[PATCH RESEND 0/4] SMP support for Broadcom NSP

On 11/5/2015 3:04 PM, Russell King - ARM Linux wrote:

On Thu, Nov 05, 2015 at 12:51:17AM -0500, Kapil Hali wrote:

quoted

Hi,

This series adds SMP support for Broadcom's Northstar Plus SoC.

There are similar SMP enablement methods for many ARMv7 bsed SoCs.
BCM NSP SoC, has a typical such mechanism - after power-on, the
secondary core is held in a standby state, primary core provides a
startup address for the secondary core and wakes it up. Booting of
the secondary core is serialized using pen_release global variable.

Why do you need the pen_release stuff?  The above implies that you
have only one secondary core, and you can control when it comes out
of standby state.

We can initiate a wake-up of the secondary core. I tested the changes
without pen_release method and it works. However, as I understand, I
think there is no other way for the primary core to know if the 
secondary core has come out of standby state other than pen_release
mechanism. When there is no other method available, will not 
smp_boot_secondary() always return successful wake-up of the
secondary core?

Please, don't assume that the pen_release stuff is any kind of recommended
or standardised system.  It isn't.  It's a hack for ARMs evaluation
platforms.

Got it. As pen_release is forbidden, I will change the SMP mechanism
to remove pen_release method in the new patch set.

Thanks,
Kapil