cpuidle: Refactor and move out NVIDIA Tegra20 driver into drivers/cpuidle

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.

Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>

4 files changed, 2 insertions, 238 deletions

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 a06a4b517fb8..000000000000
--- a/arch/arm/mach-tegra/cpuidle-tegra20.c
+++ /dev/null
@@ -1,219 +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/delay.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-
-#include <soc/tegra/flowctrl.h>
-#include <soc/tegra/irq.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 "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 long cpu, lcpu, csr;
-
-	for_each_cpu(lcpu, cpu_possible_mask) {
-		cpu = cpu_logical_map(lcpu);
-		csr = flowctrl_read_cpu_csr(cpu);
-
-		pr_err("cpu%lu: online=%d flowctrl_csr=0x%08lx\n",
-		       cpu, cpu_online(lcpu), csr);
-	}
-}
-
-static int tegra20_wait_for_secondary_cpu_parking(void)
-{
-	unsigned int retries = 3;
-
-	while (retries--) {
-		unsigned int delay_us = 10;
-		unsigned int timeout_us = 500 * 1000 / delay_us;
-
-		/*
-		 * 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;
-
-			udelay(delay_us);
-
-		} while (timeout_us--);
-
-		pr_err("secondary CPU taking too long to park\n");
-
-		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