1 /*
2 * arch/arm/mach-kirkwood/cpuidle.c
3 *
4 * CPU idle Marvell Kirkwood SoCs
5 *
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.
9 *
10 * The cpu idle uses wait-for-interrupt and DDR self refresh in order
11 * to implement two idle states -
12 * #1 wait-for-interrupt
13 * #2 wait-for-interrupt and DDR self refresh
14 */
15
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/platform_device.h>
19 #include <linux/cpuidle.h>
20 #include <linux/io.h>
21 #include <linux/export.h>
22 #include <asm/proc-fns.h>
23 #include <asm/cpuidle.h>
24 #include <mach/kirkwood.h>
25
26 #define KIRKWOOD_MAX_STATES 2
27
28 /* Actual code that puts the SoC in different idle states */
kirkwood_enter_idle(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)29 static int kirkwood_enter_idle(struct cpuidle_device *dev,
30 struct cpuidle_driver *drv,
31 int index)
32 {
33 writel(0x7, DDR_OPERATION_BASE);
34 cpu_do_idle();
35
36 return index;
37 }
38
39 static struct cpuidle_driver kirkwood_idle_driver = {
40 .name = "kirkwood_idle",
41 .owner = THIS_MODULE,
42 .en_core_tk_irqen = 1,
43 .states[0] = ARM_CPUIDLE_WFI_STATE,
44 .states[1] = {
45 .enter = kirkwood_enter_idle,
46 .exit_latency = 10,
47 .target_residency = 100000,
48 .flags = CPUIDLE_FLAG_TIME_VALID,
49 .name = "DDR SR",
50 .desc = "WFI and DDR Self Refresh",
51 },
52 .state_count = KIRKWOOD_MAX_STATES,
53 };
54
55 static DEFINE_PER_CPU(struct cpuidle_device, kirkwood_cpuidle_device);
56
57 /* Initialize CPU idle by registering the idle states */
kirkwood_init_cpuidle(void)58 static int kirkwood_init_cpuidle(void)
59 {
60 struct cpuidle_device *device;
61
62 device = &per_cpu(kirkwood_cpuidle_device, smp_processor_id());
63 device->state_count = KIRKWOOD_MAX_STATES;
64
65 cpuidle_register_driver(&kirkwood_idle_driver);
66 if (cpuidle_register_device(device)) {
67 printk(KERN_ERR "kirkwood_init_cpuidle: Failed registering\n");
68 return -EIO;
69 }
70 return 0;
71 }
72
73 device_initcall(kirkwood_init_cpuidle);
74