Commit 03978d42 authored by Dmitry Osipenko's avatar Dmitry Osipenko Committed by Thierry Reding
Browse files

soc/tegra: regulators: Bump voltages on system reboot 



Ensure that SoC voltages are at a level suitable for a system reboot.
This is important for some devices that use CPU reset method for the
rebooting. SoC CPU and core voltages now are be restored to a level
that is suitable for rebooting. This patch fixes hang on reboot on
Asus Transformer TF101, it was also reported as fixing some of reboot
issues on Toshiba AC100.

Reported-by: default avatarNikola Milosavljević <mnidza@outlook.com>
Tested-by: Nikola Milosavljević <mnidza@outlook.com> # TF101
Signed-off-by: default avatarDmitry Osipenko <digetx@gmail.com>
Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
parent 241ed23c

drivers/soc/tegra/regulators-tegra20.c

+74 −1
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#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>
@@ -21,7 +22,10 @@ struct tegra_regulator_coupler { 
	struct regulator_dev *core_rdev;

	struct regulator_dev *cpu_rdev;

	struct regulator_dev *rtc_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 *
@@ -242,6 +246,10 @@ static int tegra20_cpu_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
@@ -250,6 +258,10 @@ static int tegra20_cpu_voltage_update(struct tegra_regulator_coupler *tegra, 
	if (!cpu_min_uV_consumers)

		cpu_min_uV = cpu_uV;



	/* restore boot voltage level */

	if (tegra->sys_reboot_mode)

		cpu_min_uV = max(cpu_min_uV, tegra->cpu_min_uV);



	if (cpu_min_uV > cpu_uV) {

		err = tegra20_core_rtc_update(tegra, core_rdev, rtc_rdev,

					      cpu_uV, cpu_min_uV);
@@ -290,6 +302,8 @@ static int tegra20_regulator_balance_voltage(struct regulator_coupler *coupler, 
		return -EINVAL;

	}



	tegra->sys_reboot_mode = READ_ONCE(tegra->sys_reboot_mode_req);



	if (rdev == cpu_rdev)

		return tegra20_cpu_voltage_update(tegra, cpu_rdev,

						  core_rdev, rtc_rdev);
@@ -303,6 +317,51 @@ static int tegra20_regulator_balance_voltage(struct regulator_coupler *coupler, 
	return -EPERM;

}



static int tegra20_regulator_prepare_reboot(struct tegra_regulator_coupler *tegra,

					    bool sys_reboot_mode)

{

	int err;



	if (!tegra->core_rdev || !tegra->rtc_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 tegra20_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 = tegra20_regulator_prepare_reboot(tegra, true);



	return notifier_from_errno(ret);

}



static int tegra20_regulator_attach(struct regulator_coupler *coupler,

				    struct regulator_dev *rdev)

{
@@ -335,6 +394,14 @@ static int tegra20_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;
@@ -359,13 +426,19 @@ static struct tegra_regulator_coupler tegra20_coupler = { 
		.detach_regulator = tegra20_regulator_detach,

		.balance_voltage = tegra20_regulator_balance_voltage,

	},

	.reboot_notifier.notifier_call = tegra20_regulator_reboot,

};



static int __init tegra_regulator_coupler_init(void)

{

	int err;



	if (!of_machine_is_compatible("nvidia,tegra20"))

		return 0;



	err = register_reboot_notifier(&tegra20_coupler.reboot_notifier);

	WARN_ON(err);



	return regulator_coupler_register(&tegra20_coupler.coupler);

}

arch_initcall(tegra_regulator_coupler_init);

drivers/soc/tegra/regulators-tegra30.c

+74 −1
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#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>
@@ -22,7 +23,10 @@ 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 *
@@ -172,6 +176,10 @@ 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 +203,10 @@ 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 +275,56 @@ 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 +351,14 @@ 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 +378,19 @@ 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);