projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 0462b447 RK |
1 | /* |
| 2 | * linux/arch/arm/plat-versatile/platsmp.c | |
| 3 | * | |
| 4 | * Copyright (C) 2002 ARM Ltd. | |
| 5 | * All Rights Reserved | |
| 6 | * | |
| 7 | * This program is free software; you can redistribute it and/or modify | |
| 8 | * it under the terms of the GNU General Public License version 2 as | |
| 9 | * published by the Free Software Foundation. | |
| 10 | */ | |
| 11 | #include <linux/init.h> | |
| 12 | #include <linux/errno.h> | |
| 13 | #include <linux/delay.h> | |
| 14 | #include <linux/device.h> | |
| 15 | #include <linux/jiffies.h> | |
| 16 | #include <linux/smp.h> | |
| 17 | ||
| 18 | #include <asm/cacheflush.h> | |
| eb50439b | 19 | #include <asm/smp_plat.h> |
| 0462b447 | 20 | |
| 0462b447 RK |
21 | /* |
| 22 | * Write pen_release in a way that is guaranteed to be visible to all | |
| 23 | * observers, irrespective of whether they're taking part in coherency | |
| 24 | * or not. This is necessary for the hotplug code to work reliably. | |
| 25 | */ | |
| 8bd26e3a | 26 | static void write_pen_release(int val) |
| 0462b447 RK |
27 | { |
| 28 | pen_release = val; | |
| 29 | smp_wmb(); | |
| f45913fd | 30 | sync_cache_w(&pen_release); |
| 0462b447 RK |
31 | } |
| 32 | ||
| 33 | static DEFINE_SPINLOCK(boot_lock); | |
| 34 | ||
| 8bd26e3a | 35 | void versatile_secondary_init(unsigned int cpu) |
| 0462b447 | 36 | { |
| 0462b447 RK |
37 | /* |
| 38 | * let the primary processor know we're out of the | |
| 39 | * pen, then head off into the C entry point | |
| 40 | */ | |
| 41 | write_pen_release(-1); | |
| 42 | ||
| 43 | /* | |
| 44 | * Synchronise with the boot thread. | |
| 45 | */ | |
| 46 | spin_lock(&boot_lock); | |
| 47 | spin_unlock(&boot_lock); | |
| 48 | } | |
| 49 | ||
| 8bd26e3a | 50 | int versatile_boot_secondary(unsigned int cpu, struct task_struct *idle) |
| 0462b447 RK |
51 | { |
| 52 | unsigned long timeout; | |
| 53 | ||
| 54 | /* | |
| 55 | * Set synchronisation state between this boot processor | |
| 56 | * and the secondary one | |
| 57 | */ | |
| 58 | spin_lock(&boot_lock); | |
| 59 | ||
| 60 | /* | |
| 61 | * This is really belt and braces; we hold unintended secondary | |
| 62 | * CPUs in the holding pen until we're ready for them. However, | |
| 63 | * since we haven't sent them a soft interrupt, they shouldn't | |
| 64 | * be there. | |
| 65 | */ | |
| 4a139b64 | 66 | write_pen_release(cpu_logical_map(cpu)); |
| 0462b447 RK |
67 | |
| 68 | /* | |
| 69 | * Send the secondary CPU a soft interrupt, thereby causing | |
| 70 | * the boot monitor to read the system wide flags register, | |
| 71 | * and branch to the address found there. | |
| 72 | */ | |
| b1cffebf | 73 | arch_send_wakeup_ipi_mask(cpumask_of(cpu)); |
| 0462b447 RK |
74 | |
| 75 | timeout = jiffies + (1 * HZ); | |
| 76 | while (time_before(jiffies, timeout)) { | |
| 77 | smp_rmb(); | |
| 78 | if (pen_release == -1) | |
| 79 | break; | |
| 80 | ||
| 81 | udelay(10); | |
| 82 | } | |
| 83 | ||
| 84 | /* | |
| 85 | * now the secondary core is starting up let it run its | |
| 86 | * calibrations, then wait for it to finish | |
| 87 | */ | |
| 88 | spin_unlock(&boot_lock); | |
| 89 | ||
| 90 | return pen_release != -1 ? -ENOSYS : 0; | |
| 91 | } |