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1 | /* |
2 | * Copyright 2012 Calxeda, Inc. |
3 | * |
4 | * Based on arch/arm/plat-mxc/cpuidle.c: |
5 | * Copyright 2012 Freescale Semiconductor, Inc. |
6 | * Copyright 2012 Linaro Ltd. |
7 | * |
8 | * This program is free software; you can redistribute it and/or modify it |
9 | * under the terms and conditions of the GNU General Public License, |
10 | * version 2, as published by the Free Software Foundation. |
11 | * |
12 | * This program is distributed in the hope it will be useful, but WITHOUT |
13 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
14 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
15 | * more details. |
16 | * |
17 | * You should have received a copy of the GNU General Public License along with |
18 | * this program. If not, see <http://www.gnu.org/licenses/>. |
19 | */ |
20 | |
21 | #include <linux/cpuidle.h> |
22 | #include <linux/init.h> |
23 | #include <linux/io.h> |
24 | #include <linux/of.h> |
25 | #include <linux/time.h> |
26 | #include <linux/delay.h> |
27 | #include <linux/suspend.h> |
28 | #include <asm/cpuidle.h> |
29 | #include <asm/proc-fns.h> |
30 | #include <asm/smp_scu.h> |
31 | #include <asm/suspend.h> |
32 | #include <asm/cacheflush.h> |
33 | #include <asm/cp15.h> |
34 | |
35 | extern void highbank_set_cpu_jump(int cpu, void *jump_addr); |
36 | extern void *scu_base_addr; |
37 | |
38 | static struct cpuidle_device __percpu *calxeda_idle_cpuidle_devices; |
39 | |
40 | static inline unsigned int get_auxcr(void) |
41 | { |
42 | unsigned int val; |
43 | asm("mrc p15, 0, %0, c1, c0, 1 @ get AUXCR" : "=r" (val) : : "cc"); |
44 | return val; |
45 | } |
46 | |
47 | static inline void set_auxcr(unsigned int val) |
48 | { |
49 | asm volatile("mcr p15, 0, %0, c1, c0, 1 @ set AUXCR" |
50 | : : "r" (val) : "cc"); |
51 | isb(); |
52 | } |
53 | |
54 | static noinline void calxeda_idle_restore(void) |
55 | { |
56 | set_cr(get_cr() | CR_C); |
57 | set_auxcr(get_auxcr() | 0x40); |
58 | scu_power_mode(scu_base_addr, SCU_PM_NORMAL); |
59 | } |
60 | |
61 | static int calxeda_idle_finish(unsigned long val) |
62 | { |
63 | /* Already flushed cache, but do it again as the outer cache functions |
64 | * dirty the cache with spinlocks */ |
65 | flush_cache_all(); |
66 | |
67 | set_auxcr(get_auxcr() & ~0x40); |
68 | set_cr(get_cr() & ~CR_C); |
69 | |
70 | scu_power_mode(scu_base_addr, SCU_PM_DORMANT); |
71 | |
72 | cpu_do_idle(); |
73 | |
74 | /* Restore things if we didn't enter power-gating */ |
75 | calxeda_idle_restore(); |
76 | return 1; |
77 | } |
78 | |
79 | static int calxeda_pwrdown_idle(struct cpuidle_device *dev, |
80 | struct cpuidle_driver *drv, |
81 | int index) |
82 | { |
83 | highbank_set_cpu_jump(smp_processor_id(), cpu_resume); |
84 | cpu_suspend(0, calxeda_idle_finish); |
85 | return index; |
86 | } |
87 | |
88 | static void calxeda_idle_cpuidle_devices_uninit(void) |
89 | { |
90 | int i; |
91 | struct cpuidle_device *dev; |
92 | |
93 | for_each_possible_cpu(i) { |
94 | dev = per_cpu_ptr(calxeda_idle_cpuidle_devices, i); |
95 | cpuidle_unregister_device(dev); |
96 | } |
97 | |
98 | free_percpu(calxeda_idle_cpuidle_devices); |
99 | } |
100 | |
101 | static struct cpuidle_driver calxeda_idle_driver = { |
102 | .name = "calxeda_idle", |
103 | .en_core_tk_irqen = 1, |
104 | .states = { |
105 | ARM_CPUIDLE_WFI_STATE, |
106 | { |
107 | .name = "PG", |
108 | .desc = "Power Gate", |
109 | .flags = CPUIDLE_FLAG_TIME_VALID, |
110 | .exit_latency = 30, |
111 | .power_usage = 50, |
112 | .target_residency = 200, |
113 | .enter = calxeda_pwrdown_idle, |
114 | }, |
115 | }, |
116 | .state_count = 2, |
117 | }; |
118 | |
119 | static int __init calxeda_cpuidle_init(void) |
120 | { |
121 | int cpu_id; |
122 | int ret; |
123 | struct cpuidle_device *dev; |
124 | struct cpuidle_driver *drv = &calxeda_idle_driver; |
125 | |
126 | if (!of_machine_is_compatible("calxeda,highbank")) |
127 | return -ENODEV; |
128 | |
129 | ret = cpuidle_register_driver(drv); |
130 | if (ret) |
131 | return ret; |
132 | |
133 | calxeda_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device); |
134 | if (calxeda_idle_cpuidle_devices == NULL) { |
135 | ret = -ENOMEM; |
136 | goto unregister_drv; |
137 | } |
138 | |
139 | /* initialize state data for each cpuidle_device */ |
140 | for_each_possible_cpu(cpu_id) { |
141 | dev = per_cpu_ptr(calxeda_idle_cpuidle_devices, cpu_id); |
142 | dev->cpu = cpu_id; |
143 | dev->state_count = drv->state_count; |
144 | |
145 | ret = cpuidle_register_device(dev); |
146 | if (ret) { |
147 | pr_err("Failed to register cpu %u, error: %d\n", |
148 | cpu_id, ret); |
149 | goto uninit; |
150 | } |
151 | } |
152 | |
153 | return 0; |
154 | |
155 | uninit: |
156 | calxeda_idle_cpuidle_devices_uninit(); |
157 | unregister_drv: |
158 | cpuidle_unregister_driver(drv); |
159 | return ret; |
160 | } |
161 | module_init(calxeda_cpuidle_init); |
162 |
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