Commit | Line | Data |
---|---|---|
e50b6bef RK |
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 <asm/proc-fns.h> | |
22 | #include <mach/kirkwood.h> | |
23 | ||
24 | #define KIRKWOOD_MAX_STATES 2 | |
25 | ||
26 | static struct cpuidle_driver kirkwood_idle_driver = { | |
27 | .name = "kirkwood_idle", | |
28 | .owner = THIS_MODULE, | |
29 | }; | |
30 | ||
31 | static DEFINE_PER_CPU(struct cpuidle_device, kirkwood_cpuidle_device); | |
32 | ||
33 | /* Actual code that puts the SoC in different idle states */ | |
34 | static int kirkwood_enter_idle(struct cpuidle_device *dev, | |
35 | struct cpuidle_state *state) | |
36 | { | |
37 | struct timeval before, after; | |
38 | int idle_time; | |
39 | ||
40 | local_irq_disable(); | |
41 | do_gettimeofday(&before); | |
42 | if (state == &dev->states[0]) | |
43 | /* Wait for interrupt state */ | |
44 | cpu_do_idle(); | |
45 | else if (state == &dev->states[1]) { | |
46 | /* | |
47 | * Following write will put DDR in self refresh. | |
48 | * Note that we have 256 cycles before DDR puts it | |
49 | * self in self-refresh, so the wait-for-interrupt | |
50 | * call afterwards won't get the DDR from self refresh | |
51 | * mode. | |
52 | */ | |
53 | writel(0x7, DDR_OPERATION_BASE); | |
54 | cpu_do_idle(); | |
55 | } | |
56 | do_gettimeofday(&after); | |
57 | local_irq_enable(); | |
58 | idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC + | |
59 | (after.tv_usec - before.tv_usec); | |
60 | return idle_time; | |
61 | } | |
62 | ||
63 | /* Initialize CPU idle by registering the idle states */ | |
64 | static int kirkwood_init_cpuidle(void) | |
65 | { | |
66 | struct cpuidle_device *device; | |
67 | ||
68 | cpuidle_register_driver(&kirkwood_idle_driver); | |
69 | ||
70 | device = &per_cpu(kirkwood_cpuidle_device, smp_processor_id()); | |
71 | device->state_count = KIRKWOOD_MAX_STATES; | |
72 | ||
73 | /* Wait for interrupt state */ | |
74 | device->states[0].enter = kirkwood_enter_idle; | |
75 | device->states[0].exit_latency = 1; | |
76 | device->states[0].target_residency = 10000; | |
77 | device->states[0].flags = CPUIDLE_FLAG_TIME_VALID; | |
78 | strcpy(device->states[0].name, "WFI"); | |
79 | strcpy(device->states[0].desc, "Wait for interrupt"); | |
80 | ||
81 | /* Wait for interrupt and DDR self refresh state */ | |
82 | device->states[1].enter = kirkwood_enter_idle; | |
83 | device->states[1].exit_latency = 10; | |
84 | device->states[1].target_residency = 10000; | |
85 | device->states[1].flags = CPUIDLE_FLAG_TIME_VALID; | |
86 | strcpy(device->states[1].name, "DDR SR"); | |
87 | strcpy(device->states[1].desc, "WFI and DDR Self Refresh"); | |
88 | ||
89 | if (cpuidle_register_device(device)) { | |
90 | printk(KERN_ERR "kirkwood_init_cpuidle: Failed registering\n"); | |
91 | return -EIO; | |
92 | } | |
93 | return 0; | |
94 | } | |
95 | ||
96 | device_initcall(kirkwood_init_cpuidle); |