drivers/cpuidle/cpuidle-exynos.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (c) 2011-2014 Samsung Electronics Co., Ltd.
0004  *      http://www.samsung.com
0005  *
0006  * Coupled cpuidle support based on the work of:
0007  *  Colin Cross <ccross@android.com>
0008  *  Daniel Lezcano <daniel.lezcano@linaro.org>
0009 */
0010
0011 #include <linux/cpuidle.h>
0012 #include <linux/cpu_pm.h>
0013 #include <linux/export.h>
0014 #include <linux/init.h>
0015 #include <linux/platform_device.h>
0016 #include <linux/of.h>
0017 #include <linux/platform_data/cpuidle-exynos.h>
0018
0019 #include <asm/suspend.h>
0020 #include <asm/cpuidle.h>
0021
0022 static atomic_t exynos_idle_barrier;
0023
0024 static struct cpuidle_exynos_data *exynos_cpuidle_pdata;
0025 static void (*exynos_enter_aftr)(void);
0026
0027 static int exynos_enter_coupled_lowpower(struct cpuidle_device *dev,
0028                      struct cpuidle_driver *drv,
0029                      int index)
0030 {
0031     int ret;
0032
0033     exynos_cpuidle_pdata->pre_enter_aftr();
0034
0035     /*
0036      * Waiting all cpus to reach this point at the same moment
0037      */
0038     cpuidle_coupled_parallel_barrier(dev, &exynos_idle_barrier);
0039
0040     /*
0041      * Both cpus will reach this point at the same time
0042      */
0043     ret = dev->cpu ? exynos_cpuidle_pdata->cpu1_powerdown()
0044                : exynos_cpuidle_pdata->cpu0_enter_aftr();
0045     if (ret)
0046         index = ret;
0047
0048     /*
0049      * Waiting all cpus to finish the power sequence before going further
0050      */
0051     cpuidle_coupled_parallel_barrier(dev, &exynos_idle_barrier);
0052
0053     exynos_cpuidle_pdata->post_enter_aftr();
0054
0055     return index;
0056 }
0057
0058 static int exynos_enter_lowpower(struct cpuidle_device *dev,
0059                 struct cpuidle_driver *drv,
0060                 int index)
0061 {
0062     int new_index = index;
0063
0064     /* AFTR can only be entered when cores other than CPU0 are offline */
0065     if (num_online_cpus() > 1 || dev->cpu != 0)
0066         new_index = drv->safe_state_index;
0067
0068     if (new_index == 0)
0069         return arm_cpuidle_simple_enter(dev, drv, new_index);
0070
0071     exynos_enter_aftr();
0072
0073     return new_index;
0074 }
0075
0076 static struct cpuidle_driver exynos_idle_driver = {
0077     .name           = "exynos_idle",
0078     .owner          = THIS_MODULE,
0079     .states = {
0080         [0] = ARM_CPUIDLE_WFI_STATE,
0081         [1] = {
0082             .enter          = exynos_enter_lowpower,
0083             .exit_latency       = 300,
0084             .target_residency   = 10000,
0085             .name           = "C1",
0086             .desc           = "ARM power down",
0087         },
0088     },
0089     .state_count = 2,
0090     .safe_state_index = 0,
0091 };
0092
0093 static struct cpuidle_driver exynos_coupled_idle_driver = {
0094     .name           = "exynos_coupled_idle",
0095     .owner          = THIS_MODULE,
0096     .states = {
0097         [0] = ARM_CPUIDLE_WFI_STATE,
0098         [1] = {
0099             .enter          = exynos_enter_coupled_lowpower,
0100             .exit_latency       = 5000,
0101             .target_residency   = 10000,
0102             .flags          = CPUIDLE_FLAG_COUPLED |
0103                           CPUIDLE_FLAG_TIMER_STOP,
0104             .name           = "C1",
0105             .desc           = "ARM power down",
0106         },
0107     },
0108     .state_count = 2,
0109     .safe_state_index = 0,
0110 };
0111
0112 static int exynos_cpuidle_probe(struct platform_device *pdev)
0113 {
0114     int ret;
0115
0116     if (IS_ENABLED(CONFIG_SMP) &&
0117         (of_machine_is_compatible("samsung,exynos4210") ||
0118          of_machine_is_compatible("samsung,exynos3250"))) {
0119         exynos_cpuidle_pdata = pdev->dev.platform_data;
0120
0121         ret = cpuidle_register(&exynos_coupled_idle_driver,
0122                        cpu_possible_mask);
0123     } else {
0124         exynos_enter_aftr = (void *)(pdev->dev.platform_data);
0125
0126         ret = cpuidle_register(&exynos_idle_driver, NULL);
0127     }
0128
0129     if (ret) {
0130         dev_err(&pdev->dev, "failed to register cpuidle driver\n");
0131         return ret;
0132     }
0133
0134     return 0;
0135 }
0136
0137 static struct platform_driver exynos_cpuidle_driver = {
0138     .probe  = exynos_cpuidle_probe,
0139     .driver = {
0140         .name = "exynos_cpuidle",
0141     },
0142 };
0143 builtin_platform_driver(exynos_cpuidle_driver);