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

From	Kapil Hali <kapilh@broadcom.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH RESEND 0/4] SMP support for Broadcom NSP
Date	2015-11-06 13:10 +0100
Message-ID	<qrO0a-4jL-27@gated-at.bofh.it> (permalink)
References	<qrlKy-2wU-3@gated-at.bofh.it> <qrpbr-4Mx-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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:
>> 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

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Thread

[PATCH RESEND 0/4] SMP support for Broadcom NSP Kapil Hali <kapilh@broadcom.com> - 2015-11-05 07:00 +0100
  [PATCH RESEND 4/4] ARM: BCM: Add SMP support for Broadcom 4708 Kapil Hali <kapilh@broadcom.com> - 2015-11-05 07:00 +0100
  [PATCH RESEND 2/4] ARM: dts: add SMP support for Broadcom NSP Kapil Hali <kapilh@broadcom.com> - 2015-11-05 07:00 +0100
  [PATCH RESEND 1/4] dt-bindings: add SMP enable-method for Broadcom NSP Kapil Hali <kapilh@broadcom.com> - 2015-11-05 07:00 +0100
    Re: [PATCH RESEND 1/4] dt-bindings: add SMP enable-method for  Broadcom NSP Rob Herring <robh@kernel.org> - 2015-11-05 21:50 +0100
      Re: [PATCH RESEND 1/4] dt-bindings: add SMP enable-method for  Broadcom NSP Scott Branden <sbranden@broadcom.com> - 2015-11-05 22:00 +0100
  Re: [PATCH RESEND 0/4] SMP support for Broadcom NSP Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-05 10:40 +0100
    Re: [PATCH RESEND 0/4] SMP support for Broadcom NSP Hauke Mehrtens <hauke@hauke-m.de> - 2015-11-05 21:30 +0100
      Re: [PATCH RESEND 0/4] SMP support for Broadcom NSP Kapil Hali <kapilh@broadcom.com> - 2015-11-06 13:30 +0100
    Re: [PATCH RESEND 0/4] SMP support for Broadcom NSP Kapil Hali <kapilh@broadcom.com> - 2015-11-06 13:10 +0100

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