Lorenzo Pieralisi | 14d2c34 | 2013-06-12 17:40:01 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2013 ARM/Linaro |
| 3 | * |
| 4 | * Authors: Daniel Lezcano <daniel.lezcano@linaro.org> |
| 5 | * Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> |
| 6 | * Nicolas Pitre <nicolas.pitre@linaro.org> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License version 2 as |
| 10 | * published by the Free Software Foundation. |
| 11 | * |
| 12 | * Maintainer: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> |
| 13 | * Maintainer: Daniel Lezcano <daniel.lezcano@linaro.org> |
| 14 | */ |
| 15 | #include <linux/cpuidle.h> |
| 16 | #include <linux/cpu_pm.h> |
| 17 | #include <linux/slab.h> |
| 18 | #include <linux/of.h> |
| 19 | |
| 20 | #include <asm/cpu.h> |
| 21 | #include <asm/cputype.h> |
| 22 | #include <asm/cpuidle.h> |
| 23 | #include <asm/mcpm.h> |
| 24 | #include <asm/smp_plat.h> |
| 25 | #include <asm/suspend.h> |
| 26 | |
Lorenzo Pieralisi | d2e5c87 | 2014-06-24 16:20:28 +0100 | [diff] [blame] | 27 | #include "dt_idle_states.h" |
| 28 | |
Lorenzo Pieralisi | 14d2c34 | 2013-06-12 17:40:01 +0200 | [diff] [blame] | 29 | static int bl_enter_powerdown(struct cpuidle_device *dev, |
| 30 | struct cpuidle_driver *drv, int idx); |
| 31 | |
| 32 | /* |
| 33 | * NB: Owing to current menu governor behaviour big and LITTLE |
| 34 | * index 1 states have to define exit_latency and target_residency for |
| 35 | * cluster state since, when all CPUs in a cluster hit it, the cluster |
| 36 | * can be shutdown. This means that when a single CPU enters this state |
| 37 | * the exit_latency and target_residency values are somewhat overkill. |
| 38 | * There is no notion of cluster states in the menu governor, so CPUs |
| 39 | * have to define CPU states where possibly the cluster will be shutdown |
| 40 | * depending on the state of other CPUs. idle states entry and exit happen |
| 41 | * at random times; however the cluster state provides target_residency |
| 42 | * values as if all CPUs in a cluster enter the state at once; this is |
| 43 | * somewhat optimistic and behaviour should be fixed either in the governor |
| 44 | * or in the MCPM back-ends. |
| 45 | * To make this driver 100% generic the number of states and the exit_latency |
| 46 | * target_residency values must be obtained from device tree bindings. |
| 47 | * |
| 48 | * exit_latency: refers to the TC2 vexpress test chip and depends on the |
| 49 | * current cluster operating point. It is the time it takes to get the CPU |
| 50 | * up and running when the CPU is powered up on cluster wake-up from shutdown. |
| 51 | * Current values for big and LITTLE clusters are provided for clusters |
| 52 | * running at default operating points. |
| 53 | * |
| 54 | * target_residency: it is the minimum amount of time the cluster has |
| 55 | * to be down to break even in terms of power consumption. cluster |
| 56 | * shutdown has inherent dynamic power costs (L2 writebacks to DRAM |
| 57 | * being the main factor) that depend on the current operating points. |
| 58 | * The current values for both clusters are provided for a CPU whose half |
| 59 | * of L2 lines are dirty and require cleaning to DRAM, and takes into |
| 60 | * account leakage static power values related to the vexpress TC2 testchip. |
| 61 | */ |
| 62 | static struct cpuidle_driver bl_idle_little_driver = { |
| 63 | .name = "little_idle", |
| 64 | .owner = THIS_MODULE, |
| 65 | .states[0] = ARM_CPUIDLE_WFI_STATE, |
| 66 | .states[1] = { |
| 67 | .enter = bl_enter_powerdown, |
| 68 | .exit_latency = 700, |
| 69 | .target_residency = 2500, |
| 70 | .flags = CPUIDLE_FLAG_TIME_VALID | |
| 71 | CPUIDLE_FLAG_TIMER_STOP, |
| 72 | .name = "C1", |
| 73 | .desc = "ARM little-cluster power down", |
| 74 | }, |
| 75 | .state_count = 2, |
| 76 | }; |
| 77 | |
Lorenzo Pieralisi | d2e5c87 | 2014-06-24 16:20:28 +0100 | [diff] [blame] | 78 | static const struct of_device_id bl_idle_state_match[] __initconst = { |
| 79 | { .compatible = "arm,idle-state", |
| 80 | .data = bl_enter_powerdown }, |
| 81 | { }, |
| 82 | }; |
| 83 | |
Lorenzo Pieralisi | 14d2c34 | 2013-06-12 17:40:01 +0200 | [diff] [blame] | 84 | static struct cpuidle_driver bl_idle_big_driver = { |
| 85 | .name = "big_idle", |
| 86 | .owner = THIS_MODULE, |
| 87 | .states[0] = ARM_CPUIDLE_WFI_STATE, |
| 88 | .states[1] = { |
| 89 | .enter = bl_enter_powerdown, |
| 90 | .exit_latency = 500, |
| 91 | .target_residency = 2000, |
| 92 | .flags = CPUIDLE_FLAG_TIME_VALID | |
| 93 | CPUIDLE_FLAG_TIMER_STOP, |
| 94 | .name = "C1", |
| 95 | .desc = "ARM big-cluster power down", |
| 96 | }, |
| 97 | .state_count = 2, |
| 98 | }; |
| 99 | |
| 100 | /* |
| 101 | * notrace prevents trace shims from getting inserted where they |
| 102 | * should not. Global jumps and ldrex/strex must not be inserted |
| 103 | * in power down sequences where caches and MMU may be turned off. |
| 104 | */ |
| 105 | static int notrace bl_powerdown_finisher(unsigned long arg) |
| 106 | { |
| 107 | /* MCPM works with HW CPU identifiers */ |
| 108 | unsigned int mpidr = read_cpuid_mpidr(); |
| 109 | unsigned int cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); |
| 110 | unsigned int cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); |
| 111 | |
| 112 | mcpm_set_entry_vector(cpu, cluster, cpu_resume); |
| 113 | |
| 114 | /* |
| 115 | * Residency value passed to mcpm_cpu_suspend back-end |
| 116 | * has to be given clear semantics. Set to 0 as a |
| 117 | * temporary value. |
| 118 | */ |
| 119 | mcpm_cpu_suspend(0); |
| 120 | |
| 121 | /* return value != 0 means failure */ |
| 122 | return 1; |
| 123 | } |
| 124 | |
| 125 | /** |
| 126 | * bl_enter_powerdown - Programs CPU to enter the specified state |
| 127 | * @dev: cpuidle device |
| 128 | * @drv: The target state to be programmed |
| 129 | * @idx: state index |
| 130 | * |
| 131 | * Called from the CPUidle framework to program the device to the |
| 132 | * specified target state selected by the governor. |
| 133 | */ |
| 134 | static int bl_enter_powerdown(struct cpuidle_device *dev, |
| 135 | struct cpuidle_driver *drv, int idx) |
| 136 | { |
| 137 | cpu_pm_enter(); |
| 138 | |
| 139 | cpu_suspend(0, bl_powerdown_finisher); |
| 140 | |
| 141 | /* signals the MCPM core that CPU is out of low power state */ |
| 142 | mcpm_cpu_powered_up(); |
| 143 | |
| 144 | cpu_pm_exit(); |
| 145 | |
| 146 | return idx; |
| 147 | } |
| 148 | |
Juri Lelli | eba1c71 | 2014-08-15 15:53:14 +0100 | [diff] [blame] | 149 | static int __init bl_idle_driver_init(struct cpuidle_driver *drv, int part_id) |
Lorenzo Pieralisi | 14d2c34 | 2013-06-12 17:40:01 +0200 | [diff] [blame] | 150 | { |
Lorenzo Pieralisi | 14d2c34 | 2013-06-12 17:40:01 +0200 | [diff] [blame] | 151 | struct cpumask *cpumask; |
Lorenzo Pieralisi | 14d2c34 | 2013-06-12 17:40:01 +0200 | [diff] [blame] | 152 | int cpu; |
| 153 | |
| 154 | cpumask = kzalloc(cpumask_size(), GFP_KERNEL); |
| 155 | if (!cpumask) |
| 156 | return -ENOMEM; |
| 157 | |
Juri Lelli | eba1c71 | 2014-08-15 15:53:14 +0100 | [diff] [blame] | 158 | for_each_possible_cpu(cpu) |
| 159 | if (smp_cpuid_part(cpu) == part_id) |
Lorenzo Pieralisi | 14d2c34 | 2013-06-12 17:40:01 +0200 | [diff] [blame] | 160 | cpumask_set_cpu(cpu, cpumask); |
Lorenzo Pieralisi | 14d2c34 | 2013-06-12 17:40:01 +0200 | [diff] [blame] | 161 | |
| 162 | drv->cpumask = cpumask; |
| 163 | |
| 164 | return 0; |
| 165 | } |
| 166 | |
Chander Kashyap | e2e5436 | 2014-07-05 06:24:34 +0900 | [diff] [blame] | 167 | static const struct of_device_id compatible_machine_match[] = { |
| 168 | { .compatible = "arm,vexpress,v2p-ca15_a7" }, |
Chander Kashyap | 64a3c4c | 2014-07-05 06:24:35 +0900 | [diff] [blame] | 169 | { .compatible = "samsung,exynos5420" }, |
Kevin Hilman | 6baf6ee | 2014-08-12 17:11:05 -0700 | [diff] [blame] | 170 | { .compatible = "samsung,exynos5800" }, |
Chander Kashyap | e2e5436 | 2014-07-05 06:24:34 +0900 | [diff] [blame] | 171 | {}, |
| 172 | }; |
| 173 | |
Lorenzo Pieralisi | 14d2c34 | 2013-06-12 17:40:01 +0200 | [diff] [blame] | 174 | static int __init bl_idle_init(void) |
| 175 | { |
| 176 | int ret; |
Chander Kashyap | e2e5436 | 2014-07-05 06:24:34 +0900 | [diff] [blame] | 177 | struct device_node *root = of_find_node_by_path("/"); |
| 178 | |
| 179 | if (!root) |
| 180 | return -ENODEV; |
Lorenzo Pieralisi | 14d2c34 | 2013-06-12 17:40:01 +0200 | [diff] [blame] | 181 | |
| 182 | /* |
| 183 | * Initialize the driver just for a compliant set of machines |
| 184 | */ |
Chander Kashyap | e2e5436 | 2014-07-05 06:24:34 +0900 | [diff] [blame] | 185 | if (!of_match_node(compatible_machine_match, root)) |
Lorenzo Pieralisi | 14d2c34 | 2013-06-12 17:40:01 +0200 | [diff] [blame] | 186 | return -ENODEV; |
| 187 | /* |
| 188 | * For now the differentiation between little and big cores |
| 189 | * is based on the part number. A7 cores are considered little |
| 190 | * cores, A15 are considered big cores. This distinction may |
| 191 | * evolve in the future with a more generic matching approach. |
| 192 | */ |
| 193 | ret = bl_idle_driver_init(&bl_idle_little_driver, |
| 194 | ARM_CPU_PART_CORTEX_A7); |
| 195 | if (ret) |
| 196 | return ret; |
| 197 | |
| 198 | ret = bl_idle_driver_init(&bl_idle_big_driver, ARM_CPU_PART_CORTEX_A15); |
| 199 | if (ret) |
| 200 | goto out_uninit_little; |
| 201 | |
Lorenzo Pieralisi | d2e5c87 | 2014-06-24 16:20:28 +0100 | [diff] [blame] | 202 | /* Start at index 1, index 0 standard WFI */ |
| 203 | ret = dt_init_idle_driver(&bl_idle_big_driver, bl_idle_state_match, 1); |
| 204 | if (ret < 0) |
| 205 | goto out_uninit_big; |
| 206 | |
| 207 | /* Start at index 1, index 0 standard WFI */ |
| 208 | ret = dt_init_idle_driver(&bl_idle_little_driver, |
| 209 | bl_idle_state_match, 1); |
| 210 | if (ret < 0) |
| 211 | goto out_uninit_big; |
| 212 | |
Lorenzo Pieralisi | 14d2c34 | 2013-06-12 17:40:01 +0200 | [diff] [blame] | 213 | ret = cpuidle_register(&bl_idle_little_driver, NULL); |
| 214 | if (ret) |
| 215 | goto out_uninit_big; |
| 216 | |
| 217 | ret = cpuidle_register(&bl_idle_big_driver, NULL); |
| 218 | if (ret) |
| 219 | goto out_unregister_little; |
| 220 | |
| 221 | return 0; |
| 222 | |
| 223 | out_unregister_little: |
| 224 | cpuidle_unregister(&bl_idle_little_driver); |
| 225 | out_uninit_big: |
| 226 | kfree(bl_idle_big_driver.cpumask); |
| 227 | out_uninit_little: |
| 228 | kfree(bl_idle_little_driver.cpumask); |
| 229 | |
| 230 | return ret; |
| 231 | } |
| 232 | device_initcall(bl_idle_init); |