Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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);