step; + core_max_step = core_rdev->constraints->max_uV_step; + + if (!max_spread) { + pr_err_once("cpu-core max-spread is undefined in device-tree\n"); + max_spread = 300000; + } + + if (!cpu_max_step) { + pr_err_once("cpu max-step is undefined in device-tree\n"); + cpu_max_step = 150000; + } + + if (!core_max_step) { + pr_err_once("core max-step is undefined in device-tree\n"); + core_max_step = 150000; + } + + /* + * The CORE voltage scaling is currently not hooked up in drivers, + * hence we will limit the minimum CORE voltage to a reasonable value. + * This should be good enough for the time being. + */ + core_min_uV = tegra30_core_limit(tegra, core_rdev); + if (core_min_uV < 0) + return core_min_uV; + + err = regulator_check_consumers(core_rdev, &core_min_uV, &core_max_uV, + PM_SUSPEND_ON); + if (err) + return err; + + core_uV = regulator_get_voltage_rdev(core_rdev); + if (core_uV < 0) + return core_uV; + + cpu_min_uV = core_min_uV - max_spread; + + err = regulator_check_consumers(cpu_rdev, &cpu_min_uV, &cpu_max_uV, + PM_SUSPEND_ON); + if (err) + return err; + + err = regulator_check_consumers(cpu_rdev, &cpu_min_uV_consumers, + &cpu_max_uV, PM_SUSPEND_ON); + if (err) + return err; + + err = regulator_check_voltage(cpu_rdev, &cpu_min_uV, &cpu_max_uV); + if (err) + return err; + + cpu_uV = regulator_get_voltage_rdev(cpu_rdev); + if (cpu_uV < 0) + return cpu_uV; + + /* + * CPU's regulator may not have any consumers, hence the voltage + * must not be changed in that case because CPU simply won't + * survive the voltage drop if it's running on a higher frequency. + */ + if (!cpu_min_uV_consumers) + cpu_min_uV = cpu_uV; + + /* + * Bootloader shall set up voltages correctly, but if it + * happens that there is a violation, then try to fix it + * at first. + */ + core_min_limited_uV = tegra30_core_cpu_limit(cpu_uV); + if (core_min_limited_uV < 0) + return core_min_limited_uV; + + core_min_uV = max(core_min_uV, tegra30_core_cpu_limit(cpu_min_uV)); + + err = regulator_check_voltage(core_rdev, &core_min_uV, &core_max_uV); + if (err) + return err; + + if (core_min_limited_uV > core_uV) { + pr_err("core voltage constraint violated: %d %d %d\n", + core_uV, core_min_limited_uV, cpu_uV); + goto update_core; + } + + while (cpu_uV != cpu_min_uV || core_uV != core_min_uV) { + if (cpu_uV < cpu_min_uV) { + cpu_target_uV = min(cpu_uV + cpu_max_step, cpu_min_uV); + } else { + cpu_target_uV = max(cpu_uV - cpu_max_step, cpu_min_uV); + cpu_target_uV = max(core_uV - max_spread, cpu_target_uV); + } + + err = regulator_set_voltage_rdev(cpu_rdev, + cpu_target_uV, + cpu_max_uV, + PM_SUSPEND_ON); + if (err) + return err; + + cpu_uV = cpu_target_uV; +update_core: + core_min_limited_uV = tegra30_core_cpu_limit(cpu_uV); + if (core_min_limited_uV < 0) + return core_min_limited_uV; + + core_target_uV = max(core_min_limited_uV, core_min_uV); + + if (core_uV < core_target_uV) { + core_target_uV = min(core_target_uV, core_uV + core_max_step); + core_target_uV = min(core_target_uV, cpu_uV + max_spread); + } else { + core_target_uV = max(core_target_uV, core_uV - core_max_step); + } + + err = regulator_set_voltage_rdev(core_rdev, + core_target_uV, + core_max_uV, + PM_SUSPEND_ON); + if (err) + return err; + + core_uV = core_target_uV; + } + + return 0; +} + +static int tegra30_regulator_balance_voltage(struct regulator_coupler *coupler, + struct regulator_dev *rdev, + suspend_state_t state) +{ + struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler); + struct regulator_dev *core_rdev = tegra->core_rdev; + struct regulator_dev *cpu_rdev = tegra->cpu_rdev; + + if ((core_rdev != rdev && cpu_rdev != rdev) || state != PM_SUSPEND_ON) { + pr_err("regulators are not coupled properly\n"); + return -EINVAL; + } + + return tegra30_voltage_update(tegra, cpu_rdev, core_rdev); +} + +static int tegra30_regulator_attach(struct regulator_coupler *coupler, + struct regulator_dev *rdev) +{ + struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler); + struct device_node *np = rdev->dev.of_node; + + if (of_property_read_bool(np, "nvidia,tegra-core-regulator") && + !tegra->core_rdev) { + tegra->core_rdev = rdev; + return 0; + } + + if (of_property_read_bool(np, "nvidia,tegra-cpu-regulator") && + !tegra->cpu_rdev) { + tegra->cpu_rdev = rdev; + return 0; + } + + return -EINVAL; +} + +static int tegra30_regulator_detach(struct regulator_coupler *coupler, + struct regulator_dev *rdev) +{ + struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler); + + if (tegra->core_rdev == rdev) { + tegra->core_rdev = NULL; + return 0; + } + + if (tegra->cpu_rdev == rdev) { + tegra->cpu_rdev = NULL; + return 0; + } + + return -EINVAL; +} + +static struct tegra_regulator_coupler tegra30_coupler = { + .coupler = { + .attach_regulator = tegra30_regulator_attach, + .detach_regulator = tegra30_regulator_detach, + .balance_voltage = tegra30_regulator_balance_voltage, + }, +}; + +static int __init tegra_regulator_coupler_init(void) +{ + if (!of_machine_is_compatible("nvidia,tegra30")) + return 0; + + return regulator_coupler_register(&tegra30_coupler.coupler); +} +arch_initcall(tegra_regulator_coupler_init); -- cgit v1.2.3