2 * CPU idle for DaVinci SoCs
4 * Copyright (C) 2009 Texas Instruments Incorporated. http://www.ti.com/
6 * Derived from Marvell Kirkwood CPU idle code
7 * (arch/arm/mach-kirkwood/cpuidle.c)
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.
14 #include <linux/kernel.h>
15 #include <linux/init.h>
16 #include <linux/platform_device.h>
17 #include <linux/cpuidle.h>
19 #include <asm/proc-fns.h>
21 #include <mach/cpuidle.h>
22 #include <mach/memory.h>
24 #define DAVINCI_CPUIDLE_MAX_STATES 2
27 void (*enter) (u32 flags);
28 void (*exit) (u32 flags);
32 /* fields in davinci_ops.flags */
33 #define DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN BIT(0)
35 static struct cpuidle_driver davinci_idle_driver = {
36 .name = "cpuidle-davinci",
40 static DEFINE_PER_CPU(struct cpuidle_device, davinci_cpuidle_device);
41 static void __iomem *ddr2_reg_base;
43 static void davinci_save_ddr_power(int enter, bool pdown)
47 val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET);
53 val &= ~DDR2_SRPD_BIT;
54 val |= DDR2_LPMODEN_BIT;
56 val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT);
59 __raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET);
62 static void davinci_c2state_enter(u32 flags)
64 davinci_save_ddr_power(1, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN));
67 static void davinci_c2state_exit(u32 flags)
69 davinci_save_ddr_power(0, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN));
72 static struct davinci_ops davinci_states[DAVINCI_CPUIDLE_MAX_STATES] = {
74 .enter = davinci_c2state_enter,
75 .exit = davinci_c2state_exit,
79 /* Actual code that puts the SoC in different idle states */
80 static int davinci_enter_idle(struct cpuidle_device *dev,
83 struct cpuidle_state_usage *state_usage = &dev->states_usage[index];
84 struct davinci_ops *ops = cpuidle_get_statedata(state_usage);
85 struct timeval before, after;
89 do_gettimeofday(&before);
91 if (ops && ops->enter)
92 ops->enter(ops->flags);
93 /* Wait for interrupt state */
96 ops->exit(ops->flags);
98 do_gettimeofday(&after);
100 idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC +
101 (after.tv_usec - before.tv_usec);
103 dev->last_residency = idle_time;
108 static int __init davinci_cpuidle_probe(struct platform_device *pdev)
111 struct cpuidle_device *device;
112 struct davinci_cpuidle_config *pdata = pdev->dev.platform_data;
114 device = &per_cpu(davinci_cpuidle_device, smp_processor_id());
117 dev_err(&pdev->dev, "cannot get platform data\n");
121 ddr2_reg_base = pdata->ddr2_ctlr_base;
123 ret = cpuidle_register_driver(&davinci_idle_driver);
125 dev_err(&pdev->dev, "failed to register driver\n");
129 /* Wait for interrupt state */
130 device->states[0].enter = davinci_enter_idle;
131 device->states[0].exit_latency = 1;
132 device->states[0].target_residency = 10000;
133 device->states[0].flags = CPUIDLE_FLAG_TIME_VALID;
134 strcpy(device->states[0].name, "WFI");
135 strcpy(device->states[0].desc, "Wait for interrupt");
137 /* Wait for interrupt and DDR self refresh state */
138 device->states[1].enter = davinci_enter_idle;
139 device->states[1].exit_latency = 10;
140 device->states[1].target_residency = 10000;
141 device->states[1].flags = CPUIDLE_FLAG_TIME_VALID;
142 strcpy(device->states[1].name, "DDR SR");
143 strcpy(device->states[1].desc, "WFI and DDR Self Refresh");
144 if (pdata->ddr2_pdown)
145 davinci_states[1].flags |= DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN;
146 cpuidle_set_statedata(&device->states_usage[1], &davinci_states[1]);
148 device->state_count = DAVINCI_CPUIDLE_MAX_STATES;
150 ret = cpuidle_register_device(device);
152 dev_err(&pdev->dev, "failed to register device\n");
153 cpuidle_unregister_driver(&davinci_idle_driver);
160 static struct platform_driver davinci_cpuidle_driver = {
162 .name = "cpuidle-davinci",
163 .owner = THIS_MODULE,
167 static int __init davinci_cpuidle_init(void)
169 return platform_driver_probe(&davinci_cpuidle_driver,
170 davinci_cpuidle_probe);
172 device_initcall(davinci_cpuidle_init);