diff options
Diffstat (limited to 'drivers/soc/tegra/regulators-tegra30.c')
| -rw-r--r-- | drivers/soc/tegra/regulators-tegra30.c | 534 |
1 files changed, 534 insertions, 0 deletions
diff --git a/drivers/soc/tegra/regulators-tegra30.c b/drivers/soc/tegra/regulators-tegra30.c new file mode 100644 index 0000000000..8fd43c6891 --- /dev/null +++ b/drivers/soc/tegra/regulators-tegra30.c @@ -0,0 +1,534 @@ +// 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 <linux/init.h> +#include <linux/kernel.h> +#include <linux/of.h> +#include <linux/reboot.h> +#include <linux/regulator/coupler.h> +#include <linux/regulator/driver.h> +#include <linux/regulator/machine.h> +#include <linux/suspend.h> + +#include <soc/tegra/fuse.h> +#include <soc/tegra/pmc.h> + +struct tegra_regulator_coupler { + struct regulator_coupler coupler; + struct regulator_dev *core_rdev; + struct regulator_dev *cpu_rdev; + struct notifier_block reboot_notifier; + struct notifier_block suspend_notifier; + int core_min_uV, cpu_min_uV; + bool sys_reboot_mode_req; + bool sys_reboot_mode; + bool sys_suspend_mode_req; + bool sys_suspend_mode; +}; + +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; + + /* + * Tegra30 SoC has critical DVFS-capable devices that are + * permanently-active or active at a boot time, like EMC + * (DRAM controller) or Display controller for example. + * + * The voltage of a CORE SoC power domain shall not be dropped below + * a minimum level, which is determined by device's clock rate. + * This means that we can't fully allow CORE voltage scaling until + * the state of all DVFS-critical CORE devices is synced. + */ + if (tegra_pmc_core_domain_state_synced() && !tegra->sys_reboot_mode) { + pr_info_once("voltage state synced\n"); + return 0; + } + + 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 voltage initialized 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_cpu_nominal_uV(void) +{ + switch (tegra_sku_info.cpu_speedo_id) { + case 10 ... 11: + return 850000; + + case 9: + return 912000; + + case 1 ... 3: + case 7 ... 8: + return 1050000; + + default: + return 1125000; + + case 4 ... 6: + case 12 ... 13: + return 1237000; + } +} + +static int tegra30_core_nominal_uV(void) +{ + switch (tegra_sku_info.soc_speedo_id) { + case 0: + return 1200000; + + case 1: + if (tegra_sku_info.cpu_speedo_id != 7 && + tegra_sku_info.cpu_speedo_id != 8) + return 1200000; + + fallthrough; + + case 2: + if (tegra_sku_info.cpu_speedo_id != 13) + return 1300000; + + return 1350000; + + default: + return 1250000; + } +} + +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; + + /* prepare voltage level for suspend */ + if (tegra->sys_suspend_mode) + core_min_uV = clamp(tegra30_core_nominal_uV(), + core_min_uV, core_max_uV); + + 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; + + /* store boot voltage level */ + if (!tegra->cpu_min_uV) + tegra->cpu_min_uV = 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 = max(cpu_uV, cpu_min_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; + + /* restore boot voltage level */ + if (tegra->sys_reboot_mode) + cpu_min_uV = max(cpu_min_uV, tegra->cpu_min_uV); + + /* prepare voltage level for suspend */ + if (tegra->sys_suspend_mode) + cpu_min_uV = clamp(tegra30_cpu_nominal_uV(), + cpu_min_uV, cpu_max_uV); + + 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); + } + + if (cpu_uV == cpu_target_uV) + goto update_core; + + 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); + } + + if (core_uV == core_target_uV) + continue; + + 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; + } + + tegra->sys_reboot_mode = READ_ONCE(tegra->sys_reboot_mode_req); + tegra->sys_suspend_mode = READ_ONCE(tegra->sys_suspend_mode_req); + + return tegra30_voltage_update(tegra, cpu_rdev, core_rdev); +} + +static int tegra30_regulator_prepare_suspend(struct tegra_regulator_coupler *tegra, + bool sys_suspend_mode) +{ + int err; + + if (!tegra->core_rdev || !tegra->cpu_rdev) + return 0; + + /* + * All power domains are enabled early during resume from suspend + * by GENPD core. Domains like VENC may require a higher voltage + * when enabled during resume from suspend. This also prepares + * hardware for resuming from LP0. + */ + + WRITE_ONCE(tegra->sys_suspend_mode_req, sys_suspend_mode); + + err = regulator_sync_voltage_rdev(tegra->cpu_rdev); + if (err) + return err; + + err = regulator_sync_voltage_rdev(tegra->core_rdev); + if (err) + return err; + + return 0; +} + +static int tegra30_regulator_suspend(struct notifier_block *notifier, + unsigned long mode, void *arg) +{ + struct tegra_regulator_coupler *tegra; + int ret = 0; + + tegra = container_of(notifier, struct tegra_regulator_coupler, + suspend_notifier); + + switch (mode) { + case PM_HIBERNATION_PREPARE: + case PM_RESTORE_PREPARE: + case PM_SUSPEND_PREPARE: + ret = tegra30_regulator_prepare_suspend(tegra, true); + break; + + case PM_POST_HIBERNATION: + case PM_POST_RESTORE: + case PM_POST_SUSPEND: + ret = tegra30_regulator_prepare_suspend(tegra, false); + break; + } + + if (ret) + pr_err("failed to prepare regulators: %d\n", ret); + + return notifier_from_errno(ret); +} + +static int tegra30_regulator_prepare_reboot(struct tegra_regulator_coupler *tegra, + bool sys_reboot_mode) +{ + int err; + + if (!tegra->core_rdev || !tegra->cpu_rdev) + return 0; + + WRITE_ONCE(tegra->sys_reboot_mode_req, true); + + /* + * Some devices use CPU soft-reboot method and in this case we + * should ensure that voltages are sane for the reboot by restoring + * the minimum boot levels. + */ + err = regulator_sync_voltage_rdev(tegra->cpu_rdev); + if (err) + return err; + + err = regulator_sync_voltage_rdev(tegra->core_rdev); + if (err) + return err; + + WRITE_ONCE(tegra->sys_reboot_mode_req, sys_reboot_mode); + + return 0; +} + +static int tegra30_regulator_reboot(struct notifier_block *notifier, + unsigned long event, void *cmd) +{ + struct tegra_regulator_coupler *tegra; + int ret; + + if (event != SYS_RESTART) + return NOTIFY_DONE; + + tegra = container_of(notifier, struct tegra_regulator_coupler, + reboot_notifier); + + ret = tegra30_regulator_prepare_reboot(tegra, true); + + return notifier_from_errno(ret); +} + +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); + + /* + * We don't expect regulators to be decoupled during reboot, + * this may race with the reboot handler and shouldn't ever + * happen in practice. + */ + if (WARN_ON_ONCE(system_state > SYSTEM_RUNNING)) + return -EPERM; + + 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, + }, + .reboot_notifier.notifier_call = tegra30_regulator_reboot, + .suspend_notifier.notifier_call = tegra30_regulator_suspend, +}; + +static int __init tegra_regulator_coupler_init(void) +{ + int err; + + if (!of_machine_is_compatible("nvidia,tegra30")) + return 0; + + err = register_reboot_notifier(&tegra30_coupler.reboot_notifier); + WARN_ON(err); + + err = register_pm_notifier(&tegra30_coupler.suspend_notifier); + WARN_ON(err); + + return regulator_coupler_register(&tegra30_coupler.coupler); +} +arch_initcall(tegra_regulator_coupler_init); |