• Shreyas B. Prabhu's avatar
    powerpc/powernv: Enable Offline CPUs to enter deep idle states · 8eb8ac89
    Shreyas B. Prabhu authored
    The secondary threads should enter deep idle states so as to gain maximum
    powersavings when the entire core is offline. To do so the offline path
    must be made aware of the available deepest idle state. Hence probe the
    device tree for the possible idle states in powernv core code and
    expose the deepest idle state through flags.
    
    Since the  device tree is probed by the cpuidle driver as well, move
    the parameters required to discover the idle states into an appropriate
    common place to both the driver and the powernv core code.
    
    Another point is that fastsleep idle state may require workarounds in
    the kernel to function properly. This workaround is introduced in the
    subsequent patches. However neither the cpuidle driver or the hotplug
    path need be bothered about this workaround.
    
    They will be taken care of by the core powernv code.
    Originally-by: default avatarSrivatsa S. Bhat <srivatsa@mit.edu>
    Signed-off-by: default avatarPreeti U. Murthy <preeti@linux.vnet.ibm.com>
    Signed-off-by: default avatarShreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
    Reviewed-by: default avatarPaul Mackerras <paulus@samba.org>
    
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: Paul Mackerras <paulus@samba.org>
    Cc: Michael Ellerman <mpe@ellerman.id.au>
    Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
    Cc: linux-pm@vger.kernel.org
    Cc: linuxppc-dev@lists.ozlabs.org
    Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
    8eb8ac89
opal.h 28.7 KB