projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1ea60cf7 AT |
1 | /* |
| 2 | * based on arch/arm/mach-kirkwood/cpuidle.c | |
| 3 | * | |
| 4 | * CPU idle support for AT91 SoC | |
| 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 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 | |
| 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 <asm/proc-fns.h> | |
| 21 | #include <linux/io.h> | |
| dc28094b | 22 | #include <linux/export.h> |
| 1ea60cf7 AT |
23 | |
| 24 | #include "pm.h" | |
| 25 | ||
| 26 | #define AT91_MAX_STATES 2 | |
| 27 | ||
| 28 | static DEFINE_PER_CPU(struct cpuidle_device, at91_cpuidle_device); | |
| 29 | ||
| 30 | static struct cpuidle_driver at91_idle_driver = { | |
| 31 | .name = "at91_idle", | |
| 32 | .owner = THIS_MODULE, | |
| 33 | }; | |
| 34 | ||
| 35 | /* Actual code that puts the SoC in different idle states */ | |
| 36 | static int at91_enter_idle(struct cpuidle_device *dev, | |
| 46bcfad7 | 37 | struct cpuidle_driver *drv, |
| e978aa7d | 38 | int index) |
| 1ea60cf7 AT |
39 | { |
| 40 | struct timeval before, after; | |
| 41 | int idle_time; | |
| 42 | u32 saved_lpr; | |
| 43 | ||
| 44 | local_irq_disable(); | |
| 45 | do_gettimeofday(&before); | |
| e978aa7d | 46 | if (index == 0) |
| 1ea60cf7 AT |
47 | /* Wait for interrupt state */ |
| 48 | cpu_do_idle(); | |
| e978aa7d | 49 | else if (index == 1) { |
| 1ea60cf7 AT |
50 | asm("b 1f; .align 5; 1:"); |
| 51 | asm("mcr p15, 0, r0, c7, c10, 4"); /* drain write buffer */ | |
| 52 | saved_lpr = sdram_selfrefresh_enable(); | |
| 53 | cpu_do_idle(); | |
| 54 | sdram_selfrefresh_disable(saved_lpr); | |
| 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); | |
| e978aa7d DD |
60 | |
| 61 | dev->last_residency = idle_time; | |
| 62 | return index; | |
| 1ea60cf7 AT |
63 | } |
| 64 | ||
| 65 | /* Initialize CPU idle by registering the idle states */ | |
| 66 | static int at91_init_cpuidle(void) | |
| 67 | { | |
| 68 | struct cpuidle_device *device; | |
| 46bcfad7 | 69 | struct cpuidle_driver *driver = &at91_idle_driver; |
| 1ea60cf7 AT |
70 | |
| 71 | device = &per_cpu(at91_cpuidle_device, smp_processor_id()); | |
| 72 | device->state_count = AT91_MAX_STATES; | |
| 46bcfad7 | 73 | driver->state_count = AT91_MAX_STATES; |
| 1ea60cf7 AT |
74 | |
| 75 | /* Wait for interrupt state */ | |
| 46bcfad7 DD |
76 | driver->states[0].enter = at91_enter_idle; |
| 77 | driver->states[0].exit_latency = 1; | |
| 78 | driver->states[0].target_residency = 10000; | |
| 79 | driver->states[0].flags = CPUIDLE_FLAG_TIME_VALID; | |
| 80 | strcpy(driver->states[0].name, "WFI"); | |
| 81 | strcpy(driver->states[0].desc, "Wait for interrupt"); | |
| 1ea60cf7 AT |
82 | |
| 83 | /* Wait for interrupt and RAM self refresh state */ | |
| 46bcfad7 DD |
84 | driver->states[1].enter = at91_enter_idle; |
| 85 | driver->states[1].exit_latency = 10; | |
| 86 | driver->states[1].target_residency = 10000; | |
| 87 | driver->states[1].flags = CPUIDLE_FLAG_TIME_VALID; | |
| 88 | strcpy(driver->states[1].name, "RAM_SR"); | |
| 89 | strcpy(driver->states[1].desc, "WFI and RAM Self Refresh"); | |
| 90 | ||
| 91 | cpuidle_register_driver(&at91_idle_driver); | |
| 1ea60cf7 AT |
92 | |
| 93 | if (cpuidle_register_device(device)) { | |
| 94 | printk(KERN_ERR "at91_init_cpuidle: Failed registering\n"); | |
| 95 | return -EIO; | |
| 96 | } | |
| 97 | return 0; | |
| 98 | } | |
| 99 | ||
| 100 | device_initcall(at91_init_cpuidle); |