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From: Dmitry Osipenko <digetx@gmail.com>
To: "Thierry Reding" <thierry.reding@gmail.com>,
	"Jonathan Hunter" <jonathanh@nvidia.com>,
	"Michał Mirosław" <mirq-linux@rere.qmqm.pl>,
	"Nikola Milosavljević" <mnidza@outlook.com>,
	"Ulf Hansson" <ulf.hansson@linaro.org>,
	"Peter Geis" <pgwipeout@gmail.com>,
	"Nicolas Chauvet" <kwizart@gmail.com>,
	"Viresh Kumar" <vireshk@kernel.org>,
	"Stephen Boyd" <sboyd@kernel.org>,
	"Matt Merhar" <mattmerhar@protonmail.com>,
	"Paul Fertser" <fercerpav@gmail.com>,
	"Mark Brown" <broonie@kernel.org>,
	"Liam Girdwood" <lgirdwood@gmail.com>,
	"Krzysztof Kozlowski" <krzysztof.kozlowski@canonical.com>,
	"Mikko Perttunen" <mperttunen@nvidia.com>
Cc: linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org,
	devicetree@vger.kernel.org, linux-pm@vger.kernel.org,
	Nathan Chancellor <nathan@kernel.org>,
	linux-clk@vger.kernel.org
Subject: [PATCH v5 02/14] soc/tegra: regulators: Bump voltages on system reboot
Date: Fri, 28 May 2021 02:54:01 +0300	[thread overview]
Message-ID: <20210527235413.23120-3-digetx@gmail.com> (raw)
In-Reply-To: <20210527235413.23120-1-digetx@gmail.com>

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: Nikola Milosavljević <mnidza@outlook.com>
Tested-by: Nikola Milosavljević <mnidza@outlook.com> # TF101
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/soc/tegra/regulators-tegra20.c | 75 +++++++++++++++++++++++++-
 drivers/soc/tegra/regulators-tegra30.c | 75 +++++++++++++++++++++++++-
 2 files changed, 148 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/tegra/regulators-tegra20.c b/drivers/soc/tegra/regulators-tegra20.c
index 367a71a3cd10..3479be5ee494 100644
--- a/drivers/soc/tegra/regulators-tegra20.c
+++ b/drivers/soc/tegra/regulators-tegra20.c
@@ -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);
diff --git a/drivers/soc/tegra/regulators-tegra30.c b/drivers/soc/tegra/regulators-tegra30.c
index 0e776b20f625..18fe53d0a870 100644
--- a/drivers/soc/tegra/regulators-tegra30.c
+++ b/drivers/soc/tegra/regulators-tegra30.c
@@ -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);
-- 
2.30.2


  parent reply	other threads:[~2021-05-27 23:54 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-27 23:53 [PATCH v5 00/14] NVIDIA Tegra memory and power management changes for 5.14 Dmitry Osipenko
2021-05-27 23:54 ` [PATCH v5 01/14] regulator: core: Add regulator_sync_voltage_rdev() Dmitry Osipenko
2021-05-27 23:54 ` Dmitry Osipenko [this message]
2021-05-27 23:54 ` [PATCH v5 03/14] soc/tegra: Add stub for soc_is_tegra() Dmitry Osipenko
2021-05-27 23:54 ` [PATCH v5 04/14] soc/tegra: Add devm_tegra_core_dev_init_opp_table() Dmitry Osipenko
2021-05-27 23:54 ` [PATCH v5 05/14] soc/tegra: fuse: Add stubs needed for compile-testing Dmitry Osipenko
2021-05-27 23:54 ` [PATCH v5 06/14] clk: tegra: " Dmitry Osipenko
2021-05-27 23:54 ` [PATCH v5 07/14] memory: tegra: Fix compilation warnings on 64bit platforms Dmitry Osipenko
2021-05-27 23:54 ` [PATCH v5 08/14] memory: tegra: Enable compile testing for all drivers Dmitry Osipenko
2021-05-31 11:01   ` kernel test robot
2021-05-31 19:08     ` Dmitry Osipenko
2021-05-27 23:54 ` [PATCH v5 09/14] memory: tegra20-emc: Use devm_tegra_core_dev_init_opp_table() Dmitry Osipenko
2021-05-27 23:54 ` [PATCH v5 10/14] memory: tegra30-emc: " Dmitry Osipenko
2021-05-27 23:54 ` [PATCH v5 11/14] dt-bindings: soc: tegra-pmc: Document core power domain Dmitry Osipenko
2021-05-27 23:54 ` [PATCH v5 12/14] soc/tegra: pmc: Add " Dmitry Osipenko
2021-05-27 23:54 ` [PATCH v5 13/14] soc/tegra: pmc: Add driver state syncing Dmitry Osipenko
2021-05-27 23:54 ` [PATCH v5 14/14] soc/tegra: regulators: Support core domain " Dmitry Osipenko

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