projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 3ebabaa5 DL |
2 | /* |
| 3 | * Copyright (c) 2012 Linaro : Daniel Lezcano <[email protected]> (IBM) | |
| 4 | * | |
| 5 | * Based on the work of Rickard Andersson <[email protected]> | |
| 6 | * and Jonas Aaberg <[email protected]>. | |
| 3ebabaa5 DL |
7 | */ |
| 8 | ||
| fdc7d515 | 9 | #include <linux/init.h> |
| 3ebabaa5 | 10 | #include <linux/cpuidle.h> |
| 3ebabaa5 DL |
11 | #include <linux/spinlock.h> |
| 12 | #include <linux/atomic.h> | |
| 13 | #include <linux/smp.h> | |
| 14 | #include <linux/mfd/dbx500-prcmu.h> | |
| 1e22a8c6 | 15 | #include <linux/platform_data/arm-ux500-pm.h> |
| 8025395f | 16 | #include <linux/platform_device.h> |
| 3ebabaa5 DL |
17 | |
| 18 | #include <asm/cpuidle.h> | |
| 3ebabaa5 DL |
19 | |
| 20 | static atomic_t master = ATOMIC_INIT(0); | |
| 21 | static DEFINE_SPINLOCK(master_lock); | |
| 3ebabaa5 DL |
22 | |
| 23 | static inline int ux500_enter_idle(struct cpuidle_device *dev, | |
| 24 | struct cpuidle_driver *drv, int index) | |
| 25 | { | |
| 26 | int this_cpu = smp_processor_id(); | |
| 27 | bool recouple = false; | |
| 28 | ||
| 3ebabaa5 DL |
29 | if (atomic_inc_return(&master) == num_online_cpus()) { |
| 30 | ||
| 31 | /* With this lock, we prevent the other cpu to exit and enter | |
| 32 | * this function again and become the master */ | |
| 33 | if (!spin_trylock(&master_lock)) | |
| 34 | goto wfi; | |
| 35 | ||
| 36 | /* decouple the gic from the A9 cores */ | |
| 5cc23666 SZ |
37 | if (prcmu_gic_decouple()) { |
| 38 | spin_unlock(&master_lock); | |
| 3ebabaa5 | 39 | goto out; |
| 5cc23666 | 40 | } |
| 3ebabaa5 DL |
41 | |
| 42 | /* If an error occur, we will have to recouple the gic | |
| 43 | * manually */ | |
| 44 | recouple = true; | |
| 45 | ||
| 46 | /* At this state, as the gic is decoupled, if the other | |
| 47 | * cpu is in WFI, we have the guarantee it won't be wake | |
| 48 | * up, so we can safely go to retention */ | |
| 49 | if (!prcmu_is_cpu_in_wfi(this_cpu ? 0 : 1)) | |
| 50 | goto out; | |
| 51 | ||
| 52 | /* The prcmu will be in charge of watching the interrupts | |
| 53 | * and wake up the cpus */ | |
| 54 | if (prcmu_copy_gic_settings()) | |
| 55 | goto out; | |
| 56 | ||
| 57 | /* Check in the meantime an interrupt did | |
| 58 | * not occur on the gic ... */ | |
| 59 | if (prcmu_gic_pending_irq()) | |
| 60 | goto out; | |
| 61 | ||
| 62 | /* ... and the prcmu */ | |
| 63 | if (prcmu_pending_irq()) | |
| 64 | goto out; | |
| 65 | ||
| 66 | /* Go to the retention state, the prcmu will wait for the | |
| 67 | * cpu to go WFI and this is what happens after exiting this | |
| 68 | * 'master' critical section */ | |
| 69 | if (prcmu_set_power_state(PRCMU_AP_IDLE, true, true)) | |
| 70 | goto out; | |
| 71 | ||
| 72 | /* When we switch to retention, the prcmu is in charge | |
| 73 | * of recoupling the gic automatically */ | |
| 74 | recouple = false; | |
| 75 | ||
| 76 | spin_unlock(&master_lock); | |
| 77 | } | |
| 78 | wfi: | |
| 79 | cpu_do_idle(); | |
| 80 | out: | |
| 81 | atomic_dec(&master); | |
| 82 | ||
| 83 | if (recouple) { | |
| 84 | prcmu_gic_recouple(); | |
| 85 | spin_unlock(&master_lock); | |
| 86 | } | |
| 87 | ||
| 3ebabaa5 DL |
88 | return index; |
| 89 | } | |
| 90 | ||
| 91 | static struct cpuidle_driver ux500_idle_driver = { | |
| 92 | .name = "ux500_idle", | |
| 93 | .owner = THIS_MODULE, | |
| 3ebabaa5 DL |
94 | .states = { |
| 95 | ARM_CPUIDLE_WFI_STATE, | |
| 96 | { | |
| 97 | .enter = ux500_enter_idle, | |
| 98 | .exit_latency = 70, | |
| 99 | .target_residency = 260, | |
| b82b6cca | 100 | .flags = CPUIDLE_FLAG_TIMER_STOP, |
| 3ebabaa5 DL |
101 | .name = "ApIdle", |
| 102 | .desc = "ARM Retention", | |
| 103 | }, | |
| 104 | }, | |
| 105 | .safe_state_index = 0, | |
| 106 | .state_count = 2, | |
| 107 | }; | |
| 108 | ||
| 2c2b24d9 | 109 | static int dbx500_cpuidle_probe(struct platform_device *pdev) |
| 3ebabaa5 | 110 | { |
| 1e22a8c6 | 111 | /* Configure wake up reasons */ |
| 3ebabaa5 DL |
112 | prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) | |
| 113 | PRCMU_WAKEUP(ABB)); | |
| 114 | ||
| e8928e2e | 115 | return cpuidle_register(&ux500_idle_driver, NULL); |
| 3ebabaa5 DL |
116 | } |
| 117 | ||
| 8025395f LW |
118 | static struct platform_driver dbx500_cpuidle_plat_driver = { |
| 119 | .driver = { | |
| f28fd3b6 | 120 | .name = "db8500-cpuidle", |
| 8025395f LW |
121 | }, |
| 122 | .probe = dbx500_cpuidle_probe, | |
| 123 | }; | |
| fdc7d515 | 124 | builtin_platform_driver(dbx500_cpuidle_plat_driver); |