| 1 | |
| 2 | |
| 3 | * Low-level idle sequences
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| 4 |
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| 5 |
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| 6 | #include <linux/cpu.h>
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| 7 | #include <linux/irqflags.h>
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| 8 |
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| 9 | #include <asm/barrier.h>
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| 10 | #include <asm/cpuidle.h>
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| 11 | #include <asm/cpufeature.h>
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| 12 | #include <asm/sysreg.h>
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| 13 |
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| 14 | enum {
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| 15 | ARM64_IDLE_WFI,
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| 16 | ARM64_IDLE_YIELD,
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| 17 | ARM64_IDLE_NOP,
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| 18 | } idle = ARM64_IDLE_WFI;
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| 19 |
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| 20 | static int __init setup_idle(char *arg)
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| 21 | {
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| 22 | if (!arg)
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| 23 | return -1;
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| 24 | else if (!strcmp(arg, "wfi"))
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| 25 | idle = ARM64_IDLE_WFI;
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| 26 | else if (!strcmp(arg, "yield"))
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| 27 | idle = ARM64_IDLE_YIELD;
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| 28 | else if (!strcmp(arg, "nop"))
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| 29 | idle = ARM64_IDLE_NOP;
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| 30 | else
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| 31 | return -1;
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| 32 |
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| 33 | return 0;
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| 34 | }
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| 35 | early_param("idle", setup_idle);
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| 36 |
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| 37 | |
| 38 | * cpu_do_idle()
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| 39 | *
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| 40 | * Idle the processor (wait for interrupt).
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| 41 | *
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| 42 | * If the CPU supports priority masking we must do additional work to
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| 43 | * ensure that interrupts are not masked at the PMR (because the core will
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| 44 | * not wake up if we block the wake up signal in the interrupt controller).
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| 45 |
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| 46 | void __cpuidle cpu_do_idle(void)
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| 47 | {
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| 48 | struct arm_cpuidle_irq_context context;
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| 49 |
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| 50 | arm_cpuidle_save_irq_context(&context);
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| 51 |
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| 52 | if (likely(idle == ARM64_IDLE_WFI)) {
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| 53 | dsb(sy);
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| 54 | wfi();
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| 55 | } else if (idle == ARM64_IDLE_YIELD) {
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| 56 | dsb(sy);
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| 57 | asm volatile("yield" ::: "memory");
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| 58 | }
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| 59 |
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| 60 | arm_cpuidle_restore_irq_context(&context);
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| 61 | }
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| 62 |
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| 63 | |
| 64 | * This is our default idle handler.
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| 65 |
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| 66 | void __cpuidle arch_cpu_idle(void)
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| 67 | {
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| 68 | |
| 69 | * This should do all the clock switching and wait for interrupt
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| 70 | * tricks
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| 71 |
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| 72 | cpu_do_idle();
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| 73 | }
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