ARM: 6993/1: platsmp: Allow secondary cpu hotplug with maxcpus=1

If an ARM system has multiple cpus in the same socket and the
kernel is booted with maxcpus=1, secondary cpus are possible but
not present due to how platform_smp_prepare_cpus() is called.
Since most typical ARM processors don't actually support physical
hotplug, initialize the present map to be equal to the possible
map in generic ARM SMP code. Also, always call
platform_smp_prepare_cpus() as long as max_cpus is non-zero (0
means no SMP) to allow platform code to do any SMP setup.

After applying this patch it's possible to boot an ARM system
with maxcpus=1 on the command line and then hotplug in secondary
cpus via sysfs. This is more in line with how x86 does things.

Signed-off-by: Stephen Boyd <[email protected]>
Cc: Paul Mundt <[email protected]>
Cc: Kukjin Kim <[email protected]>
Cc: David Brown <[email protected]>
Cc: Tony Lindgren <[email protected]>
Cc: Srinidhi Kasagar <[email protected]>
Cc: Linus Walleij <[email protected]>
Signed-off-by: Russell King <[email protected]>

0 files changed, 0 insertions, 0 deletions