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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
14d2c34c LP |
2 | /* |
3 | * Copyright (c) 2013 ARM/Linaro | |
4 | * | |
5 | * Authors: Daniel Lezcano <daniel.lezcano@linaro.org> | |
6 | * Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> | |
7 | * Nicolas Pitre <nicolas.pitre@linaro.org> | |
8 | * | |
14d2c34c LP |
9 | * Maintainer: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> |
10 | * Maintainer: Daniel Lezcano <daniel.lezcano@linaro.org> | |
11 | */ | |
12 | #include <linux/cpuidle.h> | |
13 | #include <linux/cpu_pm.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/of.h> | |
16 | ||
17 | #include <asm/cpu.h> | |
18 | #include <asm/cputype.h> | |
19 | #include <asm/cpuidle.h> | |
20 | #include <asm/mcpm.h> | |
21 | #include <asm/smp_plat.h> | |
22 | #include <asm/suspend.h> | |
23 | ||
d2e5c871 LP |
24 | #include "dt_idle_states.h" |
25 | ||
14d2c34c LP |
26 | static int bl_enter_powerdown(struct cpuidle_device *dev, |
27 | struct cpuidle_driver *drv, int idx); | |
28 | ||
29 | /* | |
30 | * NB: Owing to current menu governor behaviour big and LITTLE | |
31 | * index 1 states have to define exit_latency and target_residency for | |
32 | * cluster state since, when all CPUs in a cluster hit it, the cluster | |
33 | * can be shutdown. This means that when a single CPU enters this state | |
34 | * the exit_latency and target_residency values are somewhat overkill. | |
35 | * There is no notion of cluster states in the menu governor, so CPUs | |
36 | * have to define CPU states where possibly the cluster will be shutdown | |
37 | * depending on the state of other CPUs. idle states entry and exit happen | |
38 | * at random times; however the cluster state provides target_residency | |
39 | * values as if all CPUs in a cluster enter the state at once; this is | |
40 | * somewhat optimistic and behaviour should be fixed either in the governor | |
41 | * or in the MCPM back-ends. | |
42 | * To make this driver 100% generic the number of states and the exit_latency | |
43 | * target_residency values must be obtained from device tree bindings. | |
44 | * | |
45 | * exit_latency: refers to the TC2 vexpress test chip and depends on the | |
46 | * current cluster operating point. It is the time it takes to get the CPU | |
47 | * up and running when the CPU is powered up on cluster wake-up from shutdown. | |
48 | * Current values for big and LITTLE clusters are provided for clusters | |
49 | * running at default operating points. | |
50 | * | |
51 | * target_residency: it is the minimum amount of time the cluster has | |
52 | * to be down to break even in terms of power consumption. cluster | |
53 | * shutdown has inherent dynamic power costs (L2 writebacks to DRAM | |
54 | * being the main factor) that depend on the current operating points. | |
55 | * The current values for both clusters are provided for a CPU whose half | |
56 | * of L2 lines are dirty and require cleaning to DRAM, and takes into | |
57 | * account leakage static power values related to the vexpress TC2 testchip. | |
58 | */ | |
59 | static struct cpuidle_driver bl_idle_little_driver = { | |
60 | .name = "little_idle", | |
61 | .owner = THIS_MODULE, | |
62 | .states[0] = ARM_CPUIDLE_WFI_STATE, | |
63 | .states[1] = { | |
64 | .enter = bl_enter_powerdown, | |
65 | .exit_latency = 700, | |
66 | .target_residency = 2500, | |
b82b6cca | 67 | .flags = CPUIDLE_FLAG_TIMER_STOP, |
14d2c34c LP |
68 | .name = "C1", |
69 | .desc = "ARM little-cluster power down", | |
70 | }, | |
71 | .state_count = 2, | |
72 | }; | |
73 | ||
d2e5c871 LP |
74 | static const struct of_device_id bl_idle_state_match[] __initconst = { |
75 | { .compatible = "arm,idle-state", | |
76 | .data = bl_enter_powerdown }, | |
77 | { }, | |
78 | }; | |
79 | ||
14d2c34c LP |
80 | static struct cpuidle_driver bl_idle_big_driver = { |
81 | .name = "big_idle", | |
82 | .owner = THIS_MODULE, | |
83 | .states[0] = ARM_CPUIDLE_WFI_STATE, | |
84 | .states[1] = { | |
85 | .enter = bl_enter_powerdown, | |
86 | .exit_latency = 500, | |
87 | .target_residency = 2000, | |
b82b6cca | 88 | .flags = CPUIDLE_FLAG_TIMER_STOP, |
14d2c34c LP |
89 | .name = "C1", |
90 | .desc = "ARM big-cluster power down", | |
91 | }, | |
92 | .state_count = 2, | |
93 | }; | |
94 | ||
95 | /* | |
96 | * notrace prevents trace shims from getting inserted where they | |
97 | * should not. Global jumps and ldrex/strex must not be inserted | |
98 | * in power down sequences where caches and MMU may be turned off. | |
99 | */ | |
100 | static int notrace bl_powerdown_finisher(unsigned long arg) | |
101 | { | |
102 | /* MCPM works with HW CPU identifiers */ | |
103 | unsigned int mpidr = read_cpuid_mpidr(); | |
104 | unsigned int cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); | |
105 | unsigned int cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); | |
106 | ||
107 | mcpm_set_entry_vector(cpu, cluster, cpu_resume); | |
7895f731 | 108 | mcpm_cpu_suspend(); |
14d2c34c LP |
109 | |
110 | /* return value != 0 means failure */ | |
111 | return 1; | |
112 | } | |
113 | ||
114 | /** | |
115 | * bl_enter_powerdown - Programs CPU to enter the specified state | |
116 | * @dev: cpuidle device | |
117 | * @drv: The target state to be programmed | |
118 | * @idx: state index | |
119 | * | |
120 | * Called from the CPUidle framework to program the device to the | |
121 | * specified target state selected by the governor. | |
122 | */ | |
123 | static int bl_enter_powerdown(struct cpuidle_device *dev, | |
124 | struct cpuidle_driver *drv, int idx) | |
125 | { | |
126 | cpu_pm_enter(); | |
127 | ||
128 | cpu_suspend(0, bl_powerdown_finisher); | |
129 | ||
130 | /* signals the MCPM core that CPU is out of low power state */ | |
131 | mcpm_cpu_powered_up(); | |
132 | ||
133 | cpu_pm_exit(); | |
134 | ||
135 | return idx; | |
136 | } | |
137 | ||
eba1c718 | 138 | static int __init bl_idle_driver_init(struct cpuidle_driver *drv, int part_id) |
14d2c34c | 139 | { |
14d2c34c | 140 | struct cpumask *cpumask; |
14d2c34c LP |
141 | int cpu; |
142 | ||
143 | cpumask = kzalloc(cpumask_size(), GFP_KERNEL); | |
144 | if (!cpumask) | |
145 | return -ENOMEM; | |
146 | ||
eba1c718 JL |
147 | for_each_possible_cpu(cpu) |
148 | if (smp_cpuid_part(cpu) == part_id) | |
14d2c34c | 149 | cpumask_set_cpu(cpu, cpumask); |
14d2c34c LP |
150 | |
151 | drv->cpumask = cpumask; | |
152 | ||
153 | return 0; | |
154 | } | |
155 | ||
e2e54362 CK |
156 | static const struct of_device_id compatible_machine_match[] = { |
157 | { .compatible = "arm,vexpress,v2p-ca15_a7" }, | |
f1118a28 | 158 | { .compatible = "google,peach" }, |
e2e54362 CK |
159 | {}, |
160 | }; | |
161 | ||
14d2c34c LP |
162 | static int __init bl_idle_init(void) |
163 | { | |
164 | int ret; | |
e2e54362 | 165 | struct device_node *root = of_find_node_by_path("/"); |
9456823c | 166 | const struct of_device_id *match_id; |
e2e54362 CK |
167 | |
168 | if (!root) | |
169 | return -ENODEV; | |
14d2c34c LP |
170 | |
171 | /* | |
172 | * Initialize the driver just for a compliant set of machines | |
173 | */ | |
9456823c YL |
174 | match_id = of_match_node(compatible_machine_match, root); |
175 | ||
176 | of_node_put(root); | |
177 | ||
178 | if (!match_id) | |
14d2c34c | 179 | return -ENODEV; |
194fe6f2 SH |
180 | |
181 | if (!mcpm_is_available()) | |
182 | return -EUNATCH; | |
183 | ||
14d2c34c LP |
184 | /* |
185 | * For now the differentiation between little and big cores | |
186 | * is based on the part number. A7 cores are considered little | |
187 | * cores, A15 are considered big cores. This distinction may | |
188 | * evolve in the future with a more generic matching approach. | |
189 | */ | |
190 | ret = bl_idle_driver_init(&bl_idle_little_driver, | |
191 | ARM_CPU_PART_CORTEX_A7); | |
192 | if (ret) | |
193 | return ret; | |
194 | ||
195 | ret = bl_idle_driver_init(&bl_idle_big_driver, ARM_CPU_PART_CORTEX_A15); | |
196 | if (ret) | |
197 | goto out_uninit_little; | |
198 | ||
d2e5c871 LP |
199 | /* Start at index 1, index 0 standard WFI */ |
200 | ret = dt_init_idle_driver(&bl_idle_big_driver, bl_idle_state_match, 1); | |
201 | if (ret < 0) | |
202 | goto out_uninit_big; | |
203 | ||
204 | /* Start at index 1, index 0 standard WFI */ | |
205 | ret = dt_init_idle_driver(&bl_idle_little_driver, | |
206 | bl_idle_state_match, 1); | |
207 | if (ret < 0) | |
208 | goto out_uninit_big; | |
209 | ||
14d2c34c LP |
210 | ret = cpuidle_register(&bl_idle_little_driver, NULL); |
211 | if (ret) | |
212 | goto out_uninit_big; | |
213 | ||
214 | ret = cpuidle_register(&bl_idle_big_driver, NULL); | |
215 | if (ret) | |
216 | goto out_unregister_little; | |
217 | ||
218 | return 0; | |
219 | ||
220 | out_unregister_little: | |
221 | cpuidle_unregister(&bl_idle_little_driver); | |
222 | out_uninit_big: | |
223 | kfree(bl_idle_big_driver.cpumask); | |
224 | out_uninit_little: | |
225 | kfree(bl_idle_little_driver.cpumask); | |
226 | ||
227 | return ret; | |
228 | } | |
229 | device_initcall(bl_idle_init); |