From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Elder Subject: Re: [PATCH v3 RESEND 2/5] ARM: add SMP support for Broadcom mobile SoCs Date: Thu, 15 May 2014 13:17:00 -0500 Message-ID: <5375049C.40104@linaro.org> References: <1400176691-26058-1-git-send-email-elder@linaro.org> <1400176691-26058-3-git-send-email-elder@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Florian Fainelli Cc: Matt Porter , Christian Daudt , Russell King , "devicetree@vger.kernel.org" , Arnd Bergmann , sboyd@codeaurora.org, bcm-kernel-feedback-list@broadcom.com, "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" List-Id: devicetree@vger.kernel.org On 05/15/2014 01:03 PM, Florian Fainelli wrote: > Hi Alex, > > 2014-05-15 10:58 GMT-07:00 Alex Elder : >> This patch adds SMP support for BCM281XX and BCM21664 family SoCs. >> >> This feature is controlled with a distinct config option such that a >> SMP-enabled multi-v7 binary can be configured to run these SoCs in >> uniprocessor mode. Since this SMP functionality is used for >> multiple Broadcom mobile chip families the config option is called >> ARCH_BCM_MOBILE_SMP (for lack of a better name). >> >> On SoCs of this type, the secondary core is not held in reset on >> power-on. Instead it loops in a ROM-based holding pen. To release >> it, one must write into a special register a jump address whose >> low-order bits have been replaced with a secondary core's id, then >> trigger an event with SEV. On receipt of an event, the ROM code >> will examine the register's contents, and if the low-order bits >> match its cpu id, it will clear them and write the value back to the >> register just prior to jumping to the address specified. >> >> The location of the special register is defined in the device tree >> using a "secondary-boot-reg" property in a node whose "enable-method" >> matches. >> >> Derived from code originally provided by Ray Jui >> >> Signed-off-by: Alex Elder >> --- >> arch/arm/mach-bcm/Kconfig | 18 +++- >> arch/arm/mach-bcm/Makefile | 3 + >> arch/arm/mach-bcm/platsmp.c | 201 ++++++++++++++++++++++++++++++++++++++++++++ > > Could we make that name a little bit more specific to the mobile SoCs? Sure. I thought about that but naming stuff here has been a sort of ongoing struggle... "Kona" made some sense, in some cases, but it's not perfect. Simlar with "mobile." I'll propose "kona_smp.c". OK with you? Unless I get a better suggestion I'll plan to go with that next time around. Thanks. -Alex > There are other BCM SoCs either currently supported in this directory > (BCM5310X), or making their way to be supported (brcmstb, bcm63xx), > and those share nothing with the Mobile SoC SMP code. > > Maybe we should create another level directory within mach-bcm... >