projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| e3978dc7 VK |
1 | /* |
| 2 | * linux/arch/arm/mach-spear13xx/hotplug.c | |
| 3 | * | |
| 4 | * Copyright (C) 2012 ST Microelectronics Ltd. | |
| 5 | * Deepak Sikri <deepak.sikri@st.com> | |
| 6 | * | |
| 7 | * based upon linux/arch/arm/mach-realview/hotplug.c | |
| 8 | * | |
| 9 | * This program is free software; you can redistribute it and/or modify | |
| 10 | * it under the terms of the GNU General Public License version 2 as | |
| 11 | * published by the Free Software Foundation. | |
| 12 | */ | |
| 13 | #include <linux/kernel.h> | |
| 14 | #include <linux/errno.h> | |
| 15 | #include <linux/smp.h> | |
| 16 | #include <asm/cacheflush.h> | |
| 17 | #include <asm/cp15.h> | |
| 18 | #include <asm/smp_plat.h> | |
| 19 | ||
| e3978dc7 VK |
20 | static inline void cpu_enter_lowpower(void) |
| 21 | { | |
| 22 | unsigned int v; | |
| 23 | ||
| 24 | flush_cache_all(); | |
| 25 | asm volatile( | |
| 26 | " mcr p15, 0, %1, c7, c5, 0\n" | |
| 27 | " dsb\n" | |
| 28 | /* | |
| 29 | * Turn off coherency | |
| 30 | */ | |
| 31 | " mrc p15, 0, %0, c1, c0, 1\n" | |
| 32 | " bic %0, %0, #0x20\n" | |
| 33 | " mcr p15, 0, %0, c1, c0, 1\n" | |
| 34 | " mrc p15, 0, %0, c1, c0, 0\n" | |
| 35 | " bic %0, %0, %2\n" | |
| 36 | " mcr p15, 0, %0, c1, c0, 0\n" | |
| 37 | : "=&r" (v) | |
| 38 | : "r" (0), "Ir" (CR_C) | |
| 39 | : "cc", "memory"); | |
| 40 | } | |
| 41 | ||
| 42 | static inline void cpu_leave_lowpower(void) | |
| 43 | { | |
| 44 | unsigned int v; | |
| 45 | ||
| 46 | asm volatile("mrc p15, 0, %0, c1, c0, 0\n" | |
| 47 | " orr %0, %0, %1\n" | |
| 48 | " mcr p15, 0, %0, c1, c0, 0\n" | |
| 49 | " mrc p15, 0, %0, c1, c0, 1\n" | |
| 50 | " orr %0, %0, #0x20\n" | |
| 51 | " mcr p15, 0, %0, c1, c0, 1\n" | |
| 52 | : "=&r" (v) | |
| 53 | : "Ir" (CR_C) | |
| 54 | : "cc"); | |
| 55 | } | |
| 56 | ||
| 2d8b21d9 | 57 | static inline void spear13xx_do_lowpower(unsigned int cpu, int *spurious) |
| e3978dc7 VK |
58 | { |
| 59 | for (;;) { | |
| 60 | wfi(); | |
| 61 | ||
| 62 | if (pen_release == cpu) { | |
| 63 | /* | |
| 64 | * OK, proper wakeup, we're done | |
| 65 | */ | |
| 66 | break; | |
| 67 | } | |
| 68 | ||
| 69 | /* | |
| 70 | * Getting here, means that we have come out of WFI without | |
| 71 | * having been woken up - this shouldn't happen | |
| 72 | * | |
| 73 | * Just note it happening - when we're woken, we can report | |
| 74 | * its occurrence. | |
| 75 | */ | |
| 76 | (*spurious)++; | |
| 77 | } | |
| 78 | } | |
| 79 | ||
| e3978dc7 VK |
80 | /* |
| 81 | * platform-specific code to shutdown a CPU | |
| 82 | * | |
| 83 | * Called with IRQs disabled | |
| 84 | */ | |
| 2d8b21d9 | 85 | void __ref spear13xx_cpu_die(unsigned int cpu) |
| e3978dc7 VK |
86 | { |
| 87 | int spurious = 0; | |
| 88 | ||
| 89 | /* | |
| 90 | * we're ready for shutdown now, so do it | |
| 91 | */ | |
| 92 | cpu_enter_lowpower(); | |
| 2d8b21d9 | 93 | spear13xx_do_lowpower(cpu, &spurious); |
| e3978dc7 VK |
94 | |
| 95 | /* | |
| 96 | * bring this CPU back into the world of cache | |
| 97 | * coherency, and then restore interrupts | |
| 98 | */ | |
| 99 | cpu_leave_lowpower(); | |
| 100 | ||
| 101 | if (spurious) | |
| 102 | pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); | |
| 103 | } |