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a6c0f6ec SN |
1 | /* |
2 | * CPU idle for DaVinci SoCs | |
3 | * | |
4 | * Copyright (C) 2009 Texas Instruments Incorporated. http://www.ti.com/ | |
5 | * | |
6 | * Derived from Marvell Kirkwood CPU idle code | |
7 | * (arch/arm/mach-kirkwood/cpuidle.c) | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License version 2 as | |
11 | * published by the Free Software Foundation. | |
12 | */ | |
13 | ||
14 | #include <linux/kernel.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/platform_device.h> | |
17 | #include <linux/cpuidle.h> | |
18 | #include <linux/io.h> | |
19 | #include <asm/proc-fns.h> | |
20 | ||
21 | #include <mach/cpuidle.h> | |
7ec4b243 | 22 | #include <mach/memory.h> |
a6c0f6ec SN |
23 | |
24 | #define DAVINCI_CPUIDLE_MAX_STATES 2 | |
25 | ||
26 | struct davinci_ops { | |
27 | void (*enter) (u32 flags); | |
28 | void (*exit) (u32 flags); | |
29 | u32 flags; | |
30 | }; | |
31 | ||
32 | /* fields in davinci_ops.flags */ | |
33 | #define DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN BIT(0) | |
34 | ||
35 | static struct cpuidle_driver davinci_idle_driver = { | |
36 | .name = "cpuidle-davinci", | |
37 | .owner = THIS_MODULE, | |
38 | }; | |
39 | ||
40 | static DEFINE_PER_CPU(struct cpuidle_device, davinci_cpuidle_device); | |
41 | static void __iomem *ddr2_reg_base; | |
42 | ||
a6c0f6ec SN |
43 | static void davinci_save_ddr_power(int enter, bool pdown) |
44 | { | |
45 | u32 val; | |
46 | ||
47 | val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET); | |
48 | ||
49 | if (enter) { | |
50 | if (pdown) | |
51 | val |= DDR2_SRPD_BIT; | |
52 | else | |
53 | val &= ~DDR2_SRPD_BIT; | |
54 | val |= DDR2_LPMODEN_BIT; | |
55 | } else { | |
56 | val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT); | |
57 | } | |
58 | ||
59 | __raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET); | |
60 | } | |
61 | ||
62 | static void davinci_c2state_enter(u32 flags) | |
63 | { | |
64 | davinci_save_ddr_power(1, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN)); | |
65 | } | |
66 | ||
67 | static void davinci_c2state_exit(u32 flags) | |
68 | { | |
69 | davinci_save_ddr_power(0, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN)); | |
70 | } | |
71 | ||
72 | static struct davinci_ops davinci_states[DAVINCI_CPUIDLE_MAX_STATES] = { | |
73 | [1] = { | |
74 | .enter = davinci_c2state_enter, | |
75 | .exit = davinci_c2state_exit, | |
76 | }, | |
77 | }; | |
78 | ||
79 | /* Actual code that puts the SoC in different idle states */ | |
80 | static int davinci_enter_idle(struct cpuidle_device *dev, | |
81 | struct cpuidle_state *state) | |
82 | { | |
83 | struct davinci_ops *ops = cpuidle_get_statedata(state); | |
84 | struct timeval before, after; | |
85 | int idle_time; | |
86 | ||
87 | local_irq_disable(); | |
88 | do_gettimeofday(&before); | |
89 | ||
90 | if (ops && ops->enter) | |
91 | ops->enter(ops->flags); | |
92 | /* Wait for interrupt state */ | |
93 | cpu_do_idle(); | |
94 | if (ops && ops->exit) | |
95 | ops->exit(ops->flags); | |
96 | ||
97 | do_gettimeofday(&after); | |
98 | local_irq_enable(); | |
99 | idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC + | |
100 | (after.tv_usec - before.tv_usec); | |
101 | return idle_time; | |
102 | } | |
103 | ||
104 | static int __init davinci_cpuidle_probe(struct platform_device *pdev) | |
105 | { | |
106 | int ret; | |
107 | struct cpuidle_device *device; | |
108 | struct davinci_cpuidle_config *pdata = pdev->dev.platform_data; | |
a6c0f6ec SN |
109 | |
110 | device = &per_cpu(davinci_cpuidle_device, smp_processor_id()); | |
111 | ||
112 | if (!pdata) { | |
113 | dev_err(&pdev->dev, "cannot get platform data\n"); | |
114 | return -ENOENT; | |
115 | } | |
116 | ||
948c66df | 117 | ddr2_reg_base = pdata->ddr2_ctlr_base; |
a6c0f6ec SN |
118 | |
119 | ret = cpuidle_register_driver(&davinci_idle_driver); | |
120 | if (ret) { | |
121 | dev_err(&pdev->dev, "failed to register driver\n"); | |
948c66df | 122 | return ret; |
a6c0f6ec SN |
123 | } |
124 | ||
125 | /* Wait for interrupt state */ | |
126 | device->states[0].enter = davinci_enter_idle; | |
127 | device->states[0].exit_latency = 1; | |
128 | device->states[0].target_residency = 10000; | |
129 | device->states[0].flags = CPUIDLE_FLAG_TIME_VALID; | |
130 | strcpy(device->states[0].name, "WFI"); | |
131 | strcpy(device->states[0].desc, "Wait for interrupt"); | |
132 | ||
133 | /* Wait for interrupt and DDR self refresh state */ | |
134 | device->states[1].enter = davinci_enter_idle; | |
135 | device->states[1].exit_latency = 10; | |
136 | device->states[1].target_residency = 10000; | |
137 | device->states[1].flags = CPUIDLE_FLAG_TIME_VALID; | |
138 | strcpy(device->states[1].name, "DDR SR"); | |
139 | strcpy(device->states[1].desc, "WFI and DDR Self Refresh"); | |
140 | if (pdata->ddr2_pdown) | |
141 | davinci_states[1].flags |= DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN; | |
142 | cpuidle_set_statedata(&device->states[1], &davinci_states[1]); | |
143 | ||
144 | device->state_count = DAVINCI_CPUIDLE_MAX_STATES; | |
145 | ||
146 | ret = cpuidle_register_device(device); | |
147 | if (ret) { | |
148 | dev_err(&pdev->dev, "failed to register device\n"); | |
948c66df SN |
149 | cpuidle_unregister_driver(&davinci_idle_driver); |
150 | return ret; | |
a6c0f6ec SN |
151 | } |
152 | ||
153 | return 0; | |
a6c0f6ec SN |
154 | } |
155 | ||
156 | static struct platform_driver davinci_cpuidle_driver = { | |
157 | .driver = { | |
158 | .name = "cpuidle-davinci", | |
159 | .owner = THIS_MODULE, | |
160 | }, | |
161 | }; | |
162 | ||
163 | static int __init davinci_cpuidle_init(void) | |
164 | { | |
165 | return platform_driver_probe(&davinci_cpuidle_driver, | |
166 | davinci_cpuidle_probe); | |
167 | } | |
168 | device_initcall(davinci_cpuidle_init); | |
169 |