| Sundar Iyer | 9d704c0 | 2010-09-15 10:45:51 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) STMicroelectronics 2009 |
| 3 | * Copyright (C) ST-Ericsson SA 2010 |
| 4 | * |
| 5 | * License Terms: GNU General Public License v2 |
| 6 | * Based on ARM realview platform |
| 7 | * |
| 8 | * Author: Sundar Iyer <sundar.iyer@stericsson.com> |
| 9 | * |
| 10 | */ |
| 11 | #include <linux/kernel.h> |
| 12 | #include <linux/errno.h> |
| 13 | #include <linux/smp.h> |
| 14 | #include <linux/completion.h> |
| 15 | |
| 16 | #include <asm/cacheflush.h> |
| 17 | |
| 18 | extern volatile int pen_release; |
| 19 | |
| 20 | static DECLARE_COMPLETION(cpu_killed); |
| 21 | |
| 22 | static inline void platform_do_lowpower(unsigned int cpu) |
| 23 | { |
| 24 | flush_cache_all(); |
| 25 | |
| 26 | /* we put the platform to just WFI */ |
| 27 | for (;;) { |
| 28 | __asm__ __volatile__("dsb\n\t" "wfi\n\t" |
| 29 | : : : "memory"); |
| 30 | if (pen_release == cpu) { |
| 31 | /* |
| 32 | * OK, proper wakeup, we're done |
| 33 | */ |
| 34 | break; |
| 35 | } |
| 36 | } |
| 37 | } |
| 38 | |
| 39 | int platform_cpu_kill(unsigned int cpu) |
| 40 | { |
| 41 | return wait_for_completion_timeout(&cpu_killed, 5000); |
| 42 | } |
| 43 | |
| 44 | /* |
| 45 | * platform-specific code to shutdown a CPU |
| 46 | * |
| 47 | * Called with IRQs disabled |
| 48 | */ |
| 49 | void platform_cpu_die(unsigned int cpu) |
| 50 | { |
| 51 | #ifdef DEBUG |
| 52 | unsigned int this_cpu = hard_smp_processor_id(); |
| 53 | |
| 54 | if (cpu != this_cpu) { |
| 55 | printk(KERN_CRIT "Eek! platform_cpu_die running on %u, should be %u\n", |
| 56 | this_cpu, cpu); |
| 57 | BUG(); |
| 58 | } |
| 59 | #endif |
| 60 | |
| 61 | printk(KERN_NOTICE "CPU%u: shutdown\n", cpu); |
| 62 | complete(&cpu_killed); |
| 63 | |
| 64 | /* directly enter low power state, skipping secure registers */ |
| 65 | platform_do_lowpower(cpu); |
| 66 | } |
| 67 | |
| 68 | int platform_cpu_disable(unsigned int cpu) |
| 69 | { |
| 70 | /* |
| 71 | * we don't allow CPU 0 to be shutdown (it is still too special |
| 72 | * e.g. clock tick interrupts) |
| 73 | */ |
| 74 | return cpu == 0 ? -EPERM : 0; |
| 75 | } |