Russell King | 0462b44 | 2011-01-19 10:24:56 +0000 | [diff] [blame] | 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> |
Will Deacon | eb50439 | 2012-01-20 12:01:12 +0100 | [diff] [blame] | 19 | #include <asm/smp_plat.h> |
Russell King | 0462b44 | 2011-01-19 10:24:56 +0000 | [diff] [blame] | 20 | |
Ben Dooks | 4091af6 | 2016-06-08 18:16:10 +0100 | [diff] [blame] | 21 | #include <plat/platsmp.h> |
| 22 | |
Russell King | 0462b44 | 2011-01-19 10:24:56 +0000 | [diff] [blame] | 23 | /* |
Russell King | 0462b44 | 2011-01-19 10:24:56 +0000 | [diff] [blame] | 24 | * Write pen_release in a way that is guaranteed to be visible to all |
| 25 | * observers, irrespective of whether they're taking part in coherency |
| 26 | * or not. This is necessary for the hotplug code to work reliably. |
| 27 | */ |
Paul Gortmaker | 8bd26e3 | 2013-06-17 15:43:14 -0400 | [diff] [blame] | 28 | static void write_pen_release(int val) |
Russell King | 0462b44 | 2011-01-19 10:24:56 +0000 | [diff] [blame] | 29 | { |
| 30 | pen_release = val; |
| 31 | smp_wmb(); |
Nicolas Pitre | f45913f | 2013-12-05 14:26:16 -0500 | [diff] [blame] | 32 | sync_cache_w(&pen_release); |
Russell King | 0462b44 | 2011-01-19 10:24:56 +0000 | [diff] [blame] | 33 | } |
| 34 | |
| 35 | static DEFINE_SPINLOCK(boot_lock); |
| 36 | |
Paul Gortmaker | 8bd26e3 | 2013-06-17 15:43:14 -0400 | [diff] [blame] | 37 | void versatile_secondary_init(unsigned int cpu) |
Russell King | 0462b44 | 2011-01-19 10:24:56 +0000 | [diff] [blame] | 38 | { |
| 39 | /* |
Russell King | 0462b44 | 2011-01-19 10:24:56 +0000 | [diff] [blame] | 40 | * let the primary processor know we're out of the |
| 41 | * pen, then head off into the C entry point |
| 42 | */ |
| 43 | write_pen_release(-1); |
| 44 | |
| 45 | /* |
| 46 | * Synchronise with the boot thread. |
| 47 | */ |
| 48 | spin_lock(&boot_lock); |
| 49 | spin_unlock(&boot_lock); |
| 50 | } |
| 51 | |
Paul Gortmaker | 8bd26e3 | 2013-06-17 15:43:14 -0400 | [diff] [blame] | 52 | int versatile_boot_secondary(unsigned int cpu, struct task_struct *idle) |
Russell King | 0462b44 | 2011-01-19 10:24:56 +0000 | [diff] [blame] | 53 | { |
| 54 | unsigned long timeout; |
| 55 | |
| 56 | /* |
| 57 | * Set synchronisation state between this boot processor |
| 58 | * and the secondary one |
| 59 | */ |
| 60 | spin_lock(&boot_lock); |
| 61 | |
| 62 | /* |
| 63 | * This is really belt and braces; we hold unintended secondary |
| 64 | * CPUs in the holding pen until we're ready for them. However, |
| 65 | * since we haven't sent them a soft interrupt, they shouldn't |
| 66 | * be there. |
| 67 | */ |
Will Deacon | 4a139b6 | 2011-08-09 12:24:07 +0100 | [diff] [blame] | 68 | write_pen_release(cpu_logical_map(cpu)); |
Russell King | 0462b44 | 2011-01-19 10:24:56 +0000 | [diff] [blame] | 69 | |
| 70 | /* |
| 71 | * Send the secondary CPU a soft interrupt, thereby causing |
| 72 | * the boot monitor to read the system wide flags register, |
| 73 | * and branch to the address found there. |
| 74 | */ |
Rob Herring | b1cffeb | 2012-11-26 15:05:48 -0600 | [diff] [blame] | 75 | arch_send_wakeup_ipi_mask(cpumask_of(cpu)); |
Russell King | 0462b44 | 2011-01-19 10:24:56 +0000 | [diff] [blame] | 76 | |
| 77 | timeout = jiffies + (1 * HZ); |
| 78 | while (time_before(jiffies, timeout)) { |
| 79 | smp_rmb(); |
| 80 | if (pen_release == -1) |
| 81 | break; |
| 82 | |
| 83 | udelay(10); |
| 84 | } |
| 85 | |
| 86 | /* |
| 87 | * now the secondary core is starting up let it run its |
| 88 | * calibrations, then wait for it to finish |
| 89 | */ |
| 90 | spin_unlock(&boot_lock); |
| 91 | |
| 92 | return pen_release != -1 ? -ENOSYS : 0; |
| 93 | } |