cpuidle: coupled: add parallel barrier function
authorColin Cross <ccross@android.com>
Tue, 8 May 2012 00:57:42 +0000 (17:57 -0700)
committerLen Brown <len.brown@intel.com>
Sat, 2 Jun 2012 04:49:36 +0000 (00:49 -0400)
commit20ff51a36b2cd25ee7eb3216b6d02b68935435ba
tree3c50651ca3cdc64c409afe9f867c13a8d50200e0
parent4126c0197bc8c58a0bb7fcda07b01b596b6fb4c5
cpuidle: coupled: add parallel barrier function

Adds cpuidle_coupled_parallel_barrier, which can be used by coupled
cpuidle state enter functions to handle resynchronization after
determining if any cpu needs to abort.  The normal use case will
be:

static bool abort_flag;
static atomic_t abort_barrier;

int arch_cpuidle_enter(struct cpuidle_device *dev, ...)
{
if (arch_turn_off_irq_controller()) {
    /* returns an error if an irq is pending and would be lost
   if idle continued and turned off power */
abort_flag = true;
}

cpuidle_coupled_parallel_barrier(dev, &abort_barrier);

if (abort_flag) {
    /* One of the cpus didn't turn off it's irq controller */
    arch_turn_on_irq_controller();
return -EINTR;
}

/* continue with idle */
...
}

This will cause all cpus to abort idle together if one of them needs
to abort.

Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Len Brown <len.brown@intel.com>
drivers/cpuidle/coupled.c
include/linux/cpuidle.h