diff options
Diffstat (limited to 'arch/arm/mach-ux500/platsmp.c')
| -rw-r--r-- | arch/arm/mach-ux500/platsmp.c | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/arch/arm/mach-ux500/platsmp.c b/arch/arm/mach-ux500/platsmp.c index ddedbc80c41f..f71175a766d7 100644 --- a/arch/arm/mach-ux500/platsmp.c +++ b/arch/arm/mach-ux500/platsmp.c @@ -27,6 +27,19 @@ */ volatile int __cpuinitdata pen_release = -1; +/* + * Write pen_release in a way that is guaranteed to be visible to all + * observers, irrespective of whether they're taking part in coherency + * or not. This is necessary for the hotplug code to work reliably. + */ +static void write_pen_release(int val) +{ + pen_release = val; + smp_wmb(); + __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release)); + outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1)); +} + static DEFINE_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) @@ -42,7 +55,7 @@ void __cpuinit platform_secondary_init(unsigned int cpu) * let the primary processor know we're out of the * pen, then head off into the C entry point */ - pen_release = -1; + write_pen_release(-1); /* * Synchronise with the boot thread. @@ -66,9 +79,7 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) * the holding pen - release it, then wait for it to flag * that it has been released by resetting pen_release. */ - pen_release = cpu; - __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release)); - outer_clean_range(__pa(&pen_release), __pa(&pen_release) + 1); + write_pen_release(cpu); smp_cross_call(cpumask_of(cpu), 1); @@ -89,9 +100,6 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) static void __init wakeup_secondary(void) { - /* nobody is to be released from the pen yet */ - pen_release = -1; - /* * write the address of secondary startup into the backup ram register * at offset 0x1FF4, then write the magic number 0xA1FEED01 to the |