Merge branch 'msm-core' of git://codeaurora.org/quic/kernel/dwalker/linux-msm
[pandora-kernel.git] / arch / arm / mach-omap2 / omap-hotplug.c
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 }