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,
81 struct cpuidle_driver *drv,
84 struct cpuidle_state_usage *state_usage = &dev->states_usage[index];
85 struct davinci_ops *ops = cpuidle_get_statedata(state_usage);
86 struct timeval before, after;
90 do_gettimeofday(&before);
92 if (ops && ops->enter)
93 ops->enter(ops->flags);
94 /* Wait for interrupt state */
97 ops->exit(ops->flags);
99 do_gettimeofday(&after);
101 idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC +
102 (after.tv_usec - before.tv_usec);
104 dev->last_residency = idle_time;
109 static int __init davinci_cpuidle_probe(struct platform_device *pdev)
112 struct cpuidle_device *device;
113 struct cpuidle_driver *driver = &davinci_idle_driver;
114 struct davinci_cpuidle_config *pdata = pdev->dev.platform_data;
116 device = &per_cpu(davinci_cpuidle_device, smp_processor_id());
119 dev_err(&pdev->dev, "cannot get platform data\n");
123 ddr2_reg_base = pdata->ddr2_ctlr_base;
125 /* Wait for interrupt state */
126 driver->states[0].enter = davinci_enter_idle;
127 driver->states[0].exit_latency = 1;
128 driver->states[0].target_residency = 10000;
129 driver->states[0].flags = CPUIDLE_FLAG_TIME_VALID;
130 strcpy(driver->states[0].name, "WFI");
131 strcpy(driver->states[0].desc, "Wait for interrupt");
133 /* Wait for interrupt and DDR self refresh state */
134 driver->states[1].enter = davinci_enter_idle;
135 driver->states[1].exit_latency = 10;
136 driver->states[1].target_residency = 10000;
137 driver->states[1].flags = CPUIDLE_FLAG_TIME_VALID;
138 strcpy(driver->states[1].name, "DDR SR");
139 strcpy(driver->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_usage[1], &davinci_states[1]);
144 device->state_count = DAVINCI_CPUIDLE_MAX_STATES;
145 driver->state_count = DAVINCI_CPUIDLE_MAX_STATES;
147 ret = cpuidle_register_driver(&davinci_idle_driver);
149 dev_err(&pdev->dev, "failed to register driver\n");
153 ret = cpuidle_register_device(device);
155 dev_err(&pdev->dev, "failed to register device\n");
156 cpuidle_unregister_driver(&davinci_idle_driver);
163 static struct platform_driver davinci_cpuidle_driver = {
165 .name = "cpuidle-davinci",
166 .owner = THIS_MODULE,
170 static int __init davinci_cpuidle_init(void)
172 return platform_driver_probe(&davinci_cpuidle_driver,
173 davinci_cpuidle_probe);
175 device_initcall(davinci_cpuidle_init);