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Subject[PATCH v8 13/19] cpuidle: Refactor and move out NVIDIA Tegra20 driver into drivers/cpuidle
Date
The driver's code is refactored in a way that will make it easy to
support Tegra30/114/124 SoCs by this unified driver later on. The
current functionality is equal to the old Tegra20 driver, only the
code's structure changed a tad. This is also a proper platform driver
now.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
arch/arm/mach-tegra/Makefile | 3 -
arch/arm/mach-tegra/cpuidle-tegra20.c | 215 --------------------
arch/arm/mach-tegra/cpuidle.c | 14 +-
arch/arm/mach-tegra/cpuidle.h | 4 -
drivers/cpuidle/Kconfig.arm | 8 +
drivers/cpuidle/Makefile | 1 +
drivers/cpuidle/cpuidle-tegra.c | 269 ++++++++++++++++++++++++++
include/soc/tegra/cpuidle.h | 2 +-
8 files changed, 281 insertions(+), 235 deletions(-)
delete mode 100644 arch/arm/mach-tegra/cpuidle-tegra20.c
create mode 100644 drivers/cpuidle/cpuidle-tegra.c

diff --git a/arch/arm/mach-tegra/Makefile b/arch/arm/mach-tegra/Makefile
index 965862608ff6..8425bb5608d5 100644
--- a/arch/arm/mach-tegra/Makefile
+++ b/arch/arm/mach-tegra/Makefile
@@ -12,9 +12,6 @@ obj-y += sleep-tegra20.o
obj-y += sleep-tegra30.o
obj-$(CONFIG_CPU_IDLE) += cpuidle.o
obj-$(CONFIG_ARCH_TEGRA_2x_SOC) += pm-tegra20.o
-ifeq ($(CONFIG_CPU_IDLE),y)
-obj-$(CONFIG_ARCH_TEGRA_2x_SOC) += cpuidle-tegra20.o
-endif
obj-$(CONFIG_ARCH_TEGRA_3x_SOC) += pm-tegra30.o
ifeq ($(CONFIG_CPU_IDLE),y)
obj-$(CONFIG_ARCH_TEGRA_3x_SOC) += cpuidle-tegra30.o
diff --git a/arch/arm/mach-tegra/cpuidle-tegra20.c b/arch/arm/mach-tegra/cpuidle-tegra20.c
deleted file mode 100644
index 78cc424fac35..000000000000
--- a/arch/arm/mach-tegra/cpuidle-tegra20.c
+++ /dev/null
@@ -1,215 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * CPU idle driver for Tegra CPUs
- *
- * Copyright (c) 2010-2012, NVIDIA Corporation.
- * Copyright (c) 2011 Google, Inc.
- * Author: Colin Cross <ccross@android.com>
- * Gary King <gking@nvidia.com>
- *
- * Rework for 3.3 by Peter De Schrijver <pdeschrijver@nvidia.com>
- */
-
-#include <linux/clk/tegra.h>
-#include <linux/tick.h>
-#include <linux/cpuidle.h>
-#include <linux/cpu_pm.h>
-#include <linux/kernel.h>
-#include <linux/ktime.h>
-#include <linux/module.h>
-
-#include <soc/tegra/flowctrl.h>
-#include <soc/tegra/pm.h>
-
-#include <asm/cpuidle.h>
-#include <asm/smp_plat.h>
-#include <asm/suspend.h>
-
-#include "cpuidle.h"
-#include "iomap.h"
-#include "irq.h"
-#include "reset.h"
-#include "sleep.h"
-
-#ifdef CONFIG_PM_SLEEP
-static atomic_t abort_flag;
-static atomic_t abort_barrier;
-static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
- struct cpuidle_driver *drv,
- int index);
-#define TEGRA20_MAX_STATES 2
-#else
-#define TEGRA20_MAX_STATES 1
-#endif
-
-static struct cpuidle_driver tegra_idle_driver = {
- .name = "tegra_idle",
- .owner = THIS_MODULE,
- .states = {
- ARM_CPUIDLE_WFI_STATE_PWR(600),
-#ifdef CONFIG_PM_SLEEP
- {
- .enter = tegra20_idle_lp2_coupled,
- .exit_latency = 5000,
- .target_residency = 10000,
- .power_usage = 0,
- .flags = CPUIDLE_FLAG_COUPLED |
- CPUIDLE_FLAG_TIMER_STOP,
- .name = "powered-down",
- .desc = "CPU power gated",
- },
-#endif
- },
- .state_count = TEGRA20_MAX_STATES,
- .safe_state_index = 0,
-};
-
-#ifdef CONFIG_PM_SLEEP
-#ifdef CONFIG_SMP
-static void tegra20_wake_cpu1_from_reset(void)
-{
- /* enable cpu clock on cpu */
- tegra_enable_cpu_clock(1);
-
- /* take the CPU out of reset */
- tegra_cpu_out_of_reset(1);
-
- /* unhalt the cpu */
- flowctrl_write_cpu_halt(1, 0);
-}
-#else
-static inline void tegra20_wake_cpu1_from_reset(void)
-{
-}
-#endif
-
-static void tegra20_report_cpus_state(void)
-{
- unsigned int cpu, lcpu;
-
- pr_err("secondary CPU taking too long to park\n");
-
- for_each_cpu(lcpu, cpu_possible_mask) {
- cpu = cpu_logical_map(lcpu);
-
- pr_err("cpu%u: online=%d flowctrl_csr=0x%08x\n",
- cpu, cpu_online(lcpu), flowctrl_read_cpu_csr(cpu));
- }
-}
-
-static int tegra20_wait_for_secondary_cpu_parking(void)
-{
- unsigned int retries = 3;
-
- while (retries--) {
- ktime_t timeout = ktime_add_ms(ktime_get(), 500);
-
- /*
- * The primary CPU0 core shall wait for the secondaries
- * shutdown in order to power-off CPU's cluster safely.
- * The timeout value depends on the current CPU frequency,
- * it takes about 40-150us in average and over 1000us in
- * a worst case scenario.
- */
- do {
- if (tegra_cpu_rail_off_ready())
- return 0;
-
- } while (ktime_before(ktime_get(), timeout));
-
- tegra20_report_cpus_state();
- }
-
- pr_err("timed out waiting secondaries to park\n");
-
- return -ETIMEDOUT;
-}
-
-static bool tegra20_cpu_cluster_power_down(struct cpuidle_device *dev,
- struct cpuidle_driver *drv,
- int index)
-{
- bool ret;
-
- if (tegra20_wait_for_secondary_cpu_parking())
- return false;
-
- ret = !tegra_pm_enter_lp2();
-
- if (cpu_online(1))
- tegra20_wake_cpu1_from_reset();
-
- return ret;
-}
-
-#ifdef CONFIG_SMP
-static bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev,
- struct cpuidle_driver *drv,
- int index)
-{
- cpu_suspend(dev->cpu, tegra_pm_park_secondary_cpu);
-
- return true;
-}
-#else
-static inline bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev,
- struct cpuidle_driver *drv,
- int index)
-{
- return true;
-}
-#endif
-
-static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
- struct cpuidle_driver *drv,
- int index)
-{
- bool entered_lp2 = false;
-
- if (tegra_pending_sgi())
- atomic_set(&abort_flag, 1);
-
- cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
-
- if (atomic_read(&abort_flag)) {
- cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
- /* clean flag for next coming */
- atomic_set(&abort_flag, 0);
- return -EINTR;
- }
-
- local_fiq_disable();
-
- tegra_pm_set_cpu_in_lp2();
- cpu_pm_enter();
-
- if (dev->cpu == 0)
- entered_lp2 = tegra20_cpu_cluster_power_down(dev, drv, index);
- else
- entered_lp2 = tegra20_idle_enter_lp2_cpu_1(dev, drv, index);
-
- cpu_pm_exit();
- tegra_pm_clear_cpu_in_lp2();
-
- local_fiq_enable();
-
- return entered_lp2 ? index : 0;
-}
-#endif
-
-/*
- * Tegra20 HW appears to have a bug such that PCIe device interrupts, whether
- * they are legacy IRQs or MSI, are lost when LP2 is enabled. To work around
- * this, simply disable LP2 if the PCI driver and DT node are both enabled.
- */
-void tegra20_cpuidle_pcie_irqs_in_use(void)
-{
- pr_info_once(
- "Disabling cpuidle LP2 state, since PCIe IRQs are in use\n");
- cpuidle_driver_state_disabled(&tegra_idle_driver, 1, true);
-}
-
-int __init tegra20_cpuidle_init(void)
-{
- return cpuidle_register(&tegra_idle_driver, cpu_possible_mask);
-}
diff --git a/arch/arm/mach-tegra/cpuidle.c b/arch/arm/mach-tegra/cpuidle.c
index d565c44cfc93..eee85d517783 100644
--- a/arch/arm/mach-tegra/cpuidle.c
+++ b/arch/arm/mach-tegra/cpuidle.c
@@ -14,6 +14,7 @@

#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/platform_device.h>

#include <soc/tegra/fuse.h>

@@ -23,8 +24,7 @@ void __init tegra_cpuidle_init(void)
{
switch (tegra_get_chip_id()) {
case TEGRA20:
- if (IS_ENABLED(CONFIG_ARCH_TEGRA_2x_SOC))
- tegra20_cpuidle_init();
+ platform_device_register_simple("tegra-cpuidle", -1, NULL, 0);
break;
case TEGRA30:
if (IS_ENABLED(CONFIG_ARCH_TEGRA_3x_SOC))
@@ -38,13 +38,3 @@ void __init tegra_cpuidle_init(void)
break;
}
}
-
-void tegra_cpuidle_pcie_irqs_in_use(void)
-{
- switch (tegra_get_chip_id()) {
- case TEGRA20:
- if (IS_ENABLED(CONFIG_ARCH_TEGRA_2x_SOC))
- tegra20_cpuidle_pcie_irqs_in_use();
- break;
- }
-}
diff --git a/arch/arm/mach-tegra/cpuidle.h b/arch/arm/mach-tegra/cpuidle.h
index 4e1f459f5bd8..eeb37baf18e1 100644
--- a/arch/arm/mach-tegra/cpuidle.h
+++ b/arch/arm/mach-tegra/cpuidle.h
@@ -7,15 +7,11 @@
#define __MACH_TEGRA_CPUIDLE_H

#ifdef CONFIG_CPU_IDLE
-int tegra20_cpuidle_init(void);
-void tegra20_cpuidle_pcie_irqs_in_use(void);
int tegra30_cpuidle_init(void);
int tegra114_cpuidle_init(void);
void tegra_cpuidle_init(void);
-void tegra_cpuidle_pcie_irqs_in_use(void);
#else
static inline void tegra_cpuidle_init(void) {}
-static inline void tegra_cpuidle_pcie_irqs_in_use(void) {}
#endif

#endif
diff --git a/drivers/cpuidle/Kconfig.arm b/drivers/cpuidle/Kconfig.arm
index d8530475493c..6952bf7bb260 100644
--- a/drivers/cpuidle/Kconfig.arm
+++ b/drivers/cpuidle/Kconfig.arm
@@ -86,3 +86,11 @@ config ARM_MVEBU_V7_CPUIDLE
depends on ARCH_MVEBU && !ARM64
help
Select this to enable cpuidle on Armada 370, 38x and XP processors.
+
+config ARM_TEGRA_CPUIDLE
+ bool "CPU Idle Driver for NVIDIA Tegra SoCs"
+ depends on ARCH_TEGRA && !ARM64
+ select ARCH_NEEDS_CPU_IDLE_COUPLED if SMP
+ select ARM_CPU_SUSPEND
+ help
+ Select this to enable cpuidle for NVIDIA Tegra20/30/114/124 SoCs.
diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
index ee70d5cc5b99..a15e4808d295 100644
--- a/drivers/cpuidle/Makefile
+++ b/drivers/cpuidle/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_ARM_AT91_CPUIDLE) += cpuidle-at91.o
obj-$(CONFIG_ARM_EXYNOS_CPUIDLE) += cpuidle-exynos.o
obj-$(CONFIG_ARM_CPUIDLE) += cpuidle-arm.o
obj-$(CONFIG_ARM_PSCI_CPUIDLE) += cpuidle-psci.o
+obj-$(CONFIG_ARM_TEGRA_CPUIDLE) += cpuidle-tegra.o

###############################################################################
# MIPS drivers
diff --git a/drivers/cpuidle/cpuidle-tegra.c b/drivers/cpuidle/cpuidle-tegra.c
new file mode 100644
index 000000000000..6f7955b9d4bd
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-tegra.c
@@ -0,0 +1,269 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * CPU idle driver for Tegra CPUs
+ *
+ * Copyright (c) 2010-2013, NVIDIA Corporation.
+ * Copyright (c) 2011 Google, Inc.
+ * Author: Colin Cross <ccross@android.com>
+ * Gary King <gking@nvidia.com>
+ *
+ * Rework for 3.3 by Peter De Schrijver <pdeschrijver@nvidia.com>
+ *
+ * Tegra20/124 driver unification by Dmitry Osipenko <digetx@gmail.com>
+ */
+
+#define pr_fmt(fmt) "tegra-cpuidle: " fmt
+
+#include <linux/atomic.h>
+#include <linux/cpuidle.h>
+#include <linux/cpumask.h>
+#include <linux/cpu_pm.h>
+#include <linux/errno.h>
+#include <linux/ktime.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+
+#include <linux/clk/tegra.h>
+
+#include <soc/tegra/cpuidle.h>
+#include <soc/tegra/flowctrl.h>
+#include <soc/tegra/fuse.h>
+#include <soc/tegra/irq.h>
+#include <soc/tegra/pm.h>
+
+#include <asm/cpuidle.h>
+#include <asm/smp_plat.h>
+#include <asm/suspend.h>
+
+enum {
+ TEGRA_C1,
+ TEGRA_CC6,
+ TEGRA_STATE_COUNT,
+};
+
+static atomic_t tegra_idle_barrier;
+static atomic_t tegra_abort_flag;
+
+static void tegra_cpuidle_report_cpus_state(void)
+{
+ unsigned int cpu, lcpu;
+
+ pr_err("secondary CPU taking too long to park\n");
+
+ for_each_cpu(lcpu, cpu_possible_mask) {
+ cpu = cpu_logical_map(lcpu);
+
+ pr_err("cpu%u: online=%d flowctrl_csr=0x%08x\n",
+ cpu, cpu_online(lcpu), flowctrl_read_cpu_csr(cpu));
+ }
+}
+
+static int tegra_cpuidle_wait_for_secondary_cpus_parking(void)
+{
+ unsigned int retries = 3;
+
+ while (retries--) {
+ ktime_t timeout = ktime_add_ms(ktime_get(), 500);
+
+ /*
+ * The primary CPU0 core shall wait for the secondaries
+ * shutdown in order to power-off CPU's cluster safely.
+ * The timeout value depends on the current CPU frequency,
+ * it takes about 40-150us in average and over 1000us in
+ * a worst case scenario.
+ */
+ do {
+ if (tegra_cpu_rail_off_ready())
+ return 0;
+
+ } while (ktime_before(ktime_get(), timeout));
+
+ tegra_cpuidle_report_cpus_state();
+ }
+
+ pr_err("timed out waiting secondaries to park\n");
+
+ return -ETIMEDOUT;
+}
+
+static void tegra_cpuidle_unpark_secondary_cpus(void)
+{
+ unsigned int cpu, lcpu;
+
+ for_each_cpu(lcpu, cpu_online_mask) {
+ cpu = cpu_logical_map(lcpu);
+
+ if (cpu > 0) {
+ tegra_enable_cpu_clock(cpu);
+ tegra_cpu_out_of_reset(cpu);
+ flowctrl_write_cpu_halt(cpu, 0);
+ }
+ }
+}
+
+static int tegra_cpuidle_cc6_enter(unsigned int cpu)
+{
+ int ret;
+
+ if (cpu > 0) {
+ ret = cpu_suspend(cpu, tegra_pm_park_secondary_cpu);
+ } else {
+ ret = tegra_cpuidle_wait_for_secondary_cpus_parking();
+ if (!ret)
+ ret = tegra_pm_enter_lp2();
+
+ tegra_cpuidle_unpark_secondary_cpus();
+ }
+
+ return ret;
+}
+
+static int tegra_cpuidle_coupled_barrier(struct cpuidle_device *dev)
+{
+ if (tegra_pending_sgi()) {
+ /*
+ * CPU got local interrupt that will be lost after GIC's
+ * shutdown because GIC driver doesn't save/restore the
+ * pending SGI state across CPU cluster PM. Abort and retry
+ * next time.
+ */
+ atomic_set(&tegra_abort_flag, 1);
+ }
+
+ cpuidle_coupled_parallel_barrier(dev, &tegra_idle_barrier);
+
+ if (atomic_read(&tegra_abort_flag)) {
+ cpuidle_coupled_parallel_barrier(dev, &tegra_idle_barrier);
+ atomic_set(&tegra_abort_flag, 0);
+ return -EINTR;
+ }
+
+ return 0;
+}
+
+static int tegra_cpuidle_state_enter(struct cpuidle_device *dev,
+ int index, unsigned int cpu)
+{
+ int ret;
+
+ /*
+ * CC6 state is the "CPU cluster power-off" state. In order to
+ * enter this state, at first the secondary CPU cores need to be
+ * parked into offline mode, then the last CPU should clean out
+ * remaining dirty cache lines into DRAM and trigger Flow Controller
+ * logic that turns off the cluster's power domain (which includes
+ * CPU cores, GIC and L2 cache).
+ */
+ if (index == TEGRA_CC6) {
+ ret = tegra_cpuidle_coupled_barrier(dev);
+ if (ret)
+ return ret;
+ }
+
+ local_fiq_disable();
+ tegra_pm_set_cpu_in_lp2();
+ cpu_pm_enter();
+
+ switch (index) {
+ case TEGRA_CC6:
+ ret = tegra_cpuidle_cc6_enter(cpu);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ cpu_pm_exit();
+ tegra_pm_clear_cpu_in_lp2();
+ local_fiq_enable();
+
+ return ret;
+}
+
+static int tegra_cpuidle_enter(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv,
+ int index)
+{
+ unsigned int cpu = cpu_logical_map(dev->cpu);
+ int err;
+
+ err = tegra_cpuidle_state_enter(dev, index, cpu);
+ if (err && err != -EINTR)
+ pr_err_once("cpu%u failed to enter idle state %d err: %d\n",
+ cpu, index, err);
+
+ return err ? -1 : index;
+}
+
+/*
+ * The previous versions of Tegra CPUIDLE driver used a different "legacy"
+ * terminology for naming of the idling states, while this driver uses the
+ * new terminology.
+ *
+ * Mapping of the old terms into the new ones:
+ *
+ * Old | New
+ * ---------
+ * LP3 | C1 (CPU core clock gating)
+ * LP2 | C7 (CPU core power gating)
+ * LP2 | CC6 (CPU cluster power gating)
+ *
+ * Note that that the older CPUIDLE driver versions didn't explicitly
+ * differentiate the LP2 states because these states either used the same
+ * code path or because CC6 wasn't supported.
+ */
+static struct cpuidle_driver tegra_idle_driver = {
+ .name = "tegra_idle",
+ .states = {
+ [TEGRA_C1] = ARM_CPUIDLE_WFI_STATE_PWR(600),
+ [TEGRA_CC6] = {
+ .enter = tegra_cpuidle_enter,
+ .exit_latency = 5000,
+ .target_residency = 10000,
+ .power_usage = 0,
+ .flags = CPUIDLE_FLAG_TIMER_STOP |
+ CPUIDLE_FLAG_COUPLED,
+ .name = "CC6",
+ .desc = "CPU cluster powered off",
+ },
+ },
+ .state_count = TEGRA_STATE_COUNT,
+ .safe_state_index = TEGRA_C1,
+};
+
+/*
+ * Tegra20 HW appears to have a bug such that PCIe device interrupts, whether
+ * they are legacy IRQs or MSI, are lost when CC6 is enabled. To work around
+ * this, simply disable CC6 if the PCI driver and DT node are both enabled.
+ */
+void tegra_cpuidle_pcie_irqs_in_use(void)
+{
+ if (tegra_idle_driver.states[TEGRA_CC6].disabled ||
+ tegra_get_chip_id() != TEGRA20)
+ return;
+
+ pr_info("disabling CC6 state, since PCIe IRQs are in use\n");
+ cpuidle_driver_state_disabled(&tegra_idle_driver, TEGRA_CC6, true);
+ tegra_idle_driver.states[TEGRA_CC6].disabled = true;
+}
+
+static int tegra_cpuidle_probe(struct platform_device *pdev)
+{
+ /*
+ * Required suspend-resume functionality, which is provided by the
+ * Tegra-arch core and PMC driver, is unavailable if PM-sleep option
+ * is disabled.
+ */
+ if (!IS_ENABLED(CONFIG_PM_SLEEP))
+ tegra_idle_driver.states[TEGRA_CC6].disabled = true;
+
+ return cpuidle_register(&tegra_idle_driver, cpu_possible_mask);
+}
+
+static struct platform_driver tegra_cpuidle_driver = {
+ .probe = tegra_cpuidle_probe,
+ .driver = {
+ .name = "tegra-cpuidle",
+ },
+};
+builtin_platform_driver(tegra_cpuidle_driver);
diff --git a/include/soc/tegra/cpuidle.h b/include/soc/tegra/cpuidle.h
index 029ba1f4b2cc..5665975015d8 100644
--- a/include/soc/tegra/cpuidle.h
+++ b/include/soc/tegra/cpuidle.h
@@ -6,7 +6,7 @@
#ifndef __SOC_TEGRA_CPUIDLE_H__
#define __SOC_TEGRA_CPUIDLE_H__

-#if defined(CONFIG_ARM) && defined(CONFIG_ARCH_TEGRA) && defined(CONFIG_CPU_IDLE)
+#ifdef CONFIG_ARM_TEGRA_CPUIDLE
void tegra_cpuidle_pcie_irqs_in_use(void);
#else
static inline void tegra_cpuidle_pcie_irqs_in_use(void)
--
2.24.0
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