diff options
Diffstat (limited to 'drivers/soc/tegra/regulators-tegra30.c')
| -rw-r--r-- | drivers/soc/tegra/regulators-tegra30.c | 93 |
1 files changed, 91 insertions, 2 deletions
diff --git a/drivers/soc/tegra/regulators-tegra30.c b/drivers/soc/tegra/regulators-tegra30.c index 0e776b20f625..e74bbc9c7859 100644 --- a/drivers/soc/tegra/regulators-tegra30.c +++ b/drivers/soc/tegra/regulators-tegra30.c @@ -12,17 +12,22 @@ #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 <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; - int core_min_uV; + struct notifier_block reboot_notifier; + int core_min_uV, cpu_min_uV; + bool sys_reboot_mode_req; + bool sys_reboot_mode; }; static inline struct tegra_regulator_coupler * @@ -39,6 +44,21 @@ static int tegra30_core_limit(struct tegra_regulator_coupler *tegra, 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; @@ -59,7 +79,7 @@ static int tegra30_core_limit(struct tegra_regulator_coupler *tegra, */ tegra->core_min_uV = core_max_uV; - pr_info("core minimum voltage limited to %duV\n", tegra->core_min_uV); + pr_info("core voltage initialized to %duV\n", tegra->core_min_uV); return tegra->core_min_uV; } @@ -172,6 +192,10 @@ static int tegra30_voltage_update(struct tegra_regulator_coupler *tegra, 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 @@ -195,6 +219,10 @@ static int tegra30_voltage_update(struct tegra_regulator_coupler *tegra, if (err) return err; + /* restore boot voltage level */ + if (tegra->sys_reboot_mode) + cpu_min_uV = max(cpu_min_uV, tegra->cpu_min_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); @@ -263,9 +291,56 @@ static int tegra30_regulator_balance_voltage(struct regulator_coupler *coupler, return -EINVAL; } + tegra->sys_reboot_mode = READ_ONCE(tegra->sys_reboot_mode_req); + return tegra30_voltage_update(tegra, cpu_rdev, core_rdev); } +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) { @@ -292,6 +367,14 @@ static int tegra30_regulator_detach(struct regulator_coupler *coupler, { 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; @@ -311,13 +394,19 @@ static struct tegra_regulator_coupler tegra30_coupler = { .detach_regulator = tegra30_regulator_detach, .balance_voltage = tegra30_regulator_balance_voltage, }, + .reboot_notifier.notifier_call = tegra30_regulator_reboot, }; 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); + return regulator_coupler_register(&tegra30_coupler.coupler); } arch_initcall(tegra_regulator_coupler_init); |