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7d35b8d0 SS |
1 | /* |
2 | * OMAP4 SMP cpu-hotplug support | |
3 | * | |
4 | * Copyright (C) 2010 Texas Instruments, Inc. | |
5 | * Author: | |
6 | * Santosh Shilimkar <santosh.shilimkar@ti.com> | |
7 | * | |
8 | * Platform file needed for the OMAP4 SMP. This file is based on arm | |
9 | * realview smp platform. | |
10 | * Copyright (c) 2002 ARM Limited. | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License version 2 as | |
14 | * published by the Free Software Foundation. | |
15 | */ | |
16 | ||
17 | #include <linux/kernel.h> | |
18 | #include <linux/errno.h> | |
19 | #include <linux/smp.h> | |
20 | #include <linux/completion.h> | |
21 | ||
22 | #include <asm/cacheflush.h> | |
23 | #include <mach/omap4-common.h> | |
24 | ||
25 | static DECLARE_COMPLETION(cpu_killed); | |
26 | ||
27 | int platform_cpu_kill(unsigned int cpu) | |
28 | { | |
29 | return wait_for_completion_timeout(&cpu_killed, 5000); | |
30 | } | |
31 | ||
32 | /* | |
33 | * platform-specific code to shutdown a CPU | |
34 | * Called with IRQs disabled | |
35 | */ | |
36 | void platform_cpu_die(unsigned int cpu) | |
37 | { | |
38 | unsigned int this_cpu = hard_smp_processor_id(); | |
39 | ||
40 | if (cpu != this_cpu) { | |
41 | pr_crit("platform_cpu_die running on %u, should be %u\n", | |
42 | this_cpu, cpu); | |
43 | BUG(); | |
44 | } | |
45 | pr_notice("CPU%u: shutdown\n", cpu); | |
46 | complete(&cpu_killed); | |
47 | flush_cache_all(); | |
48 | dsb(); | |
49 | ||
50 | /* | |
51 | * we're ready for shutdown now, so do it | |
52 | */ | |
53 | if (omap_modify_auxcoreboot0(0x0, 0x200) != 0x0) | |
54 | printk(KERN_CRIT "Secure clear status failed\n"); | |
55 | ||
56 | for (;;) { | |
57 | /* | |
58 | * Execute WFI | |
59 | */ | |
60 | do_wfi(); | |
61 | ||
62 | if (omap_read_auxcoreboot0() == cpu) { | |
63 | /* | |
64 | * OK, proper wakeup, we're done | |
65 | */ | |
66 | break; | |
67 | } | |
68 | pr_debug("CPU%u: spurious wakeup call\n", cpu); | |
69 | } | |
70 | } | |
71 | ||
72 | int platform_cpu_disable(unsigned int cpu) | |
73 | { | |
74 | /* | |
75 | * we don't allow CPU 0 to be shutdown (it is still too special | |
76 | * e.g. clock tick interrupts) | |
77 | */ | |
78 | return cpu == 0 ? -EPERM : 0; | |
79 | } |