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 <linux/export.h>
20 #include <asm/proc-fns.h>
21 #include <asm/cpuidle.h>
22
23 #include <mach/cpuidle.h>
24 #include <mach/ddr2.h>
25
26 #define DAVINCI_CPUIDLE_MAX_STATES 2
27
28 struct davinci_ops {
29 void (*enter) (u32 flags);
30 void (*exit) (u32 flags);
31 u32 flags;
32 };
33
34 /* Actual code that puts the SoC in different idle states */
davinci_enter_idle(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)35 static int davinci_enter_idle(struct cpuidle_device *dev,
36 struct cpuidle_driver *drv,
37 int index)
38 {
39 struct cpuidle_state_usage *state_usage = &dev->states_usage[index];
40 struct davinci_ops *ops = cpuidle_get_statedata(state_usage);
41
42 if (ops && ops->enter)
43 ops->enter(ops->flags);
44
45 index = cpuidle_wrap_enter(dev, drv, index,
46 arm_cpuidle_simple_enter);
47
48 if (ops && ops->exit)
49 ops->exit(ops->flags);
50
51 return index;
52 }
53
54 /* fields in davinci_ops.flags */
55 #define DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN BIT(0)
56
57 static struct cpuidle_driver davinci_idle_driver = {
58 .name = "cpuidle-davinci",
59 .owner = THIS_MODULE,
60 .en_core_tk_irqen = 1,
61 .states[0] = ARM_CPUIDLE_WFI_STATE,
62 .states[1] = {
63 .enter = davinci_enter_idle,
64 .exit_latency = 10,
65 .target_residency = 100000,
66 .flags = CPUIDLE_FLAG_TIME_VALID,
67 .name = "DDR SR",
68 .desc = "WFI and DDR Self Refresh",
69 },
70 .state_count = DAVINCI_CPUIDLE_MAX_STATES,
71 };
72
73 static DEFINE_PER_CPU(struct cpuidle_device, davinci_cpuidle_device);
74 static void __iomem *ddr2_reg_base;
75
davinci_save_ddr_power(int enter,bool pdown)76 static void davinci_save_ddr_power(int enter, bool pdown)
77 {
78 u32 val;
79
80 val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET);
81
82 if (enter) {
83 if (pdown)
84 val |= DDR2_SRPD_BIT;
85 else
86 val &= ~DDR2_SRPD_BIT;
87 val |= DDR2_LPMODEN_BIT;
88 } else {
89 val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT);
90 }
91
92 __raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET);
93 }
94
davinci_c2state_enter(u32 flags)95 static void davinci_c2state_enter(u32 flags)
96 {
97 davinci_save_ddr_power(1, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN));
98 }
99
davinci_c2state_exit(u32 flags)100 static void davinci_c2state_exit(u32 flags)
101 {
102 davinci_save_ddr_power(0, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN));
103 }
104
105 static struct davinci_ops davinci_states[DAVINCI_CPUIDLE_MAX_STATES] = {
106 [1] = {
107 .enter = davinci_c2state_enter,
108 .exit = davinci_c2state_exit,
109 },
110 };
111
davinci_cpuidle_probe(struct platform_device * pdev)112 static int __init davinci_cpuidle_probe(struct platform_device *pdev)
113 {
114 int ret;
115 struct cpuidle_device *device;
116 struct davinci_cpuidle_config *pdata = pdev->dev.platform_data;
117
118 device = &per_cpu(davinci_cpuidle_device, smp_processor_id());
119
120 if (!pdata) {
121 dev_err(&pdev->dev, "cannot get platform data\n");
122 return -ENOENT;
123 }
124
125 ddr2_reg_base = pdata->ddr2_ctlr_base;
126
127 if (pdata->ddr2_pdown)
128 davinci_states[1].flags |= DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN;
129 cpuidle_set_statedata(&device->states_usage[1], &davinci_states[1]);
130
131 device->state_count = DAVINCI_CPUIDLE_MAX_STATES;
132
133 ret = cpuidle_register_driver(&davinci_idle_driver);
134 if (ret) {
135 dev_err(&pdev->dev, "failed to register driver\n");
136 return ret;
137 }
138
139 ret = cpuidle_register_device(device);
140 if (ret) {
141 dev_err(&pdev->dev, "failed to register device\n");
142 cpuidle_unregister_driver(&davinci_idle_driver);
143 return ret;
144 }
145
146 return 0;
147 }
148
149 static struct platform_driver davinci_cpuidle_driver = {
150 .driver = {
151 .name = "cpuidle-davinci",
152 .owner = THIS_MODULE,
153 },
154 };
155
davinci_cpuidle_init(void)156 static int __init davinci_cpuidle_init(void)
157 {
158 return platform_driver_probe(&davinci_cpuidle_driver,
159 davinci_cpuidle_probe);
160 }
161 device_initcall(davinci_cpuidle_init);
162
163