2 * based on arch/arm/mach-kirkwood/cpuidle.c
4 * CPU idle support for AT91 SoC
6 * This file is licensed under the terms of the GNU General Public
7 * License version 2. This program is licensed "as is" without any
8 * warranty of any kind, whether express or implied.
10 * The cpu idle uses wait-for-interrupt and RAM self refresh in order
11 * to implement two idle states -
12 * #1 wait-for-interrupt
13 * #2 wait-for-interrupt and RAM self refresh
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/platform_device.h>
19 #include <linux/cpuidle.h>
21 #include <linux/export.h>
22 #include <asm/proc-fns.h>
23 #include <asm/cpuidle.h>
28 #define AT91_MAX_STATES 2
30 static DEFINE_PER_CPU(struct cpuidle_device, at91_cpuidle_device);
32 /* Actual code that puts the SoC in different idle states */
33 static int at91_enter_idle(struct cpuidle_device *dev,
34 struct cpuidle_driver *drv,
37 if (cpu_is_at91rm9200())
39 else if (cpu_is_at91sam9g45())
40 at91sam9g45_standby();
47 static struct cpuidle_driver at91_idle_driver = {
50 .en_core_tk_irqen = 1,
51 .states[0] = ARM_CPUIDLE_WFI_STATE,
53 .enter = at91_enter_idle,
55 .target_residency = 100000,
56 .flags = CPUIDLE_FLAG_TIME_VALID,
58 .desc = "WFI and DDR Self Refresh",
60 .state_count = AT91_MAX_STATES,
63 /* Initialize CPU idle by registering the idle states */
64 static int at91_init_cpuidle(void)
66 struct cpuidle_device *device;
68 device = &per_cpu(at91_cpuidle_device, smp_processor_id());
69 device->state_count = AT91_MAX_STATES;
71 cpuidle_register_driver(&at91_idle_driver);
73 if (cpuidle_register_device(device)) {
74 printk(KERN_ERR "at91_init_cpuidle: Failed registering\n");
80 device_initcall(at91_init_cpuidle);